1
|
Bharti S, Sharma P. The Aftermath of Widal Positivity on the Diagnosis of Tuberculosis and Fluoroquinolone Resistance in India. EMJ MICROBIOLOGY & INFECTIOUS DISEASES 2023. [DOI: 10.33590/emjmicrobiolinfectdis/10306500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Affiliation(s)
| | - Priya Sharma
- Department of Pulmonary Medicine, All India Institute of Medical Sciences (AIIMS) Patna, India
| |
Collapse
|
2
|
Comparative Analysis of Commercially Available Typhoid Point-of-Care Tests: Results of a Prospective and Hybrid Retrospective Multicenter Diagnostic Accuracy Study in Kenya and Pakistan. J Clin Microbiol 2022; 60:e0100022. [PMID: 36448816 PMCID: PMC9769786 DOI: 10.1128/jcm.01000-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Blood and bone marrow cultures are considered the gold standard for the diagnosis of typhoid, but these methods require infrastructure and skilled staff that are not always available in low- and middle-income countries where typhoid is endemic. The objective of the study is to evaluate the sensitivity and specificity of nine commercially available Salmonella Typhi rapid diagnostic tests (RDTs) using blood culture as a reference standard in a multicenter study. This was a prospective and retrospective multicenter diagnostic accuracy study conducted in two geographically distant areas where typhoid is endemic (Pakistan and Kenya; NCT04801602). Nine RDTs were evaluated, including the Widal test. Point estimates for sensitivity and specificity were calculated using the Wilson method. Latent class analyses were performed using R to address the imperfect gold standard. A total of 531 serum samples were evaluated (264 blood culture positive; 267 blood culture negative). The sensitivity of RDTs varied widely (range, 0 to 78.8%), with the best overall performance shown by Enterocheck WB (72.7% sensitivity, 86.5% specificity). In latent class modeling, CTK IgG was found to have the highest sensitivity (79.1%), while the highest overall accuracy was observed with Enterocheck (73.8% sensitivity, 94.5% specificity). All commercially available Salmonella Typhi RDTs evaluated in the study had sensitivity and specificity values that fell below the required levels to be recommended for an accurate diagnosis. There were minimal differences in RDT performances between regions of endemicity. These findings highlight the clear need for new and more-accurate Salmonella Typhi tests.
Collapse
|
3
|
Wang H, Zhao J, Xie N, Wang W, Qi R, Hao X, Liu Y, Sevalie S, Niu G, Zhang Y, Wu G, Lv X, Chen Y, Ye Y, Bi S, Moseray M, Cellessy S, Kalon K, Baika DI, Luo Q. A Prospective Study of Etiological Agents Among Febrile Patients in Sierra Leone. Infect Dis Ther 2021; 10:1645-1664. [PMID: 34173960 PMCID: PMC8234757 DOI: 10.1007/s40121-021-00474-y] [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: 04/09/2021] [Accepted: 05/27/2021] [Indexed: 11/30/2022] Open
Abstract
Introduction Sierra Leone has one of the highest burdens of febrile illnesses in the world. As the incidence of malaria diminishes, a better understanding of the spectrum of etiological agents was important for accurate diagnosis and empirical treatment of febrile illness. Methods Blood, nasopharyngeal, and fecal specimens were collected from febrile patients for serological, molecular detection, and microbiologic culture to identify potential pathogens. Results For this prospective study, 142 febrile patients were enrolled. The prevalence of malaria was higher in children aged 5–15 years old (P = 0.185) and adults (P = 0.018). Acute respiratory infection (ARI) presented more commonly in the under 5 years old group (P = 0.009). For diarrhea, all children groups (P = 0.024) were predominant. A total of 22.5% of the febrile patients had malaria infection, 19.7% had typhoid infection, and 2.8% were coinfected with malaria and typhoid. ARI was the most common causes of fever, accounting for 31.7% of patients, influenza A virus, Mycoplasma pneumoniae, and five other respiratory pathogens were found. Diarrhea accounted for 16.2%, and seven kinds of diarrhea bacteria were isolated. Hepatitis B accounted for 8.5%, including five cases of spontaneous bacterial peritonitis, and ascites smear staining were both Gram-negative bacteria. Tuberculous encephalitis, parasitic diseases (ascaris and filariasis), and skin infection caused by Staphylococcus aureus accounted for 0.7%, 2.1%, and 0.7%, respectively. Conclusions Evidence of a wide spectrum of febrile etiological agents other than malaria was identified. The spread of malaria rapid diagnostic tests (RDTs) out of hospital and establishment of a national standard for Widal test will reduce the misdiagnosis of febrile diseases. Antibiotics against Gram-negative bacteria are helpful for empirical treatment. Supplementary Information The online version contains supplementary material available at 10.1007/s40121-021-00474-y. Sierra Leone has one of the highest burdens of febrile illnesses in the world. Evidence of a wide spectrum of febrile pathogens other than malaria has been proven in this study. We considered that the etiology of febrile patients was closely related to local geography, heredity, immune features, economic industry, living habits, air pollution, medical and health conditions, and this was fully analyzed and discussed. The screening process used in this study can further simplify and identify the etiological agents of fever in more than 70% of the study population. This laid the foundation for the establishment of a more simplified and efficient diagnosis and treatment process in the local area. We also found the characteristics of age distribution of different febrile diseases. Children were an important susceptible population to fever. This study indicated the importance of reliable diagnostic tests for febrile pathogens and provided the necessary information for RDT requirements. The spread of malaria RDTs out of hospital and establishment of a national standard for Widal test will reduce the misdiagnosis of febrile diseases. For empirical treatment, antimalarial treatment was still targeted at falciparum malaria in Sierra Leone. Antibiotics against Gram-negative bacteria contributed to the empirical treatment of febrile diseases. For patients with acute respiratory tract infection, Gram-positive coccal antibiotics could be candidates for treatment. In addition, systematic and professional treatment of liver diseases should be promoted to reduce infection complications.
Collapse
Affiliation(s)
- Han Wang
- Department of Transfusion Medicine, The Fifth Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, People's Republic of China.
| | - Jing Zhao
- Department of Clinical Diagnostic Centre, The Fifth Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, The People's Republic of China
| | - Na Xie
- Department of Inpatient and Medical Record Management, The Fifth Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, People's Republic of China
| | - Wanxue Wang
- Nursing Department, The Fifth Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, People's Republic of China
| | - Ruping Qi
- Department of Radiology, The Fifth Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, The People's Republic of China
| | - Xiaogang Hao
- Department of Inpatient and Medical Record Management, The Fifth Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, People's Republic of China
| | - Yan Liu
- Department of Clinical Diagnostic Centre, North Hospital District, The Third Hospital of Peking University, Beijing, The People's Republic of China
| | - Stephen Sevalie
- Headquarters, 34 Military Hospital of Republic of Sierra Leone Armed Forces, Freetown, Sierra Leone
| | - Guotao Niu
- Department of Transfusion Medicine, The Fifth Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, People's Republic of China
| | - Yangli Zhang
- Department of Transfusion Medicine, The Fifth Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, People's Republic of China
| | - Ge Wu
- Department of Transfusion Medicine, The Fifth Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, People's Republic of China
| | - Xiaona Lv
- Department of Transfusion Medicine, The Fifth Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, People's Republic of China
| | - Yuhao Chen
- Department of Transfusion Medicine, The Fifth Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, People's Republic of China
| | - Yanfei Ye
- Department of Transfusion Medicine, The Fifth Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, People's Republic of China
| | - Sheng Bi
- Department of Transfusion Medicine, The Fifth Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, People's Republic of China
| | - Moses Moseray
- Department of Clinical Diagnostic Centre, 34 Military Hospital of Republic of Sierra Leone Armed Forces, Freetown, Sierra Leone
| | - Saidu Cellessy
- Department of Clinical Diagnostic Centre, 34 Military Hospital of Republic of Sierra Leone Armed Forces, Freetown, Sierra Leone
| | - Ksaidu Kalon
- Department of Clinical Diagnostic Centre, 34 Military Hospital of Republic of Sierra Leone Armed Forces, Freetown, Sierra Leone
| | - Dawud Ibrahim Baika
- Department of Clinical Diagnostic Centre, 34 Military Hospital of Republic of Sierra Leone Armed Forces, Freetown, Sierra Leone
| | - Qun Luo
- Department of Transfusion Medicine, The Fifth Medical Centre, Chinese PLA (People's Liberation Army) General Hospital, Beijing, People's Republic of China.
| |
Collapse
|
4
|
Abstract
BACKGROUND Differentiating both typhoid (Salmonella Typhi) and paratyphoid (Salmonella Paratyphi A) infection from other causes of fever in endemic areas is a diagnostic challenge. Although commercial point-of-care rapid diagnostic tests (RDTs) for enteric fever are available as alternatives to the current reference standard test of blood or bone marrow culture, or to the widely used Widal Test, their diagnostic accuracy is unclear. If accurate, they could potentially replace blood culture as the World Health Organization (WHO)-recommended main diagnostic test for enteric fever. OBJECTIVES To assess the diagnostic accuracy of commercially available rapid diagnostic tests (RDTs) and prototypes for detecting Salmonella Typhi or Paratyphi A infection in symptomatic persons living in endemic areas. SEARCH METHODS We searched the Cochrane Infectious Diseases Group Specialized Register, MEDLINE, Embase, Science Citation Index, IndMED, African Index Medicus, LILACS, ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) up to 4 March 2016. We manually searched WHO reports, and papers from international conferences on Salmonella infections. We also contacted test manufacturers to identify studies. SELECTION CRITERIA We included diagnostic accuracy studies of enteric fever RDTs in patients with fever or with symptoms suggestive of enteric fever living in endemic areas. We classified the reference standard used as either Grade 1 (result from a blood culture and a bone marrow culture) or Grade 2 (result from blood culture and blood polymerase chain reaction, or from blood culture alone). DATA COLLECTION AND ANALYSIS Two review authors independently extracted the test result data. We used a modified QUADAS-2 extraction form to assess methodological quality. We performed a meta-analysis when there were sufficient studies for the test and heterogeneity was reasonable. MAIN RESULTS Thirty-seven studies met the inclusion criteria and included a total of 5080 participants (range 50 to 1732). Enteric fever prevalence rates in the study populations ranged from 1% to 75% (median prevalence 24%, interquartile range (IQR) 11% to 46%). The included studies evaluated 16 different RDTs, and 16 studies compared two or more different RDTs. Only three studies used the Grade 1 reference standard, and only 11 studies recruited unselected febrile patients. Most included studies were from Asia, with five studies from sub-Saharan Africa. All of the RDTs were designed to detect S.Typhi infection only.Most studies evaluated three RDTs and their variants: TUBEX in 14 studies; Typhidot (Typhidot, Typhidot-M, and TyphiRapid-Tr02) in 22 studies; and the Test-It Typhoid immunochromatographic lateral flow assay, and its earlier prototypes (dipstick, latex agglutination) developed by the Royal Tropical Institute, Amsterdam (KIT) in nine studies. Meta-analyses showed an average sensitivity of 78% (95% confidence interval (CI) 71% to 85%) and specificity of 87% (95% CI 82% to 91%) for TUBEX; and an average sensitivity of 69% (95% CI 59% to 78%) and specificity of 90% (95% CI 78% to 93%) for all Test-It Typhoid and prototype tests (KIT). Across all forms of the Typhidot test, the average sensitivity was 84% (95% CI 73% to 91%) and specificity was 79% (95% CI 70% to 87%). When we based the analysis on the 13 studies of the Typhidot test that either reported indeterminate test results or where the test format means there are no indeterminate results, the average sensitivity was 78% (95% CI 65% to 87%) and specificity was 77% (95% CI 66% to 86%). We did not identify any difference in either sensitivity or specificity between TUBEX, Typhidot, and Test-it Typhoid tests when based on comparison to the 13 Typhidot studies where indeterminate results are either reported or not applicable. If TUBEX and Test-it Typhoid are compared to all Typhidot studies, the sensitivity of Typhidot was higher than Test-it Typhoid (15% (95% CI 2% to 28%), but other comparisons did not show a difference at the 95% level of CIs.In a hypothetical cohort of 1000 patients presenting with fever where 30% (300 patients) have enteric fever, on average Typhidot tests reporting indeterminate results or where tests do not produce indeterminate results will miss the diagnosis in 66 patients with enteric fever, TUBEX will miss 66, and Test-It Typhoid and prototype (KIT) tests will miss 93. In the 700 people without enteric fever, the number of people incorrectly diagnosed with enteric fever would be 161 with Typhidot tests, 91 with TUBEX, and 70 with Test-It Typhoid and prototype (KIT) tests. The CIs around these estimates were wide, with no difference in false positive results shown between tests.The quality of the data for each study was evaluated using a standardized checklist called QUADAS-2. Overall, the certainty of the evidence in the studies that evaluated enteric fever RDTs was low. AUTHORS' CONCLUSIONS In 37 studies that evaluated the diagnostic accuracy of RDTs for enteric fever, few studies were at a low risk of bias. The three main RDT tests and variants had moderate diagnostic accuracy. There was no evidence of a difference between the average sensitivity and specificity of the three main RDT tests. More robust evaluations of alternative RDTs for enteric fever are needed.
Collapse
Affiliation(s)
- Lalith Wijedoru
- Liverpool School of Tropical MedicineDepartment of Clinical SciencesLiverpoolUKL3 5QA
| | - Sue Mallett
- University of BirminghamInstitute of Applied Health SciencesEdgbastonBirminghamUKB15 2TT
| | - Christopher M Parry
- Liverpool School of Tropical MedicineDepartment of Clinical SciencesLiverpoolUKL3 5QA
| | | |
Collapse
|
5
|
Storey HL, Huang Y, Crudder C, Golden A, de los Santos T, Hawkins K. A Meta-Analysis of Typhoid Diagnostic Accuracy Studies: A Recommendation to Adopt a Standardized Composite Reference. PLoS One 2015; 10:e0142364. [PMID: 26566275 PMCID: PMC4643909 DOI: 10.1371/journal.pone.0142364] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 10/21/2015] [Indexed: 01/09/2023] Open
Abstract
Novel typhoid diagnostics currently under development have the potential to improve clinical care, surveillance, and the disease burden estimates that support vaccine introduction. Blood culture is most often used as the reference method to evaluate the accuracy of new typhoid tests; however, it is recognized to be an imperfect gold standard. If no single gold standard test exists, use of a composite reference standard (CRS) can improve estimation of diagnostic accuracy. Numerous studies have used a CRS to evaluate new typhoid diagnostics; however, there is no consensus on an appropriate CRS. In order to evaluate existing tests for use as a reference test or inclusion in a CRS, we performed a systematic review of the typhoid literature to include all index/reference test combinations observed. We described the landscape of comparisons performed, showed results of a meta-analysis on the accuracy of the more common combinations, and evaluated sources of variability based on study quality. This wide-ranging meta-analysis suggests that no single test has sufficiently good performance but some existing diagnostics may be useful as part of a CRS. Additionally, based on findings from the meta-analysis and a constructed numerical example demonstrating the use of CRS, we proposed necessary criteria and potential components of a typhoid CRS to guide future recommendations. Agreement and adoption by all investigators of a standardized CRS is requisite, and would improve comparison of new diagnostics across independent studies, leading to the identification of a better reference test and improved confidence in prevalence estimates.
Collapse
Affiliation(s)
- Helen L. Storey
- Diagnostics Program, PATH, Seattle, Washington, United States of America
- * E-mail:
| | - Ying Huang
- Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Chris Crudder
- Diagnostics Program, PATH, Seattle, Washington, United States of America
| | - Allison Golden
- Diagnostics Program, PATH, Seattle, Washington, United States of America
| | - Tala de los Santos
- Diagnostics Program, PATH, Seattle, Washington, United States of America
| | - Kenneth Hawkins
- Diagnostics Program, PATH, Seattle, Washington, United States of America
| |
Collapse
|
6
|
Waddington CS, Darton TC, Pollard AJ. The challenge of enteric fever. J Infect 2014; 68 Suppl 1:S38-50. [DOI: 10.1016/j.jinf.2013.09.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2013] [Indexed: 11/27/2022]
|
7
|
Akinwusi PO, Komolafe AO, Olayemi OO, Adeomi AA. Communicable disease-related sudden death in the 21st century in Nigeria. Infect Drug Resist 2013; 6:125-32. [PMID: 24124382 PMCID: PMC3794985 DOI: 10.2147/idr.s47959] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Some cases of sudden death (SD) have been attributed to communicable diseases (CD) in middle- and low-income countries of the world even in this 21st century. CDs produce clinical symptoms and signs over several days before culminating in death. They are also amenable to treatment with antimicrobials if affected persons present early. We sought to find out the incidence of CD-related SD at the Ladoke Akintola University of Technology Teaching Hospital (Osogbo, Osun State, Nigeria) - a tertiary health facility in southwest Nigeria - and the prevailing associated factors. METHODS We conducted a retrospective study of CD-related SD in adult patients aged 18 years and older that occurred from January 2003 to December 2011. The Statistical Package for the Social Sciences version 16 was used for analysis of the generated data. Percentages and frequencies were calculated. RESULTS There were 17 (39.6%) CD-related SDs out of the 48 cases of SD studied. CD-related SD also accounted for 2.4% of all adult medical admissions. The mean age of the patients was 37.6 ± 11.6 years, age range of 25-62 years, mode of 25 years, and median 34 years. The male-to-female ratio was 1.8:1. Typhoid sepsis was responsible for SD in 47.1% of patients, pulmonary tuberculosis in 17.7% of patients, and lobar pneumonia in 17.7% of patients. The most affected age group was the 20-29-year-old group (41.2%), while the unskilled occupational group was the most affected occupational group with 35.3% of them having SD. Most of the patients with acute bacterial infection died of multiple organ failure. CONCLUSION There is an urgent need to step up public health strategies to curtail infections in this environment, encourage better use of the existing health facilities by the people, and the government should strive hard to make health a top priority.
Collapse
Affiliation(s)
- Patience Olayinka Akinwusi
- Department of Medicine, College of Health Sciences, Osun State University, Osogbo, Osun State, Nigeria
- Department of Medicine, Ladoke Akintola University of Technology Teaching Hospital, Osogbo, Osun State, Nigeria
| | - Akinwumi Oluwole Komolafe
- Department of Morbid Anatomy, Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Osun State, Nigeria
| | - Olanrewaju Olayinka Olayemi
- Department of Medicine, Ladoke Akintola University of Technology Teaching Hospital, Osogbo, Osun State, Nigeria
| | - Adeleye Abiodun Adeomi
- Department of Community Medicine, Ladoke Akintola University of Technology Teaching Hospital, Ogbomoso, Oyo State, Nigeria
| |
Collapse
|
8
|
Bakr WMK, El Attar LA, Ashour MS, El Toukhy AM. The dilemma of widal test - which brand to use? a study of four different widal brands: a cross sectional comparative study. Ann Clin Microbiol Antimicrob 2011; 10:7. [PMID: 21303511 PMCID: PMC3050682 DOI: 10.1186/1476-0711-10-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Accepted: 02/08/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Serodiagnosis of typhoid fever by Widal test based on demonstrating the presence of agglutinins (antibodies) in the serum of an infected patient, against the H (flagellar) and O (somatic) antigens of Salmonella enterica serotype Typhi has been associated with many debates. This is why the aim of this study was to: (i) Compare the diagnostic accuracy of four different commercial kits used to perform Widal test (Remel, BioSystems, Dialab and Biotec). (ii) Compare the sensitivity and specificity of both anti-O and anti-H antibodies. (iii) Compare the validity of single versus paired serum samples with a rising titer for the diagnosis of typhoid fever. METHODS Duplicate serum samples were obtained from 150 patients clinically diagnosed as typhoid fever patients. Moreover, single serum samples were obtained from 25 patients with febrile diseases other than typhoid fever. All samples were tested using the four different Widal brands and Salmonella Typhi IgM anti-LPS ELISA. RESULTS -The results of Widal tests differed markedly using the four Widal brands in terms of sensitivity and specificity at three cut-off values of 1/80, 1/160 and 1/320. Remel brand gave the highest sensitivities and the lowest specificities and Dialab brand gave the highest specificities and the lowest sensitivities for both anti-O and anti-H antibodies at the three cut-off values.-Four fold rise in the antibodies titer was not demonstrable among clinically diagnosed typhoid fever patients-H agglutinins were less sensitive and less specific than O agglutinins CONCLUSIONS -Widal test results showed marked discrepancies using different Widal brands. None of the serum samples of the typhoid fever patients showed four fold rise in the antibody titers. Raised O agglutinins were of slightly greater diagnostic value than raised H agglutinins. SIGNIFICANCE AND IMPACT OF STUDY Widal test done sequentially using two brands could be of value in typhoid fever diagnosis. Single serum sample could be used for typhoid fever diagnosis relying on anti O titer.
Collapse
Affiliation(s)
- Wafaa MK Bakr
- Microbiology Department, High Institute of Public Health, Alexandria University, High Institute of Public Health, 165 Al Horreya avenue, Alexandria, Egypt
| | - Laila A El Attar
- Microbiology Department, High Institute of Public Health, Alexandria University, High Institute of Public Health, 165 Al Horreya avenue, Alexandria, Egypt
| | - Medhat S Ashour
- Microbiology Department, High Institute of Public Health, Alexandria University, High Institute of Public Health, 165 Al Horreya avenue, Alexandria, Egypt
| | - Ayman M El Toukhy
- Microbiology Department, High Institute of Public Health, Alexandria University, High Institute of Public Health, 165 Al Horreya avenue, Alexandria, Egypt
| |
Collapse
|
9
|
Pokhrel BM, Karmacharya R, Mishra SK, Koirala J. Distribution of antibody titer against Salmonella enterica among healthy individuals in nepal. Ann Clin Microbiol Antimicrob 2009; 8:1. [PMID: 19128506 PMCID: PMC2648941 DOI: 10.1186/1476-0711-8-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Accepted: 01/07/2009] [Indexed: 11/29/2022] Open
Abstract
Background Enteric fever is an endemic problem in Nepal and Widal agglutination test is widely used for its diagnosis but a normal baseline titer in healthy population and cutoff values have not been established. Methods We measured average baseline antibody titers against "O" and "H" antigens of Salmonella enterica serotype Typhi and "H" antigens of serotypes Paratyphi A and Paratyphi B among apparently healthy blood donors in Nepal. The antibody titers were measured using Standard Widal Confirmatory Quantitative Tube test. Results Among the 100 blood samples collected from healthy volunteers, 62 individuals had significant antibody titers (≥ 1:20) against one of the four antigens against S. enterica. Among 54 samples with an anti-O titer against serotype Typhi, 15 and 36 samples had titers of ≥ 1:60 and ≥ 1:40, respectively. A significant proportion (12% of all) had anti-O titer of ≥ 1:80. Similarly, among the 59 samples demonstrating anti-H titers of ≥ 1:20 to S. enterica serotype Typhi, 29 had a titer of ≥ 1:80 and 12 had 1:160. For S. enterica serotypes Paratyphi A and B, anti-H titers of ≥ 1:20 were found only in 12% and 3%, respectively, of all samples tested. Conclusion When a single Widal agglutination titer is used for the diagnosis of enteric fever, it will be more appropriate to change the currently used cutoff levels against S. enterica serotype Typhi to > 1:80 for anti-O and > 1:160 for anti-H titers for Nepal.
Collapse
Affiliation(s)
- Bharat M Pokhrel
- Tribhuvan University, Institute of Medicine, Department of Microbiology, Maharajgunj, Kathmandu, Nepal.
| | | | | | | |
Collapse
|
10
|
|
11
|
Chart H, Cheasty T, de Pinna E, Siorvanes L, Wain J, Alam D, Nizami Q, Bhutta Z, Threlfall EJ. Serodiagnosis of Salmonella enterica serovar Typhi and S. enterica serovars Paratyphi A, B and C human infections. J Med Microbiol 2007; 56:1161-1166. [PMID: 17761477 DOI: 10.1099/jmm.0.47197-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The aim of this study was to evaluate an immunoassay for the detection of human serum antibodies to the LPS and flagellar antigens of Salmonella Typhi and Salmonella Paratyphi A, B and C, and to the Vi capsular polysaccharide of S. Typhi and S. Paratyphi C. A total of 330 sera were used; these originated from 15 patients who were culture-positive for S. Typhi and 15 healthy controls, together with 300 sera submitted to the Laboratory of Enteric Pathogens for Salmonella serodiagnosis. By SDS-PAGE/immunoblotting, all 15 sera from culture-positive patients had serum antibodies to the 9,12 LPS antigens and 10 had antibodies to the ‘d’ flagellar antigens. Of the 300 reference sera, 22 had antibodies to the 9,12 LPS antigens, one to the 1,4,5,12 LPS antigens and 12 to the 6,7 LPS antigens. Only two sera had antibodies to flagellar antigens, one of which bound to the ‘b’ and the other to the ‘d’ antigen. An ELISA was developed that successfully detected serum antibodies to the Vi capsular polysaccharides, but because of the kinetics of serum antibody production to the Vi, these antibodies may be of limited value in the serodiagnosis of acute infection with S. Typhi and S. Paratyphi C. The immunoassays described here provide a sensitive means of detecting serum antibodies to the LPS, flagellar and Vi antigens of S. Typhi and S. Paratyphi, and constitute a viable replacement for the Widal assay for the screening of sera. The Salmonella serodiagnosis protocols described here are the new standard operating procedures used by the Health Protection Agency's National Salmonella Reference Centre based in the Laboratory of Enteric Pathogens, Colindale, UK.
Collapse
Affiliation(s)
- Henrik Chart
- Laboratory of Enteric Pathogens, Department of Gastrointestinal Infections, Centre for Infections, Health Protection Agency, 61 Colindale Avenue, London NW9 5EQ, UK
| | - Thomas Cheasty
- Laboratory of Enteric Pathogens, Department of Gastrointestinal Infections, Centre for Infections, Health Protection Agency, 61 Colindale Avenue, London NW9 5EQ, UK
| | - Elizabeth de Pinna
- Laboratory of Enteric Pathogens, Department of Gastrointestinal Infections, Centre for Infections, Health Protection Agency, 61 Colindale Avenue, London NW9 5EQ, UK
| | - Lisa Siorvanes
- Laboratory of Enteric Pathogens, Department of Gastrointestinal Infections, Centre for Infections, Health Protection Agency, 61 Colindale Avenue, London NW9 5EQ, UK
| | - John Wain
- The Wellcome Trust Sanger Institute Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Didar Alam
- Department of Paediatrics and Child Health, The Aga Khan University Medical Centre, PO Box 3500, Karachi, Pakistan
| | - Qamarauddin Nizami
- Department of Paediatrics and Child Health, The Aga Khan University Medical Centre, PO Box 3500, Karachi, Pakistan
| | - Zulfiqar Bhutta
- Department of Paediatrics and Child Health, The Aga Khan University Medical Centre, PO Box 3500, Karachi, Pakistan
| | - E John Threlfall
- Laboratory of Enteric Pathogens, Department of Gastrointestinal Infections, Centre for Infections, Health Protection Agency, 61 Colindale Avenue, London NW9 5EQ, UK
| |
Collapse
|
12
|
Abstract
BACKGROUND/AIMS The serodiagnosis of infection with Salmonella typhi, using the Widal agglutination assay, relies on patients' antibodies to the O = 9,12 lipopolysaccharide (LPS) antigens, H = d flagellar antigens, and the Vi capsular antigens. A Vi agglutination titre of > 1/40 has traditionally been regarded as indicative of recent infection with S typhi. In this study, 91 sera were used to assess the reliability of the Widal agglutination assay based on antibodies to the Vi antigens. METHODS The Widal agglutination assay was carried out using protocols established by the Central Public Health Laboratory, Colindale. Antibodies to the Vi capsular antigen were detected using a standard preparation of S typhi, ViI Bhatnagar variant strain (S typhi, ViI). Sera used in the study comprised 73 from patients who were culture positive for S typhi, 10 from patients who were culture positive for other species of Salmonella not expressing a Vi antigen (namely, S javiana, S enteritidis, S typhimurium, S stanley, S saint paul, S bareilly, or S mbandaka), and eight from healthy blood donors. RESULTS Agglutination titres of > or = 1/40 were detected to S typhi ViI in 69 of 73 sera from patients with typhoid, although 27 of these also agglutinated an unrelated control antigen. The Widal assay also detected significant amounts of agglutinating antibodies to S. typhi ViI in all eight control sera and seven sera from patients infected with S bareilly, S enteritidis, S javiana, S mbandaka, S saint paul, and S stanley. CONCLUSIONS Agglutinating antibodies to the Vi antigen can be detected by the Widal assay, but even with the appropriate control antigens the results were unreliable. The serodiagnosis of infections with S typhi should be based on the detection of antibodies to both the O = 9,12 LPS antigen and the H = d flagellar antigen by immunoblotting, and should not use the Vi antigen-based Widal assay. Conclusions should be made in the light of patients' clinical details and any knowledge of previous immunisation for typhoid.
Collapse
Affiliation(s)
- H Chart
- Laboratory of Enteric Pathogens, Division of Gastrointestinal Infections, Central Public Health Laboratory, 61 Colindale Avenue, London, NW9 5HT, UK.
| | | | | |
Collapse
|
13
|
Abstract
We review the significance of the Widal agglutination test in the diagnosis of typhoid fever. Over 100 years since its introduction as a serologic means of detecting the presence of typhoid fever, the Widal test continues to be plagued with controversies involving the quality of the antigens used and interpretation of the result, particularly in endemic areas. Areas of concern with clinical and laboratory significance discussed in this review include: the techniques of test performance, interpretation of results, limitation of the value of the test results in endemic typhoid areas, the quality of the antigens used, and alternative diagnostic tests.
Collapse
|
14
|
Chart H, Ward LR, Rowe B. An immunoblotting procedure comprising O = 9,12 and H = d antigens as an alternative to the Widal agglutination assay. J Clin Pathol 1998; 51:854-6. [PMID: 10193329 PMCID: PMC500982 DOI: 10.1136/jcp.51.11.854] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIMS To compare the established Widal agglutination assay with an immunoblotting procedure. METHODS 110 sera were used to compare the established Widal agglutination assay with an immunoblotting procedure incorporating lipopolysaccharide (LPS) (O = 9,12) and flagellar (H = d) antigens. RESULTS Antibodies to the LPS antigens were detected in 18 sera by the Widal assay and in 37 by immunoblotting. Antibodies to the flagellar antigens were detected in 27 sera by Widal assay and in 25 by immunoblotting. CONCLUSIONS An immunoblotting procedure incorporating O = 9,12 LPS and H = d flagellar antigens was rapid and more sensitive than the established Widal agglutination assay for providing evidence of infection with S typhi.
Collapse
Affiliation(s)
- H Chart
- Laboratory of Enteric Pathogens, Central Public Health Laboratory, London, UK.
| | | | | |
Collapse
|
15
|
Clegg A, Passey M, Omena M, Karigifa K, Suve N. Re-evaluation of the Widal agglutination test in response to the changing pattern of typhoid fever in the highlands of Papua New Guinea. Acta Trop 1994; 57:255-63. [PMID: 7810382 DOI: 10.1016/0001-706x(94)90071-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In 1992 it was decided to re-evaluate the Widal slide agglutination test as a rapid diagnostic test for typhoid fever in Papua New Guinea. This was in response to an apparent increase in the number of false positive Widal slide agglutinations occurring using an O cut-off titre greater than or equal to 40 which was previously shown to be appropriate in 1987. The results of the re-evaluation indicated that the Widal test using a diagnostic cut-off titre of > or = 40 lacked specificity and was no longer appropriate for this population. A new O antibody titre of > or = 160 was recommended as a diagnostic titre for typhoid fever in PNG. The fall in the specificity of the Widal slide agglutination test over the five-year period between the initial assessment and the re-evaluation is due to an increase in general population antibody levels caused by the changing pattern of typhoid in the community. Before 1987 typhoid fever occurred as sporadic, isolated outbreaks and most people living in the highlands of PNG were immunologically naive. By 1992 typhoid fever had become a well-established endemic disease and many more people had been exposed to Salmonella typhi and as a result developed antibodies. We have been able to demonstrate clearly a remarkable change in the immune status of the community, in which the proportion of healthy individuals with a Widal tube O agglutination titre of 40 or more rose from 0 to 56% in the short span of five years.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- A Clegg
- Papua New Guinea Institute of Medical Research, Eastern Highlands Province
| | | | | | | | | |
Collapse
|
16
|
West B, Richens JE, Howard PF. Evaluation in Papua New Guinea of a urine coagglutination test and a Widal slide agglutination test for rapid diagnosis of typhoid fever. Trans R Soc Trop Med Hyg 1989; 83:715-7. [PMID: 2617639 DOI: 10.1016/0035-9203(89)90407-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Two simple rapid tests for the laboratory diagnosis of typhoid fever were evaluated, a coagglutination test for detecting Salmonella typhi antigens in urine and a Widal slide agglutination for detecting serum antibodies. Ninety-two culture-confirmed typhoid cases were compared with 64 non-typhoid fever patients, 50 close contacts of typhoid patients, 30 vaccinated staff and 72 healthy community members. A strong urine Vi coagglutination was found to be 86.5% sensitive and 91.8% specific for typhoid, but was not always easy to read. The slide Widal H was found to be 99% sensitive and 95% specific whereas the slide Widal O was 98% sensitive and 98% specific. These data suggest that a single slide Widal O, at a reciprocal titre of 40, is the most suitable rapid test for the diagnosis of typhoid in a population with low typhoid antibody levels in the community, few other cross-reacting Salmonella infections, and a tendency for patients to present late in the infection.
Collapse
Affiliation(s)
- B West
- Papua New Guinea Institute of Medical Research
| | | | | |
Collapse
|
17
|
Gilman RH. General considerations in the management of typhoid fever and dysentery. SCANDINAVIAN JOURNAL OF GASTROENTEROLOGY. SUPPLEMENT 1989; 169:11-8. [PMID: 2694338 DOI: 10.3109/00365528909091326] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Typhoid fever is diagnosed on the basis of isolation of Salmonella typhi from blood, bone marrow, or bile. S. typhi found in stool or urine may reflect chronic asymptomatic carriage. Although antimicrobial therapy may not eliminate carriage, it is effective for the treatment of clinically evident acute disease. Among the drugs currently available, chloramphenicol is the most widely used. Chloramphenicol is effective and inexpensive, but it is associated with a 3% rate of chronic carriage, a high relapse rate, and, in rare cases, aplastic anemia. For these reasons, and because of the emergence of chloramphenicol-resistant strains of S. typhi, alternative drugs need to be considered. Dysentery is characterized by the passage of unformed stools that commonly contain blood and mucus and in which large numbers of leukocytes can be detected on microscopic examination. Invasion of the intestinal epithelium is the distinguishing characteristic, and Shigella sp are the most frequent cause. Although oral rehydration is useful in dehydrated patients, dehydration is not a common problem in acute dysentery, and antimicrobial treatment is indicated for this disease. An antimicrobial agent should be selected on the basis of knowledge of the susceptibility patterns of locally isolated Shigella strains.
Collapse
Affiliation(s)
- R H Gilman
- Dept. of International Health, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, MD 21205
| |
Collapse
|
18
|
|