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Diel R, Breuer C, Bös L, Geerdes-Fenge H, Günther A, Häcker B, Hannemann J, Nienhaus A, Priwitzer M, Witte P, Bauer T. [Recommendations for Contact Tracing for Tuberculosis - Update 2023]. DAS GESUNDHEITSWESEN 2023; 85:1076-1098. [PMID: 37972583 DOI: 10.1055/a-2148-7769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
The aim of contact tracing for tuberculosis is in addition to active case finding the detection of chains of infection and the prevention of the further spread of the disease. In this context, a careful selection of contact persons is necessary, depending on the type and duration of contact, to identify persons who are recently infected and therefore to increase the benefit of a preventive therapy and to avoid unnecessary testing of persons who are not at risk of infection. Since the last update of the recommendations on contact tracing, data on the use of interferon-y release assays (IGRAs) in children has been improved markedly. These are the preferred test in contact tracing of adults. For children, both IGRAs and the tuberculin skin test can be used equivalently. Rifampicin for 4 months, rifampicin and isoniazid for 3 months, or isoniazid for 9 months are recommended as preventive therapy in cases of confirmed infection.The implementation of the contact tracing in different age groups as well as legal framework conditions and socio-medical aspects and challenges are dealt with in detail. In addition, special cases, such as environmental screening in day-care centers, schools, or other community facilities, are discussed separately.
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Affiliation(s)
- Roland Diel
- Universitätsklinikum Schleswig-Holstein, Campus Kiel
- Deutsches Zentrum für Lungenforschung, Airway Research Center North (ARCN), LungenClinic Grosshansdorf, Großhansdorf
- Deutsches Zentralkomitee zur Bekämpfung der Tuberkulose, Berlin
| | - Cornelia Breuer
- Amt für Gesundheit und Prävention der Landeshauptstadt Dresden
- Deutsches Zentralkomitee zur Bekämpfung der Tuberkulose, Berlin
| | | | | | | | - Brit Häcker
- Deutsches Zentralkomitee zur Bekämpfung der Tuberkulose, Berlin
| | | | - Albert Nienhaus
- Berufsgenossenschaft für Gesundheits- und Wohlfahrtspflege, Hamburg
- Universitätskrankenhaus Eppendorf, Hamburg
| | | | - Peter Witte
- Deutsches Zentralkomitee zur Bekämpfung der Tuberkulose, Berlin
- Institut für Krankenhaushygiene, Universitätsklinikum JWK, Minden
| | - Torsten Bauer
- Helios-Klinikum Emil von Behring, Berlin
- Deutsches Zentralkomitee zur Bekämpfung der Tuberkulose, Berlin
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Diel R, Breuer C, Bös L, Geerdes-Fenge H, Günther A, Häcker B, Hannemann J, Nienhaus A, Priwitzer M, Witte P, Bauer T. [Recommendations for contact tracing for tuberculosis - update 2023]. Pneumologie 2023; 77:607-631. [PMID: 37536363 DOI: 10.1055/a-2107-2147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
The aim of contact tracing for tuberculosis is in addition to active case finding the detection of chains of infection and the prevention of the further spread of the disease. In this context, a careful selection of contact persons is necessary, depending on the type and duration of contact, to identify persons who are recently infected and therefore to increase the benefit of a preventive therapy and to avoid unnecessary testing of persons who are not at risk of infection. Since the last update of the recommendations on contact tracing, data on the use of interferon-y release assays (IGRAs) in children has been improved markedly. These are the preferred test in contact tracing of adults. For children, both IGRAs and the tuberculin skin test can be used equivalently. Rifampicin for 4 months, rifampicin and isoniazid for 3 months, or isoniazid for 9 months are recommended as preventive therapy in cases of confirmed infection.The implementation of the contact tracing in different age groups as well as legal framework conditions and socio-medical aspects and challenges are dealt with in detail. In addition, special cases, such as environmental screening in day-care centers, schools, or other community facilities, are discussed separately.
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Affiliation(s)
- Roland Diel
- Universitätsklinikum Schleswig-Holstein, Campus Kiel
- Deutsches Zentrum für Lungenforschung, Airway Research Center North (ARCN), LungenClinic Grosshansdorf, Großhansdorf
- Deutsches Zentralkomitee zur Bekämpfung der Tuberkulose, Berlin
| | - Cornelia Breuer
- Amt für Gesundheit und Prävention der Landeshauptstadt Dresden
- Deutsches Zentralkomitee zur Bekämpfung der Tuberkulose, Berlin
| | | | | | | | - Brit Häcker
- Deutsches Zentralkomitee zur Bekämpfung der Tuberkulose, Berlin
| | | | - Albert Nienhaus
- Berufsgenossenschaft für Gesundheits- und Wohlfahrtspflege, Hamburg
- Universitätskrankenhaus Eppendorf, Hamburg
| | | | - Peter Witte
- Deutsches Zentralkomitee zur Bekämpfung der Tuberkulose, Berlin
- Institut für Krankenhaushygiene, Universitätsklinikum JWK, Minden
| | - Torsten Bauer
- Helios-Klinikum Emil von Behring, Berlin
- Deutsches Zentralkomitee zur Bekämpfung der Tuberkulose, Berlin
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Meier T, Enders M. High reproducibility of the interferon-gamma release assay T-SPOT.TB in serial testing. Eur J Clin Microbiol Infect Dis 2020; 40:85-93. [PMID: 32770282 DOI: 10.1007/s10096-020-03997-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 07/27/2020] [Indexed: 10/23/2022]
Abstract
Longitudinal studies regarding the reproducibility of Interferon-gamma release assay (IGRA) T-SPOT.TB for the diagnosis of Mycobacterium tuberculosis (M. tb) infection in serial testing are limited. We retrospectively analysed results of serially tested subjects in a medical laboratory in Germany over a time period of 14 years. From October 2004 to December 2018, a total of 5440 subjects were identified with a second T-SPOT.TB test after a median time interval of 258 days (interquartile range [IQR] 62-665). Consistently negative (n = 4520) or positive results (n = 682) were observed in 5202 (95.6%) subjects, indicating a high degree of concordance in serial testing (κ = 0.83). Test conversions occurred in 101 of 4621 (2.2%) subjects with initially negative tests. Of 819 subjects with initially positive test results, 137 (16.7%) had a test reversion which was associated with low spot numbers of the first test. Of 529 subjects retested within 1 year, only 60 (11.3%) displayed a test reversion. In subjects retested after more than 1 year, 77 of 290 (26.6%) tests reverted. This significantly higher rate of test reversions after more than 1 year was age-dependent and only observed in subjects above the age of 40 years. In the medical laboratory, the T-SPOT.TB test demonstrates a high reproducibility in serial testing.
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Affiliation(s)
- Thomas Meier
- Laboratory Prof. Gisela Enders and colleagues, MVZ, Rosenbergstrasse 85, D-70193, Stuttgart, Germany.
| | - Martin Enders
- Laboratory Prof. Gisela Enders and colleagues, MVZ, Rosenbergstrasse 85, D-70193, Stuttgart, Germany
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Sivapalasingam S, Rajasingham A, Macy JT, Friedman CR, Hoekstra RM, Ayers T, Gold B, Quick RE. Recurrence of Helicobacter pylori infection in Bolivian children and adults after a population-based "screen and treat" strategy. Helicobacter 2014; 19:343-8. [PMID: 24830916 DOI: 10.1111/hel.12137] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Strategies to prevent gastric cancer by decreasing Helicobacter pylori infections in high-prevalence, low-income countries could include a population-based "screen and treat" eradication program. METHODS We tested residents of two rural villages for H. pylori infection using urea breath test (UBT), treated infected persons using directly observed therapy (DOT), retested for cure, and retested after 1 year later for H. pylori infection. FINDINGS We tested 1,065 (92%) of 1153 residents from two villages in rural Bolivia. Baseline H. pylori prevalence was 80% (95% confidence interval [CI]: 78-84). Age-specific cure rates were similar (≥92%) after DOT. Among those cured, 12% (95% CI: 8-15) had recurrent infection. Age-specific annual H. pylori recurrence rates for combined villages were 20% (95% CI: 10-29) in persons <5 years, 20% (95% CI: 10-29) in 5-9 years, 8% (95% CI: 1-15) in 10-14 years, and 8% (95% CI: 4-12) in persons ≥15 years. Compared with the referent population, those ≥15 years, recurrent infections were significantly more likely in children <5 years (odds ratios [OR] 2.7, 95% CI: 1.2-5.8) and 5-9 years (OR 2.7, 95% CI: 1.4-5.1). INTERPRETATION Children <10 years had high H. pylori recurrence rates following a population-based screen and treat program; this H. pylori eradication strategy may not be feasible in high-prevalence, low-income settings.
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Affiliation(s)
- Sumathi Sivapalasingam
- Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
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Som S, Maity A, Banik GD, Ghosh C, Chaudhuri S, Daschakraborty SB, Ghosh S, Pradhan M. Excretion kinetics of 13C-urea breath test: influences of endogenous CO2 production and dose recovery on the diagnostic accuracy of Helicobacter pylori infection. Anal Bioanal Chem 2014; 406:5405-12. [PMID: 24939135 DOI: 10.1007/s00216-014-7951-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 05/08/2014] [Accepted: 06/05/2014] [Indexed: 12/11/2022]
Abstract
We report for the first time the excretion kinetics of the percentage dose of (13)C recovered/h ((13)C-PDR %/h) and cumulative PDR, i.e. c-PDR (%) to accomplish the highest diagnostic accuracy of the (13)C-urea breath test ((13)C-UBT) for the detection of Helicobacter pylori infection without any risk of diagnostic errors using an optical cavity-enhanced integrated cavity output spectroscopy (ICOS) method. An optimal diagnostic cut-off point for the presence of H. pylori infection was determined to be c-PDR (%) = 1.47 % at 60 min, using the receiver operating characteristic curve (ROC) analysis to overcome the "grey zone" containing false-positive and false-negative results of the (13)C-UBT. The present (13)C-UBT exhibited 100 % diagnostic sensitivity (true-positive rate) and 100 % specificity (true-negative rate) with an accuracy of 100 % compared with invasive endoscopy and biopsy tests. Our c-PDR (%) methodology also manifested both diagnostic positive and negative predictive values of 100 %, demonstrating excellent diagnostic accuracy. We also observed that the effect of endogenous CO2 production related to basal metabolic rates in individuals was statistically insignificant (p = 0.78) on the diagnostic accuracy. However, the presence of H. pylori infection was indicated by the profound effect of urea hydrolysis rate (UHR). Our findings suggest that the current c-PDR (%) is a valid and sufficiently robust novel approach for an accurate, specific, fast and noninvasive diagnosis of H. pylori infection, which could routinely be used for large-scale screening purposes and diagnostic assessment, i.e. for early detection and follow-up of patients.
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Affiliation(s)
- Suman Som
- Department of Chemical, Biological and Macromolecular Sciences, S.N. Bose National Centre for Basic Sciences, Salt Lake, JD Block, Sector III, Kolkata, 700098, India
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Dynamics of Helicobacter pylori detection in stools during the first 5 years of life in Chile, a rapidly developing country. Pediatr Infect Dis J 2013; 32:99-103. [PMID: 23076385 DOI: 10.1097/inf.0b013e318278b929] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND : Helicobacter pylori colonization/infection can be transitory or persistent, conditions that have not been thoroughly evaluated in young children. We aimed to characterize the dynamics of H. pylori stool detection and to determine host and environmental factors and symptoms associated with persistence. METHOD : In a 5-year cohort study, we followed-up infants from birth with clinic visits every 3 months. Symptoms and environmental risk factor survey and a stool sample for H. pylori antigen detection were requested in every visit. Secretor/ABH histo-blood group phenotype was determined in saliva. RESULTS : Overall, 218 of 1456 (15%) stool samples were positive for H. pylori and 39 of 96 (41%) children had at least 1 positive sample. Stool detection was transitory in 16 of 39 (41%), persistent in 19 (49%) and undetermined in 4 (10%) children. Persistence was acquired largely during the first 24 months (17/19 cases) and was associated with nonsecretor phenotype (32% versus 0% for transitory infection; P = 0.02) and daycare attendance (67% versus 26% for never infected; P = 0.019). Symptoms possibly associated with persistence were referred in only 1 child. CONCLUSIONS : Nearly 20% of this Chilean cohort had persistent H. pylori stool sample detections during the first 5 years of life, acquired mostly during the first 24 months. Persistence was significantly associated with nonsecretor phenotype and daycare attendance, and possibly associated gastrointestinal symptoms were rare. This relatively common group of young children with persistent H. pylori colonization/infection will require further study.
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Sicinschi LA, Correa P, Bravo LE, Peek RM, Wilson KT, Loh JT, Yepez MC, Gold BD, Thompson DT, Cover TL, Schneider BG. Non-invasive genotyping of Helicobacter pylori cagA, vacA, and hopQ from asymptomatic children. Helicobacter 2012; 17:96-106. [PMID: 22404439 PMCID: PMC3305281 DOI: 10.1111/j.1523-5378.2011.00919.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Helicobacter pylori infection is usually acquired in childhood, but little is known about its natural history in asymptomatic children, primarily due to the paucity of non-invasive diagnostic methods. H. pylori strains harboring cagA and specific alleles of hopQ and vacA are associated with increased risk for gastric cancer. Many studies of H. pylori virulence markers in children have the bias that symptomatic subjects are selected for endoscopy, and these children may harbor the most virulent strains. Our aim is to genotype cagA, hopQ, and vacA alleles in stool DNA samples of healthy Colombian children residing in an area with high incidence of gastric cancer, to avoid selection bias resulting from endoscopy. METHODS H. pylori status of 86 asymptomatic children was assessed by (13) C-urea breath test (UBT) and PCR. H. pylori 16S rRNA, cagA, hopQ, and vacA genes were amplified from stool DNA samples and sequenced. RESULTS UBT was positive in 69 (80.2%) of 86 children; in stool DNA analysis, 78.3% were positive by 16S rRNA PCR. cagA, vacA, and hopQ were detected in 66.1%, 84.6%, and 72.3% of stool DNA samples from 16S rRNA-positive children. Of the children's DNA samples, which revealed vacA and hopQ alleles, 91.7% showed vacA s1 and 73.7% showed type I hopQ. Type I hopQ alleles were associated with cagA positivity and vacA s1 genotypes (p < 0.0001). CONCLUSIONS Using stool DNA samples, virulence markers of H. pylori were successfully genotyped in a high percentage of the asymptomatic infected children, revealing a high prevalence of genotypes associated with virulence. Type I hopQ alleles were associated with the presence of cagA and the vacA s1 genotype.
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Affiliation(s)
- Liviu A. Sicinschi
- Division of Gastroenterology, Dept. of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232,Department of Microbiology and Immunology, Holmes Regional Medical Center, Melbourne, FL 32901, USA
| | - Pelayo Correa
- Division of Gastroenterology, Dept. of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Luis E. Bravo
- Department of Pathology, School of Medicine, Universidad del Valle, Pasto, Colombia
| | - Richard M. Peek
- Division of Gastroenterology, Dept. of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Keith T. Wilson
- Division of Gastroenterology, Dept. of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232,Veterans Affairs Tennessee Valley Health Care System, Nashville, TN 37212, USA
| | - John T. Loh
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Maria C. Yepez
- Centro de Estudios de Salud, Universidad de Nariño, Pasto, Colombia
| | - Benjamin D. Gold
- Children's Center for Digestive Healthcare, Pediatric Gastroenterology, Hepatology and Nutrition, Atlanta, GA 30342
| | - Dexter T. Thompson
- Division of Gastroenterology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Timothy L. Cover
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA,Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA,Veterans Affairs Tennessee Valley Health Care System, Nashville, TN 37212, USA
| | - Barbara G. Schneider
- Division of Gastroenterology, Dept. of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
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Broussard CS, Goodman KJ, Phillips CV, Smith MA, Fischbach LA, Day RS, Aragaki CC. Antibiotics taken for other illnesses and spontaneous clearance of Helicobacter pylori infection in children. Pharmacoepidemiol Drug Saf 2009; 18:722-9. [PMID: 19455592 DOI: 10.1002/pds.1773] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
PURPOSE Factors that determine persistence of untreated Helicobacter pylori (H. pylori) infection in childhood are not well understood. We estimated risk differences for the effect of incidental antibiotic exposure on the probability of a detected clearance at the next test after an initial detected H. pylori infection. METHODS The Pasitos Cohort Study (1998-2005) investigated predictors of H. pylori infection in children from El Paso, Texas, and Juarez, Mexico. Children were screened for infection at 6-month target intervals from 6 to 84 months of age, using the 13C-urea breath test corrected for body-size-dependent variation in CO2 production. Exposure was defined as courses of any systemic antibiotic (systemic) or those with anti-H. pylori action (HP-effective) reported for the interval between initial detected infection and next test. Binomial regression models included country of residence, mother's education, adequacy of prenatal care, age at infection, and interval between tests. RESULTS Of 205 children with a test result and antibiotic data following a detected infection, the number of children who took > or =1 course in the interval between tests was 74 for systemic and 33 for HP-effective. The proportion testing negative at the next test was 66% for 0 courses, 72% for > or =1 systemic course, and 79% for > or =1 HP-effective course. Adjusted risk differences (95%CI) for apparent clearance, comparing > or =1 to 0 courses were 10% (1-20%) for systemic and 11% (0-21%) for HP-effective. CONCLUSIONS Incidental antibiotic exposure appears to influence the duration of childhood H. pylori infection but seems to explain only a small portion of spontaneous clearance.
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Phillips CV, Goodman KJ. Interpreting data in the face of competing explanations: assessing the hypothesis that observed spontaneous clearance of Helicobacter pylori was all measurement error. Int J Epidemiol 2009; 38:1110-7. [PMID: 19307253 DOI: 10.1093/ije/dyp006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND We previously reported frequent transient positive urea breath tests for Helicobacter pylori infection in a cohort study of young children, and interpreted this as evidence of frequent spontaneous clearance of this infection. In a commentary, Perry and Parsonnet suggested that all transient positive tests we observed could be false positives and thus the appearance of transient infection could be an artifact. METHODS We address the logic of the implicit argument that the transient infections were an artifact and we demonstrate a simple likelihood calculation to assess the plausibility of competing explanations. We calculate the likelihood of observing our data based on a range of clearance and measurement error rates and then how this updates a set of prior beliefs. RESULTS The likelihood calculations and resulting posterior probabilities show strong support for the hypothesis of spontaneous clearance, after allowing for measurement error, even starting with a very high prior probability of no spontaneous clearance. The scenario Perry and Parsonnet present is incompatible with our data, and thus not a plausible explanation for our observations. Attributing most observed transient infections to measurement error requires assuming a high false positive rate and a very low infection rate and/or a high false negative rate, alternatives that are not supported by evidence. CONCLUSIONS Acknowledgment of plausible levels of measurement error does not change the strong support our data provides for the hypothesis of frequent transient infection. Debate about competing explanations for observations should be accompanied by quantitative analysis that shows which is more plausible. We demonstrate one method for doing such analysis.
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Affiliation(s)
- Carl V Phillips
- Alberta Smokeless Tobacco Education and Research Group, University of Alberta, Edmonton, Alberta, Canada.
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Evaluation of a novel stool native catalase antigen test for Helicobacter pylori infection in asymptomatic North American children. J Pediatr Gastroenterol Nutr 2008; 46:399-402. [PMID: 18367951 DOI: 10.1097/mpg.0b013e318148b688] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Rapid immunochromatographic tests for Helicobacter pylori infection have been developed to allow "near-patient" testing. We therefore performed a pilot study to test a rapid immunochromatographic stool antigen test for the diagnosis of H. pylori infection in asymptomatic children. We tested stool specimens collected from children participating in a cohort study in the United States and Mexico. H. pylori-positive status was defined by positivity on at least 2 tests: a commercial H. pylori stool antigen enzyme immunoassay, an immunoglobulin G antibody enzyme immunoassay, and the C-urea breath test. Negative H. pylori status was defined by negative findings of all of these tests. Of 52 children (22 girls, 30 boys) 25 were H. pylori-positive, 19 H. pylori-negative, and 8 uncertain (eg, presumably negative; positive findings on 1 of the 3 noninvasive tests). The sensitivity and specificity of the new stool antigen test for those with definite H. pylori status were 100% (exact 95% CI 86.3%-100% and 82.4%-100%, respectively). This rapid stool antigen test may prove useful for point-of-care testing and epidemiological field studies. Larger prospective studies are needed in symptomatic and asymptomatic children for more precise estimates.
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Phillips CV. Commentary: Lack of scientific influences on epidemiology. Int J Epidemiol 2008; 37:59-64; discussion 65-8. [DOI: 10.1093/ije/dym266] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Reproducibility of QuantiFERON-TB gold in-tube assay. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2008; 15:425-32. [PMID: 18199741 DOI: 10.1128/cvi.00398-07] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Studies are needed to characterize the reproducibility of QuantiFERON-TB Gold (QFT-G) for targeted U.S. screening populations. Members of northern California households were tested with the QFT-G in-tube assay (QFT-G-IT) at two home visits 3 months apart. Reproducibility and agreement with the tuberculin skin test (TST) were assessed. Monte Carlo simulation was used to evaluate the role of test-related error. Of 63 individuals (49 adults and 14 children) completing QFT-G-IT at both time points, 79% were foreign-born (98% from Latin America) and 68% reported Mycobacterium bovis BCG vaccination. At the baseline visit, 23 (37%) were TST positive and 15 (24%) were QFT-G-IT positive (kappa = 0.48 [+/- 0.11]). At 3 months, 3/48 (6.3%; 95% confidence interval [95CI], 2 to 17) of those initially QFT-G-IT negative converted, and 5/15 (33%; 95CI, 15 to 58) of those initially QFT-G-IT positive reverted. Among the 8 individuals with inconsistent QFT-G-IT results, the maximum gamma interferon response at either visit was 0.68 IU/ml versus means of 4.99 (+/- 3.74) and 6.95 (+/- 5.6) for 10 persistent positives at the first and second visits, respectively. Expected false-reversion and -conversion rates were 32% (90CI, 25 to 39%) and 6.95% (90CI, 4.6 to 9.8%) when the sensitivity and specificity were assumed to average 70% and 98%, respectively. Transient responses to QFT-G-IT are common, and low positive results need to be interpreted with caution. Further studies are needed to characterize the predictive value of the test for U.S. foreign-born and other targeted screening populations.
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Azevedo NF, Guimarães N, Figueiredo C, Keevil CW, Vieira MJ. A new model for the transmission of Helicobacter pylori: role of environmental reservoirs as gene pools to increase strain diversity. Crit Rev Microbiol 2007; 33:157-69. [PMID: 17653985 DOI: 10.1080/10408410701451922] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Twenty-five years after the first successful cultivation and isolation of Helicobacter pylori, the scientific community is still struggling to understand the way(s) this bacterium is transmitted among the human population. Here, both epidemiologic and microbiologic evidence addressing this matter is reviewed and explored to conclude that most H. pylori successful colonizations are derived from direct person-to-person contact and that even though exposure of humans to H. pylori from environmental sources is a very common event, in most occasions the host is able to fight off infection. In addition, under a new model developed here, we propose that the near elimination of environmental reservoirs is the main responsible for the lower prevalence observed in the more industrialized countries by acting on two levels: by decreasing the number of direct infections and by diminishing the number of intraspecies recombination events for producing strain variation within H. pylori.
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Affiliation(s)
- N F Azevedo
- Institute for Biotechnology and Bioengineering, Centre for Biological Engineering, Universidade do Minho, Braga, Portugal.
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Okuda M, Miyashiro E, Booka M, Tsuji T, Nakazawa T. Helicobacter pylori colonization in the first 3 years of life in Japanese children. Helicobacter 2007; 12:324-7. [PMID: 17669105 DOI: 10.1111/j.1523-5378.2007.00510.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND Acquisition of Helicobacter pylori infection occurs in early childhood, but the exact time of the acquisition and dynamics of infection are not clear. The aim of this study was to estimate the time of acquisition of H. pylori colonization in infants. SUBJECTS AND METHODS This prospective follow-up study included 237 infants born in Wakayama Rosai Hospital from February, 2001 to April, 2002. Stool samples were collected at indicated ages, and H. pylori antigens were determined by a stool antigen test, HpSA. RESULTS One-hundred and eight infants among initially enrolled 237 children have been followed up until 24 months. Among these, 16 infants turned to be HpSA positive within 12 months, but only four remained positive by the consecutive tests with optical density values of more than 0.7. They were assumed persistent positives. The rest 12 infants reverted to be negative by the consecutive tests and were assumed transient or false-positives. The optical density values of HpSA in the transient cases were exclusively less than 0.35. CONCLUSIONS The consecutive follow up of HpSA, but not the one-point test, might be useful to diagnose persistent colonization of H. pylori in young infants, and some infants seemed to acquire H. pylori infection in the first year of life. These results should be taken into account for prevention and treatment strategies for H. pylori infection in infants.
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Affiliation(s)
- Masumi Okuda
- Department of Pediatrics, Japan Labour Health and Welfare Organization, Wakayama Rosai Hospital, Koya 435, Wakayama 640-8505, Japan.
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Perry S, de la Luz Sanchez M, Yang S, Haggerty TD, Hurst P, Perez-Perez G, Parsonnet J. Gastroenteritis and transmission of Helicobacter pylori infection in households. Emerg Infect Dis 2006; 12:1701-8. [PMID: 17283620 PMCID: PMC3372328 DOI: 10.3201/eid1211.060086] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The mode of transmission of Helicobacter pylori infection is poorly characterized. In northern California, 2,752 household members were tested for H. pylori infection in serum or stool at a baseline visit and 3 months later. Among 1,752 person considered uninfected at baseline, 30 new infections (7 definite, 7 probable, and 16 possible) occurred, for an annual incidence of 7% overall and 21% in children <2 years of age. Exposure to an infected household member with gastroenteritis was associated with a 4.8-fold (95% confidence interval [CI] 1.4-17.1) increased risk for definite or probable new infection, with vomiting a greater risk factor (adjusted odds ratio [AOR] 6.3, CI 1.6-24.5) than diarrhea only (AOR 3.0, p = 0.65). Of probable or definite new infections, 75% were attributable to exposure to an infected person with gastroenteritis. Exposure to an H. pylori-infected person with gastroenteritis, particularly vomiting, markedly increased risk for new infection.
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Affiliation(s)
- Sharon Perry
- Division of Infection Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California 94305, USA.
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