Complications and mortality of typhoid fever: A global systematic review and meta-analysis

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Complications and death are considerable among hospitalized patients with typhoid fever.

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Case fatality ratio of typhoid fever was higher in Africa compared to Asia.

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Among studies in Africa, 20% of patients with typhoid intestinal perforation died.

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Delays in care were correlated with increased typhoid case fatality ratio in Asia.

Objectives

Updated estimates of the prevalence of complications and case fatality ratio (CFR) among typhoid fever patients are needed to understand disease burden.

Methods

Articles published in PubMed and Web of Science from 1 January 1980 through 29 January 2020 were systematically reviewed for hospital or community-based non-surgical studies that used cultures of normally sterile sites, and hospital surgical studies of typhoid intestinal perforation (TIP) with intra- or post-operative findings suggestive of typhoid. Prevalence of 21 pre-selected recognized complications of typhoid fever, crude and median (interquartile range) CFR, and pooled CFR estimates using a random effects meta-analysis were calculated.

Results

Of 113 study sites, 106 (93.8%) were located in Asia and Africa, and 84 (74.3%) were non-surgical. Among non-surgical studies, 70 (83.3%) were hospital-based. Of 10,355 confirmed typhoid patients, 2,719 (26.3%) had complications. The pooled CFR estimate among non-surgical patients was 0.9% for the Asia region and 5.4% for the Africa region. Delay in care was significantly correlated with increased CFR in Asia (r = 0.84; p<0.01). Among surgical studies, the median CFR of TIP was 15.5% (6.7–24.1%) per study.

Conclusions

Our findings identify considerable typhoid-associated illness and death that could be averted with prevention measures, including typhoid conjugate vaccine introduction.

In vitro and in vivo anti-salmonella properties of hydroethanolic extract of Detarium microcarpum Guill. & Perr. (Leguminosae) root bark and LC-MS-based phytochemical analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Typhoid fever treatment remains a challenge in endemic countries. Detarium microcarpum is traditionally used to manage typhoid.

AIM OF THE STUDY

The study aims to explore the efficacy of hydroethanolic extract of Detarium microcarpum root bark in rats infected with salmonella.

MATERIAL AND METHODS

The phytochemical profile of the extract was obtained by UHPLC-MS analysis in an attempt of standardization. The in vitro antimicrobial activity was determined using broth dilution method. Salmonella infection was induced by oral administration of S. thyphimurium to immunosuppressed rats. Infected rats were then treated 2 h later with the extract (75, 150 and 300 mg/kg), distilled water (normal and salmonella control) and ciprofloxacin (8 mg/kg) for control. Body weight was monitored and stools were cultured to determine the number of colony-forming units. At the end of treatment, animals were sacrificed, blood and organs were collected for hematological, biochemical and histopathological analyses.

RESULTS

Detarium microcarpum extract as well as the isolated compound (rhinocerotinoic acid) exhibited good antimicrobial activity in vitro with bacteriostatic effects. The plant extract significantly (p < 0.05) inhibited the bacterial development in infected animals with an effective dose (ED₅₀) of 75 mg/kg. In addition, the extract prevented body weight loss, hematological, biochemical and histopathological damages in treated rats.

CONCLUSION

Detarium microcarpum extract possesses antisalmonella properties justifying its traditional use for the typhoid fever management.

Salmonella Typhi and Paratyphi A infections in Cambodian children, 2012-2016

OBJECTIVES

Enteric fever remains an important diagnostic and treatment challenge in febrile children living in the tropics. In the context of a national Salmonella enterica serovar Paratyphi A outbreak, the objective of this retrospective study was to compare features of S. Typhi and S. Paratyphi A infections in Cambodian children.

METHODS

Clinical and laboratory features were reviewed for 192 blood culture-confirmed children with S. Typhi and S. Paratyphi A infections presenting to a paediatric referral hospital in Siem Reap, 2012-2016.

RESULTS

Children with S. Typhi infections were younger, were more likely to have chills and/or diarrhoea, and were more frequently hospitalized than those with S. Paratyphi A infections. Over three quarters (88.3%) of S. Typhi isolates were multidrug-resistant, compared to none of the S. Paratyphi A.

CONCLUSIONS

In this small study of Cambodian children, S. Typhi infections were more severe than S. Paratyphi A infections. Antibiotic resistance limits treatment options for enteric fever in this population.

Changes in some haematological parameters in typhoid fever patients attending Landmark University Medical Center, Omuaran-Nigeria

Background

Typhoid or enteric fever is caused by Salmonella typhi. It is largely a disease of developing nations due to poor standard of hygiene and unavailability of potable water. The most prominent feature of the infection is fever which gradually rises to a high plateau. The prevalence of typhoid fever has been on the increase which is associated with several hematological parameters.

Objectives

This study was carried out to determine the changes in various hematological parameters in our study subjects.

Method

Four Hundred- (400) samples were obtained from volunteer subjects visiting the outpatient department of the Landmark University Medical Center. 200 typhoid positive samples were collected from subjects while 200 typhoid negative blood samples served as controls (From both male and female subjects each). Widal test was carried out as a confirmatory test for typhoid fever and evaluation of the hematological parameters were performed. The hematological parameters considered includes Packed Cell Volume (PCV), White Blood Cell count (WBC), Platelet count (PLT), Lymphocyte (LYMP) their implications on both male and female typhoid fever patients were also determined.

Results

The result showed a significant reduction in the values for PCV, WBC, ESR and HAE concentration in typhoid positive males in comparison to typhoid negative males. In females, a significant decrease was observed in values for PCV, ESR, HAE concentration and PLT in typhoid positive females when compared to typhoid negative females. These parameters when compared showed a significant decrease recorded in PCV, ESR and HAE concentration of the typhoid positive male patients in comparison to typhoid positive female patients.

Conclusion

This study implies that anemia, bone marrow suppression and hemaphagocytosis are likely resulting factors of typhoid fever due to the changes in the hematological parameters. Therefore, these parameters have to be further studied to allow for efficient management of this illness.

Designing a typhoid environmental surveillance study: A simulation model for optimum sampling site allocation

Environmental surveillance can be used for monitoring enteric disease in a population by detecting pathogens, shed by infected people, in sewage. Detection of pathogens depends on many factors: infection rates and shedding in the population, pathogen fate in the sewerage network, and also sampling sites, sample size, and assay sensitivity. This complexity makes the design of sampling strategies challenging, which creates a need for mathematical modeling to guide decision making.

In the present study, a model was developed to simulate pathogen shedding, pathogen transport and fate in the sewerage network, sewage sampling, and detection of the pathogen. The simulation study used Salmonella enterica serovar Typhi (S. Typhi) as the target pathogen and two wards in Kolkata, India as the study area. Five different sampling strategies were evaluated for their sensitivity of detecting S. Typhi, by sampling unit: sewage pumping station, shared toilet, adjacent multiple shared toilets (primary sampling unit), pumping station + shared toilets, pumping station + primary sampling units. Sampling strategies were studied in eight scenarios with different geographic clustering of risk, pathogen loss (decay, leakage), and sensitivity of detection assays. A novel adaptive sampling site allocation method was designed, that updates the locations of sampling sites based on their performance. We then demonstrated how the simulation model can be used to predict the performance of environmental surveillance and how it is improved by optimizing the allocation of sampling sites.

The results are summarized as a decision tree to guide the sampling strategy based on disease incidence, geographic distribution of risk, pathogen loss, and the sensitivity of the detection assay. The adaptive sampling site allocation method consistently outperformed alternatives with fixed site locations in most scenarios. In some cases, the optimum allocation method increased the median sensitivity from 45% to 90% within 20 updates.

A decision support system for multi-target disease diagnosis: A bioinformatics approach

Malaria and typhoid fever are revered for their ability to individually or jointly cause high mortality rate. Both malaria and typhoid fever have similar symptoms and are famous for their co-existence in the human body, hence, causes problem of under-diagnosis when doctors tries to determine the exact disease out of the two diseases. This paper proposes a Bioinformatics Based Decision Support System (BBDSS) for malaria, typhoid and malaria typhoid diagnosis. The system is a hybrid of expert system and global alignment with constant penalty. The architecture of the proposed system takes input diagnosis sequence and benchmark diagnosis sequences through the browser, store these diagnosis sequences in the Knowledge base and set up the IF-THEN rules guiding the diagnosis decisions for malaria, typhoid and malaria typhoid respectively. The matching engine component of the system receives as input the input sequence and applies global alignment technique with constant penalty for the matching between the input sequence and the three benchmark sequences in turns. The global alignment technique with constant penalty applies its pre-defined process to generate optimal alignment and determine the disease condition of the patient through alignment scores comparison for the three benchmark diagnosis sequences. In order to evaluate the proposed system, ANOVA was used to compare the means of the three independent groups (malaria, typhoid and malaria typhoid) to determine whether there is statistical evidence that the associated values on the diagnosis variables means are significantly different. The ANOVA results indicated that the mean of the values on diagnosis variables is significantly different for at least one of the disease status groups. Similarly, multiple comparisons tests was further used to explicitly identify which means were different from one another. The multiple comparisons results showed that there is a statistically significant difference in the values on the diagnosis variables to diagnose the disease conditions between the groups of malaria and malaria typhoid. Conversely, there were no differences between the groups of malaria and typhoid fever as well as between the groups of typhoid fever and malaria typhoid. In order to show mean difference in the diagnosis scores between the orthodox and the proposed diagnosis system, t-test statistics was used. The results of the t-test statistics indicates that the mean values of diagnosis from the orthodox system differ from those of the proposed system. Finally, the evaluation of the proposed diagnosis system is most efficient at providing diagnosis for malaria and malaria typhoid at 97% accuracy.

The first imported case of extensively drug-resistant Salmonella enterica serotype Typhi infection in Taiwan and the antimicrobial therapy

The first imported case of XDR typhoid fever in Taiwan contracted with a bacterial strain, which was most closely related to the bla_CTX-M-15-carrying strains linked to Pakistan. Meropenem, in combination with an antimicrobial with intracellular activity against Salmonella, should be used for the treatment of XDR typhoid fever.

[Laboratory testing and tracing analysis of a typhoid epidemic in Jiangyin city, Jiangsu Province]

To conduct outbreak identification and transmission factor analysis of typhoid epidemic occurred in Xinqiao town, Jiangyin city from June to September 2016. A total of 14 strains of Salmonella typhi isolated from confirmed cases were collected, and 65 external environment samples and 13 food samples related to the outbreak were taken. Real-time PCR was used to detect specific gene of Salmonella typhi in the samples. Conventional method was used to isolate strains. The strains isolated from both the samples and patients in the epidemic were subjected to antimicrobial susceptibility testing and PFGE molecular characteristics. Salmonella typhi strain was isolated from one external sample (well water of a deli processing plant). The results of drug susceptibility showed that 15 strains were resistant to nalidixic acid. A total of 15 strains of Salmonella typhi were divided into 2 molecular patterns by pulsed field gel electrophoresis. The fingerprints of PFGE from the 13 patients and the environmental isolate were completely consistent, and there was one band difference from the other patient isolate. Combined with the epidemiological investigation and laboratory test results, it was determined that the outbreak was caused by genetic clone of the same Salmonella typhi. Food processing plant should be one of the key links.

[Epidemiology profil of fever typhoid in Meknes (Morocco) 2013-2016]

INTRODUCTION

Twenty million cases of typhoid and paratyphoid fever (TF) are observed annually worldwide with more than 200,000deaths. These fevers occur in areas where hygiene is precarious, mainly in developing countries. The objective of this study was to describe epidemiological patterns of TF in Meknes, Morocco in order to improve preventive measures.

METHODS

We conducted a case series study based on data from 2013 to 2016 in the Meknes TF surveillance system. Data collected included socio-demographic variables, place of residence, season, mode of water supply, and food consumed. Diagnosis of TF was confirmed with the Widal test. Data were analyzed with Epi-info version 7 and mapping was done with Qgis version 2.18.1.

RESULTS

Three hundred and twenty-two cases were reported with a male/female sex ratio of 0.9. Average age was 26±20years. Incidence increased from 13 per 100.000inhabitants in 2013 to 8 per 100.000 inhabitants in 2016. Two hundred and seventy-nine (87%) cases occurred in urban areas and 174 (54%) cases developed in summer. One death was recorded.

CONCLUSION

Public awareness campaigns on health education for hygiene are needed. Focus should be placed on transmission by food handlers.

Drug-resistant enteric fever worldwide, 1990 to 2018: a systematic review and meta-analysis

BACKGROUND

Antimicrobial resistance (AMR) is an increasing threat to global health. There are > 14 million cases of enteric fever every year and > 135,000 deaths. The disease is primarily controlled by antimicrobial treatment, but this is becoming increasingly difficult due to AMR. Our objectives were to assess the prevalence and geographic distribution of AMR in Salmonella enterica serovars Typhi and Paratyphi A infections globally, to evaluate the extent of the problem, and to facilitate the creation of geospatial maps of AMR prevalence to help targeted public health intervention.

METHODS

We performed a systematic review of the literature by searching seven databases for studies published between 1990 and 2018. We recategorised isolates to allow the analysis of fluoroquinolone resistance trends over the study period. The prevalence of multidrug resistance (MDR) and fluoroquinolone non-susceptibility (FQNS) in individual studies was illustrated by forest plots, and a random effects meta-analysis was performed, stratified by Global Burden of Disease (GBD) region and 5-year time period. Heterogeneity was assessed using the I2 statistics. We present a descriptive analysis of ceftriaxone and azithromycin resistance.

FINDINGS

We identified 4557 articles, of which 384, comprising 124,347 isolates (94,616 S. Typhi and 29,731 S. Paratyphi A) met the pre-specified inclusion criteria. The majority (276/384; 72%) of studies were from South Asia; 40 (10%) articles were identified from Sub-Saharan Africa. With the exception of MDR S. Typhi in South Asia, which declined between 1990 and 2018, and MDR S. Paratyphi A, which remained at low levels, resistance trends worsened for all antimicrobials in all regions. We identified several data gaps in Africa and the Middle East. Incomplete reporting of antimicrobial susceptibility testing (AST) and lack of quality assurance were identified.

INTERPRETATION

Drug-resistant enteric fever is widespread in low- and middle-income countries, and the situation is worsening. It is essential that public health and clinical measures, which include improvements in water quality and sanitation, the deployment of S. Typhi vaccination, and an informed choice of treatment are implemented. However, there is no licenced vaccine for S. Paratyphi A. The standardised reporting of AST data and rollout of external quality control assessment are urgently needed to facilitate evidence-based policy and practice.

TRIAL REGISTRATION

PROSPERO CRD42018029432.

Chain effects of clean water: The Mills-Reincke phenomenon in early 20th-century Japan

This study explores the validity of chain effects of clean water, which are known as the "Mills-Reincke phenomenon," in early 20-century Japan. Recent studies have reported that water purifications systems are responsible for huge contributions to human capital. Although some studies have investigated the instantaneous effects of water-supply systems in pre-war Japan, little is known about the chain effects of these systems. By analyzing city-level cause-specific mortality data from 1922 to 1940, we find that a decline in typhoid deaths by one per 1000 people decreased the risk of death due to non-waterborne diseases such as tuberculosis and pneumonia by 0.742-2.942 per 1000 people. Our finding suggests that the observed Mills-Reincke phenomenon could have resulted in the relatively rapid decline in the mortality rate in early 20-century Japan.

Immunogenicity, safety and reactogenicity of a Phase II trial of Vi-DT typhoid conjugate vaccine in healthy Filipino infants and toddlers: A preliminary report

BACKGROUND

Typhoid fever remains an important public health problem in developing countries and is endemic in many parts of Asia and Africa where the incidence of disease typically peaks in school-aged children. Age restrictions and other limitations of existing oral live-attenuated typhoid and parenteral Vi polysaccharide vaccines have triggered the development of Vi conjugate vaccines with improved immunological properties, use in younger age range, and longer durability of protection. We present the safety, reactogenicity, and immunogenicity data from a Phase II study after a single dose of Vi polysaccharide conjugated to diphtheria toxoid (Vi-DT) conducted in 6-23-month old Filipino children.

METHODS

This is a randomized, observer-blinded Phase II study to assess the immunogenicity, safety and reactogenicity of Vi-DT compared to placebo, conducted in Muntinlupa City, The Philippines. Participants aged 6-23 months were enrolled and randomized to Vi-DT (25 µg) or placebo (0.9% sodium chloride) and evaluated for immunogenicity and overall safety 28 days post vaccination.

RESULTS

A total of 285 participants were enrolled and age-stratified: 6 to < 9 months, 9-12 months, and 13-23 months. Seventy-six (76) participants received Vi-DT and 19 received placebo per each strata. All participants seroconverted after a single dose of Vi-DT versus 7% of placebo recipients. Anti-Vi IgG GMT was 444.38 [95% CI (400.28; 493.34)] after a single dose of Vi-DT; there was no change in GMT after placebo administration, 0.41 [95% CI (0.33; 0.51), p < 0.0001]. A similar pattern of immunogenicity was reported across all age strata. The vaccine reported to be safe and well tolerated.

CONCLUSIONS

Vi-DT vaccine was immunogenic, safe, and well tolerated in children aged 6-23 months. ClinicalTrials.gov registration number: NCT03527355.

Antioxidant activity of dichloromethane fraction of Dichrocephala integrifolia in Salmonella typhi-infected rats

OBJECTIVE

Infectious diseases such as typhoid fever lead to the formation of free radicals which can damage the body. Many medicinal plants have antioxidant molecules that neutralize free radicals. The present work evaluated the antioxidant activity and histopathological effects of the dichloromethane fraction of Dichrocephala integrifolia in Salmonella typhi-infected rats.

METHODS

The S. typhi-infected rats concurrently received daily doses of D. integrifolia extract at doses of 25, 50 and 100 mg/kg body weight or ciprofloxacin (5 mg/kg body weight) for 15 days. Body temperature was measured daily during infection and treatment periods. At the end of treatment period, the animals were sacrificed and biological responses including hematological parameters, superoxide dismutase and catalase activities, and glutathione, malondialdehyde and nitric oxide concentrations were evaluated.

RESULTS

The elevated body temperature induced by infection was significantly decreased in animals treated with 25, 50 or 100 mg/kg of the extract. Platelet levels decreased slightly in infected rats, while treatment with the dichloromethane fraction of D. integrifolia significantly increased platelet levels; this response was greater than that elicited by ciprofloxacin. The doses of 50 and 100 mg/kg of the dichloromethane fraction of D. integrifolia notably decreased monocyte and neutrophil values. Activity of superoxide dismutase and catalase and levels of glutathione in the tissues of treated animals were increased significantly (P < 0.01), while malondialdehyde and nitric oxide levels were significantly decreased (P < 0.01), following treatment with the dichloromethane fraction of D. integrifolia.

CONCLUSION

The results of this study show that the dichloromethane fraction of D. integrifolia has protective effects against a series of pathological conditions initiated by oxidation and tissue damage in the course of a S. typhi infection.

Ovarian abscess caused by Salmonella enterica serovar Typhi: a case report

Background

Typhoid fever is a human-specific disease caused by a bacterium, Salmonella enterica subspecies enterica serovar Typhi. It is transmitted through ingestion of contaminated food or water. It is mostly diagnosed by blood culture. Salmonella Typhi usually manifests as a febrile illness with bacteremia after initial entry through the gastrointestinal route, but it can occasionally cause significant disease in extraintestinal sites. We report a case of a girl in Fiji with a right ovarian abscess infected by Salmonella Typhi.

Case presentation

A 14-year-old iTaukei (indigenous Fijian) girl presented to our hospital with abdominal pain of 1 month’s duration. Two days prior to her admission, she developed high-grade fever and nausea and had one episode of vomiting. On presentation, she appeared unwell; she was tachycardic (116 beats per minute) and febrile (38.8 °C). Her abdominal examination revealed generalized tenderness. Other examination findings were normal. The provisional diagnosis of abdominal sepsis led to an emergency laparotomy during which an enlarged right ovary was found to be spontaneously discharging pus. The ovary was incised and drained, and the patient was commenced on intravenous ceftriaxone 1 g twice daily, cloxacillin 1 g four times daily, and metronidazole 500 mg three times daily. She recovered promptly and was discharged to home on the sixth postoperative day. The purulent material from the ovary grew Salmonella Typhi.

Conclusion

Extraintestinal infections caused by Salmonella Typhi are rare but can cause severe and life-threatening disease. Our patient had a prolonged history of abdominal pain and was found to have a ruptured right ovarian abscess due to Salmonella Typhi. Ovarian abscesses in girls who are not sexually active are not associated with pelvic inflammatory disease and suggest local or hematogenous spread. This case report may increase health workers awareness to include common and endemic infections in the differential diagnosis of unusual clinical presentations to help the initiation of appropriate investigation and management as quickly as possible.

Population structure and transmission modes of indigenous typhoid in Taiwan

BACKGROUND

Indigenous typhoid fever was continuing to be identified in Taiwan which has not been endemic for the enteric fever for more than 20 years. The source and transmission by which the local patients acquired typhoid and the population structure of the indigenous typhoid strains remain not well characterized.

METHODS

During 2001 and 2014, non-duplicated clinical Salmonella enterica serovar Typhi isolates in a hospital were analyzed by whole-genome sequencing (WGS) and determined for pulsotypes. Maximum likelihood phylogeny was constructed by nucleotide alterations in core genomes and compared to the framework of global typhoid strains. Potential source and transmission were traced by correlating the phylogeny and the temporal relationship between isolates.

RESULTS

A total of 43 S. Typhi isolates from indigenous cases were analyzed and a majority (39, 90.7%) of them were belonged to six WGS-defined genotypes prevailing mainly in Southeast Asia. Genotype 3.4.0 and a multidrug-resistant type 4.3.1 (also known as pandemic H58 haplotype) were associated respectively with two solitary small-scale outbreaks, implying a transmission mode of importation followed by outbreak. Twelve isolates with nearly identical core genomes were belonged to genotype 3.2.1 but were categorized into three different pulsotypes. The 3.2.1 isolates were identified across 13 years and involved in three clusters and a sporadic case, indicating sustained local transmission of the same strain. The remaining indigenous isolates belonging to three genotypes (2.1, 3.1.2, and 3.0.0) were of substantial genetic diversity and isolated at different time points, indicating independent event of each case.

CONCLUSIONS

Indigenous typhoid in Taiwan occurred mainly with the forms of small-scale outbreaks or sporadic events likely by contracting imported strains which prevailed in Southeast Asia. Sustained local transmission of certain strain was also evident by WGS analysis, but not by conventional pulsotyping, highlighting the importance of continuing molecular surveillance of typhoid fever with adequate tools in the non-endemic region.

Analysis of isolates from Bangladesh highlights multiple ways to carry resistance genes in Salmonella Typhi

Background

Typhoid fever, caused by Salmonella Typhi, follows a fecal-oral transmission route and is a major global public health concern, especially in developing countries like Bangladesh. Increasing emergence of antimicrobial resistance (AMR) is a serious issue; the list of treatments for typhoid fever is ever-decreasing. In addition to IncHI1-type plasmids, Salmonella genomic island (SGI) 11 has been reported to carry AMR genes. Although reports suggest a recent reduction in multidrug resistance (MDR) in the Indian subcontinent, the corresponding genomic changes in the background are unknown.

Results

Here, we assembled and annotated complete closed chromosomes and plasmids for 73 S. Typhi isolates using short-length Illumina reads. S. Typhi had an open pan-genome, and the core genome was smaller than previously reported. Considering AMR genes, we identified five variants of SGI11, including the previously reported reference sequence. Five plasmids were identified, including the new plasmids pK91 and pK43; pK43and pHCM2 were not related to AMR. The pHCM1, pPRJEB21992 and pK91 plasmids carried AMR genes and, along with the SGI11 variants, were responsible for resistance phenotypes. pK91 also contained qnr genes, conferred high ciprofloxacin resistance and was related to the H58-sublineage Bdq, which shows the same phenotype. The presence of plasmids (pHCM1 and pK91) and SGI11 were linked to two H58-lineages, Ia and Bd. Loss of plasmids and integration of resistance genes in genomic islands could contribute to the fitness advantage of lineage Ia isolates.

Conclusions

Such events may explain why lineage Ia is globally widespread, while the Bd lineage is locally restricted. Further studies are required to understand how these S. Typhi AMR elements spread and generate new variants. Preventive measures such as vaccination programs should also be considered in endemic countries; such initiatives could potentially reduce the spread of AMR.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5916-6) contains supplementary material, which is available to authorized users.

Serodiagnostic evaluation of recombinant CdtB of S. Typhi as a potential candidate for acute typhoid

Typhoid fever caused by human restricted Salmonella typhi presents a considerable health burden on developing South-Asian nations like India. The suboptimal sensitivity and specificity associated with culture-based isolation of etiological agent and the extensively used surface antigen-based serological assays often lead to misdiagnosis and inappropriate antimicrobial treatment. The increasing reports of the emergence of resistant strains and undefined disease burden signify the critical need for an inexpensive, reliable, easy-to-use, and highly sensitive diagnostic test for typhoid fever. Utilizing S. typhi-specific and immunogenic antigens in sero-diagnostic assays could lead to precise diagnosis of acute typhoid and prompt treatment. In this study, we report cloning, expression, and purification of recombinant Cytolethal distending toxin subunit B (CdtB) of S. typhi, which is reported to be highly specific, immunogenic, and expressed only upon S. typhi infection. We further evaluated the purified recombinant CdtB for its diagnostic potential in an IgM-based indirect ELISA format using 33 human samples. Twenty-one serum samples from blood culture confirmed cases (n = 21) of typhoid and 12 samples from healthy controls (n = 12) were tested. The assay showed sensitivity of 100% and specificity of 83.3% respectively with positive and negative predictive values of 91.3 and 100% respectively. Efficient detection of specific IgM antibodies indicates that CdtB could be highly valuable in sero-diagnosis of acute typhoid and rapid screening of clinical samples.

In vitro characterization and preclinical immunogenicity of Typhax, a typhoid fever protein capsular matrix vaccine candidate

Typhax is an investigational typhoid fever vaccine candidate that was GMP manufactured applying Protein Capsular Matrix Vaccine (PCMV) technology. It consists of Vi polysaccharide antigen, derived from S. Typhi, non-covalently entrapped in a glutaraldehyde catalyzed cross-linked α-poly-L-lysine and CRM197 protein matrix. Analysis of Typhax determined the average molecular weight of the vaccine particles was approximately 6 x 10⁶ Daltons, corresponding to particles containing 1-2 molecules of Vi polysaccharide and 10-20 molecules of CRM197 protein. The ratio of the concentration of Vi to CRM197 protein in Typhax is 2.4:1. Preclinical immunogenicity studies in mice demonstrated that Typhax was immunogenic and elicited a significant increase in anti-Vi IgG antibody titers following each immunization. The anti-Vi IgG antibody response elicited by Typhax in rabbits increased as the dose increased from 0.1 µg to 2.5 µg. Further, at the 2.5 and 10 µg dose levels, the anti-Vi IgG antibody titers increased after the second and third immunizations. At the 10 µg dose level, 100% of rabbits seroconverted. In the non-human primate (NHP) study, 100% seroconversion was observed at both 2.5 µg and 10 µg dose levels after the first immunization. A murine in vivo immunopotency study demonstrated that Typhax stored at 4°C was stable for at least 30 months. Collectively, the Typhax in vitro profile, preclinical immunogenicity studies, and rabbit toxicology study indicate that Typhax is a viable typhoid fever vaccine candidate for Phase 1 clinical trial evaluation.

Loop-mediated isothermal amplification-based detection of typhoid fever on an automated Genie II Mk2 system - A case-control-based approach

Typhoid fever, caused by the bacterium Salmonella enterica subsp. enterica serovar Typhi, is an important cause of blood stream infections in the tropics, for which easy-to-apply molecular diagnostic approaches are desirable. The diagnostic performance of a newly introduced and a previously described loop-mediated isothermal amplification (LAMP) approach using different primer sets on a Genie II Mk2 device for the identification of Salmonella enterica ssp. enterica ser. Typhi was evaluated with well-characterized residual materials from the tropics in a case control-based approach. After in-vitro confirmation of binding characteristics of both LAMP primer sets with culture isolates (n = 112), sensitivity and specificity were 100% for the newly designed new LAMP primer set 1 with incubated blood culture materials, while specificity was reduced to 97.1% for primer set 2. For 170 EDTA blood samples, sensitivity and specificity were 10% and 98.3% for primer set 1 as well as 38.0% and 83.3% for primer set 2, respectively; qPCR from EDTA blood did not score much better with 10% sensitivity and 100% specificity. LAMP using a Genie II Mk2 device is suitable for the identification of Salmonella enterica spp. enterica ser. Typhi from incubated blood culture materials. Sensitivity and specificity were insufficient for diagnosis directly from EDTA blood samples but LAMP showed similar sensitivity as qPCR.

Raman spectroscopy based differentiation of typhoid and dengue fever in infected human sera

This study investigated the potential of Raman spectroscopy, to differentiate between two different types of human pathological conditions with some symptom similarity; typhoid and dengue. Raman spectra were recorded from 20 Salmonella Typhi infected and 22 dengue virus (DENV) infected sera samples using laser wavelength 785 nm. When Raman spectrum (540 to 1830 cm^-1) of serum samples was compared it showed significant variations. Twelve characteristic Raman bands at 562, 649, 716, 780, 838, 1099, 1144, 1156, 1260, 1386, 1556 and 1746 cm^-1 were recorded specifically in case of the typhoid infected samples, whereas four Raman bands at 756, 1218, 1672 and 1686 cm^-1 were found specifically in the DENV infected samples. For statistical differentiation principal component analysis (PCA) and linear discriminant analysis (LDA) was applied which successfully separated two sets of data. These disease specific Raman signatures may be labeled as biomarkers for identification as well as differential diagnosis of typhoid and dengue infection. Hence we propose that Raman spectroscopy has the potential to not only identify but also to differentiate between different pathological conditions, having some similar symptoms like high grade fever in this case.

Typhoid fever in the Czech Republic and an imported case after return from the Rainbow Gathering in Italy

Typhoid fever is a disease caused by the highly virulent bacterium Salmonella Typhi. It is transmitted by the oral-faecal route. In the Czech Republic, 53 cases of typhoid fever were reported in 1997-2017. Only seven of these cases were autochthonous. In August 2017, an imported case of typhoid fever was recorded in a 25-year-old unvaccinated woman who participated in the Rainbow Gathering in Italy one week prior to the onset of the disease. During her stay in Italy, she slept in a tent, ate her own food, and drank unboiled water. Presenting with persisting cough, tiredness, muscle and joint pain, and fever up to 40 °C after her return, she was admitted to the T&#345;ebí&#269; Hospital where she was diagnosed with S. Typhi. The epidemiological investigation identified six contacts. On discharge from hospital and at follow-up, the patient was tested negative. None of the contacts became ill.

Jejunal multiple perforations for combined abdominal typhoid fever and miliary peritoneal tuberculosis

Typhoid fever and tuberculosis, considered rare diseases in western countries, is still considered a notable problem of health issue in developing countries. The gastrointestinal manifestations of typhoid fever are the most common and the typhoid intestinal perforation (TIP) is considered the most dangerous complication. Abdominal localization of tuberculosis is the 6^th most frequent site for extra pulmonary involvement, it can involve any part of the digestive system, including peritoneum, causing miliary peritoneal tuberculosis (MPT). This is the case report of a 4 years old girl with multiple jejunal perforations in a setting of contemporary miliary peritoneal tuberculosis and typhoid fever occurred in "Hopital Saint Jean de Dieu" in Tanguietà, north of Benin. The patient was admitted in the emergency department with an acute abdomen and suspect of intestinal perforation, in very bad clinical conditions, underwent emergency laparotomy. The finding was a multiple perforations of the jejunum in a setting of combined abdominal typhoid fever and miliary peritoneal tuberculosis. Typhoid intestinal perforations and peritoneal tuberculosis are a very rare cause of non-traumatic peritonitis in western country, but still common in developing country. Considering the modern migratory flux and the diffusion of volunteer missions all around the world, the western surgeon should know this pathological entities, and the best treatments available, well known by surgeons with experience of working in developing countries. The combination of both TIP and MPT in the same patient, is a very rare finding which can worsen the outcome of the patient itself.

[CME: Typhoid Fever - Clinical Manifestation, Diagnosis, Therapy and Prevention]

CME: Typhoid Fever - Clinical Manifestation, Diagnosis, Therapy and Prevention Abstract. Thypoid fever is rare in Western countries. It is, however, among the most common etiologies for febrile illness in the traveller returning from tropical areas (especially South(east) Asia and Sub-Saharan Africa). There are several signs that have been described as classical findings in typhoid fever: i) febrile temperatures with relative bradycardia, ii) eosinopenia, iii) slow defervescence, and iv) systemic manifestations (e.g. hepatitis). Diagnosis is confirmed by positive blood cultures. Pretravel vaccination and safe food and water practices can prevent typhoid fever.

Management of Typhoid Fever - Clinical and Historical Perspectives in Korea

Typhoid fever, showed a dramatic decrease in its incidence from 56 per 100,000 population just after Korea's independence to <1 per 100,000 population in 2000s. The clinical features of patients with typhoid fever in Korea were not too different from those reported in textbooks. Beyond cultures and Widal test, other diagnostic techniques such as string capsule culture and polymerase chain reaction have been tried in Korea. As chloramphenicol is not used anymore in Korea, ampicillin, cotrimoxazole, fluoroquinolones, and third-generation cephalosporins have been administered for therapy of typhoid fever. Especially, ciprofloxacin and ceftriaxone were successfully tried with shorter duration of treatment (1 week). However, cases of treatment failure and resistance in ciprofloxacin were reported in Korea, which requires a great caution. As preventive vaccines, parenteral Vi polysaccharide vaccine and oral live attenuated vaccine are mainly used in Korea. The decline in the number of chronic carriers of typhoid fever in Korea by the roles of doctors and patient management from the health care authorities such as Korea Centers for Diseases Control and Prevention, prescription of effective antimicrobial agents, and increased piped water supply ratio are considered to be the major contributing factors to the reduction in the outbreak of typhoid fever in Korea.

Salmonella enterica serovar Typhi osteomyelitis in a young adult with sickle cell and thalassemia traits: A possible association

Salmonella osteomyelitis is known to occur in immunocompromised and sickle cell disease patients. It rarely occurs in other hosts. We present a case of chronic femoral osteomyelitis due to S. enterica serovar Typhi seen in a Maryland resident. Potential risk factors included traveling to an endemic area as well as a newly diagnosed sickle cell trait and thalassemia trait. It is postulated that less severe hemoglobinopathies may also contribute to an elevated risk of Salmonella osteomyelitis.