Helicobacter pylori infection in Swedish school children: lack of evidence of child-to-child transmission outside the family

A survey on the current status of Helicobacter pylori infection in households in Hainan Province, China

OBJECTIVE

This study aims to assess the prevalence of Helicobacter pylori (Hp) infection at the household level in Hainan Province in China and identify the factors that contribute to its spread. The findings of this study have significant implications for public health prevention strategies in the Hainan region.

METHODS

A total of 421 families, comprising 1355 individuals, were tested for Hp infection across five cities in Hainan Province between July 2021 and April 2022. The study utilized questionnaires that included questions about personal characteristics, household shared lifestyle and dietary habits, and potential pathways of Hp infection in children to identify potential factors linked to household Hp infection and transmission patterns.

RESULTS

The prevalence of Hp infection on an individual basis was 46.72% (629/1355), with age ≥ 20 years, being married and having junior secondary education and above as risk factors for Hp infection. The prevalence of Hp infection in households was 80.29% (338/421), household size of 5, 6 and above were risk factors for Hp infection with Odds Ratios (ORs) of 4.09 (1.17-14.33) and 15.19 (2.01-114.73), respectively, household income ≥ 100,000 yuan and drinking boiled water from a tap source were protective factors for Hp infection with ORs of 0.52 (0.31-0.89) and 0.51 (0.28-0.95), respectively. The prevalence of Hp infection among minors in the household was 24.89% (58/233), with paternal infection and maternal infection as risk factors for child infection, with ORs of 2.93 (1.29-6.62) and 2.51 (1.07-5.89), respectively.

CONCLUSION

Hp infection was prevalent among Hainan families, and interaction with infected family members may be the primary cause of transmission.

Risk factors of Helicobacter pylori infection in Bukavu, Democratic Republic of the Congo: a case-control study

Helicobacter pylori (H. pylori) is the common etiology of gastric tumors. This study aimed to evaluate the risk factors associated with H. pylori infection in the eastern part of the Democratic Republic of the Congo (DR Congo), where these tumors seem to be more frequent than in its western part.

Patients and Methods

Between January and December 2021, the authors conducted a multicenter case-control study in three hospitals in Bukavu City involving 90 individuals with dyspeptic complaints. Risk factors for H. pylori infection were assessed in a participant interview and H. pylori status from stool antigen detection.

Results

Among the risk factors assessed, only history of H. pylori in the family and the habit of adding salt to already-seasoned food were found positively associated with the risk of H. pylori infection (adjusted odds ratio: 7, 95 CI: 2.742-17.867; P<0.0001 and 2.911, 95% CI: 1.010-8.526; P=0.048, respectively). On the other hand, low-temperature food storage seems to be protective with a negative association (adjusted odds ratio: 0.044, 95% CI: 0.009-0.206; P=0.0001).

Conclusion

This study demonstrated again the importance of lifestyle-related factors on the risk of acquisition of H. pylori. These findings call for preventive interventions for this group of individuals.

Pathogenomics of Helicobacter pylori

The human stomach bacterium Helicobacter pylori, the causative agent of gastritis, ulcers and adenocarcinoma, possesses very high genetic diversity. H. pylori has been associated with anatomically modern humans since their origins over 100,000 years ago and has co-evolved with its human host ever since. Predominantly intrafamilial and local transmission, along with genetic isolation, genetic drift, and selection have facilitated the development of distinct bacterial populations that are characteristic for large geographical areas. H. pylori utilizes a large arsenal of virulence and colonization factors to mediate the interaction with its host. Those include various adhesins, the vacuolating cytotoxin VacA, urease, serine protease HtrA, the cytotoxin-associated genes pathogenicity island (cagPAI)-encoded type-IV secretion system and its effector protein CagA, all of which contribute to disease development. While many pathogenicity-related factors are present in all strains, some belong to the auxiliary genome and are associated with specific phylogeographic populations. H. pylori is naturally competent for DNA uptake and recombination, and its genome evolution is driven by extraordinarily high recombination and mutation rates that are by far exceeding those in other bacteria. Comparative genome analyses revealed that adaptation of H. pylori to individual hosts is associated with strong selection for particular protein variants that facilitate immune evasion, especially in surface-exposed and in secreted virulence factors. Recent studies identified single-nucleotide polymorphisms (SNPs) in H. pylori that are associated with the development of severe gastric disease, including gastric cancer. Here, we review the current knowledge about the pathogenomics of H. pylori.

Antibiotic resistance patterns and therapeutic outcomes of pediatric Helicobacter pylori infection in a high-migrant Singaporean cohort

BACKGROUND

Variation in Helicobacter pylori (H. pylori) disease in terms of prevalence and antibiotic resistance prevails globally requiring a need to develop region-specific surveillance. We aimed to assess the influence of immigration factors upon the interpretation of local Singaporean epidemiological trends in antimicrobial susceptibility patterns and therapeutic outcomes in children with culture-positive H. pylori.

MATERIALS AND METHODS

We retrospectively analyzed eradication outcomes of children with culture-proven H. pylori infections between 2011 and 2020 at our center, and we also analyzed the antimicrobial susceptibility profiles of the corresponding H. pylori isolates. The cohort was classified into two groups: (1) Native Singaporeans and (2) Non-native Singaporeans (First-/Second-generation immigrants and Non-residents) to correlate with resistance patterns and eradication outcomes. H. pylori culture was done via Kirby-Bauer disk diffusion for the era 2011-2016 and bioMérieux E test for 2016-2020.

RESULTS

A total of 70 children (median age 14 [2-17] years) were included in the analysis. 42.9% (30/70) of the cohort displayed some form of antibiotic resistance; clarithromycin resistance was the most prevalent (30.0%), followed by metronidazole (27.5%) and amoxicillin (7.1%). Comparing to natives, non-native Singaporeans were significantly younger at presentation (mean 11.7 vs. 13.7 years, p = 0.043), and a significantly higher proportion of non-natives carried clarithromycin-resistant (51.4% vs. 8.6%, p < 0.001), metronidazole-resistant (47.1% vs. 8.6%, p < 0.001), or multidrug-resistant (resistant to ≥2 drugs) (40.0% vs. 2.9%, p < 0.001] strains. Non-natives were significantly more likely to fail first-line eradication therapy (48.5% failure vs. 23.3%, p = 0.038). The proportion of pan-sensitive H. pylori was significantly lower in first-generation (25.0%, p = 0.001) and second-generation (42.9%, p = 0.018) immigrants compared to natives (82.86%). These conclusions did not vary when the analysis was repeated for each culture method.

CONCLUSIONS

An antibiotic susceptibility-based approach should be advocated for all patients but especially so for non-natives, who are at higher risk for antimicrobial resistant strains and poorer eradication outcomes.

Helicobacter pylori infection in Iran: demographic, endoscopic and pathological factors

Background

Helicobacter pylori (H. pylori) infection is the most important risk factor for gastritis and peptic ulcer. However, factors other than H. pylori are involved in its pathogenesis. In the current study, we aimed to compare the clinical manifestations and endoscopic and histopathological findings of patients with and without H. pylori infection.

Methods

In this cross-sectional study, 233 patients with dyspepsia, referred for endoscopy, were examined regarding the presence of H. pylori infection. During an endoscopic exam, 5 biopsy specimens were taken from the stomach. The criteria for the presence of H. pylori infection was the presence and identification of bacteria in pathology. Two groups of H. pylori-positive and H. pylori-negative patients were compared regarding their demographic, endoscopic, and pathological findings.

Results

Of 233 patients, 154 (66.1%) were non-smokers, 201 (86.3%) were not alcohol users, and 153 (65.7%) used tap water. The most common symptom, reported in 157 (67.4%) patients, was epigastric pain. There was a significant difference between patients with and without H. pylori infection in terms of the educational status, occupational status, family history of gastrointestinal cancer, and some gastrointestinal symptoms. Also, there was a significant relationship between the endoscopic and pathological findings of patients with H. pylori.

Conclusions

The results of the present study revealed that H. pylori infection was not associated with sex, alcohol consumption, or non-steroidal anti-inflammatory drug use. The role of H. pylori in the pathophysiology of peptic ulcer was clarified. Also, there was a significant difference in the endoscopic and pathological findings of patients with H. pylori.

Relationship between African Biogeographical Ancestry and Helicobacter pylori infection in children of a large Latin American urban center

BACKGROUND AND AIM

The relationship between race/ethnicity and H pylori infection has been extensively reported, with a higher prevalence of infection observed in black individuals. Whether such differences are due to genetic factors underlying African ancestry remains to be clarified. In the present study, we evaluated the association between the proportion of individual African ancestry and H pylori infection in a sample of 1046 children living in a large Latin American urban center.

MATERIALS AND METHODS

Estimation of individual biogeographical ancestry was based on 370,539 SNPs and performed using the ADMIXTURE software. Multivariate logistic regression models and mediation analysis considering the influence of previously recognized socioenvironmental risk factors to H pylori infection were performed. All analyses were conducted using the statistical package STATA v.14.0.

RESULTS

Each 10% increase in the proportion of individual African ancestry was positively and independently associated with H pylori infection in our population (adjusted OR = 1.22, 95% CI = 1.10-1.36, P < .001). Mediation analysis demonstrated that only 9.23% of the effect of the individual African ancestry on H pylori infection was explained by factors such as household income, the absence of street paving and crowding.

CONCLUSIONS

The results suggest that genetic variants that covariate with African ancestry may explain an important part of the racial differences observed for the prevalence of H pylori infection.

Association between parental history of Helicobacter pylori treatment failure and treatment failure in the offspring

BACKGROUND AND AIM

Both clarithromycin-resistant Helicobacter pylori and CYP2C19 polymorphisms may be passed down for generations and are known risk factors for the failure of H. pylori eradication therapy. However, no study has evaluated the risk of clarithromycin triple therapy failure in patients with a parental history of such failure. This study investigated the association between a history of clarithromycin triple therapy failure in parents and clarithromycin triple therapy failure in the offspring.

METHODS

This cross-sectional study was conducted using a large administrative claims database of 3 100 000 insured individuals. We identified 404 patients who had both personal and parental records of prescriptions for first-line clarithromycin triple therapy between January 2005 and February 2018. Failure of clarithromycin triple therapy was defined as treatment with second-line therapy after having received first-line clarithromycin triple therapy. A parental history of clarithromycin triple therapy failure was defined as failure of clarithromycin triple therapy by either the father or the mother. Odds ratios were estimated using logistic regression models adjusted for age, sex, diabetes mellitus, and peptic ulcer.

RESULTS

The incidence of clarithromycin triple therapy failure was 22.5% (91/404). Based on univariate analysis (odds ratio [95% confidence interval], 1.90 [1.10-3.29]) and multivariable analysis (odds ratio [95% confidence interval], 1.93 [1.10-3.39]), parental history of clarithromycin triple therapy failure was associated with failure of clarithromycin triple therapy in the offspring.

CONCLUSION

A parental history of clarithromycin triple therapy failure is a risk factor for failure of clarithromycin triple therapy in the offspring.

A Longitudinal, Population-Level, Big-Data Study of Helicobacter pylori-Related Disease across Western Australia

Helicobacter pylori, responsible for chronic ulcers and most stomach cancers, infects half of the world’s population. The Urea Breath Test (UBT) is one of the most accurate and reliable non-invasive methods for diagnosing active H. pylori infection. The objective was to use longitudinal, population-wide UBT data for Western Australia to look for H. pylori-related disease patterns. We collected 95,713 UBT results from 77,552 individuals for the years 2010–2015, likely representing all of the UBT samples analysed in Western Australia. Data collected also included sex, age and residential postcode. Other data reported here were inferred via a comparison with the 2011 Australian Census using a specially written Python program. While women appear to have more H. pylori-related disease than men, there is no difference in the disease rates once women’s higher rates of presentation for testing are taken into account. On the other hand, while the treatment strategy for H. pylori infection is generally very effective in Western Australia, failure of the first-line treatment is significantly more common in women than men. Migrants and Aboriginal Australians have elevated rates of H. pylori-related disease, while the rate for non-Aboriginal Australian-born West Australians is very low. However, no significant associations were found with other socio-economic indicators. We conclude that, for some people, H. pylori-related disease is not a solved problem.

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 infection in Icelandic children

OBJECTIVE

The prevalence of Helicobacter pylori (HP) infection is decreasing in the western world. The seroprevalence among 25-50-year-old Icelandic adults was recently shown to be 30-40%. Information on the seroprevalence in Nordic children is limited. We aimed at ascertaining the infection prevalence among healthy Icelandic children.

METHODS

The infection status in stored frozen blood samples from two cross-sectional studies on the health of 7-9-year-old children (n = 125) and 16-18-year-old adolescents (n = 80) was determined by enzyme-linked immunosorbent assay (ELISA). Information on family demographics and GI symptoms was obtained by standardized questionnaires.

RESULTS

Overall, 3.4% (7/205) of the children were infected with H. pylori. The prevalence was 2.6% (5/190), missing data n = 3, among children with both parents born in a low prevalence country compared to 17% (2/12) among those with at least one parent born in a high prevalence area (p = .026). When at least one parent was born in a high prevalence country, the odds ratio for being H. pylori seropositive was 2.2 (95% CI, 1.02-54.67), when adjusted for the educational status of the mother. There was no significant association between H. pylori infection and gastrointestinal symptoms.

CONCLUSION

Prevalence of H. pylori infection in Iceland has become very low, suggesting a great reduction in transmission from older generations. There was an association between H. pylori infection and origin from high prevalence areas but not with gastrointestinal symptoms. The results mirror recent studies of children of Scandinavian ancestry.

Intrafamilial transmission of Helicobacter pylori: genotyping of faecal samples

BACKGROUND

After more than 20 years of research, there is a little information about the detailed routes of Helicobacter pylori transmission. The aim of this study was to explore intrafamilial transmission of H. pylori in children who had indication for upper gastrointestinal endoscopy and their parents.

METHODS

Children (aged up to 15 years) were studied during September 2012 to October 2013. The parents of those with positive urea breath test results were asked to provide faecal and blood samples after giving informed consent. Non-invasive tests such as immunoassay for serological antibodies against H. pylori and detection of its antigen in faeces were measured. The genetic similarity of the family strains was investigated by the random amplification of polymorphic DNA (RAPD-PCR) genotyping method.

RESULTS

According to the genotyping results of 30 families, in 10 (33.3%) children related H. pylori genotypes to their mothers were found, while only 2 children (6.7%) had similar genotypes to their fathers. Interestingly, children with similar H. pylori genotype with their mothers had higher IgA (35.7 ± 10.8) and IgM antibody titres (87.23 ± 19.15) than other children. In addition, in these children, lower titres of IgG antibodies (9.93 ± 3.31) were found rather than children who had no H. pylori in their faeces or had no similarities with their parents (30.28 ± 6.15).

CONCLUSIONS

In conclusion, mother-to-child transmission is the main route of intrafamilial transmission of H. pylori in Iranian families. Molecular typing of H. pylori can be useful in identifying a high-risk population.

Helicobacter pylori antibodies and iron deficiency in female adolescents

Objective

Iron deficiency (ID) is a common clinical problem worldwide, affecting primarily females. Helicobacter pylori (HP) infection has been shown to be associated with ID. The objective of this study was to define the prevalence of HP antibodies in female adolescents, and to find out if there was a correlation between HP infection and ID. The secondary aim was to study if regularly performed sporting activity, have any association to HP infection, in itself.

Design

A controlled clinical trial.

Setting

A senior high school in Gothenburg, Sweden.

Subjects

All female athletes at a senior high school for top-level athletes were offered to take part, and 56 athletes took part in the study. The control group consisted of a random sample of age-matched non-athlete students of which 71 entered the study.

Main outcome measures

Iron deficiency (ID) and iron deficiency anaemia (IDA) were defined by the use of levels of haemoglobin, serum iron, total iron-binding capacity, transferrin saturation, and serum ferritin, as previously described. HP IgG-antibodies were detected by ELISA.

Results

18 of 127 (14%) adolescent females had antibodies against HP. Only 3% had IDA, while 50% had ID. In total, 66% of the HP positive females had ID compared to 48% of the negative females (p = 0.203). No correlation between sporting activity and HP infection was found. Regarding ethnicity, 11/28 of subjects from medium-high risk areas were HP-positive, compared to 7/99 coming from low-risk areas (p<0.001).

Conclusion

The main finding of this study is that the prevalence of HP IgG antibodies was 14% in adolescent females. We could not find any difference regarding frequency of ID and IDA, between HP positive and negative individuals. Ethnicity is of great importance for the risk of HP infection, while sporting activity itself seems to have no association to HP-infection.

Reduced genome size of Helicobacter pylori originating from East Asia

Helicobacter pylori (H. pylori), a major pathogen colonizing the human stomach, shows great genetic variation. Comparative analysis of strains from different H. pylori populations revealed that the genome size of strains from East Asia decreased to 1.60 Mbp, which is significantly smaller than that from Europe or Africa. In parallel with the genome reduction, the number of protein coding genes was decreased, and the guanine-cytosine content was lowered to 38.9%. Elimination of non-essential genes by mutations is likely to be a major cause of the genome reduction. Bacteria with a small genome cost less energy. Thus, H. pylori strains from East Asia may have proliferation and growth advantages over those from Western countries. This could result in enhanced capacity of bacterial spreading. Therefore, the reduced genome size potentially contributes to the high prevalence of H. pylori in East Asia.

Childcare attendance and Helicobacter pylori infection: systematic review and meta-analysis

Helicobacter pylori infection is acquired predominantly during childhood. Childcare promotes interpersonal contact and may be an important determinant of infection. The aim was to quantify the association between childcare attendance and H. pylori infection in childhood or adolescence. PubMed was searched up to July 2012 to identify eligible studies. The DerSimonian and Laird method was used to compute summary odds ratio (OR) estimates and 95% confidence intervals (CIs); heterogeneity was quantified with the I statistic and explained through stratified analyses and metaregression. Sixteen studies compared participants attending childcare with those not exposed. The summary OR was 1.12 (95% CI: 0.82-1.52, I=77.4%). Summary estimates were similar for crude and adjusted estimates, and higher when the infection was evaluated in children of 3 years or younger (OR=2.00, 95% CI: 0.94-4.29, I=55.0%). Studies based on the detection of stool antigens yielded higher estimates (OR=2.65, 95% CI: 1.24-5.66, I=36.4%). Those conducted in settings with a high prevalence of H. pylori infection yielded stronger associations (OR=1.44, 95% CI: 0.94-2.20, I=74.3%). In multivariate metaregression, there was no significant association with any of these variables; taking them into account contributed to a reduction of I to 67%. The role of childcare as a risk factor for H. pylori infection is confirmed by our results, especially in settings with a high prevalence of infection. However, the association was moderate, and the effect of the type of childcare setting or the duration or the intensity of exposure was seldom addressed, leaving considerable scope for improving our understanding of how this modifiable exposure contributes towards H. pylori infection.

Evidence-based guidelines from ESPGHAN and NASPGHAN for Helicobacter pylori infection in children

OBJECTIVE

As the clinical implications of Helicobacter pylori infection in children and adolescents continue to evolve, ESPGHAN and NASPGHAN jointly renewed clinical guidelines using a standardized evidence-based approach to develop updated recommendations for children and adolescents in North America and Europe.

METHODS

An international panel of 11 pediatric gastroenterologists, 2 epidemiologists, 1 microbiologist, and 1 pathologist was selected by societies that developed evidence-based guidelines based on the Delphi process with anonymous voting in a final face-to-face meeting. A systematic literature search was performed on 8 databases of relevance including publications from January 2000 to December 2009. After excluding nonrelevant publications, tables of evidence were constructed for different focus areas according to the Oxford classification. Statements and recommendations were formulated in the following areas: whom to test, how to test, whom to treat, and how to treat. Grades of evidence were assigned to each recommendation based on the GRADE system.

RESULTS

A total of 2290 publications were identified, from which 738 were finally reviewed. A total of 21 recommendations were generated, and an algorithm was proposed by the joint committee providing evidence-based guidelines on the diagnostic workup and treatment of children with H pylori infection.

CONCLUSIONS

These clinical practice guidelines represent updated, best-available evidence and are meant for children and adolescents living in Europe and North America, but they may not apply to those living on other continents, particularly in developing countries with a high H pylori infection rate and limited health care resources.

Younger siblings play a major role in Helicobacter pylori transmission among children from a low-income community in the Northeast of Brazil

BACKGROUND AND AIMS

To further evaluate intrafamilial transmission of H. pylori infection during childhood, we investigated the prevalence of H. pylori in family members from a poor H. pylori high-prevalence urban community in the Northeast of Brazil.

METHODS

H. pylori infection was investigated in 570 members of 128 households, by (13) C-urea breath test in children and by ELISA in mothers and other adult relatives.

RESULTS

The overall prevalence of H. pylori infection (376/570) increased with age (p < .001) and ranged from 28.9%, in children aged 6 months to 5 years, to 82% in adults over 40 years. An H. pylori positive mother and the number of infected siblings are independent risk factors for childhood H. pylori infection (OR = 2.2, 95% CI = 1.0-4.6 and OR = 4.3, 95% CI = 2.3-8.1, respectively) The number of siblings, number of younger siblings, and number of infected younger siblings were also associated with the infection in the univariate analysis. The number of infected younger siblings remained independently associated with the infection (p = .000), even after controlling for all the above cited variables, in addition to the H. pylori status of siblings and mothers, age, number of people per room, and number of children in the household.

CONCLUSION

The transmission of H. pylori occurs from infected mothers to their offspring and among siblings, notably from younger siblings to the older ones.

Evaluation of Helicobacter pylory colonization by serologic test (IgG) and dyspepsia in volunteers from the countryside of Monte Negro, in the Brazilian western Amazon region

The present study intended to analyze the seroprevalence of Helicobacter pylori, IgG, and its relation to dyspepsia in a population from the western Amazon region. During the "Projeto Bandeira Científica", a University of São Paulo Medical School program, in Monte Negro's rural areas, state of Rondônia, 266 blood samples were collected from volunteers. The material was tested for IgG antibodies anti-Helicobacter pylori by ELISA method and the participants were also interviewed on dyspepsia, hygiene and social aspects. Participants aged between five and 81 years old (34 years on average), 149 (56%) were female and 117 (44%) male. We found 210 (78.9%) positive, 50 (18.8%) negative and six (2.3%) undetermined samples. Dyspeptic complaints were found in 226 cases (85.2%). There was no statistical association between dyspepsia and positive serology for H. pylori. We concluded that the seroprevalence in all age categories is similar to results found in other studies conducted in developing countries, including those from Brazil. On the other hand, the seroprevalence found in Monte Negro was higher than that reported in developed countries. As expected, there was a progressive increase in the positivity for H. pylori in older age groups.

The incredible journey of mankind: Helicobacter pylori as the narrator

Over the past decade, sequence differences between microbes from various geographical areas have been studied with the intent to interpret population movements of their hosts. An organism that is a reliable storehouse of such data, by virtue of its long association with its human host, is Helicobacter pylori. Functional and comparative analyses of its genome provide fascinating insights into human behaviour in the ancient past.

Exposure to Helicobacter pylori-positive siblings and persistence of Helicobacter pylori infection in early childhood

OBJECTIVES

Cross-sectional studies suggest that Helicobacter pylori may be transmitted between siblings. The present study aimed to estimate the effect of an H pylori-infected sibling on the establishment of a persistent H pylori infection.

MATERIALS AND METHODS

The authors used data collected from a Texas-Mexico border population from 1998 to 2005 (the "Pasitos Cohort Study"). Starting at age 6 months, H pylori and factors thought to be associated with H pylori were ascertained every 6 months for participants and their younger siblings. Hazard ratios were estimated from proportional hazards regression models with household-dependent modeling.

RESULTS

Persistent H pylori infection in older siblings always preceded persistent infection in younger siblings. After controlling for mother's H pylori status, breast-feeding, antibiotic use, and socioeconomic factors, a strong effect was estimated for persistent H pylori infection in an older sibling on persistent infection in a younger sibling (hazard ratio 7.6, 95% confidence interval 1.6-37], especially when the difference in the age of the siblings was less than or equal to 3 years (hazard ratio 16, 95% confidence interval 2.5-112).

CONCLUSIONS

These results suggest that when siblings are close in age, the older sibling may be an important source of H pylori transmission for younger siblings.

Helicobacter species DNA in liver and gastric tissues in children and adolescents with chronic liver disease

OBJECTIVE

Enterohepatic Helicobacter species (EHS) have previously been found in adults with hepatobiliary diseases. Here, we report the prevalence of Helicobacter pylori and EHS in liver and gastric tissue in children and adolescents with chronic liver disease (CLD).

MATERIAL AND METHODS

Seventy-seven consecutive children and adolescents with CLD with or without ulcerative colitis or Crohn's disease (UC/CD) were investigated. Tissue samples were analysed using a Helicobacter genus-specific 16S rDNA polymerase chain reaction (PCR) assay and DNA-sequence analysis. Sera from 61 subjects were also analysed using enzyme immunoassay and immunoblotting.

RESULTS

The Helicobacter PCR was positive in 3/23 (13%) livers from patients with primary sclerosing cholangitis and UC, and in 1/2 livers from patients with autoimmune hepatitis (AIH) and UC. Sequenced PCR products matched the 16S rDNA of H. hepaticus, H. muridarum, H. canis, and H. pylori, respectively. H. ganmani and H. bilis were detected in gastric tissues from two AIH patients. H. hepaticus and H. pullorum were found in livers from two patients with acute liver failure and intrahepatic cholestasis. Antibody reactivity to Helicobacter cell-surface proteins was negative.

CONCLUSIONS

H. pylori and EHS can be detected in the livers of some patients with UC and concomitant liver disease, as well as in other children with liver diseases. Multicentre studies from different locations are needed to find out whether these bacteria play a pathogenetic role or whether their presence is an epiphenomenon.

Premastication: the second arm of infant and young child feeding for health and survival?

Premastication of foods for infants was a crucial behavioural adaptation to neoteny that ensured nutritional adequacy during the period of complementary feeding throughout the course of human evolution until recent times.While the paps and gruels of agricultural systems provided an alternative and modern food technology appears to make it unnecessary, we argue that, in addition to its role in nutrition, premastication also played a crucial role in supporting infant health. Its abandonment, particularly in poor communities, has placed children at increased risk of inadequate nutrition and decreased ability to confront infections associated with the introduction of complementary foods.We present two empirical studies. Section I is a cross-cultural study of the ethnographic literature in order to estimate prevalence in non-Western societies.One-third of ethnographies in the worldwide sample with data on infant feeding report premastication. Section II presents the results of a qualitative study in China, conducted in order to provide data on the likelihood that this percent is incorrect due to under-reporting.The finding that 63% of Chinese university students received premasticated food as infants, whereas none of eight ethnographic studies performed in Han China identified premastication in their reports, provides support for the conclusion that the cross-cultural study grossly underestimates its prevalence in non-Western societies. Section III is a discussion of potential benefits and risks of infant exposure to maternal saliva.We conclude with the argument for a concerted research effort to determine whether premastication can solve not only the 'weanling dilemma' in poor countries but also some of the health problems among the better-off.

Antibiotics taken for other illnesses and spontaneous clearance of Helicobacter pylori infection in children

PURPOSE

Factors that determine persistence of untreated Helicobacter pylori (H. pylori) infection in childhood are not well understood. We estimated risk differences for the effect of incidental antibiotic exposure on the probability of a detected clearance at the next test after an initial detected H. pylori infection.

METHODS

The Pasitos Cohort Study (1998-2005) investigated predictors of H. pylori infection in children from El Paso, Texas, and Juarez, Mexico. Children were screened for infection at 6-month target intervals from 6 to 84 months of age, using the 13C-urea breath test corrected for body-size-dependent variation in CO2 production. Exposure was defined as courses of any systemic antibiotic (systemic) or those with anti-H. pylori action (HP-effective) reported for the interval between initial detected infection and next test. Binomial regression models included country of residence, mother's education, adequacy of prenatal care, age at infection, and interval between tests.

RESULTS

Of 205 children with a test result and antibiotic data following a detected infection, the number of children who took > or =1 course in the interval between tests was 74 for systemic and 33 for HP-effective. The proportion testing negative at the next test was 66% for 0 courses, 72% for > or =1 systemic course, and 79% for > or =1 HP-effective course. Adjusted risk differences (95%CI) for apparent clearance, comparing > or =1 to 0 courses were 10% (1-20%) for systemic and 11% (0-21%) for HP-effective.

CONCLUSIONS

Incidental antibiotic exposure appears to influence the duration of childhood H. pylori infection but seems to explain only a small portion of spontaneous clearance.

Helicobacter pylori infection in developing countries: the burden for how long?

Approximately 50% (over 3 billion) of the world populations are known to be infected with Helicobacter pylori , mainly in the developing countries . Among those, hundreds of millions of people develop peptic ulceration during their lifetime and still tens of millions might progress to gastric cancer. Possible modes of H. pylori transmission generally described are through direct contact between family members and also through contaminated water and food. Because the high prevalence of infection occurs mainly in developing countries and because the test-and-treat strategy puts a huge economic burden on many of these countries, it is time to take an immediate action toward this bacterial infection and adopt a strategy to prevent it. To address this issue, an updated prevalence of infection, modes of transmission, economics of infection and preventative measures to block the infection process have been discussed.

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.

Helicobacter pylori infection in young children detected by a monoclonal stool antigen immunoassay

The prevalence of Helicobacter pylori infection in young children attending day care facilities was studied using a monoclonal stool antigen test. Of 316 samples, 78 (24.7%) were positive. Only 7/98 (7.1%) of the 3- to 12-month-old infants tested positive compared with 71/218 (32.5%) of the 13- to 60-month-old group. We conclude that approximately 30% of infants may become infected with H. pylori after the first year of life.

A novel noninvasive genotyping method of Helicobacter pylori using stool specimens

BACKGROUND & AIMS

The source(s) of the infection and the route(s) of transmission of Helicobacter pylori have not yet been clarified. This is to introduce a noninvasive protocol allowing molecular typing of H pylori using stool specimens.

METHODS

The genotyping method is based on 2 H pylori-specific biprobe real-time polymerase chain reaction assays using fragments of the glmM and the recA genes as target sequences. Discrimination between strains results from differences in the melting temperature during melting curve analysis. In case of identical melting temperatures in both assays, sequence analysis of the glmM amplicon was performed to confirm strain identity. The method was validated using gastric biopsy specimens and stool specimens of 97 unrelated individuals suffering from abdominal pain and stool specimens of members of 10 families in Austria (infected index child and family members) and 8 African households.

RESULTS

Of the 97 patients, 27 were infected as shown by culture, histology, and rapid urease test. The sensitivity of each of the assays was 100% in gastric biopsy specimens and 92.2% in stool specimens; the specificity was 100%. The discriminatory capacity of the method was 100%. Clonal identities were found in 9 of 10 (90%) European and 7 of 8 (87.5%) African households. In 2 African households, 2 different clonal lineages each were found.

CONCLUSIONS

The genotyping protocol introduced allows for both accurate detection and discrimination of H pylori strains in stool samples. Large-scale studies using this protocol may contribute to the clarification of the transmission pathways of infection with H pylori.

Predominance of mother-to-child transmission of Helicobacter pylori infection detected by random amplified polymorphic DNA fingerprinting analysis in Japanese families

BACKGROUND

Helicobacter pylori (H. pylori) is one of the most common bacterial pathogens in humans but the route of transmission remains unclear. We investigated transmission by DNA fingerprinting analysis of cultured H. pylori from pediatric patients and their family members.

METHODS

Forty-two index patients with a mean age of 11.7 years (range, 4-19) were diagnosed as having H. pylori gastritis with or without duodenal/gastric ulcer disease. A total of 66 family members for whom the results of the H. pylori stool antigen test and/or serum H. pylori IgG test were positive underwent endoscopic examination and biopsy or aspiration of gastric juice for H. pylori culture. The extraction of H. pylori genomic DNA and PCR-based RAPD analysis were performed.

RESULTS

Thirty-two (76%) of the 42 patients showed DNA fingerprint patterns identical to those of at least one of the respective family members. The patterns of 29 (69%) of the analyses of the H. pylori infected patients were identical to those of their mothers. The patterns for 7 patients were identical to those of their fathers, and those for 6 of the latter patients were also identical to those of their mothers. The rate of fingerprint patterns identical to those of the index patients was significantly higher in those of mothers compared with those of fathers (P < 0.01).

CONCLUSIONS

Mother-to-child transmission is the predominant route of H. pylori infection in Japan.

DNA-level diversity and relatedness of Helicobacter pylori strains in shantytown families in Peru and transmission in a developing-country setting

The efficiency of transmission of a pathogen within families compared with that between unrelated persons can affect both the strategies needed to control or eradicate infection and how the pathogen evolves. In industrialized countries, most cases of transmission of the gastric pathogen Helicobacter pylori seems to be from mother to child. An alternative model, potentially applicable among the very poor in developing countries, where infection is more common and the sanitary infrastructure is often deficient, invokes frequent transmission among unrelated persons, often via environmental sources. In the present study, we compared the genotypes of H. pylori from members of shantytown households in Peru to better understand the transmission of H. pylori in developing-country settings. H. pylori cultures and/or DNAs were obtained with informed consent by the string test (a minimally invasive alternative to endoscopy) from at least one child and one parent from each of 62 families. The random amplified polymorphic DNA fingerprints of 57 of 81 (70%) child-mother strain pairs did not match, nor did the diagnostic gene sequences (>1% DNA sequence difference), independent of the child's age (range, 1 to 39 years). Most strains from siblings or other paired family members were also unrelated. These results suggest that H. pylori infections are often community acquired in the society studied. Transmission between unrelated persons should facilitate the formation of novel recombinant genotypes by interstrain DNA transfer and selection for genotypes that are well suited for individual hosts. It also implies that the effective prevention of H. pylori infection and associated gastroduodenal disease will require anti-H. pylori measures to be applied communitywide.

A population-based study of Helicobacter pylori infection in Chinese children resident in Hong Kong: prevalence and potential risk factors

BACKGROUND

Data of Helicobacter pylori prevalence in children and its risk factors provide clues to the health authority to estimate burden of H. pylori-associated diseases usually encountered in adulthood and facilitate healthcare planning.

MATERIALS AND METHODS

A cross-sectional population-based study was conducted in Chinese children in elementary and high schools. Schools were selected from all three major areas of Hong Kong. H. pylori infection was defined by a positive (13)C-urea breath test. Study subjects were stratified into six age groups for estimation of prevalence. Potential risk factors were analyzed from data of self-administered questionnaires.

RESULTS

A total of 2480 children (aged 6-19, male: 47.3%) participated in the study. Overall, 324 (13.1%) were positive for H. pylori. There was no difference in prevalence between sexes, and no statistical trend in the prevalence across the six age groups. Multivariate logistic regression identified lack of formal education of mother (OR = 2.43, 95%CI 1.36-4.34), family history of gastric cancer (OR = 2.19, 95%CI 1.09-4.41), and household member > 5 (OR = 1.57, 95%CI 1.12-2.19) to be positively associated with H. pylori infection in our children.

CONCLUSIONS

The H. pylori prevalence of Hong Kong children is comparable to the data of developed countries. The association with family history of gastric cancer justifies further study to investigate the cost-benefit of community screening program for such children to decrease the incidence of gastric cancer in adulthood.

Using macro-arrays to study routes of infection of Helicobacter pylori in three families

BACKGROUND

Analysis of the evolutionary dynamics of Helicobacter pylori allowed tracing the spread of infection through populations on different continents but transmission pathways between individual humans have not been clearly described.

MATERIALS AND METHODS

To investigate person-to-person transmission, we studied three families each including one child with persistence of symptoms after antibiotic treatment. Ten isolates from the antrum and corpus of stomach of each family member were analyzed both by sequencing of two housekeeping genes and macroarray tests.

RESULTS

A total of 134 (8.4%) out of the 1590 coding sequences (CDSs) tested, including cag PAI and insertion sequences, were present in some but not all isolates (and are therefore defined as variable CDSs). Most of the variable CDSs encoded proteins of unknown function (76/134) or were selfish DNA including that encoding restriction/modification enzymes (13/134). Isolates colonizing the stomach of one individual can vary by point mutations, as seen in hspA, or by the gain or loss of one to five CDSs. They were considered as (genetic) variants. The phylogenetic clustering of gene profiles obtained on macro-arrays allowed identifying the different strains infecting families. Two to five strains circulated within a family. Identical strains were present in at least two members of all three families supporting the accepted model of intrafamilial transmission. Surprisingly, the mother was not implicated in the transmission of H. pylori in the two French families. Sibling-to-sibling transmission and acquisition of H. pylori from outside the family appeared to be probable in the transmission pathways.

CONCLUSION

Macroarray analysis based on previously selected CDSs gives a comprehensive view of the genome diversity of a pathogen. This approach combined with information on the origin of the hspA and glmM alleles revealed that Helicobacter pylori infection may be acquired by more diverse routes than previously expected.

Association between Helicobacter pylori infection in mothers and birth weight

Helicobacter pylori infection may cause intrauterine growth restriction (IUGR). However, it is unknown whether the growth of children from H. pylori-infected mothers is also affected or whether transmission of infection from mother to child occurs. This study aimed to determine if maternal H. pylori infection was associated with IUGR and low birth weight in a mouse model, and whether transmission of infection from mother to infant occurs. Female C57BL/6 mice were inoculated with H. pylori (n = 18) or water (control; n = 18) via gavage. Mice were mated at 6 weeks postinfection, with half of the mice sacrificed after 2 weeks of gestation. The remaining mice gave birth and a third of the litter was weighed and sacrificed at birth, during milk feeding (1.5 weeks), and during solid feeding (4 weeks). Stomachs of all mice and whole foetuses were cultured for the presence of H. pylori. There were no differences in litter size or foetus weight between control and H. pylori-infected mice. Pups from infected mothers had a lower weight during milk feeding (control, 5.91 +/- 0.23 g; H. pylori, 4.59 +/- 0.16 g; p < 0.05) and solid feeding (control, 12.73 +/- 0.58 g; H. pylori, 10.01 +/- 1.02 g; p < 0.05). H. pylori was not detected by culture in the pups at any age. H. pylori infection in mothers was associated with a decrease in infant weight during milk feeding and after weaning. Transmission of infection from mother to infant was not detected by culture, suggesting that decreased baby weight may be due to decreased milk supply or altered nutrition from the mother.

Genomic diversity in Helicobacter and related organisms

The human gastric pathogen Helicobacter pylori possesses an enormous genomic plasticity and diversity that facilitates host adaptation. Despite the ancient association with its human host, this epsilon-proteobacterium can cause gastritis, ulcers and gastric cancer. Here we focus on multiple aspects of the genome level biology, from population genomics to re-evaluating the genus definition.

Seroprevalence of Helicobacter pylori and cagA antibodies in Iceland, Estonia and Sweden

The public health implications from H. pylori infection are considerable but the transmission routes are largely unknown. In this study, the prevalence, patient characteristics and risk factors for Helicobacter pylori infection were comparatively investigated in Iceland, Sweden and Estonia. Blood samples were collected from 1046 subjects aged approximately 25-50 y (447 in Reykjavik, 359 in Uppsala and 240 in Tartu) for determination of antibodies to H. pylori and its cagA protein. The prevalence of H. pylori antibodies was 69% in Tartu, 36% in Reykjavik and 11% in Uppsala (p<0.0001). There was an increase in prevalence with age in Iceland and Sweden but not in Estonia. The prevalence of antibodies to the cagA protein in subjects seroreactive to H. pylori was lower in Reykjavik (36%) than in Uppsala (69%) and Tartu (62%) (p<0.0001). H. pylori infection, as determined by seroreactivity, was positively associated with smoking and BMI. Overall, socioeconomic development during the childhood period seems to be the most important factor for the prevalence of H. pylori infection. In adults, smoking may be a contributory factor.

Pathogenomics of helicobacter

The pathogenic bacterium Helicobacter pylori infects half of the human population and is one of the genetically most diverse bacterial species known. H. pylori was one of the first bacterial species whose genome was sequenced in 1997, and the first species for which two complete sequences from independent isolates were available for within-species comparisons. For almost 10 years, genomic and post-genomic analysis has contributed enormously to our understanding of the pathogenesis of H. pylori infection. This review summarizes the available information, emphasizing work performed in the framework of the PathoGenoMik funding initiative (2001-2006) of the German Ministry of Education and Research.

The transmission of Helicobacter pylori: the effects of analysis method and study population on inference

Although much is known about the virulence of Helicobacter pylori, the transmission pathways for this bacterium are still unresolved. Transmission has been addressed through: (1) prevalence within families; (2) detection in fecal/oral environments; (3) detection in the abiotic/biotic environment; and (4) direct inference from strain similarity. Here, we review the molecular and biochemical methods used and discuss the relative merits of each. Furthermore, as there are differences between developing and developed nations, we discuss the results obtained from transmission studies in light of the study population. We conclude that H. pylori is probably transmitted person-to-person, facilitated by fecal-oral transmission during episodes of diarrhea or gastro-oral contact during periods of vomiting. The persistence of H. pylori in abiotic and biotic environments remains unproven but possible reactivation from viable, non-culturable coccoid forms should be further investigated. Finally, we speculate on the effect of host-pathogen interactions in confounding the inference of transmission.

Socio-economic and occupational risk factors for gastric cancer: a cohort study in Sweden

The effects of socio-economic/occupational factors on gastric cancer at various subsites (including corpus, cardia and unspecified cancers) are not well known. To investigate this issue, we carried out a follow-up study on the economically active Swedish population, based on the Swedish Family-Cancer Database. We calculated standardized incidence ratios and 95% confidence intervals for different occupational groups, adjusted for age, period, region and socio-economic status. The reference group was all the economically active population. Manual workers and farmers were at an increased risk of stomach cancer. An increased risk of corpus cancer was observed for male miners and quarry workers, fishermen, construction workers, packers, loaders and warehouse workers, clerical workers and female assistant nurses and postal workers. For cardia cancer, significantly increased standardized incidence ratios were observed for gardeners, transport workers, bricklayers and chemical process workers among men. Only male miner and quarry workers showed significantly increased risk of unspecified cancer. In conclusion, the present study indicates that socio-economic groups differ in risk by almost a factor of two for corpus and unspecified cancers, and less for cardia cancers. Cement and mineral dusts appear as major occupational risk factors.

Community-based familial study of Helicobacter pylori infection among healthy Japanese Brazilians

BACKGROUND

The present study of Helicobacter pylori infection was conducted in family units of Japanese Brazilians living in São Paulo city. The authors attempted to determine the seroprevalence of H. pylori infection within family units of Japanese Brazilians and to identify risk factors associated with intrafamilial transmission.

METHODS

The seroprevalence was determined in 1037 healthy and asymptomatic volunteer subjects aged 0-69 years (530 adults and 507 children) of 265 families. Demographic data and details of living conditions were obtained from each family.

RESULTS

H. pylori seropositive infection was found in 39.2% of the parents and 9.3% of the children. A reduced risk of H. pylori infection was found for girls (odds ratio [OR] 0.45; 95% confidence interval [CI], 0.23-0.86). The prevalence of infection was 3.5% for children with uninfected parents; 9.9% (OR, 2.51; 95% CI, 0.95-6.61) for those with a seronegative mother and a seropositive father; 14.9% (OR, 4.93; 95% CI, 1.86-13.06) for those with a seropositive mother and a seronegative father; and 16.0% (OR, 5.29; 95% CI, 1.98-14.14) for those with seropositive parents. On multivariate analysis, the use of a pacifier, and mother's symptoms of nausea and vomiting were significantly associated with the risk of H. pylori infection for children, and the child having her/his own room was significantly associated with a reduced risk. Income was not associated with H. pylori infection in children and was inversely associated in parents.

CONCLUSION

The prevalence of H. pylori infection in family units of Japanese Brazilians supports the hypothesis of a predominant role for mother-child transmission of H. pylori infection, mainly through contact with regurgitated gastric juice in the mother's mouth.

Helicobacter pylori infection and gender: a meta-analysis of population-based prevalence surveys

Although most of Helicobacter pylori-related diseases are associated with male gender, the role of gender as a risk factor for H. pylori infection is still debated. To assess the true association between H. pylori and gender, we conducted a meta-analysis of large, population-based studies where the measure of association had been adjusted at least for age and socioeconomic status, and obtained primary data from authors when information on gender associations were not presented. In 18 adult populations, the test of heterogeneity was not significant and male gender was significantly associated with H. pylori infection (summary odds ratio [OR] 1.16 [95% confidence interval (CI) 1.11, 1.22]). In 10 pediatric populations, the test of heterogeneity was of borderline significance, and the summary OR computed using a random effect model was close to 1 (summary OR 1.03 [95% CI 0.91, 1.17]). This study confirms the male predominance of H. pylori infection in adults as a global and homogeneous phenomenon; such predominance is not apparent in children. Differential antibiotic exposure or differential protective immunity between genders may explain the different results observed between children and adult studies.

A population genetics pedigree perspective on the transmission of Helicobacter pylori

The inference of transmission pathways for medicinally important bacteria is important to our understanding of pathogens. Here we report analyses of transmission in Helicobacter pylori, a major carcinogen. Our study is novel in that the focal community comprises detailed family pedigrees and has a high prevalence of H. pylori. To infer transmission, we performed high-resolution analyses of nucleotide sequences for three genes and accounted for the occurrence of mutation and recombination through the use of simulation modeling. Our results demonstrate that transmission has a strong nonfamilial component potentially the result of a large proportion of infections derived from the community. These results are interesting from both a medical and an evolutionary standpoint. First, efficient control measures and beliefs about the sources of H. pylori infection should be reevaluated. Evolutionarily, our results contradict the hypothesis of strict vertical transmission, presented as an explanation for the strong correlation between human population history and H. pylori diversity. Thus the paradox of persistent phylogenetic structure, despite a permissive mode of transmission and high recombination rates, must be solved elsewhere. Here we consider the potential for recombination events to maintain genetic structure in light of horizontal transmission.

Helicobacter pylori occurrence and transmission: a family affair?

About half of the world's population is estimated to be infected with Helicobacter pylori, a gastric bacterium that contributes to the development of peptic ulcer disease and gastric cancer. H. pylori is more prevalent in low-income areas of the world and social and economic development decreases the prevalence as reflected in comparisons both within and between countries. The infection is typically acquired in early childhood and once established commonly persists throughout life unless treated. Person-to-person transmission within the family appears to be the predominant mode of transmission, particularly from mothers to children and among siblings, indicating that intimate contact is important. The route of transmission is uncertain, but the gastro-oral, oral-oral and faecal-oral routes are likely possibilities. Hence, gastroenteritis may facilitate dissemination of the infection. The community and environment may play additional roles for H. pylori transmission in some (low-income) settings. Furthermore, host and bacterial factors may modify the probabilities of acquisition and persistence of the infection. The understanding of H. pylori occurrence and transmission is of practical importance if future study deems prevention of the infection desirable in some high-prevalence populations. The present paper reviews aspects of H. pylori occurrence and transmission with an emphasis on household factors.

Role of Helicobacter pylori and autoimmunity in serological atrophic corpus gastritis in a Dutch primary care community

BACKGROUND

Atrophic corpus gastritis predisposes to vitamin B12 deficiency and gastric cancer. Little is known about the seroprevalence of atrophic corpus gastritis in the general population of Western Europe.

AIM

To investigate the seroprevalence of atrophic corpus gastritis in a West-European primary care community in relation to Helicobacter pylori infection and autoimmunity.

METHODS

Nine hundred and ninety-seven consecutive persons attending one general practice were asked to participate in the study by completing a questionnaire and donating fasting blood. Gastrin, pepsinogen A and C, and antibodies to H. pylori and parietal cells were measured by well-validated immunological methods. Criteria for serological atrophic corpus gastritis were pepsinogen A < 17 microg/l, pepsinogen A/C ratio <1.6, and gastrin >100 ng/l.

RESULTS

Thirty-four participants (3.4%) fulfilled the serological criteria of atrophic corpus gastritis. Twenty-one of them (62%) and 17 of 34 (50%) age-matched and sex-matched nested controls were H. pylori positive [NS; odds ratio, 1.62 (0.62-4.24)], while 15 of them (44%) and one of 34 controls had antibodies to parietal cells [P < 0.005; odds ratio, 24.0 (3.00-201)].

CONCLUSIONS

The seroprevalence of atrophic corpus gastritis in this primary care community is 3.4%. When compared with controls, the approximate relative risk of having atrophic corpus gastritis was significantly higher (P < 0.025) for antibodies to parietal cells (24.0) than to H. pylori (1.62). In view of the decreasing risk of H. pylori infection in the western world, it is likely that the impact of H. pylori on the development of atrophic corpus gastritis will further diminish.

Helicobacter pylori infection in 1st degree relatives of Chinese gastric cancer patients

OBJECTIVE

Familial aggregation of gastric cancer has been linked to familial clustering of Helicobacter pylori infection. Patterns and risk factors associated with H. pylori infection were investigated in 1st degree relatives of Chinese gastric cancer patients.

MATERIAL AND METHODS

Gastric cancer relatives were invited for screening endoscopy. H. pylori infection was diagnosed by endoscopic and serological methods.

RESULTS

Among the 270 cancer relatives examined, 161 (59.6%) were found to be infected with H. pylori. The prevalence of infection in cancer relatives was significantly higher than age- and gender-matched dyspeptic control (45.5%, p=0.0006). The mean age of H. pylori-infected relatives was significantly older than that of non-infected relatives (43.9 versus 38.3 years; p<0.001). The prevalence of H. pylori infection was higher in those with more siblings (p=0.013, chi(2) test for trend). Moreover, individuals whose siblings had stomach cancer were more likely to have H. pylori infection than those with a parental history of cancer (68.2% versus 51.8%, p=0.007). In contrast, the youngest sibling had a significantly lower H. pylori infection rate than other siblings (39.2% versus 64.2%, p=0.001). Using multiple logistic regression, it was found that age >45 years (OR=1.8; 95% CI, 1.02-3.3) and a history of gastric cancer in siblings (OR=1.9; 95% CI, 1.06-3.3) were independent risk factors for H. pylori infection, and that the youngest sibling in the family had a reduced risk (OR=0.45; 95% CI, 0.24-0.84).

CONCLUSIONS

This study identifies the patterns and risk factors for H. pylori in gastric cancer relatives, which may shed light on the evolving epidemiology of H. pylori infection in Chinese patients.

Deciphering host migrations and origins by means of their microbes

Mitochondrial DNA and microsatellite sequences are powerful genetic markers for inferring the genealogy and the population genetic structure of animals but they have only limited resolution for organisms that display low genetic variability due to recent strong bottlenecks. An alternative source of data for deciphering migrations and origins in genetically uniform hosts can be provided by some of their microbes, if their evolutionary history correlates closely with that of the host. In this review, we first discuss how a variety of viruses, and the bacterium Helicobacter pylori, can be used as genetic tracers for one of the most intensively studied species, Homo sapiens. Then, we review statistical problems and limitations that affect the calculation of particular population genetic parameters for these microbes, such as mutation rates, with particular emphasis on the effects of recombination, selection and mode of transmission. Finally, we extend the discussion to other host-parasite systems and advocate the adoption of an integrative approach to both sampling and analysis.

Concordance of Helicobacter pylori infection among children in extended-family homes

Helicobacter pylori is transmitted within households and high concordance is observed among siblings. To better understand the contributions of close interpersonal contact and family relatedness to transmission, we compared concordance of H. pylori infection among 241 sibling and non-sibling children aged 2-18 years in 68, predominantly low-income, Hispanic households with at least two nuclear families. Prevalence of H. pylori infection was 24%. Compared to children with no infected siblings or non-siblings and adjusting for age, odds of H. pylori infection were 1.2 (95% CI 0.52-2.9), 3.2 (95% CI 1.14-9.1), and 9.4 (95% CI 3.1-28.5) for children residing with at least one infected non-sibling, one infected sibling, and with at least one infected sibling and non-sibling, respectively. The study further implicates intersibling transmission as a pathway for H. pylori infection in childhood. In addition, living with a non-sibling in extended-family homes may contribute to infection risk but only in households with prevalent H. pylori infection within all family groups.

Five-year follow-up study of mother-to-child transmission of Helicobacter pylori infection detected by a random amplified polymorphic DNA fingerprinting method

Recent studies have speculated on the possible role of the mother in transmitting Helicobacter pylori infection to their children. In an attempt to either prove or disprove this supposition, we investigated the rates of infection of children born to H. pylori-positive mothers from birth to 5 years of age using serology and the stool antigen test. When infection of the children did occur, the strains from the children were compared to those of their mothers using DNA analysis. Sixty-nine of the 350 pregnant mothers (19.7%) had a positive serology for H. pylori. Fifty-one children underwent serological examinations and stool antigen tests at 4 to 6 days after birth, followed by 1, 3, and 6 months. They were continuously given the stool antigen test at 4- to 6-month intervals until the age of 5 years. Gastric juice samples were collected from the infected children and their mothers for culture and DNA analyses using a random amplified polymorphic DNA fingerprinting method. None of the 51 children acquired H. pylori infection during the first year of life. Of the 44 children enrolled in a 5-year follow-up study, five (11%) acquired H. pylori infection. They acquired the infection at the age of 1 year 2 months, 1 year 3 months, 1 year 6 months, 1 year 8 months, and 4 years 4 months. Random amplified polymorphic DNA fingerprinting confirmed that the strains of the five children exhibited DNA fingerprinting patterns identical to those of their mothers. These findings suggest that mother-to-child transmission is the most probable cause of intrafamilial spread of H. pylori.

Helicobacter pylori infection and abdominal symptoms among Swedish school children

BACKGROUND

The role of Helicobacter pylori infection in the etiology of abdominal symptoms remains unclear. Our aim was to investigate the association between type-specific H. pylori infection and gastrointestinal symptoms among school children in Stockholm, Sweden.

METHODS

In a community-based cross-sectional study, 695 children aged 10-12 years participated with a blood sample and a questionnaire on sociodemographic characteristics and gastrointestinal symptoms, including minor abdominal pain not necessitating medical consultation, during the preceding six months. Infection was investigated by an enzyme-linked immuno-sorbent assay and confirmed by immunoblot and urea breath test.

RESULTS

Abdominal pain was reported by 440 (63%) children and recurrent abdominal pain (RAP) by 88 (13%). Of 112 (16%) infected children, 73% had antibodies to CagA and 59% to VacA. There was no positive association between H. pylori status and the occurrence of abdominal pain; in fact, the association with any abdominal pain report was inverse (odds ratio [OR] 0,5; 95% Confidence Interval [CI] 0.3-0.8), while RAP was unrelated to the infection (OR 1.0; 95% CI 0.5-2.1) when adjusted for gender, age and family background variables. The prevalence of RAP tended to be lower among children harboring CagA+/VacA+ infections than among the uninfected (adjusted OR 0.3; 95%CI 0.1-1.1). Furthermore, CagA+/VacA+ infected children reported less acid regurgitation (adjusted OR 0.2; 95% CI 0.1-0.5).

CONCLUSIONS

Taking background factors into account, the presence of H. pylori is not accompanied by an increased occurrence of abdominal symptoms in Swedish 10-12-year-olds. However, unexpected differential associations with strain specific infections may indicate a so far overlooked complex relationship that needs to be further confirmed.