H. pylori-infection and antibody immune response in a rural Tanzanian population

Prevalence and associated risk factors of Helicobacter pylori infection in East Africa: a systematic review and meta-analysis

BACKGROUND

Helicobacter pylori is the main cause of chronic gastritis, peptic ulcer, lymphoma, and gastric cancer in humans. The prevalence and factors associated with H. pylori infection are varied across countries. Thus, a comprehensive review has not been done on prevalence and associated factors in East Africa. Therefore, this systematic review and meta-analysis aimed to estimate the pooled prevalence and identify factors associated with H. pylori infection in East Africa.

METHODS

Articles written in English language were retrieved from PubMed, Scopus, and Science Direct. Relevant articles were selected and screened using Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Publication bias was assessed qualitatively and qualitatively using funnel plot symmetry and Egger's test, respectively. Heterogeneity was assessed using the I2 measure. Data were analyzed using Stata software, version 14, and the "metan" command.

RESULTS

A total of 231 articles were retrieved from nineteen countries in East Africa. Of these, 70 articles were eligible for the review. The pooled prevalence of H. pylori in East Africa was 50.98% (95% CI: 45.05-56.90). The prevalence of H. pylori infection ranged from 7.7 to 94.5% in East African countries. The highest pooled prevalence was from Sudan (61.3%, 95% CI: 52.6-69.9), and the lowest prevalence was reported from Uganda (40.7%, 95% CI: 33-48.3). Persons with no formal education (OR: 2.03; 95% CI: 1.22-2.83), lack of hand washing habit after toilet (OR: 2.24; 95% CI: 1.45-3.02), having a history of dyspepsia (OR: 2.25; 95% CI: 1.31-3.18), living in rural areas (OR = 1.80; 95% CI: 0.38-3.23), and having unclean water source (OR = 1.5; 95% CI:0.45-3.45) were all associated with higher risk for H. pylori infection.

CONCLUSION

More than half of the populations of East African countries were positive for H. pylori infection. Rural residence, source of water, and alcohol consumption were significantly associated with H. pylori infection. Therefore, healthcare workers could provide health education on the aforementioned risk factors, and the government and other stakeholders could improve the source of drinking water in East Africa.

Histologic detection of Helicobacter pylori by the immunohistochemical method using anti-Helicobacter pylori polyclonal antibody: A cross-sectional study of patients with gastric pathologies at the Muhimbili National Hospital in Dar-es-salaam, Tanzania

BACKGROUND AND STUDY AIM

Immunohistochemistry is one of the superior methods and is regarded as the gold standard for the detection of Helicobacter pylori. We aimed to detect the presence of Helicobacter pylori in gastric biopsies among patients at the Muhimbili National Hospital from January 2012 to December 2016. Also, we determined the predictors of Helicobacter pylori infection.

PATIENTS AND METHODS

Retrospectively, we retrieved the tissue blocks of gastric biopsies at the Central Pathology Laboratory of the patients with different gastric pathologies at the Muhimbili National Hospital from January 2012 to December 2016. Helicobacter pylori were detected using anti-Helicobacter pylori polyclonal antibodies. Binary logistic regression analysis was done to determine the predictors of Helicobacter pylori infection. A two-tailed p < 0.05 was considered significant.

RESULTS

The prevalence of detection of Helicobacter pylori was 37.1% (63/170) using immunohistochemistry compared to 32.4% (55/170) using histology. Peptic ulcer disease, the absence of gastric cancer, and chronic gastritis were the predictors of Helicobacter pylori infection in our study (AOR = 0.2, 95% CI = 0.06-0.70, p = 0.011, AOR = 3.23, 95% CI = 1.02-10.29, p = 0.047, AOR = 0.32, 95% CI = 0.12-0.87, p = 0.025, respectively).

CONCLUSION

In this study, Helicobacter pylori infection was associated with the presence of peptic ulcer disease, chronic gastritis, and the absence of gastric cancer. The rate of detection of Helicobacter pylori infection was higher in tissue blocks of elderly patients than in those of young patients. Also, gastric cancer was more prevalent in old female patients.

Assessment of the diagnostic accuracy and relevance of a novel ELISA system developed for seroepidemiologic surveys of Helicobacter pylori infection in African settings

Beside diagnostic uncertainties due to the lack of a perfect gold standard test for Helicobacter pylori infection, the diagnosis and the prevalence estimation for this infection encounter particular challenges in Africa including limited diagnostic tools and specific genetic background. We developed and evaluated the accuracy of an enzyme-linked immunosorbent assay (ELISA) system tailored for H. pylori genetics in Africa (HpAfr-ELISA). Strains belonging to main genetic populations infecting Africans were exploited as sources for whole-cell antigens to establish in-house the ELISA system. A phase II unmatched case-control study explored the diagnostic accuracy of the HpAfr-ELISA using a training set of samples collected from dyspeptic patients from Kinshasa, the Democratic Republic of Congo (DRC) who had been tested with invasive standard tests (i.e., histology, culture, and rapid urease test) in 2017. Then the assay was cross-validated through a community-based survey assessing the prevalence of H. pylori and associated factors in 425 adults from Mbujimayi, DRC in 2018. Bayesian inferences were used to deal with statistical uncertainties of estimates (true prevalence, sensitivity, and specificity) in the study population. At its optimal cut-off-value 20.2 U/mL, the assay achieved an estimated sensitivity of 97.6% (95% credible interval [95%CrI]: 89.2; 99.9%) and specificity of 90.5% (95%CrI: 78.6; 98.5). Consistent outcomes obtained at repeated tests attested the robustness of the assay (negative and positive agreements always > 70%). The true prevalence of H. pylori was estimated 53.8% [95%CrI: 42.8; 62.7%]. Increasing age (adjusted odds ratio [aOR] > 1.0 [95% confidence interval (CI): > 1.0; 1.1]; p<0.001), overcrowding households (aOR = 3.2 [95%CI: 2.0; 5.1]; p<0.001), and non-optimal hand hygiene (aOR = 4.5 [95%CI: 2.0; 11.4]; p = 0.001) were independently associated with the H. pylori-seropositivity. The novel ELISA system has demonstrated good diagnostic accuracy and potential usefulness for management and mitigation strategies for H. pylori infection in African settings.

Prevalence of Helicobacter pylori in asymptomatic patients at surgical outpatient department: Harare hospitals

Background

Helicobacter pylori infection is present in more than 50% of the world's population. The estimated life time risk of peptic ulcer disease is 20 percent and of gastric cancer is 1–2 percent.

Materials and methods

A cross sectional study was done at two Central hospitals in Harare, Zimbabwe, with the objective being to estimate the prevalence of Helicobacter pylori infection in asymptomatic individuals. Other objectives were to determine the association of the Helicobacter pylori infection with potential risk factors.

Four hundred and fifty patients visiting the outpatient surgical clinics for other complaints other than upper gastrointestinal symptoms were recruited in the study. Drops of whole blood were obtained by fingertip puncture from each patient. The Onsite H. pylori Combo Rapid Test was used to confirm the presence or absence of antibodies against Helicobacter pylori. A questionnaire was used to record the sociodemographics of the participants.

Results

Three hundred patients, 186 males (62%) and 114 females (38%) participated. The prevalence of Helicobacter pylori infection was 67.7 percent (203/300). The prevalence of H pylori infection was significantly correlated with increasing age (p = 0.012), sharing of a bed with siblings during childhood (p = 0.013) and the mode of sanitation methods (p = 0.023). There was no association found between H pylori infection and other risk factors such as; gender, level of education, employment status or number of rooms in a house.

Conclusion

H. pylori infection prevalence was significantly associated with increasing age, sharing of a bed with siblings during childhood and the mode of sanitation used. Clinicians and the public have to be aware of the important role of H pylori in upper gastrointestinal disease. Use of better sanitation methods, appropriate hygiene, avoidance of over-crowding amongst other measures should be encouraged as a means to reduce the acquisition and transmission of H pylori.

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Prevalence of H. pylori infection is 67.7%.

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The results are from Zimbabwe.

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It is associated with increasing age and the mode of sanitation.

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It is associated with sharing of a bed with siblings during childhood.

Risk factors for mortality among patients admitted with upper gastrointestinal bleeding at a tertiary hospital: a prospective cohort study

Background

Upper gastrointestinal bleeding (UGIB) is a common gastrointestinal emergency, which is potentially fatal. Proper management of UGIB requires risk-stratification of patients which can guide the type and aggressiveness of management. The aim of this was study was identify the causes of UGIB and factors that increase the risk of mortality in these patients.

Methods

This was a prospective cohort study conducted over a period of seven months at a tertiary hospital. Adults admitted with UGIB were included in the study. Demographic data, laboratory parameters and endoscopic findings were recorded. Patients were then followed up for 60 days to identify the occurrence of mortality. Chi-square tests and cox-regression was used to determine association between risk factors and mortality in the bivariate and multivariate analysis, respectively.

Results

A total of 170 patients with UGIB were included. Males accounted for the majority (71.2%). Median age of the study population was 40.0 years. Chronic liver disease was present in 30.6% of study patients. The most common cause of UGIB among the 86 patients who underwent endoscopy was oesophageal varices (57%), followed by peptic ulcer disease (18%) and gastritis (10%). Mortality occurred in 57 patients (33.5%) and was significantly higher in patients with high white blood cell count (HR 2.45, p 0.011), raised serum alanine aminotransferase (HR 4.22, p 0.016), raised serum total bilirubin (HR 5.79, p 0.008) and lack of an endoscopic procedure done (HR 4.40, p <0.001). Rebleeding was reported in 12 patients (7.1%) and readmission due to UGIB in 4 patients (2.4%)

Conclusions

Oesophageal varices was the most common cause of UGIB. One-third of patients admitted with upper gastrointestinal bleeding died within 60 days of admission, signifying a high burden. Rebleeding and readmission rates were low. A high WBC count, raised serum ALT, raised serum total bilirubin and a lack of endoscopy were independent predictors of mortality. These findings can be used to risk-stratify patients who may benefit from early and more aggressive management.

Sero-prevalence and associated factors of Helicobacter pylori infection among adult patients with dyspepsia attending the gastroenterology unit in a tertiary hospital in Mwanza, Tanzania

BACKGROUND

Prevalence of H.pylori infection varies greatly between populations in different countries. This study was conducted to determine the magnitude of H.pylori among adult patients with dyspepsia attending the gastroenterology unit at Bugando medical centre.

METHODS

A cross sectional study involving 202 dyspeptic patients was conducted between June and July 2014. A Standardized data collection tool was used to collect socio-demographic characteristics. H.pylori antibodies were detected using rapid immunochromatographic tests according to manufacturer's instructions.

RESULTS

The median age of study population was 42 (IQR: 33-54). Females 105 (51.9%) formed majority of the population studied. Of 202 participants; 119 (58.9%) were from rural areas. Seroprevalence of H.pylori infection was found to be 79/202 (39.1%, 95% CI: 32.3-45.7). As the age increased the risk of having H.pylori infection also increased (OR: 1.02 95% CI: 1-1.04, P=0.02). On multivariate logistic regression analysis untreated drinking water was found to predict H.pylori seropositivity (OR: 2.33, CI: 1.09-4.96, p=0.028).

CONCLUSION

The seroprevalence of H.pylori among dyspeptic patients is high in this setting. Therefore the community in Mwanza should be educated on the use of safe drinking water in order to minimize H. pylori infections.

Mechanistic insight into the TH1-biased immune response to recombinant subunit vaccines delivered by probiotic bacteria-derived outer membrane vesicles

Recombinant subunit vaccine engineering increasingly focuses on the development of more effective delivery platforms. However, current recombinant vaccines fail to sufficiently stimulate protective adaptive immunity against a wide range of pathogens while remaining a cost effective solution to global health challenges. Taking an unorthodox approach to this fundamental immunological challenge, we isolated the TLR-targeting capability of the probiotic E. coli Nissle 1917 bacteria (EcN) by engineering bionanoparticlate antigen carriers derived from EcN outer membrane vesicles (OMVs). Exogenous model antigens expressed by these modified bacteria as protein fusions with the bacterial enterotoxin ClyA resulted in their display on the surface of the carrier OMVs. Vaccination with the engineered EcN OMVs in a BALB/c mouse model, and subsequent mechanism of action analysis, established the EcN OMV’s ability to induce self-adjuvanted robust and protective humoral and T_H1-biased cellular immunity to model antigens. This finding appears to be strain-dependent, as OMV antigen carriers similarly engineered from a standard K12 E. coli strain derivative failed to generate a comparably robust antigen-specific T_H1 bias. The results demonstrate that unlike traditional subunit vaccines, these biomolecularly engineered “pathogen-like particles” derived from traditionally overlooked, naturally potent immunomodulators have the potential to effectively couple recombinant antigens with meaningful immunity in a broadly applicable fashion.

Gastric cancer in Africa: what do we know about incidence and risk factors?

Gastric cancer is a major contributor to mortality worldwide, yet its incidence varies widely around the world in a way which our current understanding of aetiology cannot fully explain. Incidence data from Africa are weak, reflecting poor diagnostic resources, but there are firm data on intestinal metaplasia and gastric atrophy which are important steps in the carcinogenesis pathway. The available registry data suggest that incidence is unlikely to be dramatically different from Europe or North America. Helicobacter pylori infection is an important permissive factor in the development of cancer, but H. pylori seroprevalence is high all over Africa and cannot clearly be correlated with cancer. However, there is evidence that specific bacterial virulence genes, particularly vacA and iceA allele1, do contribute to cancer risk. Intestinal metaplasia and gastric atrophy have been the focus of twelve studies and are common in Africa. Epstein-Barr virus, which causes 10% of cancer worldwide, is the focus of only one African study. Work in other continents demonstrates that other risk factors apply only to one or other of the two major histological types, intestinal and diffuse. Diet, smoking, alcohol and salt intake predispose to the intestinal type of cancer, but genetic factors predispose to the diffuse type. There is a pressing need for information on the histological types occurring in Africa, and their associated risk factors. Most urgently, information on dietary predisposition to cancer is required to inform public health policy with respect to the demographic transition (urbanisation and lifestyle changes) which is occurring all over the continent.

Helicobacter pylori in apparently healthy children aged 0-12 years in urban Kampala, Uganda: a community-based cross sectional survey

Background

Helicobacter pylori is one of the most common causes of bacterial infection in human beings. Studies have showed a high prevalence of Helicobacter pylori among people in low-income countries and colonization early in life. A monoclonal antigen test, performed on faeces, HpSA^®ImmunoCardSTAT, has a high sensitivity, specificity and accuracy and the faecal test can be performed in all ages, also in resource-limited settings. The main objective of this study was to determine the prevalence and factors associated with Helicobacter pylori colonization in apparently healthy children aged 0-12 years in urban Kampala, Uganda.

Method

We tested 427 apparently healthy children, age 0-12 years (211 males, 216 females), in a cross sectional survey for Helicobacter pylori colonization using HpSA ^®ImmunoCardSTAT. A short standardized interview with socio-demographic information and medical history was used to assess risk factors.

Results

The overall prevalence of Helicobacter pylori in the 427 children was 44.3% (189 out of 427). Early colonization was common, 28.7%, in children younger than 1 year of age. The age specific rates were 46.0% in children age 1- < 3 years, 51.7% in children age 3- < 6 years, 54.8% in children age 6- < 9 years and 40.0% in children age 9- < 12 years. There was a significant difference in prevalence by gender; female 38.5% versus male 49.8% and by type of housing; permanent house 38.5% versus semi-permanent house 48.6%. Congestive living and education level of the female caretaker showed a clear trend for a difference in prevalence. Factors independently associated with Helicobacter pylori colonization included: drugs taken last three months, using a pit latrine, sources of drinking water and wealth index.

Conclusion

The prevalence of Helicobacter pylori colonization among urban Ugandan children is high at an early age and increases with age. The impact of Helicobacter pylori colonization on children's health in Uganda needs to be further clarified.

Factors contributing to the underestimation of Helicobacter pylori-associated gastric cancer risk in a high-prevalence population

OBJECTIVE

This study aimed to identify sources of underestimation of the association between Helicobacter pylori infection and non-cardia gastric cancer, in a high-risk European population.

METHODS

Non-cardia gastric cancer patients (n = 420) recruited in two major hospitals in North of Portugal and population controls (n = 1,389) were evaluated. Whole-cell IgG antibodies against H. pylori were quantified by ELISA and Western Blot testing was conducted in a subsample (272 cases and 186 controls) allowing for the detection of current infection marker and CagA. Sex- and age-adjusted odds ratios (OR) and 95% confidence intervals (95% CI) were computed.

RESULTS

When assessing infection by ELISA, the OR for its association with gastric cancer decreases and reverts as IgG titers increased, from 1.96 (95% CI: 1.09-3.54) for borderline positive results (16.0-21.9 RU/ml) to 0.52 (95% CI: 0.36-0.74) for the highest IgG levels (> or = 102.0 RU/ml). The same pattern was observed across strata of age and blood collection timing with stronger associations among younger subjects and those providing blood samples earlier after diagnosis. The presence of CagA (Western Blot) was associated with an increased risk of gastric cancer (OR = 11.32; 95% CI: 5.64-22.73).

CONCLUSION

The use of methods with low sensitivity to detect past infection leads to a substantial underestimation of gastric cancer risk in high-prevalence settings.

Associations between Helicobacter pylori infection, co-morbid infections, gastrointestinal symptoms, and circulating cytokines in African children

BACKGROUND

Refugee children have complex medical needs and often have multiple infections. The relationship between infection, gastrointestinal symptoms, and systemic inflammation is poorly understood. We investigated these parameters in refugee children with a high prevalence of Helicobacter pylori, helminth, and malaria infection.

MATERIALS AND METHODS

African refugee children were recruited at resettlement health screening. Data were collected on demography, gastrointestinal symptoms, co-morbid infection, and serum for peripheral cytokine levels. Helicobacter pylori infection was diagnosed by a fecal-based immunoassay.

RESULTS

Data from 163 children were analyzed, of which 84.0% were positive for H. pylori. Infected children were significantly older (9.2 years +/- 3.7 vs 7.1 years +/- 3.9, p = .01). Half the cohort (84/163, 51.5%) described gastrointestinal symptoms but these were not strongly associated with co-morbid infections. Helicobacter pylori-infected children had significantly lower circulating log-interleukin-8 (IL-8) (odds ratio 0.61, 95% confidence interval (CI) 0.40, 0.94, p = .025). Helminth infections were common (75/163, 46%) and associated with elevated log-IL-5 (beta: 0.42, 95% CI 0.077, 0.76). Children with malaria (15/163, 9.2%) had elevated log-tumor necrosis factor-alpha (TNFalpha) and log-IL-10 (beta: 0.67, 95% CI 0.34, 1.0 and beta: 1.3, 95% CI 0.67, 1.9, respectively). IL-10 : IL-12 ratios were increased in H. pylori-infected children with malaria or helminth infections. Symptoms were generally not associated with levels of circulating peripheral cytokines irrespective of co-morbid infection diagnosis.

CONCLUSIONS

There is a high prevalence of asymptomatic H. pylori infection in recently resettled African refugee children. Gastrointestinal symptoms were not predictive of H. pylori nor of helminth infections. Serum cytokines, particularly IL-5, IL-10, and TNFalpha, were significantly elevated in children with malaria and helminth infections but not in those with H. pylori infection.

Helicobacter pylori antigenemia in an asymptomatic population of Eastern Cape Province, South Africa: public health implications

Helicobacter pylori is a major cause of such upper gastrointestinal diseases as gastritis, peptic ulcer, and gastric cancer. The risk of infection is increased in those living in the developing world, which has been ascribed to precarious hygiene standards, crowded households, and deficient sanitation common in this part of the world. Fecal samples were collected from 356 apparently healthy subjects, consisting of 168 males and 188 females aged from 3 months to > or = 60 years (Mean = 31 years). A standardized questionnaire describing demographic characteristic including age, sex, household hygiene, socioeconomic status, and so on was applied. A sandwich-type enzyme immunoassay amplification technology (Amplified IDEIA Hp StAR, Oxoid, UK) was used to analyze the fecal samples for the detection of H. pylori antigens using monoclonal antibodies specific for H. pylori antigens. Fisher's exact test was used to assess the univariate association between H. pylori infection and the possible risk factors. Odds ratio (OR) and the corresponding 95% confidence interval (CI) were calculated to measure the strength of association using EPI INFO 3.41 package. P values of < .05 were required for significance. H. pylori antigen was detected in 309 of the 356 subjects giving an overall prevalence of 86.8%. Prevalence increased with age from 75.9% in children < 12 years age to 100% in young adults aged 25-47 years and subjects aged > or = 60 years (P < .05). H. pylori prevalence was higher in females than in males. Of 188 females who participated in the study, H. pylori antigen was detected in 172 (91.5%) versus 144 (85.7%) 168 males (P > .05). Interestingly, H. pylori antigen was detected more often (100%) in the high socioeconomic group than in those of low socioeconomic group (85.9%) (P > .05). The results of this study have revealed a high prevalence of H. pylori antigens in fecal samples of asymptomatic individuals in the Nkonkobe municipality, an indication of active infection. Socioeconomic status, contaminated water, and poor sanitation may play a role in H. pylori transmission in this population. This finding is of public health and epidemiologic significance.

Acquisition of Helicobacter pylori infection in early childhood: independent contributions of infected mothers, fathers, and siblings

OBJECTIVES

Infected siblings, mothers, and fathers have all been suggested to be major sources for Helicobacter pylori acquisition among children, but few studies have addressed the potential role of various family members simultaneously.

METHODS

A systematic review was performed on studies investigating intrafamilial transmission of childhood H. pylori infection. Within the Ulm Birth Cohort Study, which consists of 1,066 healthy newborns, born between November 2000 and November 2001 and followed up to age 4, and their siblings and parents, the independent role of the infection status of parents and siblings in transmission of H. pylori among children at age 4 was assessed.

RESULTS

Among four studies reporting infected mothers and siblings as independent risk factors for childhood H. pylori infection, odds ratios (ORs) for childhood infection given an infected sibling decreased meaningfully after adjustment for maternal infection status. Within the Ulm Birth Cohort Study, the prevalence of infection was 3.0% among index children at age 4. In bivariate analyses, maternal, paternal, and sibling infection were all strongly and significantly related to infection of the child. However, after multivariate adjustment, only maternal infection persisted as the single strong and significant risk factor (OR 13.0, 95% confidence interval 3.0-55.2).

CONCLUSIONS

These patterns suggest that mutual control for H. pylori status of other family members is crucial for estimating the role of mothers, fathers, and siblings in the transmission of childhood H. pylori infection. In populations with low H. pylori prevalence the infected mother is likely to be the main source for childhood H. pylori infection.

Host, family and community proxies for infections potentially associated with leukaemia

Three hypotheses have proposed the involvement of infections in the aetiology of childhood leukaemia, suggesting either a specific leukaemogenic infection or a series of common infections that lead to a dysregulation of the immune system. Much of the evidence for the link with infections has been based on epidemiological observations, often using proxy measures of infection. Proxy measures include population mixing, parental occupation, age distribution of incidence, spatial and space-time clustering of cases, birth order and day care during infancy. This paper discusses the proxies used and examines to what extent a commonly used proxy measure, birth order, is a fair representation of either specific infections or general infectious load. It is clear that although leukaemia, and other diseases, may be linked with infections, one needs to (1) measure specific and general infections with more accuracy and (2) understand how proxy measures relate to real infections in the population.

Diagnosis of Helicobacter pylori infection in a high-prevalence pediatric population: a comparison of 2 fecal antigen testing methods and serology

OBJECTIVES

Accurate methods for diagnosing active Helicobacter pylori infection in children have been limited to invasive or time-consuming techniques. Recently, fecal antigen testing has been used successfully for the diagnosis of H pylori infection in the pediatric population. We compared 2 monoclonal fecal antigen diagnostic methods in a population of children with a suspected high prevalence of H pylori infection. We also assessed the diagnostic performance of H pylori immunoglobulin G serology.

MATERIALS AND METHODS

In a cross-sectional study of African refugee children (<16 years) we compared an immunochromatographic technique (ICT) and serology with a monoclonal fecal antigen enzyme immunoassay (MFAT) method for the detection of active H pylori infection. Following the manufacturer's instructions, an optical density of >or=0.190 was used as a cutoff for MFAT. Sensitivity, specificity, and positive and negative predictive values were calculated.

RESULTS

Of the 193 eligible children enrolled, active H pylori infection was detected in 149 of 182 (81.9%) in whom MFAT was performed. The prevalence of active infection increased with age; children with active infection were significantly older, and there were no sex differences. ICT and serology underperformed in comparison with MFAT (ICT sensitivity 74.6%, specificity 63.6%, positive predictive value 89.8%, negative predictive value 36.8%; and serology sensitivity 57.9%, specificity 77.4%, positive predictive value 92.0%, negative predictive value 29.9%).

CONCLUSIONS

Monoclonal enzyme immunoassay fecal antigen testing is a practical and feasible alternative to traditional invasive diagnostic methods in high-prevalence pediatric populations. Neither immunochromatography nor serology is useful for the diagnosis of active H pylori infection in these children.