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Mylona E, Pham Thanh D, Keane JA, Dongol S, Basnyat B, Dolecek C, Voong Vinh P, Tran Vu Thieu N, Nguyen Thi Nguyen T, Karkey A, Baker S. A retrospective investigation of the population structure and geospatial distribution of Salmonella Paratyphi A in Kathmandu, Nepal. PLoS Negl Trop Dis 2024; 18:e0011864. [PMID: 38889189 PMCID: PMC11216570 DOI: 10.1371/journal.pntd.0011864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 07/01/2024] [Accepted: 05/25/2024] [Indexed: 06/20/2024] Open
Abstract
Salmonella Paratyphi A, one of the major etiologic agents of enteric fever, has increased in prevalence in recent decades in certain endemic regions in comparison to S. Typhi, the most prevalent cause of enteric fever. Despite this increase, data on the prevalence and molecular epidemiology of S. Paratyphi A remain generally scarce. Here, we analysed the whole genome sequences of 216 S. Paratyphi A isolates originating from Kathmandu, Nepal between 2005 and 2014, of which 200 were from patients with acute enteric fever and 16 from the gallbladder of people with suspected chronic carriage. By exploiting the recently developed genotyping framework for S. Paratyphi A (Paratype), we identified several genotypes circulating in Kathmandu. Notably, we observed an unusual clonal expansion of genotype 2.4.3 over a four-year period that spread geographically and systematically replaced other genotypes. This rapid genotype replacement is hypothesised to have been driven by both reduced susceptibility to fluoroquinolones and genetic changes to virulence factors, such as functional and structural genes encoding the type 3 secretion systems. Finally, we show that person-to-person is likely the most common mode of transmission and chronic carriers seem to play a limited role in maintaining disease circulation.
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Affiliation(s)
- Elli Mylona
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), University of Cambridge, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Duy Pham Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Program, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Jacqueline A. Keane
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), University of Cambridge, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Christiane Dolecek
- The Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Program, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Nga Tran Vu Thieu
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Program, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - To Nguyen Thi Nguyen
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia
| | - Abhilasha Karkey
- The Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Stephen Baker
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), University of Cambridge, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
- IAVI Human Immunology Laboratory, Chelsea and Westminster Hospital, London, United Kingdom
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Martin LB, Khanam F, Qadri F, Khalil I, Sikorski MJ, Baker S. Vaccine value profile for Salmonella enterica serovar Paratyphi A. Vaccine 2023; 41 Suppl 2:S114-S133. [PMID: 37951691 DOI: 10.1016/j.vaccine.2023.01.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 12/27/2022] [Accepted: 01/23/2023] [Indexed: 11/14/2023]
Abstract
In Asia, there are an estimated 12 million annual cases of enteric fever, a potentially fatal systemic bacterial infection caused by Salmonella enterica serovars Typhi (STy) and Paratyphi A (SPA). The recent availability of typhoid conjugate vaccines (TCV), an increasing incidence of disease caused by SPA and growing antimicrobial resistance (AMR) across the genus Salmonella makes a bivalent STy/SPA vaccine a useful public health proposition. The uptake of a stand-alone paratyphoid vaccine is likely low thus, there is a pipeline of bivalent STy/SPA candidate vaccines. Several candidates are close to entering clinical trials, which if successful should facilitate a more comprehensive approach for enteric fever control. Additionally, the World Health Organization (WHO) has made advancing the development of vaccines that protect young children and working aged adults against both agents of enteric fever a priority objective. This "Vaccine Value Profile" (VVP) addresses information related predominantly to invasive disease caused by SPA prevalent in Asia. Information is included on stand-alone SPA candidate vaccines and candidate vaccines targeting SPA combined with STy. Out of scope for the first version of this VVP is a wider discussion on the development of a universal Salmonella combination candidate vaccine, addressing both enteric fever and invasive non-typhoidal Salmonella disease, for use globally. This VVP is a detailed, high-level assessment of existing, publicly available information to inform and contextualize the public health, economic, and societal potential of pipeline vaccines and vaccine-like products for SPA. Future versions of this VVP will be updated to reflect ongoing activities such as vaccine development strategies and "Full Vaccine Value Assessment" that will inform the value proposition of an SPA vaccine. This VVP was developed by an expert working group from academia, non-profit organizations, public-private partnerships, and multi-lateral organizations as well as in collaboration with stakeholders from the WHO South-East Asian Region. All contributors have extensive expertise on various elements of the VVP for SPA and collectively aimed to identify current research and knowledge gaps.
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Affiliation(s)
- Laura B Martin
- Independent Consultant (current affiliation US Pharmacopeia Convention), USA.
| | - Farhana Khanam
- International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Bangladesh.
| | - Firdausi Qadri
- International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Bangladesh.
| | | | | | - Stephen Baker
- University of Cambridge School of Clinical Medicine, UK.
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LeBoa C, Shrestha S, Shakya J, Naga SR, Shrestha S, Shakya M, Yu AT, Shrestha R, Vaidya K, Katuwal N, Aiemjoy K, Bogoch II, Uzzell CB, Garrett DO, Luby SP, Andrews JR, Tamrakar D. Environmental sampling for typhoidal Salmonellas in household and surface waters in Nepal identifies potential transmission pathways. PLoS Negl Trop Dis 2023; 17:e0011341. [PMID: 37851667 PMCID: PMC10615262 DOI: 10.1371/journal.pntd.0011341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 10/30/2023] [Accepted: 09/06/2023] [Indexed: 10/20/2023] Open
Abstract
INTRODUCTION Salmonella Typhi and Salmonella Paratyphi, fecal-oral transmitted bacterium, have temporally and geographically heterogeneous pathways of transmission. Previous work in Kathmandu, Nepal implicated stone waterspouts as a dominant transmission pathway after 77% of samples tested positive for Salmonella Typhi and 70% for Salmonella Paratyphi. Due to a falling water table, these spouts no longer provide drinking water, but typhoid fever persists, and the question of the disease's dominant pathway of transmission remains unanswered. METHODS We used environmental surveillance to detect Salmonella Typhi and Salmonella Paratyphi A DNA from potential sources of transmission. We collected 370, 1L drinking water samples from a population-based random sample of households in the Kathmandu and Kavre Districts of Nepal between February and October 2019. Between November 2019 and July 2021, we collected 380, 50mL river water samples from 19 sentinel sites on a monthly interval along the rivers leading through the Kathmandu and Kavre Districts. We processed drinking water samples using a single qPCR and processed river water samples using differential centrifugation and qPCR at 0 and after 16 hours of liquid culture enrichment. A 3-cycle threshold (Ct) decrease of Salmonella Typhi or Salmonella Paratyphi, pre- and post-enrichment, was used as evidence of growth. We also performed structured observations of human-environment interactions to understand pathways of potential exposure. RESULTS Among 370 drinking water samples, Salmonella Typhi was detected in 7 samples (1.8%) and Salmonella Paratyphi A was detected in 4 (1.0%) samples. Among 380 river water samples, Salmonella Typhi was detected in 171 (45%) and Salmonella Paratyphi A was detected in 152 (42%) samples. Samples located upstream of the Kathmandu city center were positive for Salmonella Typhi 12% of the time while samples from locations in and downstream were positive 58% and 67% of the time respectively. Individuals were observed bathing, washing clothes, and washing vegetables in the rivers. IMPLICATIONS These results suggest that drinking water was not the dominant pathway of transmission of Salmonella Typhi and Salmonella Paratyphi A in the Kathmandu Valley in 2019. The high degree of river water contamination and its use for washing vegetables raises the possibility that river systems represent an important source of typhoid exposure in Kathmandu.
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Affiliation(s)
- Christopher LeBoa
- Stanford University, Division of Infectious Diseases and Geographic Medicine, Stanford, California, United States of America
- University of California Berkeley, Department of Environmental Health Sciences, Berkeley, California, United States of America
| | - Sneha Shrestha
- Research and Development Division, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
| | - Jivan Shakya
- Institute for Research in Science and Technology, Lalitpur, Nepal
| | - Shiva Ram Naga
- Research and Development Division, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
- Center for Infectious Disease Research and Surveillance, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
| | - Sony Shrestha
- Research and Development Division, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
| | - Mudita Shakya
- Research and Development Division, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
| | - Alexander T. Yu
- Stanford University, Division of Infectious Diseases and Geographic Medicine, Stanford, California, United States of America
| | - Rajeev Shrestha
- Research and Development Division, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
- Center for Infectious Disease Research and Surveillance, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
| | - Krista Vaidya
- Research and Development Division, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
| | - Nishan Katuwal
- Research and Development Division, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
- Center for Infectious Disease Research and Surveillance, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
| | - Kristen Aiemjoy
- University of California Davis, Division of Public Health Sciences, California, United States of America
- Mahidol University Faculty of Tropical Medicine, Department of Microbiology and Immunology, Bangkok, Thailand
| | - Isaac I. Bogoch
- Toronto General Hospital, Division of Infectious Diseases, Toronto, Canada, and Department of Medicine, University of Toronto, Toronto Canada
| | - Christopher B. Uzzell
- Imperial College London, School of Public Health, Norfolk Place, London, United Kingdom
| | - Denise O. Garrett
- Sabin Vaccine Institute, Applied Epidemiology Section, Washington, DC, United States of America
| | - Stephen P. Luby
- Stanford University, Division of Infectious Diseases and Geographic Medicine, Stanford, California, United States of America
| | - Jason R. Andrews
- Stanford University, Division of Infectious Diseases and Geographic Medicine, Stanford, California, United States of America
| | - Dipesh Tamrakar
- Research and Development Division, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
- Center for Infectious Disease Research and Surveillance, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
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Pokhrel N, Chapagain R, Thakur CK, Basnet A, Amatya I, Singh R, Ghimire R. Salmonella infection among the pediatric population at a tertiary care children's hospital in central Nepal: a retrospective study. Front Microbiol 2023; 14:1218864. [PMID: 37840726 PMCID: PMC10570616 DOI: 10.3389/fmicb.2023.1218864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 07/10/2023] [Indexed: 10/17/2023] Open
Abstract
Background Typhoid fever, an infective bacterial disease, is capable of causing fatal systemic infection in humans, and in an era of antimicrobial resistance, it has become of public health importance. This study aimed to investigate the laboratory diagnosis of Salmonella bloodstream infection, its serotype, antimicrobial resistance pattern, and seasonal variation at a tertiary care children's hospital. Methods We undertook a retrospective, cross-sectional study by reviewing hospital-based laboratory records of patients whose blood culture samples were submitted from the outpatient department to the laboratory of a tertiary care children's hospital in Kathmandu, Nepal, from January 2017 to January 2019. Results Among the total blood culture samples obtained (n = 39,771), bacterial isolates (n = 1,055, 2.65%) belonged either to the Genus Enterobacteriaceae or Genus Acinetobacter. Altogether (n = 91, 8.63%), isolates were positive for Salmonella spp., which were further identified as Salmonella enterica subsp. enterica ser. Typhi (n = 79, 7.49%), Salmonella enterica subsp. enterica ser. Paratyphi A (n = 11, 1.04%), and Salmonella enterica subsp. enterica ser. Paratyphi B (n = 1, 0.1%). The median age of patients was 6 years (IQR: 4-9), with male and female patients constituting (n = 53, 58.24%; OR, 1.0; 95% CI, 0.60-1.67) and (n = 38, 41.76%; OR, 0.98; 95% CI, 0.49-2.05) cases, respectively. The disease was observed throughout the year, with a high prevalence toward the spring season (March-May). An antibiogram showed resistance more toward nalidixic acid with S. Typhi, comprising half the isolates (n = 52, 65.82%; p = 0.11). Resistance toward β-lactams with β-lactamase inhibitors (amoxicillin/clavulanate; 1.27%) was seen in a single isolate of S. Typhi. The multidrug resistance pattern was not pronounced. The multiple antibiotic resistance (MAR) index was in the range between 0.14 and 0.22 in S. Typhi and 0.22 and 0.23 in S. Paratyphi. Conclusion Salmonella Typhi was the predominant ser. Infection was common among children between 1 and 5 years of age, showing male predominance and with the spring season contributing to a fairly higher number of cases. Antimicrobial susceptibility testing of S. Typhi showed more resistance toward nalidixic acid, with only a single isolate resistant to β-lactamase inhibitors (amoxicillin/clavulanate). Alarming multidrug resistance patterns were not observed. The MAR index in this study indicates the importance of the judicious use of antimicrobials and hospital infection prevention and control practices.
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Affiliation(s)
| | - Ramhari Chapagain
- Department of Pediatrics, Kanti Children’s Hospital, Kathmandu, Nepal
| | | | - Ajaya Basnet
- Shi-Gan International College of Science and Technology, Kathmandu, Nepal
| | - Isha Amatya
- Nepal Health Research Council, Kathmandu, Nepal
| | | | - Raghav Ghimire
- Department of Pediatric Cardiology, Shahid Gangalal National Heart Centre, Kathmandu, Nepal
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Kim C, Goucher GR, Tadesse BT, Lee W, Abbas K, Kim JH. Associations of water, sanitation, and hygiene with typhoid fever in case-control studies: a systematic review and meta-analysis. BMC Infect Dis 2023; 23:562. [PMID: 37644449 PMCID: PMC10464135 DOI: 10.1186/s12879-023-08452-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 07/11/2023] [Indexed: 08/31/2023] Open
Abstract
BACKGROUND Water, sanitation, and hygiene (WASH) play a pivotal role in controlling typhoid fever, as it is primarily transmitted through oral-fecal pathways. Given our constrained resources, staying current with the most recent research is crucial. This ensures we remain informed about practical insights regarding effective typhoid fever control strategies across various WASH components. We conducted a systematic review and meta-analysis of case-control studies to estimate the associations of water, sanitation, and hygiene exposures with typhoid fever. METHODS We updated the previous review conducted by Brockett et al. We included new findings published between June 2018 and October 2022 in Web of Science, Embase, and PubMed. We used the Risk of Bias in Non-Randomized Studies of Interventions (ROBINS-I) tool for risk of bias (ROB) assessment. We classified WASH exposures according to the classification provided by the WHO/UNICEF Joint Monitoring Programme for Water Supply, Sanitation, and Hygiene (JMP) update in 2015. We conducted the meta-analyses by only including studies that did not have a critical ROB in both Bayesian and frequentist random-effects models. RESULTS We identified 8 new studies and analyzed 27 studies in total. Our analyses showed that while the general insights on the protective (or harmful) impact of improved (or unimproved) WASH remain the same, the pooled estimates of OR differed. Pooled estimates of limited hygiene (OR = 2.26, 95% CrI: 1.38 to 3.64), untreated water (OR = 1.96, 95% CrI: 1.28 to 3.27) and surface water (OR = 2.14, 95% CrI: 1.03 to 4.06) showed 3% increase, 18% decrease, and 16% increase, respectively, from the existing estimates. On the other hand, improved WASH reduced the odds of typhoid fever with pooled estimates for improved water source (OR = 0.54, 95% CrI: 0.31 to 1.08), basic hygiene (OR = 0.6, 95% CrI: 0.38 to 0.97) and treated water (OR = 0.54, 95% CrI: 0.36 to 0.8) showing 26% decrease, 15% increase, and 8% decrease, respectively, from the existing estimates. CONCLUSIONS The updated pooled estimates of ORs for the association of WASH with typhoid fever showed clear changes from the existing estimates. Our study affirms that relatively low-cost WASH strategies such as basic hygiene or water treatment can be an effective tool to provide protection against typhoid fever in addition to other resource-intensive ways to improve WASH. TRIAL REGISTRATION PROSPERO 2021 CRD42021271881.
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Affiliation(s)
- Chaelin Kim
- International Vaccine Institute, Seoul, South Korea
| | | | | | - Woojoo Lee
- Graduate School of Public Health, Seoul National University, Seoul, South Korea
| | - Kaja Abbas
- London School of Hygiene & Tropical Medicine, London, UK
| | - Jong-Hoon Kim
- International Vaccine Institute, Seoul, South Korea.
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Khan M, Shamim S. Understanding the Mechanism of Antimicrobial Resistance and Pathogenesis of Salmonella enterica Serovar Typhi. Microorganisms 2022; 10:2006. [PMID: 36296282 PMCID: PMC9606911 DOI: 10.3390/microorganisms10102006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 09/22/2022] [Accepted: 09/26/2022] [Indexed: 11/17/2022] Open
Abstract
Salmonella enterica serovar Typhi (S. Typhi) is a Gram-negative pathogen that causes typhoid fever in humans. Though many serotypes of Salmonella spp. are capable of causing disease in both humans and animals alike, S. Typhi and S. Paratyphi are common in human hosts only. The global burden of typhoid fever is attributable to more than 27 million cases each year and approximately 200,000 deaths worldwide, with many regions such as Africa, South and Southeast Asia being the most affected in the world. The pathogen is able to cause disease in hosts by evading defense systems, adhesion to epithelial cells, and survival in host cells in the presence of several virulence factors, mediated by virulence plasmids and genes clustered in distinct regions known as Salmonella pathogenicity islands (SPIs). These factors, coupled with plasmid-mediated antimicrobial resistance genes, enable the bacterium to become resistant to various broad-spectrum antibiotics used in the treatment of typhoid fever and other infections caused by Salmonella spp. The emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains in many countries of the world has raised great concern over the rise of antibiotic resistance in pathogens such as S. Typhi. In order to identify the key virulence factors involved in S. Typhi pathogenesis and infection, this review delves into various mechanisms of virulence, pathogenicity, and antimicrobial resistance to reinforce efficacious disease management.
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Affiliation(s)
| | - Saba Shamim
- Institute of Molecular Biology and Biotechnology, The University of Lahore, Defence Road Campus, Lahore 54000, Pakistan
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Adhikari P, Maharjan R, Paudel S, Malla B, Shah PK, Bastola A, Shrestha UT. gyrA ser83 mutation among fluoroquinolone-resistant Salmonella enterica serovars from enteric fever patients in tertiary care hospital, Kathmandu. BMC Microbiol 2022; 22:51. [PMID: 35144539 PMCID: PMC8830085 DOI: 10.1186/s12866-022-02456-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 01/25/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The management of enteric fever through antibiotics is difficult these days due to the emerging resistance of Salmonella to various antimicrobial agents. The development of antimicrobial resistance is associated with multiple factors including mutations in the specific genes. To know the current status of mutation-mediated fluoroquinolone-resistance among Salmonella enterica serovars; Typhi, Paratyphi A, B and C, this study was focused on detecting gyrA ser83 mutation by restriction digestion analysis of gyrA gene using HinfI endonuclease. RESULTS A total of 948 blood samples were processed for isolation of Salmonella spp. and 3.4% of them were found to be positive for Salmonella growth. Out of the 32 Salmonella isolates, 2.2% were S. Typhi and 1.2% were S. Paratyphi A. More interestingly, we observed less than 5% of isolates were resistant to first-line drugs including chloramphenicol, cotrimoxazole and ampicillin. More than 80% of isolates were resistant to fluoroquinolones accounting for 84.4% to levofloxacin followed by 87.5% to ofloxacin and 100% to ciprofloxacin by disc diffusion methods. However, the minimum inhibitory concentration method using agar dilution showed only 50% of isolates were resistant to ciprofloxacin. A total of 3.1% of isolates were multidrug-resistant. Similarly, 90.6% of the Salmonella isolates showed gyrA ser83 mutation with resistance to nalidixic acid. CONCLUSIONS The increased resistance to fluoroquinolones and nalidixic acid in Salmonella isolates in our study suggests the use of alternative drugs as empirical treatment. Rather, the treatment should focus on prescribing first-line antibiotics since we observed less than 5% of Salmonella isolates were resistant to these drugs.
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Affiliation(s)
- Prashanna Adhikari
- Department of Microbiology, Tri-Chandra Multiple Campus, Tribhuvan University, Ghantaghar, Kathmandu, Nepal
| | - Roshani Maharjan
- Department of Microbiology, Tri-Chandra Multiple Campus, Tribhuvan University, Ghantaghar, Kathmandu, Nepal
| | - Subash Paudel
- Department of Microbiology, Tri-Chandra Multiple Campus, Tribhuvan University, Ghantaghar, Kathmandu, Nepal
| | - Bikram Malla
- Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | - Pradeep Kumar Shah
- Department of Microbiology, Tri-Chandra Multiple Campus, Tribhuvan University, Ghantaghar, Kathmandu, Nepal
| | - Anup Bastola
- Sukraraj Tropical and Infectious Disease Hospital, Teku, Kathmandu, Nepal
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Khadka S, Shrestha B, Pokhrel A, Khadka S, Joshi RD, Banjara MR. Antimicrobial Resistance in Salmonella Typhi Isolated From a Referral Hospital of Kathmandu, Nepal. Microbiol Insights 2021; 14:11786361211056350. [PMID: 34916803 PMCID: PMC8669115 DOI: 10.1177/11786361211056350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 10/09/2021] [Indexed: 11/16/2022] Open
Abstract
Purpose: The morbidity and mortality due to typhoid fever can be significantly reduced with the use of effective antibiotics. At present, fluoroquinolones, third generation cephalosporins, and azithromycin are widely used to treat typhoid fever. However, changing antibiotic susceptibility among Salmonella Typhi and Salmonella Paratyphi poses a particular challenge to the therapeutic management of enteric fever. The objective of this study was to assess the antibiotic susceptibility pattern of Salmonella Typhi isolates. Patients and Methods: A total of 706 blood specimens were collected from febrile patients attending the outpatient department of Kathmandu Model Hospital during June to September, 2018. The antibiotic susceptibility testing for 11 different antibiotics (nalidixic acid, ciprofloxacin, ofloxacin, levofloxacin, cefixime, ceftriaxone, cefotaxime, azithromycin, cotrimoxazole, chloramphenicol, and amoxicillin) was performed by disk diffusion method. Furthermore, minimum inhibitory concentration (MIC) values of ciprofloxacin, ofloxacin, and azithromycin were determined by agar dilution method. Mutation at gyrA ser83 associated with reduced susceptibility to fluoroquinolones was determined by PCR-RFLP. Results: Out of 706 blood samples, 6.94% (n = 49) were culture positive for Salmonella enterica (S. Typhi, n = 46). It was revealed that 97.8% S. Typhi isolates were susceptible to conventional first-line antibiotics (ampicillin, chloramphenicol, and cotrimoxazole), 97.3% to cephalosporins and 95.7% to azithromycin. S. Typhi were either resistant or intermediately susceptible to fluoroquinolones: 97.8% to ciprofloxacin, 91.3% to ofloxacin, and 89.1% to levofloxacin. The MIC of ciprofloxacin, ofloxacin, and azithromycin for S. Typhi ranged from 0.008 to 32, 0.03 to 16, and 2 to 8 μg/mL, respectively. Out of 46 S. Typhi isolates, 44 (95.65%) had gyrA ser83 mutation. Conclusion: Fluoroquinolones have poor activity against Salmonella Typhi. The trends of increasing azithromycin MIC value among S. Typhi might limit its use for the treatment of typhoid fever. Effectiveness of conventional first-line antibiotics in vitro suggests considering their clinical use after large-scale studies.
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Affiliation(s)
- Saroj Khadka
- Central Department of Microbiology, Tribhuvan University, Kirtipur, Nepal
| | - Basudha Shrestha
- Department of Microbiology, Kathmandu Model Hospital, Kathmandu, Nepal
| | - Anil Pokhrel
- Central Department of Microbiology, Tribhuvan University, Kirtipur, Nepal
| | - Sachin Khadka
- Department of Medicine, Kathmandu Model Hospital, Kathmandu, Nepal
| | | | - Megha Raj Banjara
- Central Department of Microbiology, Tribhuvan University, Kirtipur, Nepal
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Giri S, Mohan VR, Srinivasan M, Kumar N, Kumar V, Dhanapal P, Venkatesan J, Gunasekaran A, Abraham D, John J, Kang G. Case-Control Study of Household and Environmental Transmission of Typhoid Fever in India. J Infect Dis 2021; 224:S584-S592. [PMID: 35238355 PMCID: PMC8892545 DOI: 10.1093/infdis/jiab378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Background Typhoid fever causes substantial morbidity and mortality in low- and middle-income countries. We conducted a case-control study in Vellore, southern India, to understand risk factors for transmission of typhoid. Methods From April 2018 to October 2019, households of blood culture-confirmed typhoid cases that occurred within a fever surveillance cohort aged 6 months–15 years, and controls matched for age, sex, geographic location, and socioeconomic status, were recruited. Information on risk factors was obtained using standard questionnaires. Household and environmental samples were collected for detection of Salmonella Typhi using real-time polymerase chain reaction. Multivariable analysis was used to evaluate associations between risk factors and typhoid. Results One hundred pairs of cases and controls were recruited. On multivariable regression analysis, mothers eating food from street vendors during the previous week (odds ratio [OR] = 2.04; 95% confidence interval [CI], 1.03–4.12; P = .04) was independently associated with typhoid, whereas treatment of household drinking water (OR = 0.45; 95% CI, 0.25–0.80; P = .007) was protective. There was no significant difference in S Typhi detection between the environmental samples from case and control households. Conclusions Street-vended food is a risk factor for typhoid in densely populated urban communities of Vellore. Improved sanitation facilities and awareness about point-of-use water treatment are likely to contribute to typhoid control.
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Affiliation(s)
- Sidhartha Giri
- Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | | | | | - Nirmal Kumar
- Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Vinoth Kumar
- Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Pavithra Dhanapal
- Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | | | - Annai Gunasekaran
- Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Dilip Abraham
- Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Jacob John
- Department of Community Health, Christian Medical College, Vellore, India
| | - Gagandeep Kang
- Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
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10
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Phillips MT, Meiring JE, Voysey M, Warren JL, Baker S, Basnyat B, Clemens JD, Dolecek C, Dunstan SJ, Dougan G, Gordon MA, Thindwa D, Heyderman RS, Holt KE, Qadri F, Pollard AJ, Pitzer VE. A Bayesian approach for estimating typhoid fever incidence from large-scale facility-based passive surveillance data. Stat Med 2021; 40:5853-5870. [PMID: 34428309 PMCID: PMC9291985 DOI: 10.1002/sim.9159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 07/23/2021] [Accepted: 07/27/2021] [Indexed: 12/04/2022]
Abstract
Decisions about typhoid fever prevention and control are based on estimates of typhoid incidence and their uncertainty. Lack of specific clinical diagnostic criteria, poorly sensitive diagnostic tests, and scarcity of accurate and complete datasets contribute to difficulties in calculating age‐specific population‐level typhoid incidence. Using data from the Strategic Typhoid Alliance across Africa and Asia program, we integrated demographic censuses, healthcare utilization surveys, facility‐based surveillance, and serological surveillance from Malawi, Nepal, and Bangladesh to account for under‐detection of cases. We developed a Bayesian approach that adjusts the count of reported blood‐culture‐positive cases for blood culture detection, blood culture collection, and healthcare seeking—and how these factors vary by age—while combining information from prior published studies. We validated the model using simulated data. The ratio of observed to adjusted incidence rates was 7.7 (95% credible interval [CrI]: 6.0‐12.4) in Malawi, 14.4 (95% CrI: 9.3‐24.9) in Nepal, and 7.0 (95% CrI: 5.6‐9.2) in Bangladesh. The probability of blood culture collection led to the largest adjustment in Malawi, while the probability of seeking healthcare contributed the most in Nepal and Bangladesh; adjustment factors varied by age. Adjusted incidence rates were within or below the seroincidence rate limits of typhoid infection. Estimates of blood‐culture‐confirmed typhoid fever without these adjustments results in considerable underestimation of the true incidence of typhoid fever. Our approach allows each phase of the reporting process to be synthesized to estimate the adjusted incidence of typhoid fever while correctly characterizing uncertainty, which can inform decision‐making for typhoid prevention and control.
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Affiliation(s)
- Maile T Phillips
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, USA
| | - James E Meiring
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK.,National Institute for Health Research Oxford Biomedical Research Centre, Oxford, UK.,Malawi Liverpool Wellcome Programme, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Merryn Voysey
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK.,National Institute for Health Research Oxford Biomedical Research Centre, Oxford, UK
| | - Joshua L Warren
- Department of Biostatistics, Yale School of Public Health, New Haven, Connecticut, USA
| | - Stephen Baker
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - John D Clemens
- International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Christiane Dolecek
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.,Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Sarah J Dunstan
- The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Gordon Dougan
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Melita A Gordon
- Malawi Liverpool Wellcome Programme, Kamuzu University of Health Sciences, Blantyre, Malawi.,Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Deus Thindwa
- Malawi Liverpool Wellcome Programme, Kamuzu University of Health Sciences, Blantyre, Malawi.,Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Robert S Heyderman
- Malawi Liverpool Wellcome Programme, Kamuzu University of Health Sciences, Blantyre, Malawi.,NIHR Global Health Research Unit on Mucosal Pathogens, Division of Infection and Immunity, University College London, London, UK
| | - Kathryn E Holt
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, Victoria, Australia.,Department of Infection Biology, London School of Hygiene and Tropical Medicine, London
| | - Firdausi Qadri
- International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK.,National Institute for Health Research Oxford Biomedical Research Centre, Oxford, UK
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, USA
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11
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Khanam F, Darton TC, Meiring JE, Sarker PK, Biswas PK, Bhuiyan MAI, Rajib NH, Tonks S, Pollard AJ, Clemens JD, Qadri F. Salmonella Typhi stool shedding by enteric fever patients and asymptomatic chronic carriers in an endemic urban setting. J Infect Dis 2021; 224:S759-S763. [PMID: 34586391 PMCID: PMC8687075 DOI: 10.1093/infdis/jiab476] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The burden of Salmonella Typhi shedding in stool and its contribution to transmission in endemic settings is unknown. During passive surveillance S. Typhi shedding was seen during convalescence in 332 bacteremic typhoid patients although none persisted at one-year follow-up. Anti-Vi-IgG titres were measured in age-stratified cohort of serosurveillance participants. Systematic stool sampling of 303 participants with high anti-Vi-IgG titres identified one asymptomatic carrier shedding. These findings suggest ongoing S. Typhi transmission in this setting is more likely to occur from acute convalescent cases although better approaches are needed to identify true chronic carriers in the community to enable typhoid elimination.
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Affiliation(s)
- Farhana Khanam
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh.,School of Medical Science, Griffith University, Gold Coast, Australia
| | - Thomas C Darton
- Department of Infection, Immunity and Cardiovascular Disease, and the Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, UK
| | - James E Meiring
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Protup Kumer Sarker
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Prasanta Kumar Biswas
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Md Amirul Islam Bhuiyan
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Nazmul Hasan Rajib
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Susan Tonks
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - John D Clemens
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Firdausi Qadri
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
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12
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Schultz BM, Melo-Gonzalez F, Salazar GA, Porto BN, Riedel CA, Kalergis AM, Bueno SM. New Insights on the Early Interaction Between Typhoid and Non-typhoid Salmonella Serovars and the Host Cells. Front Microbiol 2021; 12:647044. [PMID: 34276584 PMCID: PMC8282409 DOI: 10.3389/fmicb.2021.647044] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 06/08/2021] [Indexed: 11/13/2022] Open
Abstract
Salmonella enterica is a common source of food and water-borne infections, causing a wide range of clinical ailments in both human and animal hosts. Immunity to Salmonella involves an interplay between different immune responses, which are rapidly initiated to control bacterial burden. However, Salmonella has developed several strategies to evade and modulate the host immune responses. In this sense, the main knowledge about the pathogenicity of this bacterium has been obtained by the study of mouse models with non-typhoidal serovars. However, this knowledge is not representative of all the pathologies caused by non-typhoidal serovars in the human. Here we review the most important features of typhoidal and non-typhoidal serovars and the diseases they cause in the human host, describing the virulence mechanisms used by these pathogens that have been identified in different models of infection.
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Affiliation(s)
- Bárbara M Schultz
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Felipe Melo-Gonzalez
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Geraldyne A Salazar
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Bárbara N Porto
- Laboratory of Clinical and Experimental Immunology, School of Medicine, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil.,Program in Translational Medicine, Hospital for Sick Children, Toronto, ON, Canada
| | - Claudia A Riedel
- Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Millennium Institute on Immunology and Immunotherapy, Universidad Andrés Bello, Santiago, Chile
| | - Alexis M Kalergis
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Susan M Bueno
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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13
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Affiliation(s)
- Buddha Basnyat
- Oxford University Clinical Research Unit-Patan Academy of Health Science Kathmandu, Nepal
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | | | | | | | - Christopher M Parry
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
- Alder Hey Children' Hospital and Liverpool University Hospitals. Liverpool, UK
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14
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Gauld JS, Olgemoeller F, Nkhata R, Li C, Chirambo A, Morse T, Gordon MA, Read JM, Heyderman RS, Kennedy N, Diggle PJ, Feasey NA. Domestic River Water Use and Risk of Typhoid Fever: Results From a Case-control Study in Blantyre, Malawi. Clin Infect Dis 2021; 70:1278-1284. [PMID: 31144715 DOI: 10.1093/cid/ciz405] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 05/16/2019] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Typhoid fever remains a major cause of morbidity and mortality in low- and middle-income settings. In the last 10 years, several reports have described the reemergence of typhoid fever in southern and eastern Africa, associated with multidrug-resistant H58 Salmonella Typhi. Here, we identify risk factors for pediatric typhoid fever in a large epidemic in Blantyre, Malawi. METHODS A case-control study was conducted between April 2015 and November 2016. Cases were recruited at a large teaching hospital, and controls were recruited from the community, matched by residential ward. Stepwise variable selection and likelihood ratio testing were used to select candidate risk factors for a final logistic regression model. RESULTS Use of river water for cooking and cleaning was highly associated with risk of typhoid fever (odds ratio [OR], 4.6 [95% confidence interval {CI}, 1.7-12.5]). Additional risk factors included protective effects of soap in the household (OR, 0.6 [95% CI, .4-.98]) and >1 water source used in the previous 3 weeks (OR, 3.2 [95% CI, 1.6-6.2]). Attendance at school or other daycare was also identified as a risk factor (OR, 2.7 [95% CI, 1.4-5.3]) and was associated with the highest attributable risk (51.3%). CONCLUSIONS These results highlight diverse risk factors for typhoid fever in Malawi, with implications for control in addition to the provision of safe drinking water. There is an urgent need to improve our understanding of transmission pathways of typhoid fever, both to develop tools for detecting S. Typhi in the environment and to inform water, sanitation, and hygiene interventions.
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Affiliation(s)
- Jillian S Gauld
- Institute for Disease Modeling, Bellevue, Washington.,Centre for Health Informatics, Computing, and Statistics, Lancaster University, United Kingdom
| | - Franziska Olgemoeller
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, United Kingdom.,Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre
| | - Rose Nkhata
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre
| | - Chao Li
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, United Kingdom.,Xi'an Jiaotong University Health Science Center, Shaanxi, China
| | - Angeziwa Chirambo
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre.,Institute of Infection and Global Health, University of Liverpool, United Kingdom
| | - Tracy Morse
- Centre for Water, Environment, Sustainability and Public Health, University of Strathclyde, Glasgow, United Kingdom.,Centre for Water, Sanitation, Health and Appropriate Technology Development, University of Malawi-Polytechnic, Blantyre
| | - Melita A Gordon
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre.,Institute of Infection and Global Health, University of Liverpool, United Kingdom
| | - Jonathan M Read
- Centre for Health Informatics, Computing, and Statistics, Lancaster University, United Kingdom
| | - Robert S Heyderman
- Division of Infection and Immunity, University College London, United Kingdom
| | - Neil Kennedy
- Department of Paediatrics, College of Medicine, University of Malawi, Blantyre.,School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, United Kingdom
| | - Peter J Diggle
- Centre for Health Informatics, Computing, and Statistics, Lancaster University, United Kingdom
| | - Nicholas A Feasey
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, United Kingdom.,Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre
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15
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Brockett S, Wolfe MK, Hamot A, Appiah GD, Mintz ED, Lantagne D. Associations among Water, Sanitation, and Hygiene, and Food Exposures and Typhoid Fever in Case-Control Studies: A Systematic Review and Meta-Analysis. Am J Trop Med Hyg 2020; 103:1020-1031. [PMID: 32700668 DOI: 10.4269/ajtmh.19-0479] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Typhoid fever transmission occurs through ingestion of food or water contaminated with Salmonella Typhi, and case-control studies are often conducted to identify outbreak sources and transmission vehicles. However, there is no current summary of the associations among water, sanitation, and hygiene (WASH); and food exposures and typhoid from case-control studies. We conducted a systematic review and meta-analysis of case-control studies to evaluate the associations among typhoid fever and predicted WASH or food exposure risk factors (13), and protective factors (7). Overall, 19 manuscripts describing 22 case-control studies were included. Two studies were characterized as having low risk of bias, one as medium risk, and 19 as high risk. In total, nine of 13 predicted risk factors were associated with increased odds of typhoid (odds ratio [OR] = 1.4-2.4, I 2 = 30.5-74.8%.), whereas five of seven predicted protective factors were associated with lower odds of typhoid (OR = 0.52-0.73, I 2 = 38.7-84.3%). In five types of sensitivity analyses, two (8%) of 26 summary associations changed significance from the original analysis. Results highlight the following: the importance of household hygiene transmission pathways, the need for further research around appropriate food interventions and the risk of consuming specific foods and beverages outside the home, and the absence of any observed association between sanitation exposures and typhoid fever. We recommend that typhoid interventions focus on interrupting household transmission routes and that future studies provide more detailed information about WASH and food exposures to inform better targeted interventions.
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Affiliation(s)
- Sarah Brockett
- Tufts University School of Medicine, Boston, Massachusetts
| | - Marlene K Wolfe
- Department of Civil and Environmental Engineering, Stanford University, Stanford, California.,Department of Civil and Environmental Engineering, Tufts University, Medford, Massachusetts
| | - Asa Hamot
- Department of Civil and Environmental Engineering, Tufts University, Medford, Massachusetts
| | - Grace D Appiah
- Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Eric D Mintz
- Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Daniele Lantagne
- Department of Civil and Environmental Engineering, Tufts University, Medford, Massachusetts
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16
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Baldassi F, Cenciarelli O, Malizia A, Gaudio P. First Prototype of the Infectious Diseases Seeker (IDS) Software for Prompt Identification of Infectious Diseases. J Epidemiol Glob Health 2020; 10:367-377. [PMID: 32959625 PMCID: PMC7758858 DOI: 10.2991/jegh.k.200714.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 06/20/2020] [Indexed: 12/19/2022] Open
Abstract
The rapid detection of ongoing outbreak – and the identification of causative pathogen – is pivotal for the early recognition of public health threats. The emergence and re-emergence of infectious diseases are linked to several determinants, both human factors – such as population density, travel, and trade – and ecological factors – like climate change and agricultural practices. Several technologies are available for the rapid molecular identification of pathogens [e.g. real-time polymerase chain reaction (PCR)], and together with on line monitoring tools of infectious disease activity and behaviour, they contribute to the surveillance system for infectious diseases. Web-based surveillance tools, infectious diseases modelling and epidemic intelligence methods represent crucial components for timely outbreak detection and rapid risk assessment. The study aims to integrate the current prevention and control system with a prediction tool for infectious diseases, based on regression analysis, to support decision makers, health care workers, and first responders to quickly and properly recognise an outbreak. This study has the intention to develop an infectious disease regressive prediction tool working with an off-line database built with specific epidemiological parameters of a set of infectious diseases of high consequences. The tool has been developed as a first prototype of a software solution called Infectious Diseases Seeker (IDS) and it had been established in two main steps, the database building stage and the software implementation stage (MATLAB® environment). The IDS has been tested with the epidemiological data of three outbreaks occurred recently: severe acute respiratory syndrome epidemic in China (2002–2003), plague outbreak in Madagascar (2017) and the Ebola virus disease outbreak in the Democratic Republic of Congo (2018). The outcomes are promising and they reveal that the software has been able to recognize and characterize these outbreaks. The future perspective about this software regards the developing of that tool as a useful and user-friendly predictive tool appropriate for first responders, health care workers, and public health decision makers to help them in predicting, assessing and contrasting outbreaks.
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Affiliation(s)
- F Baldassi
- Department of Industrial Engineering, University of Rome Tor Vergata, Rome, Italy
| | - O Cenciarelli
- International CBRNe Master Courses, University of Rome Tor Vergata, Rome, Italy
| | - A Malizia
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - P Gaudio
- Department of Industrial Engineering, University of Rome Tor Vergata, Rome, Italy
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17
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Gibani MM, Voysey M, Jin C, Jones C, Thomaides-Brears H, Jones E, Baker P, Morgan M, Simmons A, Gordon MA, Cerundolo V, Pitzer VE, Angus B, Levine MM, Darton TC, Pollard AJ. The Impact of Vaccination and Prior Exposure on Stool Shedding of Salmonella Typhi and Salmonella Paratyphi in 6 Controlled Human Infection Studies. Clin Infect Dis 2020; 68:1265-1273. [PMID: 30252031 PMCID: PMC6452003 DOI: 10.1093/cid/ciy670] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 08/07/2018] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Shedding of Salmonella Typhi or Paratyphi in the stool or urine leads to contamination of food or water, which is a prerequisite for transmission of enteric fever. Currently, there are limited data on the effect of vaccination or prior exposure on stool shedding. METHODS Six Salmonella Typhi or Paratyphi human challenge studies were conducted between 2011 and 2017. Participants were either unvaccinated or vaccinated with 1 of 4 vaccines: Vi-polysaccharide (Vi-PS), Vi-tetanus-toxoid conjugate vaccine (Vi-TT), live oral Ty21a vaccine, or an experimental vaccine (M01ZH09). Daily stool cultures were collected for 14 days after challenge. RESULTS There were 4934 stool samples collected from 430 volunteers. Participants who received Vi-PS or Vi-TT shed less than unvaccinated participants (odds ratio [OR], 0.34; 95% confidence interval [CI], 0.15-0.77; P = .010 and OR, 0.41; 95% CI, 0.19-0.91, P = .029 for Vi-PS and Vi-TT, respectively). Higher anti-Vi immunoglobulin G titers were associated with less shedding of S. Typhi (P < .0001). A nonsignificant reduction in shedding was associated with Ty21a vaccine (OR, 0.57; 95% CI, 0.27-1.20; P = .140). Individuals previously exposed to S. Typhi shed less than previously unexposed individuals (OR, 0.30; 95% CI, 0.1-0.8; P = .016). Shedding of S. Typhi was more common than S. Paratyphi. CONCLUSIONS Prior vaccination with Vi vaccines, or natural infection, reduces onward transmission of S. Typhi. Field trials of Vi-TT should be designed to detect indirect protection, reflecting the consequence of reduced stool shedding observed in the human challenge model.
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Affiliation(s)
- Malick M Gibani
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford
| | - Merryn Voysey
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford.,Nuffield Department of Primary Care Health Sciences, University of Oxford, United Kingdom
| | - Celina Jin
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford
| | - Claire Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford
| | | | - Elizabeth Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford
| | - Philip Baker
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford
| | - Marcus Morgan
- Oxford University Hospitals, National Health Service Foundation Trust, United Kingdom
| | - Alison Simmons
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, University of Oxford, United Kingdom.,Translational Gastroenterology Unit, University of Oxford, United Kingdom
| | - Melita A Gordon
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre.,Institute for Infection and Global Health, University of Liverpool, United Kingdom
| | - Vincenzo Cerundolo
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, University of Oxford, United Kingdom
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut
| | - Brian Angus
- Oxford University Hospitals, National Health Service Foundation Trust, United Kingdom.,Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Myron M Levine
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore
| | - Thomas C Darton
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford.,Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford.,National Institute for Health Research Oxford Biomedical Research Centre, United Kingdom
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18
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Salerno-Goncalves R, Kayastha D, Fasano A, Levine MM, Sztein MB. Crosstalk between leukocytes triggers differential immune responses against Salmonella enterica serovars Typhi and Paratyphi. PLoS Negl Trop Dis 2019; 13:e0007650. [PMID: 31412039 PMCID: PMC6709971 DOI: 10.1371/journal.pntd.0007650] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 08/26/2019] [Accepted: 07/23/2019] [Indexed: 12/30/2022] Open
Abstract
Enteric fevers, caused by the Salmonella enterica serovars Typhi (ST), Paratyphi A (PA) and Paratyphi B (PB), are life-threatening illnesses exhibiting very similar clinical symptoms but with distinct epidemiologies, geographical distributions and susceptibilities to antimicrobial treatment. Nevertheless, the mechanisms by which the host recognizes pathogens with high levels of homology, such as these bacterial serovars, remain poorly understood. Using a three-dimensional organotypic model of the human intestinal mucosa and PA, PB, and ST, we observed significant differences in the secretion patterns of pro-inflammatory cytokines and chemokines elicited by these serovars. These cytokines/chemokines were likely to be co-regulated and influenced the function of epithelial cells, such as the production of IL-8. We also found differing levels of polymorphonuclear leukocyte (PMN) migration among various infection conditions that either included or excluded lymphocytes and macrophages (Mϕ), strongly suggesting feedback mechanisms among these cells. Blocking experiments showed that IL-1β, IL-6, IL-8, TNF-α and CCL3 cytokines were involved in the differential regulation of migration patterns. We conclude that the crosstalk among the lymphocytes, Mϕ, PMN and epithelial cells is cytokine/chemokine-dependent and bacterial-serotype specific, and plays a pivotal role in orchestrating the functional efficiency of the innate cells and migratory characteristics of the leukocytes.
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Affiliation(s)
- Rosangela Salerno-Goncalves
- Center for Vaccine Development and Global Health, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Darpan Kayastha
- Center for Vaccine Development and Global Health, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Alessio Fasano
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital for Children, Boston, MA, United States of America
| | - Myron M. Levine
- Center for Vaccine Development and Global Health, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Marcelo B. Sztein
- Center for Vaccine Development and Global Health, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States of America
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19
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Abstract
Purpose of review Enteric fever remains a major global-health concern, estimated to be responsible for between 11.9 and 26.9 million cases annually. Long-term prevention of enteric fever will require improved access to safe drinking water combined with investment in sanitation and hygiene interventions. In the short-to-medium term, new control strategies for typhoid fever have arrived in the form of typhoid Vi-conjugate vaccines (TCVs), offering hope that disease control can be achieved in the near future. Recent findings The diagnosis of enteric fever is complicated by its nonspecific clinical presentation, coupled with the low sensitivity of commonly used diagnostics. Investment in diagnostics has the potential to improve management, to refine estimates of disease burden and to facilitate vaccine impact studies. A new generation of reliable, diagnostic tests is needed that are simultaneously accessible, cost-effective, sensitive, and specific. The emergence and global dissemination of multidrug-resistant, fluoroquinolone-resistant, and extensively drug-resistant (XDR) strains of Salmonella Typhi emphasizes the importance of continued surveillance and appropriate antibiotic stewardship, integrated into a global strategy to address antimicrobial resistance (AMR). Current empirical treatment guidelines are out of date and should be updated to respond to local trends in AMR, so as to guide treatment choices in the absence of robust diagnostics and laboratory facilities. In September 2017, the WHO Strategic Advisory Group of Experts (SAGE) immunization recommended the programmatic use of TCVs in high burden countries. Ongoing and future studies should aim to study the impact of these vaccines in a diverse range of setting and to support the deployment of TCVs in high-burden countries. Summary The advent of new generation TCVs offers us a practical and affordable public-health tool that – for the first time – can be integrated into routine childhood immunization programmes. In this review, we advocate for the deployment of TCVs in line with WHO recommendations, to improve child health and limit the spread of antibiotic-resistant S. Typhi.
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20
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Kaljee LM, Pach A, Garrett D, Bajracharya D, Karki K, Khan I. Social and Economic Burden Associated With Typhoid Fever in Kathmandu and Surrounding Areas: A Qualitative Study. J Infect Dis 2018; 218:S243-S249. [PMID: 28973415 PMCID: PMC6226633 DOI: 10.1093/infdis/jix122] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Typhoid fever is a significant contributor to infectious disease mortality and morbidity in low- and middle-income countries, particularly in South Asia. With increasing antimicrobial resistance, commonly used treatments are less effective and risks increase for complications and hospitalizations. During an episode of typhoid fever, households experience multiple social and economic costs that are often undocumented. In the current study, qualitative interview data from Kathmandu and surrounding areas provide important insights into the challenges that affect those who contract typhoid fever and their caregivers, families, and communities, as well as insight into prevention and treatment options for health providers and outreach workers. When considering typhoid fever cases confirmed by blood culture, our data reveal delays in healthcare access, financial and time costs burden on households, and the need to increase health literacy. These data also illustrate the impact of limited laboratory diagnostic equipment and tools on healthcare providers' abilities to distinguish typhoid fever from other febrile conditions and treatment challenges associated with antimicrobial resistance. In light of these findings, there is an urgent need to identify and implement effective preventive measures including vaccination policies and programs focused on at-risk populations and endemic regions such as Nepal.
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Affiliation(s)
- Linda M Kaljee
- Global Health Initiative, Henry Ford Health System, Detroit, Michigan
| | - Alfred Pach
- International Vaccine Institute, Seoul, Korea
| | - Denise Garrett
- Coalition Against Typhoid, Sabin Institute, Washington, District of Columbia
| | | | | | - Imran Khan
- Coalition Against Typhoid, Sabin Institute, Washington, District of Columbia
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21
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Petersiel N, Shresta S, Tamrakar R, Koju R, Madhup S, Shresta A, Bedi TRS, Zmora N, Paran Y, Schwartz E, Neuberger A. The epidemiology of typhoid fever in the Dhulikhel area, Nepal: A prospective cohort study. PLoS One 2018; 13:e0204479. [PMID: 30261024 PMCID: PMC6160059 DOI: 10.1371/journal.pone.0204479] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 09/11/2018] [Indexed: 11/25/2022] Open
Abstract
Introduction Typhoid fever (TF) continues to cause considerable morbidity and mortality in Nepal, but only limited epidemiologic data is available about TF outside Kathmandu. Methods As part of an interventional trial, we performed a prospective cohort study of bacteremic TF patients in Dhulikhel Hospital between October 2012 and October 2014. Demographic, epidemiological, clinical, and microbiologic data were recorded. Results 116 bacteremic typhoid patients were included in the study. Most were young, healthy, adults (mean age 27.9±12 years), 41.4% of whom were female. More than 70% of patients were employed in non-manual services or were university students. Salmonella Typhi accounted for 64/115 (55.7%) of all isolates, while Salmonella Paratyphi accounted for 51/115 (44.3%), of which 42 were Paratyphi A and 9 Paratyphi B. A significant proportion of TF cases occurred also during the dry season (48/116, 41.6%). The clinical presentation of Salmonella Typhi and Paratyphi infections was similar, except for a greater proportion of arthralgia in patients with Salmonella Typhi. Most Salmonella Typhi and Paratyphi isolates were resistant to nalidixic acid and susceptible to older antibiotics. One Salmonella Paratyphi isolate was resistant to ceftriaxone. Conclusions TF remains common in the Dhulikhel area, even among those with a high level of education. Public health measures aimed at reducing the incidence of TF in the Dhulikhel area are warranted. The relative burden of TF caused by Salmonella Paratyphi is rising; a vaccine with activity against Salmonella Paratyphi is needed. Since Salmonella Paratyphi B was more prevalent in this cohort than in large cohorts of patients from Kathmandu, it is likely that there are significant regional variations in the epidemiology of TF outside Kathmandu.
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Affiliation(s)
- Neta Petersiel
- Unit of Infectious Diseases–Tropical Diseases & Travel Medicine, Internal Medicine B, Rambam Medical Center, Haifa, Israel
- * E-mail:
| | - Sudeep Shresta
- Dhulikhel Hospital, Kathmandu University Hospital, Dhulikhel, Nepal
| | | | - Rajendra Koju
- Dhulikhel Hospital, Kathmandu University Hospital, Dhulikhel, Nepal
| | - Surendra Madhup
- Dhulikhel Hospital, Kathmandu University Hospital, Dhulikhel, Nepal
| | - Ashish Shresta
- Dhulikhel Hospital, Kathmandu University Hospital, Dhulikhel, Nepal
| | - TRS Bedi
- Dhulikhel Hospital, Kathmandu University Hospital, Dhulikhel, Nepal
| | - Niv Zmora
- Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yael Paran
- Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eli Schwartz
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- The Center for Geographic Medicine and Tropical Diseases, the Chaim Sheba Medical Center, Tel Hashomer, Israel
| | - Ami Neuberger
- Unit of Infectious Diseases–Tropical Diseases & Travel Medicine, Internal Medicine B, Rambam Medical Center, Haifa, Israel
- Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
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22
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Zellweger RM, Basnyat B, Shrestha P, Prajapati KG, Dongol S, Sharma PK, Koirala S, Darton TC, Boinett C, Thompson CN, Thwaites GE, Baker S, Karkey A. Changing Antimicrobial Resistance Trends in Kathmandu, Nepal: A 23-Year Retrospective Analysis of Bacteraemia. Front Med (Lausanne) 2018; 5:262. [PMID: 30283784 PMCID: PMC6156253 DOI: 10.3389/fmed.2018.00262] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 08/30/2018] [Indexed: 11/23/2022] Open
Abstract
A comprehensive longitudinal understanding of the changing epidemiology of the agents causing bacteraemia and their AMR profiles in key locations is crucial for assessing the progression and magnitude of the global AMR crisis. We performed a retrospective analysis of routine microbiological data from April 1992 to December 2014, studying the time trends of non-Salmonella associated bacteraemia at a single Kathmandu healthcare facility. The distribution of aetiological agents, their antimicrobial susceptibility profiles, and the hospital ward of isolation were assessed. Two hundred twenty-four thousand seven hundred forty-one blood cultures were performed over the study period, of which, 30,353 (13.5%) exhibited growth for non-contaminant bacteria. We observed a significant increasing trend in the proportion of MDR non-Salmonella Enterobacteriaceae (p < 0.001), other Gram-negative organisms (p = 0.006), and Gram-positive organisms (p = 0.006) over time. Additionally, there was an annual increasing trend in the proportion of MDR organisms in bacteria-positive blood cultures originating from patients attending the emergency ward (p = 0.006) and the outpatient department (p = 0.006). This unique dataset demonstrates that community acquired non-Salmonella bacteraemia has become an increasingly important cause of hospital admission in Kathmandu. An increasing burden of bacteraemia associated with MDR organisms in the community underscores the need for preventing the circulation of MDR bacteria within the local population.
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Affiliation(s)
- Raphaël M Zellweger
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal.,Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom.,Global Antibiotic Resistance Partnership, Centre for Disease Dynamics Economics and Policy, Washington, DC, United States
| | - Poojan Shrestha
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | | | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Paban K Sharma
- Patan Academy of Health Sciences, Patan Hospital, Kathmandu, Nepal
| | - Samir Koirala
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Thomas C Darton
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam.,Sheffield teaching hospitals NHS trust foundation and the University of Sheffield, Sheffield, United Kingdom
| | - Christine Boinett
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Corinne N Thompson
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Guy E Thwaites
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Stephen Baker
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom.,The Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Abhilasha Karkey
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal.,Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom.,Global Antibiotic Resistance Partnership, Centre for Disease Dynamics Economics and Policy, Washington, DC, United States
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Abstract
Typhoid fever, caused by Salmonella enterica serovar Typhi (S. Typhi), is a diminishing public health problem in Vietnam, and this process may represent a prototype for typhoid elimination in Asia. Here, we review typhoid epidemiology in Vietnam over 20 years and assess the potential drivers associated with typhoid reduction. In the 1990s, multidrug resistant S. Typhi were highly prevalent in a sentinel hospital in southern Vietnam. A national typhoid incidence rate of 14.7/100,000 population per year was estimated around the new millennium. The Vietnamese government recognized the public health issue of typhoid in the 1990s and initiated vaccine campaigns to protect the most vulnerable members of the population. At their peak, these campaigns immunized approximately 1,200,000 children in 35 provinces. Concurrently, Vietnam experienced unprecedented economic development from 1998 to 2014, with the gross national income per capita increasing from $360 to $1,890 over this period. More recent typhoid incidence data are not available, but surveillance suggests that the current disease burden is negligible. This trajectory can be considered a major public health success. However, a paucity of systematic data makes it difficult to disaggregate the roles of immunization and water, sanitation, and hygiene (WASH) interventions in typhoid reduction in Vietnam. Given the limitations of typhoid vaccines, we surmise the practical elimination of typhoid was largely driven by economic development and improvement in general population living standards. Better designed WASH intervention studies with clinical endpoints and systematic incidence data are essential to glean a greater understanding of contextual factors that impact typhoid incidence reduction.
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Affiliation(s)
- Tran Vu Thieu Nga
- Wellcome Trust Major Overseas Programme, Hospital for Tropical Diseases, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Pham Thanh Duy
- Wellcome Trust Major Overseas Programme, Hospital for Tropical Diseases, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Nguyen Phu Huong Lan
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom.,Wellcome Trust Major Overseas Programme, Hospital for Tropical Diseases, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Nguyen Van Vinh Chau
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, United Kingdom
| | - Stephen Baker
- Wellcome Trust Major Overseas Programme, Hospital for Tropical Diseases, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Department of Medicine, University of Cambridge, Cambridge, United Kingdom.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, United Kingdom
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24
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Bhutta ZA, Gaffey MF, Crump JA, Steele D, Breiman RF, Mintz ED, Black RE, Luby SP, Levine MM. Typhoid Fever: Way Forward. Am J Trop Med Hyg 2018; 99:89-96. [PMID: 30047361 PMCID: PMC6128357 DOI: 10.4269/ajtmh.18-0111] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The Tackling Typhoid supplement shows that typhoid fever continues to be a problem globally despite socioeconomic gains in certain settings. Morbidity remains high in many endemic countries, notably in sub-Saharan Africa and South Asia. In addition, antimicrobial resistance is a growing issue that poses a challenge for clinical management. The findings from this supplement revealed that outside of high-income countries, there were few reliable population-based estimates of typhoid and paratyphoid fever derived from surveillance systems. This indicates the need for monitoring systems that can also characterize the effectiveness of interventions, particularly in low- and middle-income settings. The country case studies indicated that gains in economic conditions, education, and environmental health may be associated with reductions in typhoid fever burden. Over the study period, the effect is mainly notable in countries with higher baseline levels of economic development, female literacy, and investments in public sanitation. High burden countries must continue to invest in strategies at the local level to address environmental factors such as access to safe drinking water and improved public sanitation that are known to interrupt transmission or diminish the risk of acquiring typhoid. Developing more effective vaccines and incorporating appropriate immunization strategies that target populations with the greatest risk could potentially alleviate disease burden.
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Affiliation(s)
- Zulfiqar A Bhutta
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada.,Dalla Lana School of Public Health, University of Toronto, Toronto, Canada.,Center of Excellence in Women and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Michelle F Gaffey
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
| | - John A Crump
- Centre for International Health, University of Otago, Dunedin, New Zealand
| | - Duncan Steele
- Enteric and Diarrheal Diseases, Bill & Melinda Gates Foundation, Seattle, Washington
| | - Robert F Breiman
- Emory Global Health Institute, Emory University, Atlanta, Georgia
| | - Eric D Mintz
- National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Robert E Black
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Stephen P Luby
- Centre for Innovation in Global Health, Woods Institute for the Environment, Stanford University, Stanford, California
| | - Myron M Levine
- Global Health, Vaccinology and Infectious Diseases, University of Maryland School of Medicine, Baltimore, Maryland
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25
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Estimating Typhoid Fever Risk Associated with Lack of Access to Safe Water: A Systematic Literature Review. JOURNAL OF ENVIRONMENTAL AND PUBLIC HEALTH 2018; 2018:9589208. [PMID: 30174699 PMCID: PMC6076975 DOI: 10.1155/2018/9589208] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 05/28/2018] [Indexed: 11/17/2022]
Abstract
Background Unsafe water is a well-known risk for typhoid fever, but a pooled estimate of the population-level risk of typhoid fever resulting from exposure to unsafe water has not been quantified. An accurate estimation of the risk from unsafe water will be useful in demarcating high-risk populations, modeling typhoid disease burden, and targeting prevention and control activities. Methods We conducted a systematic literature review and meta-analysis of observational studies that measured the risk of typhoid fever associated with drinking unimproved water as per WHO-UNICEF's definition or drinking microbiologically unsafe water. The mean value for the pooled odds ratio from case-control studies was calculated using a random effects model. In addition to unimproved water and unsafe water, we also listed categories of other risk factors from the selected studies. Results The search of published studies from January 1, 1990, to December 31, 2013 in PubMed, Embase, and World Health Organization databases provided 779 publications, of which 12 case-control studies presented the odds of having typhoid fever for those exposed to unimproved or unsafe versus improved drinking water sources. The odds of typhoid fever among those exposed to unimproved or unsafe water ranged from 1.06 to 9.26 with case weighted mean of 2.44 (95% CI: 1.65–3.59). Besides water-related risk, the studies also identified other risk factors related to socioeconomic aspects, type of food consumption, knowledge and awareness about typhoid fever, and hygiene practices. Conclusions In this meta-analysis, we have quantified the pooled risk of typhoid fever among people exposed to unimproved or unsafe water which is almost two and a half times more than people who were not exposed to unimproved or unsafe water. However, caution should be exercised in applying the findings from this study in modeling typhoid fever disease burden at country, regional, and global levels as improved water does not always equate to safe water.
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26
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Zellweger RM, Basnyat B, Shrestha P, Prajapati KG, Dongol S, Sharma PK, Koirala S, Darton TC, Dolecek C, Thompson CN, Thwaites GE, Baker SG, Karkey A. A 23-year retrospective investigation of Salmonella Typhi and Salmonella Paratyphi isolated in a tertiary Kathmandu hospital. PLoS Negl Trop Dis 2017; 11:e0006051. [PMID: 29176850 PMCID: PMC5720835 DOI: 10.1371/journal.pntd.0006051] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 12/07/2017] [Accepted: 10/19/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Salmonella serovars Typhi (S. Typhi) and Paratyphi A (S. Paratyphi A), the causative agents of enteric fever, have been routinely isolated organisms from the blood of febrile patients in the Kathmandu Valley since the early 1990s. Susceptibility against commonly used antimicrobials for treating enteric fever has gradually changed throughout South Asia since this time, posing serious treatment challenges. Here, we aimed to longitudinally describe trends in the isolation of Salmonella enterica and assess changes in their antimicrobial susceptibility in Kathmandu over a 23-year period. METHODS We conducted a retrospective analysis of standardised microbiological data from April 1992 to December 2014 at a single healthcare facility in Kathmandu, examining time trends of Salmonella-associated bacteraemia and the corresponding antimicrobial susceptibility profiles of the isolated organisms. RESULTS Over 23 years there were 30,353 positive blood cultures. Salmonella enterica accounted for 65.4% (19,857/30,353) of all the bacteria positive blood cultures. S. Typhi and S. Paratyphi A were the dominant serovars, constituting 68.5% (13,592/19,857) and 30.5% (6,057/19,857) of all isolated Salmonellae. We observed (i) a peak in the number of Salmonella-positive cultures in 2002, a year of heavy rainfall and flooding in the Kathmandu Valley, followed by a decline toward pre-flood baseline by 2014, (ii) an increase in the proportion of S. Paratyphi in all Salmonella-positive cultures between 1992 and 2014, (iii) a decrease in the prevalence of MDR for both S. Typhi and S. Paratyphi, and (iv) a recent increase in fluoroquinolone non-susceptibility in both S. Typhi and S. Paratyphi isolates. CONCLUSIONS Our work describes significant changes in the epidemiology of Salmonella enterica in the Kathmandu Valley during the last quarter of a century. We highlight the need to examine current treatment protocols for enteric fever and suggest a change from fluoroquinolone monotherapy to combination therapies of macrolides or cephalosporins along with older first-line antimicrobials that have regained their efficacy.
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Affiliation(s)
- Raphaël M. Zellweger
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
- Global Antibiotic Resistance Partnership, Centre for Disease Dynamics Economics and Policy, Washington DC, Unites States of America
| | - Poojan Shrestha
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | | | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Paban K. Sharma
- Patan Academy of Health Sciences, Patan Hospital, Kathmandu, Nepal
| | - Samir Koirala
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Thomas C. Darton
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Christiane Dolecek
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Corinne N. Thompson
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Guy E. Thwaites
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Stephen G. Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
- The Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Abhilasha Karkey
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
- Global Antibiotic Resistance Partnership, Centre for Disease Dynamics Economics and Policy, Washington DC, Unites States of America
- * E-mail:
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27
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Darton TC, Jones C, Dongol S, Voysey M, Blohmke CJ, Shrestha R, Karkey A, Shakya M, Arjyal A, Waddington CS, Gibani M, Carter MJ, Basnyat B, Baker S, Pollard AJ. Assessment and Translation of the Antibody-in-Lymphocyte Supernatant (ALS) Assay to Improve the Diagnosis of Enteric Fever in Two Controlled Human Infection Models and an Endemic Area of Nepal. Front Microbiol 2017; 8:2031. [PMID: 29109704 PMCID: PMC5660281 DOI: 10.3389/fmicb.2017.02031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 10/04/2017] [Indexed: 11/17/2022] Open
Abstract
New diagnostic tests for enteric fever are urgently needed to assist with timely antimicrobial treatment of patients and to measure the efficacy of prevention measures such as vaccination. In a novel translational approach, here we use two recently developed controlled human infection models (CHIM) of enteric fever to evaluate an antibody-in-lymphocyte supernatant (ALS) assay, which can detect recent IgA antibody production by circulating B cells in ex vivo mononuclear cell culture. We calculated the discriminative ability of the ALS assay to distinguish diagnosed cases in the two CHIM studies in Oxford, prior to evaluating blood culture-confirmed diagnoses of patients presenting with fever to hospital in an endemic areas of Kathmandu, Nepal. Antibody responses to membrane preparations and lipopolysaccharide provided good sensitivity (>90%) for diagnosing systemic infection after oral challenge with Salmonella Typhi or S. Paratyphi A. Assay specificity was moderate (~60%) due to imperfect sensitivity of blood culture as the reference standard and likely unrecognized subclinical infection. These findings were augmented through the translation of the assay into the endemic setting in Nepal. Anti-MP IgA responses again exhibited good sensitivity (86%) but poor specificity (51%) for detecting blood culture-confirmed enteric fever cases (ROC AUC 0.79, 95%CI 0.70–0.88). Patients with anti-MP IgA ALS titers in the upper quartile exhibited a clinical syndrome synonymous with enteric fever. While better reference standards are need to assess enteric fever diagnostics, routine use of this ALS assay could be used to rule out infection and has the potential to double the laboratory detection rate of enteric fever in this setting over blood culture alone.
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Affiliation(s)
- Thomas C Darton
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford, National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom.,Wellcome Trust Major Overseas Programme, Hospital for Tropical Diseases, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Claire Jones
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford, National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Merryn Voysey
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford, National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom.,Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, United Kingdom
| | - Christoph J Blohmke
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford, National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Rajendra Shrestha
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Abhilasha Karkey
- Wellcome Trust Major Overseas Programme, Hospital for Tropical Diseases, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Mila Shakya
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Amit Arjyal
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Claire S Waddington
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford, National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Malick Gibani
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford, National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Michael J Carter
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford, National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom.,Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Stephen Baker
- Wellcome Trust Major Overseas Programme, Hospital for Tropical Diseases, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Andrew J Pollard
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford, National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
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Kuijpers LMF, Phe T, Veng CH, Lim K, Ieng S, Kham C, Fawal N, Fabre L, Le Hello S, Vlieghe E, Weill FX, Jacobs J, Peetermans WE. The clinical and microbiological characteristics of enteric fever in Cambodia, 2008-2015. PLoS Negl Trop Dis 2017; 11:e0005964. [PMID: 28931025 PMCID: PMC5624643 DOI: 10.1371/journal.pntd.0005964] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 10/02/2017] [Accepted: 09/14/2017] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Enteric fever remains a major public health problem in low resource settings and antibiotic resistance is increasing. In Asia, an increasing proportion of infections is caused by Salmonella enterica serovar Paratyphi A, which for a long time was assumed to cause a milder clinical syndrome compared to Salmonella enterica serovar Typhi. METHODOLOGY A retrospective chart review study was conducted of 254 unique cases of blood culture confirmed enteric fever who presented at a referral adult hospital in Phnom Penh, Cambodia between 2008 and 2015. Demographic, clinical and laboratory data were collected from clinical charts and antibiotic susceptibility testing was performed. Whole genome sequence analysis was performed on a subset of 121 isolates. RESULTS One-hundred-and-ninety unique patients were diagnosed with Salmonella Paratyphi A and 64 with Salmonella Typhi. In the period 2008-2012, Salmonella Paratyphi A comprised 25.5% of 47 enteric fever cases compared to 86.0% of 207 cases during 2013-2015. Presenting symptoms were identical for both serovars but higher median leukocyte counts (6.8 x 109/L vs. 6.3 x 109/L; p = 0.035) and C-reactive protein (CRP) values (47.0 mg/L vs. 36 mg/L; p = 0.034) were observed for Salmonella Typhi infections. All but one of the Salmonella Typhi isolates belonged to haplotype H58 associated with multidrug resistance (MDR) (i.e. resistance to ampicillin, chloramphenicol and co-trimoxazole).;42.9% actually displayed MDR compared to none of the Salmonella Paratyphi A isolates. Decreased ciprofloxacin susceptibility (DCS) was observed in 96.9% (62/64) of Salmonella Typhi isolates versus 11.5% (21/183) of Salmonella Paratyphi A isolates (all but one from 2015). All isolates were susceptible to azithromycin and ceftriaxone. CONCLUSIONS In Phnom Penh, Cambodia, Salmonella Paratyphi A now causes the majority of enteric fever cases and decreased susceptibility against ciprofloxacin is increasing. Overall, Salmonella Typhi was significantly more associated with MDR and DCS compared to Salmonella Paratyphi A.
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Affiliation(s)
- Laura M. F. Kuijpers
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
- Department of Microbiology & Immunology, KU Leuven, Leuven, Belgium
- * E-mail:
| | - Thong Phe
- Sihanouk Hospital Center of HOPE, Phnom Penh, Cambodia
| | - Chhun H. Veng
- Sihanouk Hospital Center of HOPE, Phnom Penh, Cambodia
| | - Kruy Lim
- Sihanouk Hospital Center of HOPE, Phnom Penh, Cambodia
| | - Sovann Ieng
- Sihanouk Hospital Center of HOPE, Phnom Penh, Cambodia
| | - Chun Kham
- Sihanouk Hospital Center of HOPE, Phnom Penh, Cambodia
| | - Nizar Fawal
- Unité des Bactéries Pathogènes Entériques, Centre National de Référence des E. coli, Shigella et Salmonella, Institut Pasteur, Paris, France
| | - Laetitia Fabre
- Unité des Bactéries Pathogènes Entériques, Centre National de Référence des E. coli, Shigella et Salmonella, Institut Pasteur, Paris, France
| | - Simon Le Hello
- Unité des Bactéries Pathogènes Entériques, Centre National de Référence des E. coli, Shigella et Salmonella, Institut Pasteur, Paris, France
| | - Erika Vlieghe
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
- Department of General Internal Medicine, Infectious diseases and Tropical Medicine, University Hospital Antwerp, Antwerp, Belgium
| | - François-Xavier Weill
- Unité des Bactéries Pathogènes Entériques, Centre National de Référence des E. coli, Shigella et Salmonella, Institut Pasteur, Paris, France
| | - Jan Jacobs
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
- Department of Microbiology & Immunology, KU Leuven, Leuven, Belgium
| | - Willy E. Peetermans
- Department of Internal Medicine, University Hospital Leuven, Leuven, Belgium
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Meiring JE, Gibani M. The Typhoid Vaccine Acceleration Consortium (TyVAC): Vaccine effectiveness study designs: Accelerating the introduction of typhoid conjugate vaccines and reducing the global burden of enteric fever. Report from a meeting held on 26-27 October 2016, Oxford, UK. Vaccine 2017; 35:5081-5088. [PMID: 28802757 DOI: 10.1016/j.vaccine.2017.08.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 07/31/2017] [Accepted: 08/01/2017] [Indexed: 11/26/2022]
Abstract
Typhoid fever is estimated to cause between 11.9-26.9 million infections globally each year with 129,000-216,510 deaths. Access to improved water sources have reduced disease incidence in parts of the world but the use of efficacious vaccines is seen as an important public health tool for countries with a high disease burden. A new generation of Vi typhoid conjugate vaccines (TCVs), licensed for use in young children and expected to provide longer lasting protection than previous vaccines, are now available. The WHO Strategic Advisory Group of Experts on Immunization (SAGE) has convened a working group to review the evidence on TCVs and produce an updated WHO position paper for all typhoid vaccines in 2018 that will inform Gavi, the Vaccine Alliance's future vaccine investment strategies for TCVs. The Typhoid Vaccine Acceleration Consortium (TyVAC) has been formed through a $36.9 million funding program from the Bill & Melinda Gates Foundation to accelerate the introduction of TCVs into Gavi-eligible countries. In October 2016, a meeting was held to initiate planning of TCV effectiveness studies that will provide the data required by policy makers and stakeholders to support decisions on TCV use in countries with a high typhoid burden. Discussion topics included (1) the latest evidence and data gaps in typhoid epidemiology; (2) WHO and Gavi methods and data requirements; (3) data on TCV efficacy; (4) cost effectiveness analysis for TCVs from mathematical models; (5) TCV delivery and effectiveness study design. Specifically, participants were asked to comment on study design in 3 sites for which population-based typhoid surveillance is underway. The conclusion of the meeting was that country-level decision making would best be informed by the respective selected sites in Africa and Asia vaccinating children aged from 9-months to 15-years-old, employing either an individual or cluster randomized design with design influenced by population characteristics, transmission dynamics, and statistical considerations.
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Affiliation(s)
- James E Meiring
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom.
| | - Malick Gibani
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
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A cross-sectional seroepidemiological survey of typhoid fever in Fiji. PLoS Negl Trop Dis 2017; 11:e0005786. [PMID: 28727726 PMCID: PMC5549756 DOI: 10.1371/journal.pntd.0005786] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 08/08/2017] [Accepted: 07/06/2017] [Indexed: 12/26/2022] Open
Abstract
Fiji, an upper-middle income state in the Pacific Ocean, has experienced an increase in confirmed case notifications of enteric fever caused by Salmonella enterica serovar Typhi (S. Typhi). To characterize the epidemiology of typhoid exposure, we conducted a cross-sectional sero-epidemiological survey measuring IgG against the Vi antigen of S. Typhi to estimate the effect of age, ethnicity, and other variables on seroprevalence. Epidemiologically relevant cut-off titres were established using a mixed model analysis of data from recovering culture-confirmed typhoid cases. We enrolled and assayed plasma of 1787 participants for anti-Vi IgG; 1,531 of these were resident in mainland areas that had not been previously vaccinated against S. Typhi (seropositivity 32.3% (95%CI 28.2 to 36.3%)), 256 were resident on Taveuni island, which had been previously vaccinated (seropositivity 71.5% (95%CI 62.1 to 80.9%)). The seroprevalence on the Fijian mainland is one to two orders of magnitude higher than expected from confirmed case surveillance incidence, suggesting substantial subclinical or otherwise unreported typhoid. We found no significant differences in seropositivity prevalences by ethnicity, which is in contrast to disease surveillance data in which the indigenous iTaukei Fijian population are disproportionately affected. Using multivariable logistic regression, seropositivity was associated with increased age (odds ratio 1.3 (95% CI 1.2 to 1.4) per 10 years), the presence of a pit latrine (OR 1.6, 95%CI 1.1 to 2.3) as opposed to a septic tank or piped sewer, and residence in settlements rather than residential housing or villages (OR 1.6, 95% CI 1.0 to 2.7). Increasing seropositivity with age is suggestive of low-level endemic transmission in Fiji. Improved sanitation where pit latrines are used and addressing potential transmission routes in settlements may reduce exposure to S. Typhi. Widespread unreported infection suggests there may be a role for typhoid vaccination in Fiji, in addition to public health management of cases and outbreaks. Fiji has experienced a decade-long increase in typhoid fever cases, a potentially life-threatening systemic bacterial disease caused by Salmonella Typhi. We undertook a representative blood-serum community survey to measure antibodies (IgG) against the Vi antigen of Salmonella Typhi using a rigorous survey design. We found one in three residents of mainland, unvaccinated Fiji had detectable antibody against Vi. This was higher than would be expected from confirmed case notifications received by the national surveillance system. Additionally, similar antibody responses were detected in Fijians of all ethnicities, which contrasts to surveillance cases in which indigenous iTaukei Fijians were disproportionately affected. Serology on a Fijian island where a significant proportion of the population has been vaccinated found that three-quarters of residents were seropositive three years after the Vi-polysaccharide typhoid vaccination campaign. Importantly, in mainland participants, seroprevalence increased with age, suggesting long-standing, low-level, endemic transmission. Pit latrines were associated with seropositivity when compared with septic tanks, and settlements compared with residential housing. Very high antibody titres in a small percentage of participants may suggest carriage of Salmonella Typhi. The seroprevalence findings suggest eliminating typhoid from Fiji by focussing on cases and outbreaks alone will be challenging. Our results support typhoid vaccination and further development of water, sanitation and hygiene infrastructure in Fiji.
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Lu X, Li Z, Yan M, Pang B, Xu J, Kan B. Regional Transmission of Salmonella Paratyphi A, China, 1998-2012. Emerg Infect Dis 2017; 23:833-836. [PMID: 28418315 PMCID: PMC5403048 DOI: 10.3201/eid2305.151539] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
To explore transmission patterns and genetic relationships of Salmonella enterica serovar Paratyphi A in China, we conducted a genome-wide single-nucleotide polymorphism analysis on the strains in the 4 provinces in which incidence was highest during 1998-2012. Markedly phylogeographic clustering suggested regional virus circulation after introduction from areas in southeastern China.
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Tran Vu Thieu N, Trinh Van T, Tran Tuan A, Klemm EJ, Nguyen Ngoc Minh C, Voong Vinh P, Pham Thanh D, Ho Ngoc Dan T, Pham Duc T, Langat P, Martin LB, Galan J, Liang L, Felgner PL, Davies DH, de Jong HK, Maude RR, Fukushima M, Wijedoru L, Ghose A, Samad R, Dondorp AM, Faiz A, Darton TC, Pollard AJ, Thwaites GE, Dougan G, Parry CM, Baker S. An evaluation of purified Salmonella Typhi protein antigens for the serological diagnosis of acute typhoid fever. J Infect 2017; 75:104-114. [PMID: 28551371 PMCID: PMC5522525 DOI: 10.1016/j.jinf.2017.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 05/15/2017] [Accepted: 05/16/2017] [Indexed: 12/14/2022]
Abstract
Objectives The diagnosis of typhoid fever is a challenge. Aiming to develop a typhoid diagnostic we measured antibody responses against Salmonella Typhi (S. Typhi) protein antigens and the Vi polysaccharide in a cohort of Bangladeshi febrile patients. Methods IgM against 12 purified antigens and the Vi polysaccharide was measured by ELISA in plasma from patients with confirmed typhoid fever (n = 32), other confirmed infections (n = 17), and healthy controls (n = 40). ELISAs with the most specific antigens were performed on plasma from 243 patients with undiagnosed febrile disease. Results IgM against the S. Typhi protein antigens correlated with each other (rho > 0.8), but not against Vi (rho < 0.6). Typhoid patients exhibited higher IgM against 11/12 protein antigens and Vi than healthy controls and those with other infections. Vi, PilL, and CdtB exhibited the greatest sensitivity and specificity. Specificity and sensitivity was improved when Vi was combined with a protein antigen, generating sensitivities and specificities of 0.80 and >0.85, respectively. Applying a dynamic cut-off to patients with undiagnosed febrile disease suggested that 34–58% had an IgM response indicative of typhoid. Conclusions We evaluated the diagnostic potential of several S. Typhi antigens; our assays give good sensitivity and specificity, but require further assessment in differing patient populations.
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Affiliation(s)
- Nga Tran Vu Thieu
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Tan Trinh Van
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Anh Tran Tuan
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Elizabeth J Klemm
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Chau Nguyen Ngoc Minh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Duy Pham Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Thanh Ho Ngoc Dan
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Trung Pham Duc
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Pinky Langat
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Laura B Martin
- Sclavo Berhing Vaccines Institute for Global Health, Siena, Italy
| | - Jorge Galan
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Li Liang
- Department of Medicine, Division of Infectious Diseases, University of California, Irvine, CA, USA
| | - Philip L Felgner
- Department of Medicine, Division of Infectious Diseases, University of California, Irvine, CA, USA
| | - D Huw Davies
- Department of Medicine, Division of Infectious Diseases, University of California, Irvine, CA, USA
| | - Hanna K de Jong
- Department of Internal Medicine, Division of Infectious Diseases and Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Rapeephan R Maude
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Masako Fukushima
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Lalith Wijedoru
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | - Rasheda Samad
- Chittagong Medical College Hospital, Chittagong, Bangladesh
| | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Malaria Research Group and Dev Care Foundation, Bangladesh
| | - Abul Faiz
- Malaria Research Group and Dev Care Foundation, Bangladesh
| | - Thomas C Darton
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam; Sheffield Teaching Hospitals NHS Trust Foundation and the University of Sheffield, Sheffield, United Kingdom
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Guy E Thwaites
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam; Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Gordon Dougan
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom; The Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Christopher M Parry
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam; Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom; The Department of Medicine, University of Cambridge, Cambridge, United Kingdom.
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Evaluating the Trends of Bloodstream Infections among Pediatric and Adult Patients at a Teaching Hospital of Kathmandu, Nepal: Role of Drug Resistant Pathogens. CANADIAN JOURNAL OF INFECTIOUS DISEASES & MEDICAL MICROBIOLOGY 2017; 2017:8763135. [PMID: 28484498 PMCID: PMC5397624 DOI: 10.1155/2017/8763135] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/12/2017] [Accepted: 03/27/2017] [Indexed: 11/18/2022]
Abstract
Bloodstream infections (BSIs) are among the significant causes of morbidity and mortality for patients of all age groups. However, very little is known about the trends of bacterial bloodstream infections and antimicrobial susceptibilities among pediatric and adult population from Nepal. In this study, we have investigated the different etiological agents responsible for bloodstream infections among pediatric and adult patients and the role of drug resistant organisms in these infections at a tertiary care teaching hospital of Kathmandu, Nepal. A total of 3,088 blood culture specimens obtained from pediatric and adult patients suspected to have bloodstream infections were processed by standard microbiological methods. Significant bacterial pathogens were identified by morphological, biochemical, and serological methods as suggested by American Society for Microbiology. In vitro antimicrobial susceptibility testing was performed by Kirby-Bauer disk diffusion method and interpreted according to the guidelines of Clinical and Laboratory Standards Institute. Overall, incidence of bloodstream infections among the suspected patients was 7.48%. Pediatric patients (n = 90, 9.37%) were the significant subgroup of patients affected with bloodstream infections compared to adults (p < 0.05, CI-95%). Gram positive (n = 49, 54.4%) bacteria in pediatric and gram negative bacteria (n = 141, 78.7%) in adult patients were the most common isolates for BSI. Staphylococcus aureus (n = 41, 45.6%) in pediatric patients and Salmonella enterica (n = 40, 28.3%) in adult patients were the leading pathogens. Trends of antimicrobial resistance among isolated bacterial strains were significantly high in adults compared to pediatric patients. Methicillin resistant Staphylococcus aureus (MRSA) (31.4%), extended spectrum beta-lactamase (ESBL) (12.5%), and metallo-beta-lactamase (MBL) (3.9%) producing gram negatives were major resistant strains. Our study shows higher rates of bloodstream infections in pediatric patients compared to adult patients. Alarming rates of antimicrobial resistance among blood culture isolates is a serious issue. Prompt and accurate diagnosis and rational antimicrobial therapy are extremely needed.
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Khan MI, Franco-Paredes C, Sahastrabuddhe S, Ochiai RL, Mogasale V, Gessner BD. Barriers to typhoid fever vaccine access in endemic countries. Res Rep Trop Med 2017; 8:37-44. [PMID: 30050343 PMCID: PMC6034652 DOI: 10.2147/rrtm.s97309] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Typhoid vaccines have been available as a means of disease control and prevention since 1896; however, their use as a routine tool for disease prevention in endemic settings has been hampered because of: 1) insufficient data on disease burden particularly regarding the lack of health care access in the poorest communities affected by typhoid; 2) limitations of the typhoid vaccine, such as shorter duration of protection, moderate efficacy in young children, and no efficacy for infants; 3) inadequate evidence on potential economic benefits when used for a larger population; 4) neglect in favor of alternative interventions that require massive infrastructure; 5) no financial support or commitment regarding vaccine delivery cost; 6) ambivalence about whether to invest in water and sanitation hygiene versus the vaccine; and 7) clarity on global policy for country adoption. If current typhoid-protein conjugate vaccines live up to their promise of higher efficacy, longer duration of protection, and efficacy in young children, typhoid vaccine use will be a critical component of short- and medium-term disease control strategies. Typhoid control could be accelerated if the global framework includes plans for accelerated introduction of the conjugate typhoid vaccine in developing countries.
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Affiliation(s)
- M Imran Khan
- Center of Excellence in Women and Child Health, The Aga Khan University, Karachi, Pakistan,
| | - Carlos Franco-Paredes
- Hospital Infantil de México, Federico Gómez, México DF., Mexico.,Phoebe Putney Memorial Hospital, Albany, GA, USA
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Im J, Nichols C, Bjerregaard-Andersen M, Sow AG, Løfberg S, Tall A, Pak GD, Aaby P, Baker S, Clemens JD, Espinoza LMC, Konings F, May J, Monteiro M, Niang A, Panzner U, Park SE, Schütt-Gerowitt H, Wierzba TF, Marks F, von Kalckreuth V. Prevalence of Salmonella Excretion in Stool: A Community Survey in 2 Sites, Guinea-Bissau and Senegal. Clin Infect Dis 2016; 62 Suppl 1:S50-5. [PMID: 26933022 DOI: 10.1093/cid/civ789] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Chronic and convalescent carriers play an important role in the transmission and endemicity of many communicable diseases. A high incidence of Salmonella enterica serovar Typhi and invasive nontyphoidal Salmonella (NTS) infection has been reported in parts of sub-Saharan Africa, yet the prevalence of Salmonella excretion in the general population is unknown. METHODS Stool specimens were collected from a random sample of households in 2 populations in West Africa: Bissau, Guinea-Bissau, and Dakar, Senegal. Stool was cultured to detect presence of Salmonella, and antimicrobial susceptibility testing was performed on the isolated organisms. RESULTS Stool was cultured from 1077 and 1359 individuals from Guinea-Bissau and Senegal, respectively. Salmonella Typhi was not isolated from stool samples at either site. Prevalence of NTS in stool samples was 24.1 (95% confidence interval [CI], 16.5-35.1; n = 26/1077) per 1000 population in Guinea-Bissau and 10.3 (95% CI, 6.1-17.2; n = 14/1359) per 1000 population in Senegal. CONCLUSIONS Evidence of NTS excretion in stool in both study populations indicates a possible NTS transmission route in these settings.
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Affiliation(s)
- Justin Im
- International Vaccine Institute, Seoul, Republic of Korea
| | | | | | - Amy Gassama Sow
- Institut Pasteur de Dakar Université Cheikh Anta Diop de Dakar, Senegal
| | - Sandra Løfberg
- Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau
| | | | - Gi Deok Pak
- International Vaccine Institute, Seoul, Republic of Korea
| | - Peter Aaby
- Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau
| | - Stephen Baker
- Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University London School of Hygiene and Tropical Medicine, United Kingdom
| | - John D Clemens
- International Vaccine Institute, Seoul, Republic of Korea International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka Fielding School of Public Health, University of California, Los Angeles
| | | | - Frank Konings
- International Vaccine Institute, Seoul, Republic of Korea
| | - Jürgen May
- Bernhard Nocht Institute for Tropical Medicine, and German Center for Infection Research, partner site Hamburg-Borstel-Lübeck, Hamburg
| | - Mario Monteiro
- Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau
| | | | - Ursula Panzner
- International Vaccine Institute, Seoul, Republic of Korea
| | - Se Eun Park
- International Vaccine Institute, Seoul, Republic of Korea
| | - Heidi Schütt-Gerowitt
- International Vaccine Institute, Seoul, Republic of Korea Institute of Medical Microbiology, University of Cologne, Germany
| | | | - Florian Marks
- International Vaccine Institute, Seoul, Republic of Korea
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Kuijpers LMF, Le Hello S, Fawal N, Fabre L, Tourdjman M, Dufour M, Sar D, Kham C, Phe T, Vlieghe E, Bouchier C, Jacobs J, Weill FX. Genomic analysis of Salmonella enterica serotype Paratyphi A during an outbreak in Cambodia, 2013-2015. Microb Genom 2016; 2:e000092. [PMID: 28348832 PMCID: PMC5320704 DOI: 10.1099/mgen.0.000092] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 10/05/2016] [Indexed: 01/01/2023] Open
Abstract
In 2013, an unusual increase in the number of Salmonella enterica serotype Paratyphi A (Salmonella Paratyphi A) infections was reported in patients in Phnom Penh, Cambodia, and in European, American and Japanese travellers returning from Cambodia. Epidemiological investigations did not identify a common source of exposure. To analyse the population structure and genetic diversity of these Salmonella Paratyphi A isolates, we used whole-genome sequencing on 65 isolates collected from 1999 to 2014: 55 from infections acquired in Cambodia and 10 from infections acquired in other countries in Asia, Africa and Europe. Short-read sequences from 80 published genomes from around the world and from 13 published genomes associated with an outbreak in China were also included. Pulsed-field gel electrophoresis (PFGE) was performed on a subset of isolates. Genomic analyses were found to provide much more accurate information for tracking the individual strains than PFGE. All but 2 of the 36 isolates acquired in Cambodia during 2013–2014 belonged to the same clade, C5, of lineage C. This clade has been isolated in Cambodia since at least 1999. The Chinese outbreak isolates belonged to a different clade (C4) and were resistant to nalidixic acid, whereas the Cambodian outbreak isolates displayed pan-susceptibility to antibiotics. Since 2014, the total number of cases has decreased, but there has been an increase in the frequency with which nalidixic acid-resistant C5 isolates are isolated. The frequency of these isolates should be monitored over time, because they display decreased susceptibility to ciprofloxacin, the first-choice antibiotic for treating paratyphoid fever.
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Affiliation(s)
- Laura Maria Francisca Kuijpers
- 1Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.,2Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium
| | - Simon Le Hello
- 3Institut Pasteur, Unité des Bactéries Pathogènes Entériques, Centre National de Référence des Escherichia coli, Shigella et Salmonella, Paris, France
| | - Nizar Fawal
- 3Institut Pasteur, Unité des Bactéries Pathogènes Entériques, Centre National de Référence des Escherichia coli, Shigella et Salmonella, Paris, France
| | - Laetitia Fabre
- 3Institut Pasteur, Unité des Bactéries Pathogènes Entériques, Centre National de Référence des Escherichia coli, Shigella et Salmonella, Paris, France
| | - Mathieu Tourdjman
- 4Santé Publique France, Direction des Maladies Infectieuses, Saint-Maurice, France
| | - Muriel Dufour
- 5Institute of Environmental Science and Research Limited, NCBID, Wallaceville, New Zealand
| | - Dara Sar
- 6Sihanouk Hospital Centre of HOPE, Phnom Penh, Cambodia
| | - Chun Kham
- 6Sihanouk Hospital Centre of HOPE, Phnom Penh, Cambodia
| | - Thong Phe
- 6Sihanouk Hospital Centre of HOPE, Phnom Penh, Cambodia
| | - Erika Vlieghe
- 1Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.,7Department of Tropical Diseases, University Hospital Antwerp, Antwerp, Belgium
| | | | - Jan Jacobs
- 1Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.,2Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium
| | - François-Xavier Weill
- 3Institut Pasteur, Unité des Bactéries Pathogènes Entériques, Centre National de Référence des Escherichia coli, Shigella et Salmonella, Paris, France
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Pham Thanh D, Karkey A, Dongol S, Ho Thi N, Thompson CN, Rabaa MA, Arjyal A, Holt KE, Wong V, Tran Vu Thieu N, Voong Vinh P, Ha Thanh T, Pradhan A, Shrestha SK, Gajurel D, Pickard D, Parry CM, Dougan G, Wolbers M, Dolecek C, Thwaites GE, Basnyat B, Baker S. A novel ciprofloxacin-resistant subclade of H58 Salmonella Typhi is associated with fluoroquinolone treatment failure. eLife 2016; 5:e14003. [PMID: 26974227 PMCID: PMC4805543 DOI: 10.7554/elife.14003] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/19/2016] [Indexed: 01/22/2023] Open
Abstract
The interplay between bacterial antimicrobial susceptibility, phylogenetics and patient outcome is poorly understood. During a typhoid clinical treatment trial in Nepal, we observed several treatment failures and isolated highly fluoroquinolone-resistant Salmonella Typhi (S. Typhi). Seventy-eight S. Typhi isolates were genome sequenced and clinical observations, treatment failures and fever clearance times (FCTs) were stratified by lineage. Most fluoroquinolone-resistant S. Typhi belonged to a specific H58 subclade. Treatment failure with S. Typhi-H58 was significantly less frequent with ceftriaxone (3/31; 9.7%) than gatifloxacin (15/34; 44.1%)(Hazard Ratio 0.19, p=0.002). Further, for gatifloxacin-treated patients, those infected with fluoroquinolone-resistant organisms had significantly higher median FCTs (8.2 days) than those infected with susceptible (2.96) or intermediately resistant organisms (4.01)(p<0.001). H58 is the dominant S. Typhi clade internationally, but there are no data regarding disease outcome with this organism. We report an emergent new subclade of S. Typhi-H58 that is associated with fluoroquinolone treatment failure. Clinical trial registration: ISRCTN63006567. DOI:http://dx.doi.org/10.7554/eLife.14003.001 People who ingest a type of bacteria called Salmonella Typhi can develop the symptoms of typhoid fever. This disease is common in low-income settings in Asia and Africa, and causes a high rate of death in people who are not treated with antimicrobial drugs. During a study in Nepal, Thanh et al. tried to evaluate which of two antimicrobials was better for treating typhoid fever. One of the drugs – called gatifloxacin – did not work in some of the patients. To understand why this treatment failed, Thanh et al. decoded the entire DNA sequences of all the Salmonella Typhi bacteria isolated during the study. Comparing this genetic data to the clinical data of the patients identified a new variant of Salmonella Typhi. These bacteria have a specific combination of genetic mutations that render them resistant to the family of drugs that gatifloxacin belongs to – the fluoroquinolones. Patients infected with the variant bacteria and treated with gatifloxacin were highly likely to completely fail treatment and have longer-lasting fevers. On further investigation Thanh et al. found these organisms were likely recently introduced into Nepal from India. Fluoroquinolones are amongst the most effective and common antimicrobials used to treat typhoid fever and other bacterial infections. However, the presence of bacteria that are resistant to these compounds in South Asia means that they should no longer be the first choice of drug to treat typhoid fever in this location. DOI:http://dx.doi.org/10.7554/eLife.14003.002
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Affiliation(s)
- Duy Pham Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Abhilasha Karkey
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Nhan Ho Thi
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Corinne N Thompson
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom.,The London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Maia A Rabaa
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Amit Arjyal
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Kathryn E Holt
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Australia
| | - Vanessa Wong
- The Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Nga Tran Vu Thieu
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Tuyen Ha Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | | | | | | | - Derek Pickard
- The Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Christopher M Parry
- The London School of Hygiene and Tropical Medicine, London, United Kingdom.,School of Tropical Medicine and Global Health, Department of Clinical Research, Nagasaki University, Nagasaki, Japan
| | - Gordon Dougan
- The Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Marcel Wolbers
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Christiane Dolecek
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom.,Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Guy E Thwaites
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom.,The London School of Hygiene and Tropical Medicine, London, United Kingdom
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Karkey A, Jombart T, Walker AW, Thompson CN, Torres A, Dongol S, Tran Vu Thieu N, Pham Thanh D, Tran Thi Ngoc D, Voong Vinh P, Singer AC, Parkhill J, Thwaites G, Basnyat B, Ferguson N, Baker S. The Ecological Dynamics of Fecal Contamination and Salmonella Typhi and Salmonella Paratyphi A in Municipal Kathmandu Drinking Water. PLoS Negl Trop Dis 2016; 10:e0004346. [PMID: 26735696 PMCID: PMC4703202 DOI: 10.1371/journal.pntd.0004346] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 12/09/2015] [Indexed: 11/20/2022] Open
Abstract
One of the UN sustainable development goals is to achieve universal access to safe and affordable drinking water by 2030. It is locations like Kathmandu, Nepal, a densely populated city in South Asia with endemic typhoid fever, where this goal is most pertinent. Aiming to understand the public health implications of water quality in Kathmandu we subjected weekly water samples from 10 sources for one year to a range of chemical and bacteriological analyses. We additionally aimed to detect the etiological agents of typhoid fever and longitudinally assess microbial diversity by 16S rRNA gene surveying. We found that the majority of water sources exhibited chemical and bacterial contamination exceeding WHO guidelines. Further analysis of the chemical and bacterial data indicated site-specific pollution, symptomatic of highly localized fecal contamination. Rainfall was found to be a key driver of this fecal contamination, correlating with nitrates and evidence of S. Typhi and S. Paratyphi A, for which DNA was detectable in 333 (77%) and 303 (70%) of 432 water samples, respectively. 16S rRNA gene surveying outlined a spectrum of fecal bacteria in the contaminated water, forming complex communities again displaying location-specific temporal signatures. Our data signify that the municipal water in Kathmandu is a predominant vehicle for the transmission of S. Typhi and S. Paratyphi A. This study represents the first extensive spatiotemporal investigation of water pollution in an endemic typhoid fever setting and implicates highly localized human waste as the major contributor to poor water quality in the Kathmandu Valley. Aiming to understand the ecology of municipal drinking water and measure the potential exposure to pathogens that cause typhoid fever (Salmonella Typhi and Salmonella Paratyphi A) in Kathmandu, Nepal, we collected water samples from 10 water sources weekly for one year and subjected them to comprehensive chemical, bacteriological and molecular analyses. We found that Kathmandu drinking water exhibits longitudinal fecal contamination in excess of WHO guidelines. The chemical composition of water indicated site-specific pollution profiles, which were likely driven by localized contamination with human fecal material. We additionally found that Salmonella Typhi and Salmonella Paratyphi A could be detected throughout the year in every water sampling location, but specifically peaked after the monsoons. A microbiota analysis (a method for studying bacterial diversity in biological samples) revealed the water to be contaminated by complex populations of fecal bacteria, which again exhibited a unique profile by both location and time. This study shows that Salmonella Typhi and Salmonella Paratyphi A can be longitudinally detected in drinking water in Kathmandu and represents the first major investigation of the spatiotemporal dynamics of drinking water pollution in an endemic typhoid setting.
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Affiliation(s)
- Abhilasha Karkey
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Thibaut Jombart
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Alan W. Walker
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
- Microbiology Group, The Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, United Kingdom
| | - Corinne N. Thompson
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom
| | - Andres Torres
- Grupo de Investigación Ciencia e Ingeniería del Agua y el Ambiente, Facultad de Ingeniería, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Nga Tran Vu Thieu
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Duy Pham Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Dung Tran Thi Ngoc
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Andrew C. Singer
- NERC Centre for Ecology and Hydrology, Wallingford, Oxfordshire, United Kingdom
| | - Julian Parkhill
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Guy Thwaites
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Neil Ferguson
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom
- The London School of Hygiene and Tropical Medicine, London, United Kingdom
- * E-mail:
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Adhikari A, Rauniyar R, Raut PP, Manandhar KD, Gupta BP. Evaluation of sensitivity and specificity of ELISA against Widal test for typhoid diagnosis in endemic population of Kathmandu. BMC Infect Dis 2015; 15:523. [PMID: 26573629 PMCID: PMC4647669 DOI: 10.1186/s12879-015-1248-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 10/28/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Widal test, which has poor predictive outcomes in predominant typhoid population, is not standard enough to predict accurate diagnosis. This study aims to compare the diagnostic accuracy of Widal test to ELISA using blood culture as gold standard. METHODS The blood samples were collected in Capital Hospital, Kathmandu, Nepal from febrile patients having ≥48 h fever in 3 years study period for blood culture, Widal test and IgG-IgM ELISA. RESULTS Amongst 1371 febrile cases, 237 were Salmonella typhi positive to blood culture and 71.4 % typhoid fever patient were of 46-60 years old with male to female ratio of 2:1. Blood culture confirmed patients had ≥1:40 anti-TH and anti-TO titre in 45.56 % (n = 108) and 43.88 % (n = 104) patients respectively. The sensitivity and specificity of IgG (0.96 and 0.95) and IgM (0.95 and 0.94) at 95 % confidence level were significant compared to Widal anti-TH (0.72 and 0.58) and TO (0.80 and 0.51) test (p value, 0.038) at titre level ≥1:200. Further the PPV of Widal TH and TO (0.38 and 0.23) was low compared to IgG and IgM ELISA (0.78 and 0.77) (p value, 0.045). CONCLUSION Widal test is not sensitive enough for an endemic setting like Nepal and thus should be either replaced with more accurate test like ELISA or follow an alternative diagnostic methodology.
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Affiliation(s)
- Anurag Adhikari
- Asian Institute of Technology & Management, Lalitpur, Nepal. .,Everest Institute of Virology and Immunology, Kathmandu, Nepal.
| | | | | | - Krishna Das Manandhar
- Central Department of Biotechnology, Tribhuvan University, Kirtipur, Kathmandu, Nepal. .,Everest Institute of Virology and Immunology, Kathmandu, Nepal.
| | - Birendra Prasad Gupta
- Central Department of Biotechnology, Tribhuvan University, Kirtipur, Kathmandu, Nepal. .,Everest Institute of Virology and Immunology, Kathmandu, Nepal.
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Mogasale V, Maskery B, Ochiai RL, Lee JS, Mogasale VV, Ramani E, Kim YE, Park JK, Wierzba TF. Burden of typhoid fever in low-income and middle-income countries: a systematic, literature-based update with risk-factor adjustment. LANCET GLOBAL HEALTH 2015; 2:e570-80. [PMID: 25304633 DOI: 10.1016/s2214-109x(14)70301-8] [Citation(s) in RCA: 336] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND No access to safe water is an important risk factor for typhoid fever, yet risk-level heterogeneity is unaccounted for in previous global burden estimates. Since WHO has recommended risk-based use of typhoid polysaccharide vaccine, we revisited the burden of typhoid fever in low-income and middle-income countries (LMICs) after adjusting for water-related risk. METHODS We estimated the typhoid disease burden from studies done in LMICs based on blood-culture-confirmed incidence rates applied to the 2010 population, after correcting for operational issues related to surveillance, limitations of diagnostic tests, and water-related risk. We derived incidence estimates, correction factors, and mortality estimates from systematic literature reviews. We did scenario analyses for risk factors, diagnostic sensitivity, and case fatality rates, accounting for the uncertainty in these estimates and we compared them with previous disease burden estimates. FINDINGS The estimated number of typhoid fever cases in LMICs in 2010 after adjusting for water-related risk was 11·9 million (95% CI 9·9-14·7) cases with 129 000 (75 000-208 000) deaths. By comparison, the estimated risk-unadjusted burden was 20·6 million (17·5-24·2) cases and 223 000 (131 000-344 000) deaths. Scenario analyses indicated that the risk-factor adjustment and updated diagnostic test correction factor derived from systematic literature reviews were the drivers of differences between the current estimate and past estimates. INTERPRETATION The risk-adjusted typhoid fever burden estimate was more conservative than previous estimates. However, by distinguishing the risk differences, it will allow assessment of the effect at the population level and will facilitate cost-effectiveness calculations for risk-based vaccination strategies for future typhoid conjugate vaccine.
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Affiliation(s)
| | | | | | | | | | - Enusa Ramani
- International Vaccine Institute, Seoul, South Korea
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Kariuki S, Gordon MA, Feasey N, Parry CM. Antimicrobial resistance and management of invasive Salmonella disease. Vaccine 2015; 33 Suppl 3:C21-9. [PMID: 25912288 PMCID: PMC4469558 DOI: 10.1016/j.vaccine.2015.03.102] [Citation(s) in RCA: 177] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/24/2015] [Accepted: 03/26/2015] [Indexed: 01/08/2023]
Abstract
Invasive Salmonella infections (typhoidal and non-typhoidal) cause a huge burden of illness estimated at nearly 3.4 million cases and over 600,000 deaths annually especially in resource-limited settings. Invasive non-typhoidal Salmonella (iNTS) infections are particularly important in immunosuppressed populations especially in sub-Saharan Africa, causing a mortality of 20-30% in vulnerable children below 5 years of age. In these settings, where routine surveillance for antimicrobial resistance is rare or non-existent, reports of 50-75% multidrug resistance (MDR) in NTS are common, including strains of NTS also resistant to flouroquinolones and 3rd generation cephalosporins. Typhoid (enteric) fever caused by Salmonella Typhi and Salmonella Paratyphi A remains a major public health problem in many parts of Asia and Africa. Currently over a third of isolates in many endemic areas are MDR, and diminished susceptibility or resistance to fluoroquinolones, the drugs of choice for MDR cases over the last decade is an increasing problem. The situation is particularly worrying in resource-limited settings where the few remaining effective antimicrobials are either unavailable or altogether too expensive to be afforded by either the general public or by public health services. Although the prudent use of effective antimicrobials, improved hygiene and sanitation and the discovery of new antimicrobial agents may offer hope for the management of invasive salmonella infections, it is essential to consider other interventions including the wider use of WHO recommended typhoid vaccines and the acceleration of trials for novel iNTS vaccines. The main objective of this review is to describe existing data on the prevalence and epidemiology of antimicrobial resistant invasive Salmonella infections and how this affects the management of these infections, especially in endemic developing countries.
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Affiliation(s)
- Samuel Kariuki
- Centre for Microbiology Research, Kenya Medical Research Institute, PO Box 43640-00100, Nairobi, Kenya; The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom.
| | - Melita A Gordon
- Institute for Infection and Global Health, University of Liverpool, United Kingdom; Malawi Liverpool Wellcome Trust Clinical Research Programme, United Kingdom
| | - Nicholas Feasey
- Malawi Liverpool Wellcome Trust Clinical Research Programme, United Kingdom; Liverpool School of Tropical Medicine, United Kingdom
| | - Christopher M Parry
- Department of Clinical Research, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 5HT, United Kingdom; School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
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McCullagh D, Dobinson HC, Darton T, Campbell D, Jones C, Snape M, Stevens Z, Plested E, Voysey M, Kerridge S, Martin LB, Angus B, Pollard AJ. Understanding paratyphoid infection: study protocol for the development of a human model of Salmonella enterica serovar Paratyphi A challenge in healthy adult volunteers. BMJ Open 2015; 5:e007481. [PMID: 26082464 PMCID: PMC4480031 DOI: 10.1136/bmjopen-2014-007481] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 01/27/2015] [Accepted: 01/28/2015] [Indexed: 01/09/2023] Open
Abstract
INTRODUCTION This study will develop the first human challenge model of paratyphoid infection which may then be taken forward to evaluate paratyphoid vaccine candidates. Salmonella Paratyphi A is believed to cause a quarter of the estimated 20 million cases of enteric fever annually. Epidemiological evidence also suggests that an increasing proportion of the enteric fever burden is attributable to S. Paratyphi infection meriting further attention and interest in vaccine development. Assessment of paratyphoid vaccine efficacy in preclinical studies is complicated by the lack of a small animal model and the human-restricted nature of the infection. The use of experimental human infection in healthy volunteers provides an opportunity to address these problems in a cost-effective manner. METHODS AND ANALYSIS Volunteers will ingest virulent S. Paratyphi A bacteria (NVGH308 strain) with a bicarbonate buffer solution to establish the infectious dose resulting in an 'attack rate' of 60-75%. Using an a priori decision-making algorithm, the challenge dose will be escalated or de-escalated to achieve the target attack rate, with the aim of reaching the study end point while exposing as few individuals as possible to infection. The attack rate will be determined by the proportion of paratyphoid infection in groups of 20 healthy adult volunteers, with infection being defined by one or more positive blood cultures (microbiological end point) and/or fever, defined as an oral temperature exceeding 38 °C sustained for at least 12 h (clinical end point); 20-80 participants will be required. Challenge participants will start a 2-week course of an oral antibiotic on diagnosis of infection, or after 14 days follow-up. ETHICS AND DISSEMINATION The strict eligibility criterion aims to minimise risk to participants and their close contacts. Ethical approval has been obtained. The results will be disseminated in a peer-reviewed journal and presented at international congresses. TRIAL REGISTRATION NUMBER NCT02100397.
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Affiliation(s)
- David McCullagh
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, Oxfordshire, UK
| | - Hazel C Dobinson
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, Oxfordshire, UK
| | - Thomas Darton
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, Oxfordshire, UK
| | - Danielle Campbell
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, Oxfordshire, UK
| | - Claire Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, Oxfordshire, UK
| | - Matthew Snape
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, Oxfordshire, UK
| | - Zoe Stevens
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, Oxfordshire, UK
| | - Emma Plested
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, Oxfordshire, UK
| | - Merryn Voysey
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, Oxfordshire, UK
- Primary Care Clinical Trials Unit, Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, Oxfordshire, UK
| | - Simon Kerridge
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, Oxfordshire, UK
| | - Laura B Martin
- Novartis Vaccines Institute for Global Health, Siena, Italy
| | - Brian Angus
- Nuffield Department of Medicine, University of Oxford, Oxford, Oxfordshire, UK
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, Oxfordshire, UK
- Primary Care Clinical Trials Unit, Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, Oxfordshire, UK
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Watson CH, Edmunds WJ. A review of typhoid fever transmission dynamic models and economic evaluations of vaccination. Vaccine 2015; 33 Suppl 3:C42-54. [PMID: 25921288 PMCID: PMC4504000 DOI: 10.1016/j.vaccine.2015.04.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 03/31/2015] [Accepted: 04/01/2015] [Indexed: 01/22/2023]
Abstract
There are relatively few dynamic models or economic analyses of typhoid vaccination. The relative contribution of carriage to transmission is a key uncertainty. Published economic analyses use static models that omit indirect protection of vaccines. Nevertheless, vaccines appear highly cost-effective against WHO criteria in high-incidence settings. No economic model was found to compare vaccine and sanitation.
Despite a recommendation by the World Health Organization (WHO) that typhoid vaccines be considered for the control of endemic disease and outbreaks, programmatic use remains limited. Transmission models and economic evaluation may be informative in decision making about vaccine programme introductions and their role alongside other control measures. A literature search found few typhoid transmission models or economic evaluations relative to analyses of other infectious diseases of similar or lower health burden. Modelling suggests vaccines alone are unlikely to eliminate endemic disease in the short to medium term without measures to reduce transmission from asymptomatic carriage. The single identified data-fitted transmission model of typhoid vaccination suggests vaccines can reduce disease burden substantially when introduced programmatically but that indirect protection depends on the relative contribution of carriage to transmission in a given setting. This is an important source of epidemiological uncertainty, alongside the extent and nature of natural immunity. Economic evaluations suggest that typhoid vaccination can be cost-saving to health services if incidence is extremely high and cost-effective in other high-incidence situations, when compared to WHO norms. Targeting vaccination to the highest incidence age-groups is likely to improve cost-effectiveness substantially. Economic perspective and vaccine costs substantially affect estimates, with disease incidence, case-fatality rates, and vaccine efficacy over time also important determinants of cost-effectiveness and sources of uncertainty. Static economic models may under-estimate benefits of typhoid vaccination by omitting indirect protection. Typhoid fever transmission models currently require per-setting epidemiological parameterisation to inform their use in economic evaluation, which may limit their generalisability. We found no economic evaluation based on transmission dynamic modelling, and no economic evaluation of typhoid vaccination against interventions such as improvements in sanitation or hygiene.
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Affiliation(s)
- Conall H Watson
- Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, United Kingdom.
| | - W John Edmunds
- Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, United Kingdom
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Abstract
Control of typhoid fever relies on clinical information, diagnosis, and an understanding for the epidemiology of the disease. Despite the breadth of work done so far, much is not known about the biology of this human-adapted bacterial pathogen and the complexity of the disease in endemic areas, especially those in Africa. The main barriers to control are vaccines that are not immunogenic in very young children and the development of multidrug resistance, which threatens efficacy of antimicrobial chemotherapy. Clinicians, microbiologists, and epidemiologists worldwide need to be familiar with shifting trends in enteric fever. This knowledge is crucial, both to control the disease and to manage cases. Additionally, salmonella serovars that cause human infection can change over time and location. In areas of Asia, multidrug-resistant Salmonella enterica serovar Typhi (S Typhi) has been the main cause of enteric fever, but now S Typhi is being displaced by infections with drug-resistant S enterica serovar Paratyphi A. New conjugate vaccines are imminent and new treatments have been promised, but the engagement of local medical and public health institutions in endemic areas is needed to allow surveillance and to implement control measures.
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Affiliation(s)
- John Wain
- Norwich Medical School, University of East Anglia, Norwich, UK.
| | - Rene S Hendriksen
- National Food Institute, Technical University of Denmark, WHO Collaborating Centre for Antimicrobial Resistance in Foodborne Pathogens and European Union Reference Laboratory for Antimicrobial Resistance, Kongens Lyngby, Denmark
| | - Matthew L Mikoleit
- National Enteric Reference Laboratory Team, Enteric Diseases Laboratory Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Karen H Keddy
- Centre for Enteric Diseases, National Institute for Communicable Diseases, Division in the National Health Laboratory Service (NHLS), Johannesburg, South Africa; Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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Watson CH. Evaluating typhoid vaccine effectiveness in travelers' vaccination. J Travel Med 2015; 22:76-7. [PMID: 25753021 DOI: 10.1111/jtm.12185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 12/01/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Conall H Watson
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
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Gunn JS, Marshall JM, Baker S, Dongol S, Charles RC, Ryan ET. Salmonella chronic carriage: epidemiology, diagnosis, and gallbladder persistence. Trends Microbiol 2014; 22:648-55. [PMID: 25065707 PMCID: PMC4252485 DOI: 10.1016/j.tim.2014.06.007] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 06/26/2014] [Accepted: 06/27/2014] [Indexed: 12/13/2022]
Abstract
Typhoid (enteric fever) remains a major cause of morbidity and mortality worldwide, causing over 21 million new infections annually, with the majority of deaths occurring in young children. Because typhoid fever-causing Salmonella have no known environmental reservoir, the chronic, asymptomatic carrier state is thought to be a key feature of continued maintenance of the bacterium within human populations. Despite the importance of this disease to public health, our understanding of the molecular mechanisms that catalyze carriage, as well as our ability to reliably identify and treat the Salmonella carrier state, have only recently begun to advance.
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Affiliation(s)
- John S Gunn
- Department of Microbial Infection and Immunity, Center for Microbial Interface Biology, The Ohio State University, OH, USA.
| | - Joanna M Marshall
- Department of Microbial Infection and Immunity, Center for Microbial Interface Biology, The Ohio State University, OH, USA
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam; Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom; The London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Richelle C Charles
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, USA; Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Edward T Ryan
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, USA; Department of Medicine, Harvard Medical School, Boston, MA, USA; Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
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Dougan G, Baker S. Salmonella entericaSerovar Typhi and the Pathogenesis of Typhoid Fever. Annu Rev Microbiol 2014; 68:317-36. [DOI: 10.1146/annurev-micro-091313-103739] [Citation(s) in RCA: 191] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Gordon Dougan
- The Wellcome Trust Sanger Institute, The Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom;
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Program, Oxford University, Clinical Research Unit, Ho Chi Minh City, Vietnam;
- Centre for Tropical Medicine, Oxford University, Oxford OX3 7FZ, United Kingdom
- The London School of Hygiene and Tropical Medicine, London WC1E 7HT, United Kingdom
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Näsström E, Vu Thieu NT, Dongol S, Karkey A, Voong Vinh P, Ha Thanh T, Johansson A, Arjyal A, Thwaites G, Dolecek C, Basnyat B, Baker S, Antti H. Salmonella Typhi and Salmonella Paratyphi A elaborate distinct systemic metabolite signatures during enteric fever. eLife 2014; 3. [PMID: 24902583 PMCID: PMC4077204 DOI: 10.7554/elife.03100] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 05/26/2014] [Indexed: 12/31/2022] Open
Abstract
The host-pathogen interactions induced by Salmonella Typhi and Salmonella Paratyphi A during enteric fever are poorly understood. This knowledge gap, and the human restricted nature of these bacteria, limit our understanding of the disease and impede the development of new diagnostic approaches. To investigate metabolite signals associated with enteric fever we performed two dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC/TOFMS) on plasma from patients with S. Typhi and S. Paratyphi A infections and asymptomatic controls, identifying 695 individual metabolite peaks. Applying supervised pattern recognition, we found highly significant and reproducible metabolite profiles separating S. Typhi cases, S. Paratyphi A cases, and controls, calculating that a combination of six metabolites could accurately define the etiological agent. For the first time we show that reproducible and serovar specific systemic biomarkers can be detected during enteric fever. Our work defines several biologically plausible metabolites that can be used to detect enteric fever, and unlocks the potential of this method in diagnosing other systemic bacterial infections.
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Affiliation(s)
- Elin Näsström
- Department of Chemistry, Computational Life Science Cluster, Umeå University, Umeå, Sweden
| | - Nga Tran Vu Thieu
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Abhilasha Karkey
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Phat Voong Vinh
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Tuyen Ha Thanh
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Anders Johansson
- Department of Clinical Microbiology, Umeå University, Umeå, Sweden
| | - Amit Arjyal
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Guy Thwaites
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Christiane Dolecek
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Stephen Baker
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Henrik Antti
- Department of Chemistry, Computational Life Science Cluster, Umeå University, Umeå, Sweden
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Sadhu R, Pourzehad Gilani A, Lanteri M, Kumar M. Psychosis in paratyphoid fever - a case report from Australia. Australas Psychiatry 2014; 22:242-244. [PMID: 24820292 DOI: 10.1177/1039856214534000] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Neuropsychiatric presentation in paratyphoid fever is not a well-known entity. In countries such as Australia, where the prevalence of enteric fever is one of the lowest, this presentation seems to be unlikely. METHOD We present a case that demonstrates the importance of considering this possibility in Australian context in returned travellers. RESULTS A young male, who recently returned to Australia from his home country in South East Asia, presented with abnormal behaviour in the context of febrile illness. His behaviour was characterised by grandiosity, aggression, hallucinatory behaviour and paranoia, along with disturbed biological functions. Detailed inpatient assessment revealed him to be suffering from Salmonella Paratyphi A infection and psychotic illness because of his general medical condition. Although his fever and inflammatory markers responded to antibiotics, antipsychotics were required for treatment of his mental health problems. CONCLUSION This case demonstrates that paratyphoid fever, which is considered to be a less common variant of enteric fever, can present with neuropsychiatric manifestations.
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Affiliation(s)
- Raja Sadhu
- Department of Psychiatry, Werribee Mercy Hospital, Werribee, VIC, Australia
| | | | - Marc Lanteri
- Department of Medicine, Werribee Mercy Hospital, Werribee, VIC, Australia
| | - Manoj Kumar
- Department of Psychiatry, Werribee Mercy Hospital, Werribee, VIC, Australia
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Shared sanitation versus individual household latrines: a systematic review of health outcomes. PLoS One 2014; 9:e93300. [PMID: 24743336 PMCID: PMC3990518 DOI: 10.1371/journal.pone.0093300] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 03/04/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND More than 761 million people rely on shared sanitation facilities. These have historically been excluded from international sanitation targets, regardless of the service level, due to concerns about acceptability, hygiene and access. In connection with a proposed change in such policy, we undertook this review to identify and summarize existing evidence that compares health outcomes associated with shared sanitation versus individual household latrines. METHODS AND FINDINGS Shared sanitation included any type of facilities intended for the containment of human faeces and used by more than one household, but excluded public facilities. Health outcomes included diarrhoea, helminth infections, enteric fevers, other faecal-oral diseases, trachoma and adverse maternal or birth outcomes. Studies were included regardless of design, location, language or publication status. Studies were assessed for methodological quality using the STROBE guidelines. Twenty-two studies conducted in 21 countries met the inclusion criteria. Studies show a pattern of increased risk of adverse health outcomes associated with shared sanitation compared to individual household latrines. A meta-analysis of 12 studies reporting on diarrhoea found increased odds of disease associated with reliance on shared sanitation (odds ratio (OR) 1.44, 95% CI: 1.18-1.76). CONCLUSION Evidence to date does not support a change of existing policy of excluding shared sanitation from the definition of improved sanitation used in international monitoring and targets. However, such evidence is limited, does not adequately address likely confounding, and does not identify potentially important distinctions among types of shared facilities. As reliance on shared sanitation is increasing, further research is necessary to determine the circumstances, if any, under which shared sanitation can offer a safe, appropriate and acceptable alternative to individual household latrines.
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