Prevalence of Helicobacter pylori infection in infants and family contacts in a poor Bangladesh community

Asymptomatic Duodenitis and Helicobacter pylori associated Dyspepsia in 2-Year-Old Chronic Malnourished Bangladeshi Slum-Dwelling Children: A Cross-Sectional Study

AIM

There is insufficient knowledge on the * duodenal histology and Helicobacter pylori infection in malnourished Bangladeshi children. Therefore, we attempted to explore the prevalence of H. pylori infection and duodenal histopathology in 2-year-old chronic malnourished Bangladeshi slum-dwelling children and investigate their association with dyspeptic symptoms.

METHODS

This cross-sectional study was conducted using the data of the Bangladesh Environmental Enteric Dysfunction study in an urban slum of Dhaka, Bangladesh. With a view to address the association of environmental enteric dysfunction (EED) with stunting, upper gastrointestinal endoscopy was performed on 54 chronic malnourished children {31 stunted [length-for-age Z-scores (LAZ) <-2] and 23 at risk of stunting (LAZ <-1 to -2)} aged between 12-24 months and the mucosal biopsies were subjected to histopathological examination after obtaining proper clinical history. Stool antigen for H. pylori (HpSA) was assessed to determine H. pylori status.

RESULTS

In all, 83.3% (45/54) of the children had histopathological evidence of duodenitis. Chronic mild duodenitis was found to be the most prevalent form of duodenitis (53.7%) in the children. Only 8.9% (4/45) of the children with duodenitis had dyspepsia (p < 0.05). The 14.8% (8/54) of the children were found positive for H. pylori infection. Logistic regression analysis revealed children positive for HpSA had significant association with dyspepsia (OR 9.34; 95% CI 1.54-56.80).

CONCLUSIONS

The number of chronic malnourished children suffering from duodenitis was found to be very high. Majority of these children was asymptomatic. Children positive for HpSA had significant association with dyspeptic symptoms.

Helicobacter pylori infection is associated with fecal biomarkers of environmental enteric dysfunction but not with the nutritional status of children living in Bangladesh

Background

Because Helicobacter pylori (H. pylori) infection and Environmental Enteric Dysfunction (EED) follow a similar mode of transmission, there can be a complex interplay between H. pylori infection and EED, both of which can influence childhood growth. We sought to investigate the factors associated with H. pylori infection and identify its relationship with the fecal biomarkers of EED including Myeloperoxidase (MPO), Neopterin (NEO), Calprotectin, Reg1B and Alpha-1 antitrypsin (AAT), and nutritional status of the children.

Methodology

Data from an on-going community-based nutrition intervention study was used for this analysis. Total 319 children aged between 12–18 months were evaluated at enrolment and at the end of a 90-day nutrition intervention. Multivariable linear regression with generalized estimating equations was done to examine the association of H. pylori infection with stool biomarker of EED and nutritional status of the children.

Principal findings

One-fifth of the participants had H. pylori infection at both the time points, with 13.8% overall persistence. Children living in crowded households had higher odds of being infected by H. pylori (AOR = 2.02; 95% CI = 1.02, 4.10; p-value = 0.045). At enrolment, 60%, 99%, 69% and 85% of the stool samples were elevated compared to the reference values set for MPO, NEO, AAT and Calprotectin in the non-tropical western countries. The proportions reduced to 52%, 99%, 67%, and 77% for the same biomarkers after the nutrition intervention. Infection with H. pylori had significant positive association with fecal AAT concentrations (Coefficient = 0.26; 95% CI = 0.02, 0.49; p-value = 0.03) and inverse relationship with Reg1B concentrations measured in the stool samples (Coefficient = -0.32; 95% CI = -0.59, -0.05; p-value = 0.02). However, H. pylori infection was not associated with the indicators of childhood growth.

Conclusions

The study findings affirmed that the acquisition and persistence of H. pylori infection in the early years of life may exert an adverse impact on intestinal health, induce gut inflammation and result in increased intestinal permeability.

Infection with H. pylori, a substantial public health burden in the tropical countries, follows the similar mode of transmission analogous to Environmental Enteric Dysfunction (EED). There can be a complex interplay between H. pylori infection and EED–both of which can influence childhood growth–but the definite role of H. pylori infection contributing to EED and subsequent growth failure is poorly understood. In this study, the authors present data from an ongoing community-based nutrition intervention study and investigated the factors associated with H. pylori infection and identify its relationship with fecal biomarkers of EED and indicators of the nutritional status of the children hailing from a resource-poor urban settlement. They demonstrated the acquisition and persistence of H. pylori infection during early childhood. The study results also corroborate that infection with H. pylori had significant positive association with fecal Alpha-1 antitrypsin concentrations and an inverse relationship with Reg1B concentrations measured in stool samples of the children. The findings revealed in this study may contribute to a better understanding of the role of H. pylori infection in contributing to EED as well as alteration of gut function in the early years of life.

Helicobacter pylori: a perspective in low- and middle-income countries

BACKGROUND

In adults, Helicobacter pylori is aetiologically associated with peptic ulcer disease and gastric cancer. However, the relationship between this bacteria and gastro-intestinal symptoms in children is less clear.

AIMS

To review the recent literature on H. pylori in children and to outline the approach to diagnosis and management.

METHODS

The English language literature was searched for articles on H. pylori in children. Special attention was paid to prevalence, diagnosis and management pertinent to low- and middle-income countries (LMIC).

RESULTS

Although the prevalence of H. pylori is 60-80% in LMIC, only 5% of infected children develop peptic ulcer disease. The virulence of the organism determines the outcome. There is a suggestion that H. pylori causes iron deficiency anaemia, growth retardation and idiopathic thrombocytopenic purpura, but the evidence is not sufficiently strong to justify screening. There is no evidence to suggest a link between H. pylori infection and recurrent abdominal pain. Endoscopy (with invasive tests) is the preferred method of investigation as the primary goal is to determine the underlying cause of the symptoms. Children with H. pylori-related diseases should be treated with a standard triple-drug regimen consisting of a protein pump inhibitor and two antibiotics for 10-14 days. All treated patients should be monitored for eradication with non-invasive tests such as the urea (13-C) breath test or stool antigen tests.

CONCLUSIONS

Although H. pylori infection is common in LMIC, most children are asymptomatic. There is no association between H. pylori and recurrent abdominal pain. Invasive tests are preferred for diagnosis and a triple-drug regimen is the treatment of choice.

When is Helicobacter pylori acquired in populations in developing countries? A birth-cohort study in Bangladeshi children

Helicobacter pylori colonization is prevalent throughout the world, and is predominantly acquired during childhood. In developing countries, >70% of adult populations are colonized with H. pylori and >50% of children become colonized before the age of 10 years. However, the exact timing of acquisition is unknown. We assessed detection of H. pylori acquisition among a birth cohort of 105 children in Mirzapur, Bangladesh. Blood samples collected at time 0 (cord blood), and at 6, 12, 18, and 24 months of life were examined for the presence of IgG and IgA antibodies to whole cell H. pylori antigen and for IgG antibodies to the CagA antigen using specific ELISAs and immunoblotting. Breast milk samples were analyzed for H. pylori-specific IgA antibodies. Cord blood was used to establish maternal colonization status. H. pylori seroprevalence in the mothers was 92.8%. At the end of the two-year follow-up period, 50 (47.6%) of the 105 children were positive for H. pylori in more than one assay. Among the colonized children, CagA prevalence was 78.0%. A total of 58 children seroconverted: 50 children showed persistent colonization and 8 (7.6%) children showed transient seroconversion, but immunoblot analysis suggested that the transient seroconversion observed by ELISA may represent falsely positive results. Acquisition of H. pylori was not influenced by the mother H. pylori status in serum or breastmilk. In this population with high H. pylori prevalence, we confirmed that H. pylori in developing countries is detectable mainly after the first year of life.

Helicobacter pylori outer membrane protein and virulence marker differences in expatriate patients

We studied the prevalence of Helicobacter pylori virulence markers, e.g. cytotoxin associated gene (cagA), cagA promoter, vacuolating associated cytotoxin A (vacA) alleles induced by contact with epithelium (iceA type), and outer membrane protein Q (hopQ) in expatriates and compared them with those in local residents. Gastric biopsies were obtained at endoscopy for culture, histology and PCR for virulence marker and hopQ. Of 309 patients, 236 (76%) were males with a mean age of 45 years. A total of 102 patients were expatriates. hopQ type 1 was present in 98 (47%) local residents compared to 88 (86%) expatriates (P < 0·001), while hopQ type 2 was present in 176 (85%) local residents, compared to 60 (59%) expatriates (P < 0·001). H. pylori virulence marker cagA was positive in 97 (47%) local residents compared to 86 (84%) expatriates (P < 0·001) while cagA-P was positive in 72 (35%) local residents compared to 87 (85%) expatriates (P < 0·001). iceA type 1 was positive in 157 (76%) local residents compared to 45 (44%) expatriates (P < 0·001), while iceA type 2 was positive in 81 (39%) local residents compared to 86 (84%) expatriates (P < 0·001). Distribution of H. pylori cagA, cagA promoter, iceA and hopQ type in local residents and expatriates was different. H. pylori virulence markers were associated with severe pathology in expatriates.

Observation of gastric mucosa in Bangladesh, the country with the lowest incidence of gastric cancer, and Japan, the country with the highest incidence

BACKGROUND

The prevalence of Helicobacter pylori (H. pylori) infection is high, but the incidence of gastric cancer is low in natives of Bangladesh. The gastric mucosa was observed in Bangladeshi patients to investigate the differences between Bangladeshis and Japanese.

MATERIALS AND METHODS

The study involved 418 Bangladeshi and 2356 Japanese patients with abdominal complaints who underwent endoscopy examinations and had no history of H. pylori eradication. The prevalence of H. pylori infection and the gastric mucosa in H. pylori-positive patients were compared between age-, gender-, and endoscopic diagnosis-matched Bangladeshi and Japanese subjects.

RESULTS

The prevalence of H. pylori infection was higher in Bangladeshi than in Japanese subjects (60.2 and 45.1%, respectively). All the scores for chronic inflammation, neutrophil activity, glandular atrophy, and intestinal metaplasia were significantly lower in H. pylori-positive Bangladeshis than in H. pylori-positive Japanese. The ratio of the corpus gastritis score (C) to the antrum gastritis score (A) (C/A ratio) was <1 (antrum-predominant gastritis) in all age groups of Bangladeshi subjects, whereas the C/A ratio changed from <1 to more than 1 (corpus-predominant gastritis) with aging in Japanese subjects.

CONCLUSIONS

The scores for glandular atrophy and intestinal metaplasia in H. pylori-positive Bangladeshis were significantly lower than those in Japanese. All age groups of Bangladeshis had antrum-predominant gastritis, whereas corpus-predominant gastritis was more common than antrum-predominant gastritis in older Japanese age groups. These results may explain the low incidence of gastric cancer in Bangladeshis and the high incidence in Japanese.

Helicobacter pylori: a poor man's gut pathogen?

Helicobacter pylori is one of the human pathogens with highest prevalence around the world; yet, its principal mode of transmission remains largely unknown. The role of H. pylori in gastric disease and cancer has not been established until the end of the 20^th century. Since then, its epidemiology has been extensively studied, and an accruing body of literature suggests that not all humans are equally at risk of infection by this gut pathogen. Here, we briefly review the different epidemiological aspects of H. pylori infection with emphasis on those factors related to human poverty. The epidemiology of H. pylori infection is characterized by marked differences between developing and developed countries, notably among children. In addition, congruent lines of evidence point out to socioeconomic factors and living standards as main determinants of the age-dependent acquisition rate of H. pylori, and consequently its prevalence. These data are alarming in the light of the changing global climate and birth rate, which are expected to change the demography of our planet, putting more children at risk of H. pylori and its complications for years to come.

Helicobacter pylori: a poor man's gut pathogen?

Helicobacter pylori is one of the human pathogens with highest prevalence around the world; yet, its principal mode of transmission remains largely unknown. The role of H. pylori in gastric disease and cancer has not been established until the end of the 20th century. Since then, its epidemiology has been extensively studied, and an accruing body of literature suggests that not all humans are equally at risk of infection by this gut pathogen. Here, we briefly review the different epidemiological aspects of H. pylori infection with emphasis on those factors related to human poverty. The epidemiology of H. pylori infection is characterized by marked differences between developing and developed countries, notably among children. In addition, congruent lines of evidence point out to socioeconomic factors and living standards as main determinants of the age-dependent acquisition rate of H. pylori, and consequently its prevalence. These data are alarming in the light of the changing global climate and birth rate, which are expected to change the demography of our planet, putting more children at risk of H. pylori and its complications for years to come.

Evidence of intra-familial transmission of Helicobacter pylori by PCR-based RAPD fingerprinting in Bangladesh

Helicobacter pylori is a genetically diverse bacterial species, which has facilitated adaptation to new hosts and persists worldwide. The main objective of this study was to explore intra-familial transmission of H. pylori in Bangladesh. We characterized H. pylori in 35 families including 138 family members using random amplified polymorphic DNA (RAPD) fingerprinting. Forty-six percent of H. pylori isolated from the mother shared a related genotype with strains isolated from their children. Twenty-nine percent of H. pylori isolates of the mother are related to the youngest children. Only 6% of the parents shared related genotype of H. pylori. These findings suggest that mother-to-child transmission occurs in early childhood and is the most probable route of transmission of H. pylori in Bangladesh.

Infection by Helicobacter pylori in Bangladeshi children from birth to two years: relation to blood group, nutritional status, and seasonality

BACKGROUND

A birth cohort of 238 children was followed in an urban slum in Dhaka, Bangladesh, to determine incidence, prevalence, and epidemiologic factors related to Helicobacter pylori infection.

METHODS

H. pylori infection was determined by a specific stool antigen test as well as enzyme-linked immunosorbent assay for detecting specific IgA and IgG antibodies in sera in children who completed 2 years of follow-up.

RESULTS

Using the stool antigen test and serology, 50% and 60% of infants respectively, were positive for H. pylori by 2 years; an increase in the infection rate was seen after 6 months of age. Determination of specific antibodies in sera and detection of H. pylori antigen in stool were comparable. A typical seasonality, peaking in spring and autumn, was observed for acquisition of initial H. pylori infection. Children with blood group "A" were more susceptible to H. pylori infection than those with other ABO blood groups. Malnutrition did not seem to promote colonization by H. pylori. However, H. pylori-infected children were more often infected by multiple enteropathogens, often isolated at different time points.

CONCLUSIONS

This study shows that noninvasive diagnostic methods such as serology and the stool antigen test are suitable for the study of acquisition of H. pylori infections in infants and can be used in field settings as well as in laboratories and clinical setting having less well equipped facilities. The study also shows seasonality for initial H. pylori infection and a relationship between blood group "A" and infection.

Causal relationship of Helicobacter pylori with iron-deficiency anemia or failure of iron supplementation in children

BACKGROUND & AIMS

We investigated Helicobacter pylori (H pylori)-infection as a cause of iron deficiency (ID) and iron-deficiency anemia (IDA) or treatment failure of iron supplementation.

METHODS

We randomized 200 Hp-infected children (positive urea breath test) 2-5 years of age with IDA (hemoglobin level <110 g/L; serum ferritin level <12 microg/L; and soluble transferrin receptor >8.3 mg/L) or ID (serum ferritin level <12 microg/L or soluble transferrin receptor level >8.3 mg/L) to 1 of 4 regimens: 2-week anti-Hp therapy (amoxicillin, clarithromycin, and omeprazole) plus 90-day oral ferrous sulfate (anti-Hp plus iron), 2-week anti-Hp therapy alone, 90-day oral iron alone, or placebo. Sixty noninfected children with IDA received iron treatment as negative control.

RESULTS

Hp-infected children receiving iron had significantly less frequent treatment failure compared with those with no iron in correcting IDA (11% [95% confidence interval (CI), 2%-20%] for anti-Hp plus iron, 0% for iron alone vs 33% [95% CI, 26%-46%] for anti-Hp and 45% [95% CI, 31%-59%] for placebo; chi(2) = 127; P < .0001), ID (19% [95% CI, 8%-30%] for anti-Hp plus iron, 7% [95% CI, 0%-14%] for iron alone vs 65% [95% CI, 52%-78%] for anti-Hp alone, and 78% [95% CI, 66%-90%] for placebo; chi(2) = 124; P < .0001), or anemia (34% [95% CI, 20%-40%] for anti-Hp plus iron, 27% [95% CI, 14%-40%] for iron alone vs 65% [95% CI, 52%-78%] for anti-Hp alone and 78% [95% CI, 66%-90%] for placebo; chi(2) = 46; P < .0001). Cure rates of IDA, ID, or anemia with iron were comparable with that of the negative control group. Improvements in iron status also were significantly greater in groups with iron.

CONCLUSIONS

H pylori is neither a cause of IDA/ID nor a reason for treatment failure of iron supplementation in young Bangladeshi children.

Childhood Helicobacter pylori infection and growth impairment in developing countries: a vicious cycle?

We hypothesize that infection with the gastric pathogen Helicobacter pylori in children in developing countries is the initiator of a vicious cycle of events that result ultimately in malnutrition and growth impairment. Acute infection with H. pylori is accompanied by hypochlorhydria, which facilitates the acquisition of other enteropathogens because of removal of the gastric acid barrier, which then results in diarrheal disease and iron-deficiency anemia. This is likely to occur most frequently in developing regions where the prevalence of H. pylori infection is disproportionately high and multiple enteric coinfections are common. The consequent synergistic impact of diarrheal disease and micronutrient deficiency on growth and cognitive function in children has significant public health implications for socioeconomic development in these countries.

Epidemiology and pathophysiology of Helicobacter pylori infection in children

Helicobacter pylori is one of the commonest bacterial pathogens in human. The organism is associated with development of peptic ulcer diseases, lymphoproliferative disorders and gastric cancer. Residence in a developing country, poor socio-economic conditions and genetic predisposition are regarded as risk factors. Prevalence of infection is higher in developing countries and re-infection is higher among under five children. It is transmitted mainly through feco-oral route in developing countries and gastro-oral route in developed nations. Transmission of 'close-contact infection' depends on the degree of mixing and age-distribution between susceptible and infected individuals. Host and bacterial factors with interaction of environment contribute pathogenicity. H. pylori cytotoxin-associated geneA (cagA), vacuolating toxinA (vacA) and adherence factors to gastric epithelium have been linked to enhanced pathogenicity of the bacterium. Host genetic polymorphism of cytokines, related legends, receptors and enzymes influence H. pylori infection.

Intra-familial transmission of Helicobacter pylori infection in children of households with multiple generations in Vietnam

This community-based cross-sectional study in 533 participants from 135 households with multiple generations living in the same household aimed at investigating the relationship between Helicobacter pylori infection in children and the other household members. H. pylori infection in children was found significantly associated with the infection in mothers [OR (95% CI): 2.50 (1.19-5.26)], even after being adjusted for sex, age group and sibling number [adjusted OR (95% CI): 2.47 (1.12-5.47)]. It was also significantly associated with the infection in both parents [adjusted OR (95% CI): 4.14 (1.29-13.23)]. No significant association between H. pylori infection in the father, grandparent(s), uncle or aunt with that in their children was found. Results from the present study showed intra-familial transmission in a multi-generation population and supported the hypothesis of person-to-person transmission of H. pylori infection.

Causal role of Helicobacter pylori infection in gastric cancer: An Asian enigma

Helicobacter pylori (H pylori) has been etiologically linked to gastric cancer. H pylori infection is more frequent in less developed Asian countries like India, Bangladesh, Pakistan, and Thailand and is acquired at early age than in more developed Asian countries like Japan and China. Frequency of gastric cancer, however, is very low in India, Bangladesh, Pakistan and Thailand compared to that in Japan and China. Similar enigma has been reported from Africa as compared to the West. Seroprevalence of H pylori infection in adult populations of India, Bangladesh, Pakistan and Thailand varies from 55% to 92%. In contrast, seroprevalence of H pylori in Chinese and Japanese adults is 44% and 55%, respectively. Annual incidence rate of gastric cancer in India, Bangladesh, and Thailand is 10.6, 1.3, 7.1 per 100 000 populations, respectively; in contrast, that in China and Japan is 32-59 and 80-115 per 100 000 populations, respectively. Several studies from India failed to show higher frequency of H pylori infection in patients with gastric cancer than controls. Available evidences did not support difference in H pylori strains as an explanation for this enigma. Despite established etiological role of H pylori, situation is somewhat enigmatic in Asian countries because in countries with higher frequency of infection, there is lower rate of gastric cancer. Host’s genetic make-up and dietary and environmental factors might explain this enigma. Studies are urgently needed to solve this issue.

The Nobel Prize in 2005 for the discovery of Helicobacter pylori: implications for child health

The Nobel Prize in Physiology or Medicine in 2005 has been awarded to B. Marshall and R. Warren for their discovery that peptic ulcer disease is caused by an infection with Helicobacter pylori. This infection, which affects about half of the world's population and is already extremely prevalent in adolescents in developing countries, starts as an asymptomatic gastritis which, under certain conditions, is followed by gastric or duodenal ulcer disease.

CONCLUSION

No proven benefit has yet been found by treating H. pylori-infected children with gastritis unless they have a peptic ulcer. Vaccination against H. pylori infection during early childhood is considered a means of preventing peptic ulcer disease and also possibly adenocarcinoma.

Evidence of mother-child transmission of Helicobacter pylori infection

BACKGROUND

Low socioeconomical status is a major risk factor for natural acquisition of Helicobacter pylori (H. pylori) infection in developing countries. Its transmission route is unknown but studies suggest person-to-person transmission.

AIM

To evaluate seropositivity of anti-H. pylori antibodies in family members of infected symptomatic index patients as compared to family members of symptomatic uninfected index patients.

PATIENTS AND METHODS

One hundred and twelve family members of 38 patients who underwent endoscopy to exclude peptic disease were studied. Patients were deemed H. pylori infected or not infected when rapid urease test and histology were both positive or both negative. The family members underwent ELISA serology using the Cobas Core II Kit (Roche) and were classified into three groups: I - 29 family members of 10 H. pylori (+) duodenal ulcer index patients; II - 57 family members of 17 H. pylori (+) index patients without duodenal ulcer; III - 26 family members of 11 H. pylori (-) index patients.

RESULTS

Seropositivity of group I and II (infected patients) was higher than the control group, 83% vs 38%, specially in mothers, 81% vs 18%, and in siblings 76% vs 20%. Differences between fathers' seropositivity was not statistically significant in the three groups: 100% vs 86% vs 70%. Seropositivity of all family members (mother, father and siblings) between infected group (I vs II) was similar.

CONCLUSION

Prevalence of H. pylori infection was higher in family members of infected patients, but was similar among family members of infected patients with and without duodenal ulcer. H. pylori infection is more frequent in mothers and siblings of infected index children. A common source of infection cannot be excluded, but facts suggest that person-to-person transmission occurs, specially from mother to child.

Antimicrobial susceptibility of Helicobacter pylori strains isolated in Bangladesh

Antimicrobial susceptibility of 120 Helicobacter pylori isolates to metronidazole, tetracycline, clarithromycin, and amoxicillin was determined, and 77.5, 15, 10, and 6.6% of the isolates, respectively, were resistant. Only rdxA inactivation and both rdxA and frxA inactivation were responsible for metronidazole resistance in 66% (8 of 12) and 33% (4 of 12) of the isolates, respectively.

Early Helicobacter pylori colonisation: the association with growth faltering in The Gambia

BACKGROUND

Helicobacter pylori is one of the commonest causes of chronic infection of mankind, yet the natural history of acute infection is poorly understood. Some studies suggest that gastric colonisation with H pylori is associated with suboptimal nutrition and growth in childhood.

AIMS

To describe the clinical features of early H pylori colonisation and assess its role in the development of infant malnutrition and growth faltering.

METHODS

Two consecutive prospective longitudinal cohort studies were conducted at the Medical Research Council Laboratories in a rural community in The Gambia, West Africa. The first birth cohort of 125 infants was followed by a second of 65 children from the same community. H pylori colonisation was detected by sequential 13C urea breath tests, and infant growth was monitored by serial measurements.

RESULTS

Children with early H pylori colonisation became significantly lighter, shorter, and thinner than their peers in late infancy. The association was found in both cohorts. No socioeconomic or demographic confounding variables were identified to explain this, and the weight deficit was no longer detectable when the children were aged 5-8 years.

CONCLUSIONS

Results suggest that H pylori colonisation in early infancy predisposes to the development of malnutrition and growth faltering, although the effect did not persist into later childhood.

Helicobacter pylori infection, iron absorption, and gastric acid secretion in Bangladeshi children

BACKGROUND

Nonheme-iron absorption requires an acidic milieu. Reduced gastric acid output as a consequence of Helicobacter pylori infection could be an important limiting factor for iron absorption.

OBJECTIVE

We measured gastric acid output and iron absorption from a non-water-soluble iron compound (ferrous fumarate) and a water-soluble iron compound (ferrous sulfate) in children with and without H. pylori infection.

DESIGN

Gastric acid output was quantified before (basal acid output, or BAO) and after pentagastrin stimulation (stimulated acid output, or SAO) in 2-5-y-old children with iron deficiency anemia who were (n = 13) or were not (n = 12) infected with H. pylori. Iron absorption was measured by using a double-stable-isotope technique. H. pylori-infected children were studied before and after eradication therapy.

RESULTS

BAO and SAO were significantly lower in the H. pylori-infected children (0.2 +/- 0.2 and 1.6 +/- 0.9 mmol/h, respectively) than in the uninfected children (0.9 +/- 0.7 and 3.1 +/- 0.9 mmol/h, respectively; P = 0.01 and P < 0.005). BAO and SAO improved to 0.8 +/- 1.3 and 3.3 +/- 2.4 mmol/h, respectively, after therapy. Iron absorption from ferrous sulfate was significantly greater than that from ferrous fumarate both before (geometric : 19.7% compared with 5.3%; P < 0.0001) and after (22.5% compared with 6.4%; P < 0.0001) treatment in H. pylori-infected children. Corresponding values for uninfected children were 15.6% and 5.4%, respectively (P < 0.001; n = 12).

CONCLUSIONS

Iron absorption from ferrous fumarate was significantly lower than that from ferrous sulfate in both H. pylori-infected and uninfected Bangladeshi children. Treatment of H. pylori infection improved gastric acid output but did not significantly influence iron absorption. The efficacy of ferrous fumarate in iron fortification programs to prevent iron deficiency in young children should be evaluated.

Placental acquisition of maternal specific IgG and Helicobacter pylori colonization in infancy

BACKGROUND

Colonization with Helicobacter pylori generally occurs in infancy, and the microorganism is often acquired from close family members. Rate of infant colonization may be affected by maternal immune status.

METHODS

To investigate the potential protective effect of anti-H. pylori immunoglobulin G (IgG) acquired via the placenta, 65 mothers and their infants were studied from the infant's birth for 1 year. Circulating IgG antibodies were measured by enzyme-linked immunosorbent assay (ELISA) in cord blood and every 8 weeks. Immunoblotting was performed on sera from infants with significant increases in IgG levels. Rate of infant H. pylori colonization was measured by 13C urea breath tests every 4 weeks from the age of 12 weeks.

RESULTS

Maternal and infant cord blood specific IgG levels were correlated (R2 =.747, p <.001). Infant H. pylori specific IgG fell 5-fold compared to maternal levels over the first 6 months of life, and rose subsequently in many cases, with the development of novel immunoblot patterns. There were no significant associations between the age at first positive urea breath test and maternal or infant cord specific H. pylori IgG levels.

CONCLUSIONS

Transplacentally acquired specific IgG antibody does not protect infants from colonization by H. pylori.

Helicobacter in the developing world

Helicobacter pylori in the developing world is associated with many unique challenges not encountered in an industrialized setting. The 20% prevalence of infection with H. pylori among adolescents in the United States pales in comparison to infection rates exceeding 90% by 5 years of age in parts of the developing world. While H. pylori within the developed world is associated with gastritis, which may lead to peptic ulcer and gastric carcinoma, the infection in the developing world appears to also be linked with chronic diarrhea, malnutrition and growth faltering as well as predisposition to other enteric infections, including typhoid fever and cholera. Once identified, treatment of H. pylori within the developing world presents increased difficulties due to the frequency of antibiotic resistance as well as the frequency of recurrence after successful treatment. Control, and possibly eradication, of H. pylori could likely be achieved through increased standards of living and improved public health, as it has in the industrialized world. However, these measures are distant objectives for most developing countries, making long-term control of the organism dependent on the development and administration of an effective vaccine.

DNA-level characterization of Helicobacter pylori strains from patients with overt disease and with benign infections in Bangladesh

The complex relation between the genotype of Helicobacter pylori and its association with clinical outcome is not well understood. Studies in the West have showed that strains expressing certain virulence factors (vacAs1, vacAm1, and cagA) are associated with duodenal ulcer disease. However, the H. pylori genotype is known to vary with geographic region. In the present study, we compared several virulence markers (cagA, vacA, and iceA) and neutral markers (IS605, IS606, and IS608) in H. pylori strains isolated from 65 adult patients with peptic ulcer (PU) and 50 patients with nonulcer dyspepsia (NUD). PCR tests indicated that cagA is present in 75% of the strains from patients with PU compared to 55% in patients with NUD, and 80% of the isolates from patients with PU carried potentially toxigenic vacAs1 alleles of the vacuolating cytotoxin gene (vacA) compared to 60% in isolates from patients with NUD. However, no significant difference in any other virulence marker was observed in isolates from both groups. Phylogenetic analysis of the vacA middle region and the 5' end of the cagA gene indicates that Bangladeshi isolates are more closely related to H. pylori isolates from India and are different from isolates from East Asia.

Recrudescence and reinfection with Helicobacter pylori after eradication therapy in Bangladeshi adults

BACKGROUND & AIMS

In developing countries where Helicobacter pylori infection is widespread, posttherapeutic recurrence rates may be high. Many of the limited studies available have methodological problems and show varied recurrence rates. We determined late recrudescence rates, true reinfection, and ulcer recurrence.

METHODS

One hundred five Bangladeshi patients with H. pylori infection and duodenal ulcer disease were treated with a triple therapy. Follow-up included 13C-urea breath tests, endoscopy, and biopsy-based tests. In reinfected patients, genomic typing compared pretherapeutic and posttherapeutic strains.

RESULTS

Recrudescence, associated with nitroimidazole-based treatment, occurred in 15 of 105 patients (14%) within the first 3 months, but only 8 of 105 patients tested positive 4 weeks after therapy ended. True reinfection was diagnosed in 11 of 105 patients between 3 and 18 months after therapy. The annual reinfection rate was 13%, based on a total follow-up of 84.7 patient years. Ulcer relapse occurred in 2 of 15 (13%) recrudescence cases and in 6 of 11 (55%) reinfection cases, but also in 4 of 73 (5%) H. pylori-negative patients.

CONCLUSIONS

In Bangladesh, late recrudescence of H. pylori after eradication therapy occurs within the first 3 months. The reinfection rate is high and might influence cost-benefit analyses for determining diagnostic and therapeutic procedures.

Epidemiology of Helicobacter pylori infection in children: a serologic study of the Kyushu region in Japan

BACKGROUND

The prevalence of Helicobacter pylori infection in children varies as a function of socioeconomic development, with low rates in developed countries and high rates in developing countries. The prevalence of H. pylori infection in Japanese children is unknown.

METHODS

The present study examined the effect of living conditions on the prevalence of H. pylori infection in children. We determined the prevalence of H. pylori infection in healthy children of the Kyushu region in Japan and compared it with the prevalence in institutionalized children with severe neurologic illness. Serum concentrations of anti-H. pylori IgG antibody were measured by an enzyme-linked immunosorbent assay in 336 healthy children and 56 patients with severe neurologic impairment. An antibody concentration > 50 units/mL was taken as evidence of infection.

RESULTS

The prevalence of H. pylori seropositivity in healthy children increased with age (P < 0.0001) and was 29% in children 15-19 years of age. This value is slightly higher than prevalences reported in developed countries (5-15%), but is lower than in developing countries (30-60%). Seropositivity did not vary with respect to gender, water supply or location of housing. Helicobacter pylori seropositivity was more prevalent among institutionalized children aged 5-19 years than their healthy counterparts (P < 0.005).

CONCLUSIONS

The intermediate prevalence of H. pylori seropositivity in healthy children between that measured in developed and developing countries is consistent with the socioeconomic 'westernization' of Japan.

Distinctiveness of genotypes of Helicobacter pylori in Calcutta, India

The genotypes of 78 strains of Helicobacter pylori from Calcutta, India (55 from ulcer patients and 23 from more-benign infections), were studied, with a focus on putative virulence genes and neutral DNA markers that were likely to be phylogenetically informative. PCR tests indicated that 80 to 90% of Calcutta strains carried the cag pathogenicity island (PAI) and potentially toxigenic vacAs1 alleles of the vacuolating cytotoxin gene (vacA), independent of disease status. This was higher than in the West (where cag PAI(+) vacAs1 genotypes are disease associated) but lower than in east Asia. The iceA2 gene was weakly disease associated in Calcutta, whereas in the West the alternative but unrelated iceA1 gene at the same locus is weakly disease associated. DNA sequence motifs of vacAm1 (middle region) alleles formed a cluster that was distinct from those of east Asia and the West, whereas the cagA sequences of Calcutta and Western strains were closely related. An internal deletion found in 20% of Calcutta iceA1 genes was not seen in any of approximately 200 strains studied from other geographic regions and thus seemed to be unique to this H. pylori population. Two mobile DNAs that were rare in east Asian strains were also common in Calcutta. About 90% of Calcutta strains were metronidazole resistant. These findings support the idea that H. pylori gene pools differ regionally and emphasize the potential importance of studies of Indian and other non-Western H. pylori populations in developing a global understanding of this gastric pathogen and associated disease.

Interpreting the 13C-urea breath test among a large population of young children from a developing country

The 13C-urea breath test is a noninvasive tool for the diagnosis of gastric Helicobacter pylori infection. However, it has not been validated in young children from the developing world, where infection is very common. 13C urea breath tests were performed on 1532 occasions on 247 Gambian infants and children aged from 3 to 48 mo. The means and variances of the separate sub-populations of 13C enrichment results contained within the overall dataset were estimated by a Genstat procedure using the EM algorithm, thereby identifying a cut-off value to discriminate positive from negative results. To illustrate the appropriateness of this calculated cut-off value, 13C urea breath tests were performed upon a small group of 14 patients aged 6 to 28 mo undergoing diagnostic upper endoscopy. Fixed gastric antral biopsies were examined to identify H. pylori. Two subpopulations were identified within the large dataset. A cut-off value of 5.47 delta per thousand relative to Pee Dee Belemnite limestone above baseline at 30 min identified 95% of the normally distributed negative sub-population and 99.4% of the log normal distributed positive sub-population. Comparison with endoscopic data confirmed that this cut-off value was appropriate for this population, as 7/7 children without H. pylori on their gastric biopsies had negative urea breath tests, and 6/7 children with gastric H. pylori colonization had positive urea breath tests. These findings confirm the value of the urea breath test as a diagnostic tool in young children from developing countries. They also offer a way to calculate the most appropriate cut-off value for use in different populations and the likelihood that it will correctly assign any value into the appropriate sub-population, without the need for endoscopy.

Helicobacter pylori colonization in early life

Helicobacter pylori infection is a major cause of upper gastrointestinal disease throughout the world. Colonization begins in childhood, although little is known about its age of onset, rate, or mode of colonization. Our aim was to identify the age of acquisition of H. pylori colonization in Gambian children. A cohort of 248 Gambian children aged 3 to 45 months was studied at intervals of 3 months for 2 years, using the 13C-urea breath test, specific IgM and specific IgG serology. The prevalence of positive breath tests rose from 19% at 3 months of age to 84% by age 30 months. Elevated specific IgG and IgM antibody levels were associated with positive breath tests, although there was discrepancy between breath test results and serology, particularly IgG serology, during the 1st year of life. Neither IgG nor IgM serology could be validated as reliable diagnostic tools for infant H. pylori colonization compared with the 13C-urea breath test. Reversion to negative breath test, in association with declining specific antibody levels, occurred in 48/248 (20%) of children. On the assumption that the 13C-urea breath test is a reliable index of H. pylori colonization, we conclude that the infection is extremely common from an early age in Gambian children. Transient colonization may occur. Previous studies relying on serodiagnosis may have significantly underestimated the true early prevalence of colonization in the developing world, where the target age for intervention studies is probably early infancy.

Evaluation of serology, 13C-urea breath test, and polymerase chain reaction of stool samples to detect Helicobacter pylori in Bangladeshi children

BACKGROUND

Serologic methods to detect Helicobacter pylori in infants, especially in developing countries, may be limited because of decreased immune response caused by malnutrition. The true prevalence may therefore be underestimated in this age group. Urea breath test is considered to be a good screening method in children but is expensive and therefore is not suitable for screening in developing countries. Simple, inexpensive, and accurate noninvasive methods to detect H. pylori in infants and young children are needed.

METHODS

Enzyme immunoassay (EIA) and immunoblot (IB) serologic analyses, 13C-urea breath test (UBT), and immunomagnetic separation--polymerase chain reaction (IMS-PCR) were performed on stool specimens, to detect H. pylori in 68 children between 4 and 24 months of age (mean, 11.5 months) in an endemic area in Bangladesh and the results compared.

RESULTS

The occurrence of H. pylori was 57% (n=39) using only UBT, 60% (n=41) using only IMS-PCR, and 78% (n=53) using UBT and IMS-PCR together. The concordance between UBT and IMS-PCR results was 62%. Immunoblot was positive in only 9% (n=6). Results in all 68 children were negative using EIA.

DISCUSSION

The prevalence of H. pylori infection in this periurban community and age group was high. Only serologic methods seem to be unsatisfactory for screening of H. pylori infection in infants and may not reflect the true prevalence. Immunomagnetic separation-PCR is a simple and rapid method for detection of H. pylori in stool and is an attractive method for analysis of colonization in infants. However, it may reflect a different stage of disease than UBT. Further studies are needed to clarify this.

Comparison of biopsy and serological methods of diagnosis of Helicobacter pylori infection and the potential role of antibiotics

OBJECTIVE

Endoscopic biopsy and serological methods were compared for their ability to detect Helicobacter pylori infection in patients undergoing upper gastrointestinal endoscopy at a state university hospital.

METHODS

Subjects were characterized on the basis of gastrointestinal symptoms, endoscopic findings, socioeconomic and demographic features, and the use of certain medications, tobacco, and alcohol. Current infection was detected in gastric antral specimens by rapid urease testing, histopathology, and bacterial culture. Serum levels of IgG to H. pylori were measured by ELISA.

RESULTS

Of 240 subjects, 115 (47.9%) were currently infected as determined by rapid urease testing, histopathology, and/or culture results, whereas 63.3% had elevated anti-H. pylori IgG levels (p < 0.001). This difference in the prevalence of current infection and seropositivity was preserved when the study population was analyzed according to age, race, gender, and other characteristics. Prior use of antibiotics was associated with a significant reduction in the frequency of H. pylori infection.

CONCLUSIONS

Serological evidence of H. pylori infection was consistently greater than the prevalence of infection documented by biopsy methods in this study, suggesting suppression or recent clearance of infection. Further studies are needed to examine the factors that may affect the detection of H. pylori infection.

Treatment of Helicobacter pylori infection in infants in rural Bangladesh with oral immunoglobulins from hyperimmune bovine colostrum

BACKGROUND

Antibodies from hyperimmune bovine colostrum have been shown to be effective in treatment against a variety of microorganisms, including Helicobacter pylori in adults.

AIM

To test this form of treatment in a small group of H. pylori infected children in a periurban community in Bangladesh.

METHODS

Twenty-four infants, 4-29 months old (mean age 16.5+/-7.7 months) and infected with H. pylori, were treated with purified immunoglobulins from hyperimmune bovine colostrum for 1 month, in a placebo-controlled, double-blind pilot study. Diagnosis was established with 13C-urea breath test (UBT) before and after the treatment period and at a 1-month follow-up.

RESULTS

None of the hyperimmune bovine colostrum-treated children became UBT negative. Five children initially positive in the UBT screening spontaneously became negative by the start of the study with hyperimmune bovine colostrum/placebo. At the end of the 1-month study period, three had became positive again.

CONCLUSION

Hyperimmune bovine colostrum does not eradicate H. pylori infection in infants. Transient H. pylori infection is common among infants in high endemic areas, as is reinfection after clearance. This presents obstacles to evaluation of therapeutic investigations in young children in areas where H. pylori is prevalent.

Disorders of the oesophagus and stomach in infants

Pathological processes and disease entities in the upper gastrointestinal (GI) tract, specifically those of the oesophagus and the stomach in infancy, have received a disproportionately small amount of attention until recently when appreciation of their pathophysiology and concordant importance in terms of symptomatology has been highlighted. This is probably a phenomenon secondary to improved diagnostic yield from the recent technical advances in areas such as infant endoscopy and a shift in opinion regarding the pathophysiological origin of ubiquitous symptoms of infancy such as feeding disorders, colic and irritability. In addition, the apparently complex interactions of various aetiological factors such as pH-independent gastro-oesophageal reflux (GOR), cow's milk protein intolerance (CMPI), Helicobacter pylori gastritis and upper GI motor disorders have in the past 1-2 years become underlined in terms of aetiopathogenesis and have radically changed thinking regarding diagnosis and therapy of infants with apparent upper-GI-associated symptoms. The contribution to comprehension of infant upper GI disorders of inflammatory paradigms and ontogeny of the upper GI tract is also a recent area worthy of mention. The recent advances in all of these areas and their contribution to the understanding, and subsequent diagnosis and therapy, of upper GI symptoms and their explanation by way of aetiopathogenesis will be explored in this chapter.

High prevalence of duodenal ulcer and gastric cancer in dyspeptic patients in Korea

BACKGROUND

Although gastric cancer and duodenal ulcer are both related to Helicobacter pylori infection, they are mutually exclusive diseases such that patients with a history of duodenal ulcer have a markedly reduced risk of developing gastric cancer. It has been hypothesized that different strains of H. pylori may be related to the different diseases. Our aim was to study the prevalence of duodenal ulcer disease and gastric cancer in dyspeptic patients in South Korea, a country with a high incidence of gastric cancer.

METHODS

The study population consisted of consecutive patients between the ages of 20 and 81 years referred to Guro Hospital's Endoscopic Unit for evaluation of dyspepsia. Patients with a history of peptic ulcer or gastric cancer were excluded. Each patient underwent endoscopy and completed a detailed questionnaire. Peptic ulcer was defined as the presence of an active ulcer, red scar, or white scar.

RESULTS

One thousand patients were evaluated, and 867 (43% men and 57% women) met the entry criteria. The prevalence of peptic ulcer and gastric cancer were 24% and 7%, respectively. Among peptic ulcer patients, duodenal ulcer was commoner (75%) than gastric ulcer or coexistent duodenal and gastric ulcer (21% and 4%, respectively). The mean age of duodenal and gastric ulcer patients (45 +/- 14 and 48 +/- 12 years, respectively) was significantly lower than that of gastric cancer patients (59 +/- 11 years) (P < 0.01). Only 44 (7%) of the 597 remaining patients had definite endoscopic abnormalities (for example, erosive esophagitis, duodenitis, or pyloric deformity).

CONCLUSION

Gastric cancer and duodenal ulcer were prevalent diagnoses among Korean patients undergoing endoscopy for evaluation of dyspepsia. Korea may be the ideal country to investigate the relation between specific H. pylori strains and different H. pylori diseases.