Royal Society of Tropical Medicine and Hygiene Meeting at Manson House, London, 16 February 1995. Aspects of Helicobacter pylori infection in the developing and developed world. Helicobacter pylori infection, nutrition and growth of West African infants

Breastfeeding Is Associated with Lower Likelihood of Helicobacter Pylori Colonization in Babies, Based on a Prospective USA Maternal-Infant Cohort

BACKGROUND

Mother-to-child transmission of Helicobacter pylori (H. pylori) is the primary source of intrafamilial spread in early childhood in regions of high H. pylori prevalence. However, early-in-life H. pylori colonization and associated protective or risk factors have not been fully evaluated in lower prevalence regions, such as the USA.

AIMS

Therefore, from a well-characterized prospective US cohort, we selected women who provided fecal samples during pregnancy and had paired fecal samples from their babies up to 24 months postpartum. We evaluated maternal and baby factors associated with likelihood of H. pylori colonization in the babies. Fecal antigen testing was used to determine H. pylori status. We also evaluated the association between maternal breastmilk cytokines and H. pylori colonization in breastfed babies.

RESULTS

Among included mother-baby pairs (n = 66), H. pylori prevalence was 31.8% in mothers and 19.7% in their babies. Dominant breastfeeding (adjusted odds ratio [aOR] 0.17, 95% CI 0.03-0.98) and maternal IBD (aOR 0.05, 95% CI 0.01-0.27) were associated with significantly lower likelihood of H. pylori colonization among babies; no other clinical factors were associated with H. pylori colonization in the babies. Matrix metalloproteinase-10 (MMP-10) and tumor necrosis factor-related activation-induced cytokine expression were significantly higher in breastmilk of mothers with H. pylori positive vs negative babies.

CONCLUSIONS

Consistent with data from high H. pylori prevalence regions, our findings suggest dominant breastfeeding may protect against early H. pylori colonization. Downregulation of pro-inflammatory cytokines such as MMP-10 may be relevant in mediating this protection among breastfed babies, but more data are needed.

Prevalence of helicobacter pylori infection among children living in a rural setting in Sub-Saharan Africa

BACKGROUND

Helicobacter pylori infection affects more than half of the world's population. It is generally acquired during childhood with no symptoms but has long- term clinical sequelae. This study estimated the prevalence of H. pylori infection amongst children in a rural environment in Africa.

METHODS

We conducted a cross-sectional study over a four (4)-month period within two rural communities. 240 asymptomatic children were tested using lateral flow immunochromatographic assay for the qualitative detection of H. pylori antigen in a fecal specimen. Statistical analysis and processing was done using Stata version 11.

RESULTS

The mean age of the participants was 10.5 ± 2.7 years with the predominant age range being 8-10 years (34.6%), and a mean household size of 7.1 ± 1.7. The study population showed a female preponderance of 57.1%. 88% of the H. pylori positive children lacked pipe and borehole drinking water. All of the positive H. pylori children practiced open-air defecation. The overall prevalence of H. pylori infection among children in this study was at least 14.2%.

CONCLUSION

Our study demonstrated a high prevalence of H. pylori infection among children in a rural setting. Educational status of parents did not affect H. pylori prevalence but increasing household numbers, female gender, source of drinking water other than pipe and borehole, open-air defecation and younger age were associated with a higher H. pylori prevalence.

Helicobacter pylori and gastric acid: an intimate and reciprocal relationship

Helicobacter pylori (Hp) is the main cause of gastritis, peptic ulcer disease and gastric cancer. There are still unanswered questions related to the interaction between Hp and man, like what determines the susceptibility for the initial infection and the mechanisms for the carcinogenic effect. The initial infection seems to require a temporal gastric hypoacidity. For Hp to survive in the gastric mucous layer, some acidity is necessary. Hp itself is probably not directly carcinogenic. Only when inducing oxyntic mucosal inflammation and atrophy with hypoacidity, Hp predisposes for gastric cancer. Gastrin most likely plays a central role in the Hp pathogenesis of duodenal ulcer and gastric cancer.

Vacuolating cytotoxin A (VacA) - A multi-talented pore-forming toxin from Helicobacter pylori

Helicobacter pylori is associated with severe and chronic diseases of the stomach and duodenum such as peptic ulcer, non-cardial adenocarcinoma and gastric lymphoma, making Helicobacter pylori the only bacterial pathogen which is known to cause cancer. The worldwide rate of incidence for these diseases is extremely high and it is estimated that about half of the world's population is infected with H. pylori. Among the bacterial virulence factors is the vacuolating cytotoxin A (VacA), which represents an important determinant of pathogenicity. Intensive characterization of VacA over the past years has provided insight into an ample variety of mechanisms contributing to host-pathogen interactions. The toxin is considered as an important target for ongoing research for several reasons: i) VacA displays unique features and structural properties and its mechanism of action is unrelated to any other known bacterial toxin; ii) the toxin is involved in disease progress and colonization by H. pylori of the stomach; iii) VacA is a potential and promising candidate for the inclusion as antigen in a vaccine directed against H. pylori and iv) the vacA gene is characterized by a high allelic diversity, and allelic variants contribute differently to the pathogenicity of H. pylori. Despite the accumulation of substantial data related to VacA over the past years, several aspects of VacA-related activity have been characterized only to a limited extent. The biologically most significant effect of VacA activity on host cells is the formation of membrane pores and the induction of vacuole formation. This review discusses recent findings and advances on structure-function relations of the H. pylori VacA toxin, in particular with a view to membrane channel formation, oligomerization, receptor binding and apoptosis.

Role of Helicobacter pylori infection on nutrition and metabolism

Helicobacter pylori (H. pylori) is a gram-negative pathogen that is widespread all over the world, infecting more than 50% of the world’s population. It is etiologically associated with non-atrophic and atrophic gastritis, peptic ulcer and shows a deep association with primary gastric B-cell lymphoma and gastric adenocarcinoma. Recently, the medical research focused on the modification of the gastric environment induced by H. pylori infection, possibly affecting the absorption of nutrients and drugs as well as the production of hormones strongly implicated in the regulation of appetite and growth. Interestingly, the absorption of iron and vitamin B12 is impaired by H. pylori infection, while infected subjects have lower basal and fasting serum levels of ghrelin and higher concentration of leptin compared to controls. Since leptin is an anorexigenic hormone, and ghrelin stimulates powerfully the release of growth hormone in humans, H. pylori infection may finally induce growth retardation if acquired very early in the childhood and in malnourished children. This review is focused on the nutritional effects of H. pylori infection, such as the reduced bioavailability or the malabsorbption of essential nutrients, and of gastrointestinal hormones, as well as on the relationship between H. pylori and the metabolic syndrome.

Vaccinating against Helicobacter pylori in the developing world

Helicobacter pylori infects more than half the world's population and in developing nations the incidence can be over 90%. The morbidity and mortality associated with H. pylori-associated diseases including ulcers and gastric cancer therefore, disproportionately impact the developing world. Mice have been used extensively to demonstrate the feasibility of developing a vaccine for H. pylori infection, and for testing antigens, routes of immunization, dose, and adjuvants. These successes however, have not translated well in clinical trials. Although there are examples where immune responses have been activated, there are few instances of achieving a reduced bacterial load. In vivo and in vitro analyses in both mice and humans demonstrates that the host responds to H. pylori infection through the activation of immunoregulatory mechanisms designed to suppress the anti-H. pylori response. Improved vaccine efficacy therefore, will require the inclusion of factors that over-ride or re-program these immunoregulatory rersponse mechanisms.

PCR-based genotyping of Helicobacter pylori of Gambian children and adults directly from biopsy specimens and bacterial cultures

Background

Helicobacter pylori is an important agent of gastroduodenal disease in Africa and throughout the world. We sought to determine an optimum method for genotyping H. pylori strains from children and adults in The Gambia, West Africa.

Results

Virulence genes were amplified in 127 of 190 cases tested (121 adults and 6 children); each of 60 bacterial cultures, and 116 from DNA extracted directly from biopsies. The proportion of biopsies that were cagA+, the ratio of vacAs1/s2, and vacAm1/m2, and the proportion of mixed strain populations in individual subjects changed with age. Strains lacking virulence cagA and vacA genes and with apparently homogeneous (one predominant strain) infections were more common among infants than adults.

Conclusions

In order to detect the range of bacterial genotypes harbored by individual patients, direct PCR proved slightly superior to isolation of H. pylori by biopsy culture, but the techniques were complementary, and the combination of both culture and direct PCR produced the most complete picture. The seemingly higher virulence of strains from adult than infant infections in The Gambia merits further analysis.

Malnutrition and gastrointestinal and respiratory infections in children: a public health problem

Infectious disease is the major cause of morbidity and mortality in developing countries, particularly in children. Increasing evidence suggests that protein-calorie malnutrition is the underlying reason for the increased susceptibility to infections observed in these areas. Moreover, certain infectious diseases also cause malnutrition, which can result in a vicious cycle. Malnutrition and bacterial gastrointestinal and respiratory infections represent a serious public health problem. The increased incidence and severity of infections in malnourished children is largely due to the deterioration of immune function; limited production and/or diminished functional capacity of all cellular components of the immune system have been reported in malnutrition. In this review, we analyze the cyclical relationship between malnutrition, immune response dysfunction, increased susceptibility to infectious disease, and metabolic responses that further alter nutritional status. The consequences of malnutrition are diverse and included: increased susceptibility to infection, impaired child development, increased mortality rate and individuals who come to function in suboptimal ways.

Helicobacter pylori infection among a pediatric population with sickle cell disease

OBJECTIVES

Recurrent abdominal pain (RAP) is a common presenting symptom in children with sickle cell disease (SCD). This may be as a result of complications of the disease, surgical problems, or Helicobacter pylori gastritis. The prevalence of H pylori infection in SCD children is not known. This study aimed to determine the prevalence and association of H pylori infection with RAP in SCD children.

METHODS

This was a prospective case-control study conducted at the Lagos State University Teaching Hospital, Nigeria, involving SCD children (subject, n = 118) and non-SCD children (control, n = 118) matched for age, sex, and socioeconomic status. Seroprevalence status of the children was determined by measuring immunoglobulin G antibodies against H pylori using enzyme-linked immunosorbent assay that had been validated for pediatric use.

RESULTS

The overall prevalence of H pylori infection was 155 of 236 (SCD, 67.8%; non-SCD, 63.6%; OR, 1.1; 95% CI, 0.89-1.28; p = .493). The prevalence increased with age in both SCD and non-SCD children and was significantly highest at the age of 6 to 10 years (p < .001 in each case). H pylori infection was significantly associated with socioeconomic status of the parents (OR, 4.25; 95% CI, 1.49-12.1; p = .004) but not significantly associated with RAP in SCD children (OR, 1.21: 95% CI, 0.55-2.66; p = .632).

CONCLUSIONS

Prevalence of H pylori infection is high in SCD and non-SCD children in Lagos, Nigeria. There was no significant association between H pylori infection and recurrent abdominal pain in SCD children.

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.

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.

An optimized 13C-urea breath test for the diagnosis of H pylori infection

AIM: To validate an optimized 13C-urea breath test (¹³C-UBT) protocol for the diagnosis of H pylori infection that is cost-efficient and maintains excellent diagnostic accuracy.

METHODS: 70 healthy volunteers were tested with two simplified ¹³C-UBT protocols, with test meal (Protocol 2) and without test meal (Protocol 1). Breath samples were collected at 10, 20 and 30 min after ingestion of 50 mg ¹³C-urea dissolved in 10 mL of water, taken as a single swallow, followed by 200 mL of water (pH 6.0) and a circular motion around the waistline to homogenize the urea solution. Performance of both protocols was analyzed at various cut-off values. Results were validated against the European protocol.

RESULTS: According to the reference protocol, 65.7% individuals were positive for H pylori infection and 34.3% were negative. There were no significant differences in the ability of both protocols to correctly identify positive and negative H pylori individuals. However, only Protocol 1 with no test meal achieved accuracy, sensitivity, specificity, positive and negative predictive values of 100%. The highest values achieved by Protocol 2 were 98.57%, 97.83%, 100%, 100% and 100%, respectively.

CONCLUSION: A 10 min, 50 mg ¹³C-UBT with no test meal using a cut-off value of 2-2.5 is a highly accurate test for the diagnosis of H pylori infection at a reduced cost.

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.

Elevated 13C urea breath test values females infected with Helicobacter pylori

(13)C-urea breath test (UBT) for the diagnosis of Helicobacter pylori requires a high density and active bacteria and has the potential to provide a noninvasive index of bacterial growth. We describe the gender differences in delta over baseline (13)C-UBT values in 7373 patients (4531 females and 2842 males) who underwent (13)C-UBT test for the diagnosis of H. pylori infection. A significantly (P<.001) higher mean +/- SD excess delta (13)CO(2) excretion was recorded in females (24.7+/-17.4) compared to males (17.6+/-11.8) aged 10-80 years. The age-adjusted difference between sexes was 7.1 (95% confidence interval, 6.4-7.9). Our analysis demonstrates quantitatively for the first time gender associated differences in H. pylori host interaction. This study suggests that infected females have a higher bacterial load and therefore may potentially infect their children at a higher degree than males.

Effect of infections and environmental factors on growth and nutritional status in developing countries

Despite numerous advances and improvements in child health globally, malnutrition remains a major problem and underlies a significant proportion of child deaths. A large proportion of the hidden burden of malnutrition is represented by widespread single and multiple micronutrient deficiencies. A number of factors may influence micronutrient deficiencies in developing countries, including poor body stores at birth, dietary deficiencies and high intake of inhibitors of absorption such as phytates and increased losses from the body. Although the effects of poor intake and increased micronutrient demands are well described, the potential effects of acute and chronic infections on the body's micronutrient status are less well appreciated. Even more obscure is the potential effect of immunostimulation and intercurrent infections on the micronutrient distribution and homeostasis. The association therefore of relatively higher rates of micronutrient deficiencies with infectious diseases may be reflective of both increased predisposition to infections in deficient populations as well as a direct effect of the infection itself on micronutrient status indicators. Recently the association of increased micronutrient losses such as those of zinc and copper with acute diarrhea has been recognized and a net negative balance of zinc has been shown in zinc metabolic studies in children with persistent diarrhea. It is also recognized that children with shigellosis can lose a significant amount of vitamin A in the urine, thus further aggravating preexisting subclinical vitamin A deficiency. Given the epidemiological association between micronutrient deficiencies and diarrhea, supplementation strategies in endemic areas are logical. The growing body of evidence on the key role of zinc supplementation in accelerating recovery from diarrheal illnesses in developing countries supports its use in public health strategies.

Helicobacter pylori infection and typhoid fever in Jakarta, Indonesia

We evaluated the association between typhoid fever and Helicobacter pylori infection, as the latter microorganism may influence gastric acid secretion and consequently increase susceptibility to Salmonella typhi infection. Anti-H. pylori IgG and IgA antibody titres (ELISA) and gastrin concentration (RIA) were determined in the plasma of 87 blood culture-confirmed typhoid fever cases (collected after clinical recovery) and 232 random healthy controls without a history of typhoid fever, in the Jatinegara district, Jakarta. Patients with typhoid fever more often than controls were seropositive for H. pylori IgG (67% vs. 50%, P<0.008), when antibody titres were dichotomized around median titres observed in controls. H. pylori IgA seropositivity was not associated with typhoid fever. Plasma gastrin concentrations indicative of hypochlorhydria (i.e. gastrin > or =25 or > or =100 ng/l) were not significantly elevated in typhoid fever cases compared to controls (P=0.54 and P=0.27 respectively). In a multivariate analysis, typhoid fever was independently associated with young age (<33 years, median age of the controls) [odds ratio (OR) 7.93, 95% confidence interval (CI) 3.90-16.10], and H. pylori IgG seropositivity (OR 1.93, 95% CI 1.10-3.40). Typhoid fever was independently associated with H. pylori IgG seropositivity, but not with elevated gastrin concentration. Therefore, the association suggests a common risk of environmental exposure to both bacteria, e.g. poor hygiene, rather than a causal relationship via reduced gastric acid production.

Investigation of human colostrum Helicobacter pylori IgA content in lactating women

OBJECTIVE

The objective was to investigate the colostral H. pylori-specific IgA content in a sample of the female population in Turkey where a high endemicity for H. pylori has always been reported.

MATERIALS AND METHODS

One hundred and sixty-one pregnant women with positive serum H. pylori IgG antibody at the time of the last trimester were enrolled into the study. During the initial postpartum 24h, we obtained colostrum samples from each mother to test the presence and concentration of H. pylori-specific IgA. Breast milk antibody concentrations of H. pylori were measured by commercial ELISA tests. Sample absorbance/cut-off absorbance (s/c) ratio was used for semiquantitative interpretation. Ratios >1.1 were considered positive, ratios < or =1.1 negative. The statistical significance was tested by the Mann-Whitney U-test, and p < 0.05 was regarded as statistically significant.

RESULTS

At least 2 ml of colostrum was obtained and analyzed (mean volume 2.5+/-0.45 ml). The results indicated the absence of H. pylori-specific IgA in 64 colostral samples (39.8%). However, the rest of the women (n = 97; 60.2%) had a mean H. pylori-specific IgA s/c ratio of 4.31+/-2.51 (range 1.2-10.3) in their colostral milk samples. The mean gestational age at the time of delivery was 38 weeks and 5 days, and the mean birth weight was 3, 224+/-433 g (range 4, 300-1, 940 g). Gestational age at birth and mode of delivery were not correlated with the colostral-specific IgA levels.

CONCLUSIONS

Most of the lactating women (60.2%), who were seropositive for H. pylori, had some IgA in their colostral milk. Colostral milk theoretically can decrease H. pylori and perhaps many other enteric infections, whether or not it contains H. pylori-specific IgA. Therefore, breastfeeding is of utmost importance for neonates and should be encouraged. The H. pylori-specific IgA antibody concentration of colostral milk should be investigated in large-scale prospective studies for its effectiveness in the protection against neonatal transmission of this infection.

Helicobacter pylori-specific immune response in maternal serum, cord blood, and human milk among mothers with and without current Helicobacter pylori infection

We assessed the patterns of Helicobacter pylori (H. pylori) specific maternal antibodies in maternal serum, cord blood, and milk, which might play a role in prevention of H. pylori infection because transferred to the infant. Between November 2000 and November 2001, mothers were recruited after delivery of their offspring. H. pylori infection status was determined by 13C-urea breath test (UBT). Specific H. pylori antibody profiles were analysed using commercial H. pylori-specific enzyme-linked immunosorbent assay and Western blots. Among 898 mothers, 23% had a current H. pylori infection. Median H. pylori IgG antibody titers in serum and cord blood of UBT-positive mothers were 23.8 U/mL and 24.0 U/mL, respectively. Whereas prevalences of H. pylori-specific antibodies in serum of UBT-negative mothers were clearly lower than those among UBT-positive mothers, patterns of H. pylori-specific IgA antibodies in milk were similar among UBT-positive and UBT-negative mothers. Neonates born from H. pylori-infected women are provided with large amounts of transplacentally transferred specific IgG H. pylori antibodies. Breast-fed neonates are additionally provided with specific IgA antibodies in human milk. Notably, the latter may also be activated if exposure of the mother to H. pylori might have been long time ago and been cleared in the meantime.

Does increased duration of exclusive breastfeeding protect against Helicobacter pylori Infection? The Newcastle Thousand Families Cohort Study at age 49-51 years

OBJECTIVE

Helicobacter pylori acquired in childhood is an important risk factor for gastric carcinoma. Once colonization is established, infection may be carried for life. This study used prospectively recorded, detailed information on infant feeding and investigated the potential link between duration of exclusive breastfeeding in infancy and seropositivity at age 50 years, as measured by enzyme-linked immunosorbent assay.

METHODS

H. pylori seropositivity at age 50 years was investigated among 407 individuals born in Newcastle in May and June 1947 and related to the duration of exclusive breastfeeding after adjusting for measures of socioeconomic status and adverse housing conditions at birth.

RESULTS

Duration of exclusive breastfeeding in infancy was significantly associated with H. pylori seropositivity (odds ratio per 30 days, 0.88; 95% confidence interval, 0.78 to 0.98). The significant protective trend was only seen among men (odds ratio per 30 days, 0.78; 95% confidence interval, 0.65 to 0.95), with no significant effect seen among women.

CONCLUSION

Increased duration of exclusive breastfeeding in infancy may have a long-term protective effect against chronic H. pylori infection and hence the risk of gastric carcinoma. Although further research is required, particularly as to why a significant effect was only seen among men, the results provide additional support for the concept that breastfeeding may have long-term influences on health and that human milk is the ideal complete first diet for human infants.

Helicobacter pylori antigens in the faeces of asymptomatic children in the Buea and Limbe health districts of Cameroon: a pilot study

OBJECTIVE

To determine the prevalence and identify intra-familial risk factors associated with Helicobacter pylori infection in a paediatric population.

METHODS

Cross-sectional study in the Buea and Limbe health districts, South West Cameroon. Stool samples were collected from 176 randomly selected apparently healthy children from two communities with different socioeconomic status. They comprised 86 males and 90 females aged 0-10 years with a mean age of 4.29. Helicobacter pylori status was determined using an enzyme-linked immunosorbent assay, the H. pylori stool antigen (HpSA) test. The test uses polyclonal anti-H. pylori capture antibody to detect H. pylori antigens in human stool. Epidemiological data were analysed using the Fisher test and odds ratio (OR) at 95% confidence intervals (CI).

RESULTS

The overall prevalence of H. pylori was 52.27% (92 of 176). Univariate analysis showed that H. pylori prevalence was significantly higher in children of the low socioeconomic class, 62.50% (55 of 88) than in those of the high socioeconomic class, 42.05% (37 of 88) (P < 0.05; OR = 2.41, 95% CI: 1.26-4.64). Helicobacter pylori prevalence increased with age from 37.50% (12 of 32) for children aged <3 years, 50.00% (53 of 106) aged 3-6 years and 71.05% (27 of 38) aged 7-10 years (P > 0.05; OR = 0.81, 95% CI: 0.34-1.91). The frequency of infection was significantly higher in males, 64.00% (55 of 86) than in females, 41.11% (37 of 90), (P < 0.05; OR = 2.67, 95% CI: 1.39-5.17).

CONCLUSIONS

This study highlights the continuing importance of age, sex and socioeconomic status in the acquisition of H. pylori infection.

Serologic prevalence of antibodies to Helicobacter pylori in internationally adopted children

BACKGROUND

Helicobacter pylori (H. pylori) infection has been linked to gastritis, diarrhea, peptic ulcers, failure-to-thrive, anemia, as well as predisposition to gastric malignancies. Because many internationally adopted children have diarrhea, failure-to-thrive, and anemia on arrival to the US, we determined the prevalence of HP antibodies among these children.

METHODS

Serum samples from 226 unselected children from 18 countries who were evaluated in the International Adoption Clinic at New England Medical Center were tested for antibodies to H. pylori. The results of serologic screening were analyzed in relation to age at adoption, site of residence prior to adoption, weight and height, and the presence or absence of anemia, diarrhea, or intestinal parasites.

RESULTS

31% of internationally adopted children had antibodies to H. pylori. The presence of H. pylori-antibodies was associated with residence in an orphanage (vs. foster care) prior to adoption, older age at adoption, and coinfection with intestinal parasites. No direct effects on height or weight were identified; no associations with diarrhea or anemia were found.

CONCLUSIONS

Internationally adopted children have a high incidence of exposure to H. pylori, as diagnosed serologically. Residence in an orphanage (compared with foster care), older age at adoption, and coinfection with intestinal parasites were more common among children seropositive for anti-H. pylori antibodies.

Protective efficacy of anti-Helicobacter pylori immunity following systemic immunization of neonatal mice

Helicobacter pylori infection of the gastric mucosa is a significant cause of morbidity and mortality because of its etiologic role in symptomatic gastritis, peptic ulcer disease, and gastric adenocarcinoma. Infection occurs in young children; therefore, a prophylactic vaccine would have to be administered within the first year of life, a period thought to be immunologically privileged. We investigated vaccine formulations administered by different routes to confer protective anti-H. pylori immunity in neonatal mice. Neonatal mice immunized with a single dose of vaccine in complete Freund's adjuvant (CFA) generated antigen-specific gamma interferon-, interleukin-2 (IL-2)-, IL-4-, and IL-5-secreting T cells in numbers similar to those in immunized adult mice, while vaccine administered to neonates in incomplete Freund's adjuvant (IFA) induced such cells in reduced numbers compared to those in adult mice. Both IFA and CFA, however, provided partial protection from a challenge with infectious H. pylori when the vaccine was administered subcutaneously. Neonatal immunized mice also had reduced bacterial loads when immunized intraperitoneally with CFA. In all cases, protection was equivalent to that achieved when adult counterparts were immunized. These studies suggest that an efficacious vaccine might be successfully administered to very young children to prevent perinatal infection of H. pylori.

Growth slowing after acute Helicobacter pylori infection is age-dependent

OBJECTIVE

Most infections occur during childhood, but the health effects of childhood infection are poorly understood. We investigated whether growth decreases in the 2 months after acute seroconversion.

METHODS

We performed a nested case-control study among children 6 months to 12 years of age in a community on the outskirts of Lima, Peru. Health interviews were completed daily. Anthropometric measurements were taken monthly. Sera were collected every 4 months and tested for immunoglobulin G. Two-month height and weight gains of seroconverters were compared with gains of sex, age, and size-matched seronegative controls.

RESULTS

In the 2 months after infection, 26 seroconverters gained a median of 24% less weight than 26 matched controls (interquartile range, 63% less to 21% more). In multivariate analysis, infection attenuated weight gain only among children aged 2 years or older. This decrease was not explained by increased diarrhea.

CONCLUSIONS

seroconversion is associated with a slowing of weight gain in children aged 2 years or older. Reasons for this finding merit additional study.

History of breastfeeding and Helicobacter pylori infection in pre-school children: results of a population-based study from Germany

BACKGROUND

Helicobacter pylori infection is predominantly acquired in early childhood. Therefore, childhood nutrition may be related to acquisition of infection. However, there are few current data from developed countries to elucidate this association. We investigated the relation between history of breastfeeding and H. pylori infection in a large population-based sample.

METHODS

Study subjects were all pre-school children in the city of Ulm, located in southern Germany and two nearby communities who were screened for school fitness between January and July 1997. The infection status of the children and of the accompanying mother was determined by the 13C-urea breath test. The parents provided additional information through a standardized questionnaire.

RESULTS

In all, 946 children (mean age 5.9 years) and their mothers were included in the final analysis (response in study population 80.2%). Overall, H. pylori prevalence was 9.8% in children and 34.7% in their mothers; there was a strong association between children's and mother's infection. Of the children, 82.5% had ever been breastfed. Prevalence of H. pylori infection was higher in children breastfed compared to never breastfed children (10.1% versus 8.4%) and showed a positive relationship with duration of breastfeeding. After controlling for covariates, including mother's H. pylori status, by means of multivariable analysis, the odds ratio (OR) for children's H. pylori infection was 1.56 (95% CI: 0.79-3.11) for any versus never breastfeeding and 2.57 (95% CI: 1.19-5.55) given the child was breastfed > or =6 months.

CONCLUSIONS

These data suggest that breastfeeding in infancy does not protect against H. pylori infection among pre-school children in industrialized countries.

The African enigma: low prevalence of gastric atrophy, high prevalence of chronic inflammation in West African adults and children

BACKGROUND

Helicobacter pylori infection is very common in Africa, yet peptic ulcer disease and gastric malignancy are rare.

AIM

The aim of this study was to quantify mucosal responses to H. pylori in Gambian adults and children and to estimate the prevalence of antibodies to bacterial virulence factors (cagA and vacA) in a symptomatic population.

PATIENTS AND METHODS

Adults (mean 36 SD 12 years) with dyspepsia and children (mean 1.4 years SD 0.4 years) with malnutrition underwent gastroscopy with biopsy. Blood was simultaneously drawn for cagA and vacA antibody status. Histopathological scoring used the modified Sydney classification.

RESULTS

Both adults (n = 45) and children (n = 37) mainly demonstrated chronic mild antral inflammation. Only 2/83 cases of focal atrophy (GA) and 4/83 cases of intestinal metaplasia (IM) were observed. Adults tended to demonstrate more frequent acute (AI) and chronic inflammation (CI) (38% compared with 18% and 85% compared with 72%, respectively). Sixty-seven percent of children were cagA IgG+ and 21% vacA IgG+ and 93% of adults were IgG cagA+ and 86% vacA+. There were no differences in mucosal responses between those who were cagA or vacA positive compared with those who were negative.

CONCLUSION

Gambian adults and children mount a CI response to H. pylori but GA, IM and AI are uncommon. cagA and vacA are commonly expressed in Gambian strains of H. pylori. Further studies are needed in order to confirm that GA and IM are not late findings in old age.

Acute Helicobacter pylori infection is followed by an increase in diarrheal disease among Peruvian children

BACKGROUND

Cohort and case-crossover studies were conducted to evaluate whether new Helicobacter pylori infections are followed by increased diarrhea.

METHODS

Participants were 6-month-old to 12-year-old shantytown residents living near Lima, Peru. Baseline data were collected from community households. Health interviews were completed daily, and sera, drawn every 4 months, were tested for H pylori immunoglobulin G. Diarrhea rates among newly H pylori-infected (seroconverting) children were compared with rates among persistently uninfected and infected children using cohort and case-crossover analyses.

RESULTS

Sera were obtained from 345 children from January 1, 1995, through September 1, 1997. H pylori incidence was 12% per year (36 H pylori infections in 109 866 seronegative days). In adjusted cohort analyses, seroconverters had more diarrhea days (rate ratio: 2.0; 95% confidence interval: 1.6-2.4), episodes, and sick days in the year after infection than did uninfected children; and more diarrhea days and sick days than did persistently infected children. This effect was strongest in the first 2 months. Case-crossover analyses supported these findings.

CONCLUSION

Preventing H pylori infection may help reduce pediatric diarrheal disease.

Helicobacter pylori in school children from the Western province of Sri Lanka

BACKGROUND

Little is known about the prevalence of Helicobacter pylori in Sri Lanka and nothing is known about its prevalence in children. Therefore the prevalence of H. pylori in a group of school children in Sri Lanka was determined.

MATERIALS AND METHODS

The presence of H. pylori colonisation was determined by detection of faecal antigen and salivary antibody (IgG) by enzyme immuno assay, in 184 children aged between 5 and 19 years, in the Western Province-Colombo district of Sri Lanka.

RESULTS

Overall, only 12/184 (6.5%) had detectable H. pylori antigen in their stools and were considered infected with H. pylori, while 51/184 (27.7%) had H. pylori IgG in saliva. H. pylori salivary IgG declined with age while H. pylori antigen detection increased with age. H. pylori infection, as determined by salivary antibody (66%), was greater in children living in overcrowded conditions, although this was not statistically significant.

CONCLUSION

The prevalence of H. pylori among school children in Sri Lanka was 6.5% by detection of faecal antigen and 27.7% by detection of salivary antibody, respectively. Initial infection with H. pylori appeared to occur in early childhood whilst active disease began in late childhood. Overcrowding appears to facilitate the transmission of the organism. Overall the prevalence of H. pylori was low in Sri Lanka compared with other countries in South-east Asia.

Helicobacter pylori infection in preschool and school-aged minority children: effect of socioeconomic indicators and breast-feeding practices

Helicobacter pylori infection was examined among 356 asymptomatic white Hispanic and black children aged 2--16 years attending 13 licensed day care centers in Houston. Demographic information and socioeconomic factors were evaluated. H. pylori status was determined by (13)C-urea breath testing. The prevalence of active H. pylori infection was 24% and increased with age. Prevalence was almost identical among white Hispanic and black children. Children living in the most crowded conditions were at the greatest risk for H. pylori acquisition, and an inverse correlation was seen between the mother's education and H. pylori positivity in children. Breast-feeding played a protective role against the acquisition of H. pylori infection. Understanding the epidemiology of H. pylori infection in childhood requires better understanding of the interactions between environment, ethnic group, and socioeconomic conditions.

Helicobacter pylori infection and eradication in paediatric patients

Helicobacter pylori is now recognised to be typically acquired during childhood. Studies also indicate that the infection is frequently lost in childhood; however, it is still unclear whether this is related to the use of antibacterials, the natural history of the infection, or both. H. pylori colonises gastric mucosa and is causally related to chronic gastritis and peptic ulcer disease in both children and adults. Successful eradication of H. pylori has resulted in the healing of duodenal ulcers and the lowering of the ulcer relapse rate in children. Therapy to cure the infection should be started in all children with peptic (duodenal or gastric) ulcer who are still infected. The ideal anti-H. pylori regimen should be safe, cheap, easy to comply with, well tolerated by children and able to achieve a high cure rate. Although US data are lacking, it is anticipated that the treatment regimen for children should be similar to that in adults (a triple therapy regimen that combines a proton pump inhibitor with 2 antimicrobial agents for 14 days). It is inappropriate to prescribe anti-H. pylori therapy without a firm diagnosis. The use of multiple antibacterials in a paediatric patient with an ulcer but without H. pylori infection cannot provide any benefit to the patient or the community. Such an approach only provides the possibility for adverse effects, for example development of antibacterial resistance among bystander bacteria. It is very important to confirm the diagnosis of H. pylori infection. The [13C]urea breath test is the noninvasive method of choice to determine H. pylori status in children and the ideal test for post-therapy testing. There is a need for post-therapy confirmation because of the likelihood of poor outcome for some treatment regimens, which is why post-therapy testing should be the standard of care. There is weak and inconsistent evidence of an association between H. pylori infection and recurrent abdominal pain (RAP) in children, in part because of the unclear definition of RAP in the literature. Therefore, there is still considerable debate regarding the treatment of infected children with RAP.

Helicobacter pylori and epidemic Vibrio cholerae O1 infection in Peru

In a cross-sectional study of the 1991 Peruvian cholera epidemic, Vibrio cholerae O1 infection was associated with Helicobacter pylori infection, particularly in young children. These data support the hypothesis that hypochlorhydria induced by H. pylori is important in the pathogenesis of diarrhoeal disease.

Helicobacter pylori is not a determinant factor of persistent diarrhoea or malnutrition in Peruvian children

To investigate the role of Helicobacter pylori in childhood diarrhoea, specific IgG antibodies to H. pylori (determined by an ELISA) were sought in 119 infants aged 3-36 months in Peru. Thirty one of the infants had acute diarrhoea (defined as lasting < 72 h and not present in the previous 3 weeks), 67 had persistent diarrhoea (lasting > or = 14 days with no more than 1 intervening diarrhoea-free day) and the remaining 21 had not had diarrhoea in the previous 3 weeks. The children with diarrhoea had been admitted to hospital in Lima for diarrhoea treatment, and the diarrhoea-free children for investigation of possible tuberculosis. Aspirates of duodenal contents and duplicate stool samples were investigated for the presence of bacterial overgrowth and of pathogenic bacteria, viruses and parasites. Anthropometric measurements were also made. There were no statistically significant differences between the prevalence rates of IgG against H. pylori in the children with acute diarrhoea, persistent diarrhoea and without diarrhoea (32%, 43% and 29%, respectively). In addition, H. pylori infection (as evidenced by specific antibodies) had no apparent influence on the presence of small-bowel overgrowth (in 20% of seropositive children compared with 18% of seronegative children) or of pathogens in the stool (in 53% of seropositive children compared with 49% of seronegative children) or on the occurrence of malnutrition in the groups of children considered as a whole. We conclude that H. pylori infection is not associated with acute or persistent diarrhoeal disease, small-bowel overgrowth, stool pathogens or malnutrition in Peruvian children.

Less diarrhoea but no change in growth: 15 years' data from three Gambian villages

AIMS

To review diarrhoea presentations and nutritional status in young rural Gambian children over a 15 year period as a test of an earlier hypothesis that reduced diarrhoea prevalence would lead to improved growth and a reduced prevalence of malnutrition.

SUBJECTS AND METHODS

Growth and morbidity were documented routinely in 1190 children under 2 years of age attending the Dunn Nutrition Group clinic at Keneba between 1979 and 1993.

RESULTS

The numbers of presentations with diarrhoea (1069 in 1979; 220 in 1993) and the proportion of clinic attendees with diarrhoea (30% in 1979; 8% in 1993) fell steadily between 1979 and 1993. However, at both 1 year old, mean weights (Z scores: 1979, -1.8; 1993, -1.8) and mean lengths (Z scores: 1979, -1.3; 1993, -1.7), and at 2 years old, mean weights (Z scores: 1979, -2.0; 1993, -1.9) and mean lengths (Z scores: 1979, -2.0; 1993, -2.1) did not change noticeably over the 15 year period.

CONCLUSION

Major progressive reductions in clinic presentations with diarrhoea have not been associated with improved nutritional status in this population of young rural Gambian children.

Stable isotope breath tests

There is a need for non-invasive tests of gastrointestinal and nutritional function. Clinical problems peculiar to infancy and childhood require prompt diagnosis, and methods that are invasive or involve the use of radioisotopes are often impractical or ethically unacceptable. What the pediatrician and clinical scientist seek are tests that are simple, repeatable, and unequivocal in their result for diagnosis, to assess the effects of treatment, and to measure the development of gastrointestinal function during early life. Stable isotope breath tests offer a ready and attractive answer to these needs. They involve the ingestion of substrates labeled with the non-radioactive isotope of carbon (13C), followed by the collection of serial breath samples for analysis of the enrichment of 13CO2, the end product of substrate metabolism. Their non-invasive nature recommends them for use in infancy and childhood, and they can be performed in the ward, clinic, laboratory, and home. In this article I discuss to what degree stable isotope breath tests fulfill the pediatrician's and scientist's needs. I have chosen two examples from the work of myself and my colleagues to illustrate the principles and use of 13C breath tests to detect Helicobacter pylori infection and to measure fat digestion in infancy and childhood.

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.

Helicobacter pylori infection, gastric acid secretion, and infant growth

BACKGROUND

Helicobacter pylori infection is very common in Gambian infants and children, who are also at risk of chronic diarrhoea and undernutrition. Acute H. pylori infection is associated with depressed gastric acid secretion, and loss of the gastric acid barrier may predispose to enteric infections.

METHODS

In a prospective study a noninvasive test of gastric acid output (measurement of change in urine acid output before and after a feed) was performed on a population of Gambian infants at high risk of H. pylori infection. The 13C urea breath tests was used to measure the prevalence of H. pylori infection and growth was measured by serial anthropometry.

RESULTS

In 101 infants aged 3 to 12 months, there was a significant relation between H. pylori infection and depressed urine acid output in those aged 6 months, during weaning when growth failure and malnutrition begin. Those infants with sustained H. pylori infection grew less well than those without.

CONCLUSIONS

We speculate that H. pylori, acquired in infancy, could be a "key that opens the door" to enteric infection in childhood, leading to recurrent diarrhoea, malnutrition, and growth failure.

Gastric acid secretion and enteric infection in Bangladesh

In developing countries many enteric infections are caused by acid-sensitive pathogens. Failure of the gastric acid barrier to infection has been reported in cholera but gastric acid secretion has been little studied in other enteric infections. We therefore studied basal and stimulated gastric acid in 185 Bangladeshi men admitted to hospital for the treatment of enteric infection. Patients with dysentery (amoebiasis, n = 24 and shigellosis, n = 19) and culture-negative diarrhoea (n = 69) had similar mean gastric acid levels (basal, 3-5 mmol/h; stimulated, 11-17 mmol/h), which remained stable in those patients studied throughout 12 weeks of convalescence. In contrast, patients with secretory diarrhoea caused by cholera or enterotoxigenic Escherichia coli (ETEC) had low gastric acid levels (P < 0.05 compared with other groups) (cholera, n = 34: basal mean 1.8 mmol/h [SD = 2.2], stimulated mean 7.9 mmol/h [SD = 6.4]; ETEC, n = 39: basal mean 2.7 mmol/h [SD = 2.8], stimulated mean 9.4 mmol/h [SD = 7.5]). Cholera patients' gastric acid level rose during convalescence to similar levels to the dysentery patients'. Low gastric acid level was associated with severe disease in patients with cholera (P < 0.02) or ETEC (P < 0.05). Gastric acid level fell with increasing age (P < 0.007) but this did not account for the differences between groups. Gastric acid levels were not associated with Giardia duodenalis or Strongyloides stercoralis co-infection, fever, use of tobacco, or chewing betel nut. Cholera and secretory diarrhoea caused by ETEC may, therefore, partly result from a reduction in gastric acid level which does not occur during dysentery. Factors which impair gastric acid secretion may predispose to diarrhoeal disease in developing countries.

Nutritional factors and Helicobacter pylori infection in Colombian children

BACKGROUND

Helicobacter pylori infection occurs most frequently in impoverished populations; however, little is known about specific determinants of susceptibility. This report describes the relationship between H. pylori infection and nutritional indicators among children from a rural village in the Colombian Andes, where a prevalence of 69% was observed in children from 2 to 9 years old.

METHODS

In a cross-sectional study of 684 children, comprising 92% of the 2- to 9-year-old population of Aldana, Colombia, information was obtained on dietary factors by questionnaire, height and weight by direct measurement, and H. pylori status using the carbon-13 urea breath test. Multivariate logistic regression was used to estimate relative risks for nutritional indicators.

RESULTS

The infection was least frequent among children who are several servings of fruits and vegetables daily, drank two or more cups of milk daily, and were in the upper quintile of height for their age. The odds of infection increased 19-fold (95% confidence interval, 4.0-91.9) among children who consumed less than two daily servings of fruits and vegetables compared with the modal intake of three to five daily servings. Children whose daily vitamin C intake from fruits and vegetables was less than 40 mg had greatly increased odds of infection (odds ratio, 7.2; 95% confidence interval, 1.5-34.1) compared to the modal intake of 80-119 mg; for beta-carotene, the odds ratio was 3.1 (95% confidence interval, 1.2-7.9) for intakes of less than 300 IU per day, compared with the modal daily intake of 900 IU or more.

CONCLUSIONS

The results of this population-based study suggest that nutritional factors may play a role in determining susceptibility to H. pylori infection.