Evidence from a nine-year birth cohort study in Japan of transmission pathways of Helicobacter pylori infection

Association of Helicobacter pylori in Children With Self-Hand Hygiene, Maternal Hand Hygiene, Cooking, and Feeding Practices

Background and objective Helicobacter pylori infection is widely prevalent, but its route of transmission is not clear. Person-to-person transmission seems plausible, with hand hygiene being one of the many factors that play a role. The objective of this study was to study the effect of the children's and their mother's hand hygiene and feeding practices on the prevalence of H. pylori in children. Methodology This cross-sectional study involved 475 children and their mothers. A questionnaire was administered to mothers to gather information about maternal hygiene practices, specifically handwashing before food handling and after using the toilet. Additionally, both mothers and children underwent assessments for nail length (whether cut or uncut) and the presence or absence of dirt under their nails, if nails were uncut. The association of these parameters with H. pylori seropositivity in children was comprehensively examined. Furthermore, children were divided into two distinct groups: a younger age group (one month to two years and 11 months) and an older age group (three years to 15 years). For one specific parameter - the presence of dirt under mothers' nails (i.e., if nails were uncut) - the association was further analyzed separately within these age groups. The chi-square test was applied to all variables. P < 0.05 was considered significant Results The association of all variables with H. pylori seropositivity in children was tested. Association with H. pylori seropositivity was not present in mothers with uncut nails (P = 0.050315), mothers with uncut nails harboring dirt under their nails within the entire sample of 475 mothers (P = 0.39476), and mothers with uncut nails harboring dirt under their nails in the older age group (three years to 15 years) of children (P = 0.760071). Association with H. pylori seropositivity was present in mothers with dirt under their uncut nails belonging to the younger age group of children (one month to two years and 11 months (P = 0.014127) and mothers who did not wash their hands before food handling (P = 0.003032) and after using the toilet (P = 0.003082). In all 475 children, association with H. pylori seropositivity was significant with dirt under the uncut nails of children (P = 0.015194) and was not significant for children with merely grown nails but not harboring dirt under them (P = 0.355967).  Conclusions Mother-to-child transmission is one of the likely routes of transmission of H. pylori, and poor hand hygiene seems to play a major role in this process.

Intracellular presence of Helicobacter pylori antigen and genes within gastric and vaginal Candida

BACKGROUND

Helicobacter pylori infections are generally acquired during childhood and affect half of the global population, but its transmission route remains unclear. It is reported that H. pylori can be internalized into Candida, but more evidence is needed for the internalization of H. pylori in human gastrointestinal Candida and vaginal Candida.

METHODS

Candida was isolated from vaginal discharge and gastric mucosa biopsies. We PCR-amplified and sequenced H. pylori-specific genes from Candida genomic DNA. Using optical and immunofluorescence microscopy, we identified and observed bacteria-like bodies (BLBs) in Candida isolates and subcultures. Intracellular H. pylori antigen were detected by immunofluorescence using Fluorescein isothiocyanate (FITC)-labeled anti-H. pylori IgG antibodies. Urease activity in H. pylori internalized by Candida was detected by inoculating with urea-based Sabouraud dextrose agar, which changed the agar color from yellow to pink, indicating urease activity.

RESULTS

A total of 59 vaginal Candida and two gastric Candida strains were isolated from vaginal discharge and gastric mucosa. Twenty-three isolates were positive for H. pylori 16S rDNA, 12 were positive for cagA and 21 were positive for ureA. The BLBs could be observed in Candida cells, which were positive for H. pylori 16S rDNA, and were viable determined by the LIVE/DEAD BacLight Bacterial Viability kit. Fluorescein isothiocyanate (FITC)-conjugated antibodies could be reacted specifically with H. pylori antigen inside Candida cells by immunofluorescence. Finally, H. pylori-positive Candida remained positive for H. pylori 16S rDNA even after ten subcultures. Urease activity of H. pylori internalized by Candida was positive.

CONCLUSION

In the form of BLBs, H. pylori can internalize into gastric Candida and even vaginal Candida, which might have great significance in its transmission and pathogenicity.

Controversies regarding management of Helicobacter pylori infections

PURPOSE OF REVIEW

The recognition that Helicobacter pylori should be considered and treated as an infectious disease has yet to fundamentally change diagnostic and treatment practices and has resulted in many controversies.

RECENT FINDINGS

We discuss the following controversies: whether the current 'per-patient' approach to H. pylori testing based on symptoms should be expanded to include achieving population-level H. pylori eradication, whether H. pylori should be approached as an infectious gastrointestinal disease similar to that of other infectious diseases of similar severity and outcome, whether treatment of H. pylori should be primarily empiric or based on antibiotic susceptibility and locally proven successful therapies as are other infectious diseases, whether it is necessary to obtain confirmation of treatment success in every patient treated for H. pylori , and whether potassium-competitive acid blockers should replace proton pump inhibitors in H. pylori therapy.

SUMMARY

Available guidelines and meta-analyses do not yet address H. pylori as an infectious disease. The diagnosis and management and treatment success of H. pylori infections trails behind that of other important infectious diseases. We provide new insights and propose changes in the traditional understanding required to modernize the management of H. pylori infections.

Prevalence of Oral Helicobacter pylori Infection in an Indigenous Community in Southwest Mexico

Purpose

Epidemiological studies have been conducted to improve the health and economic quality of life of indigenous communities in Mexico. These studies have found that infections cause frequent health problems. Helicobacter pylori are responsible for conditions ranging from gastritis to stomach cancer. This study determined the prevalence of H. pylori in families from Siltepec, Chiapas, Mexico.

Patient and Methods

Ninety-nine dental plaque samples from 36 families were studied. Real-time PCR was performed to detect H. pylori using previously reported primers. The Mann-Whitney U-test was used for the statistical analysis. According to the family role of H. pylori-positive individuals, the VacA s1/m1 genotype and CagA gene correlated.

Results

The mother had the highest expression of VacA s1/m1-/cagA- with 19% (8/42), followed by the first child with 14.3% (6/42). The major roles for the vacA s1/m1+/cagA- were the mother and first child with 9.5% (4/42), followed by the remaining children with 4.8% (2/42). The vacA s1/m1-/cagA+ genotype was 7.1% (3/42) for the mother and 4.8% (2/42) for the father. Finally, the vacA s1/m1+/cagA+ genotype only appeared in the mother, son I, and son III with 2.4% (1/42).

Conclusion

The vacA s1/m1/cagA genotypes predominated in the mother, suggesting potential transmission between the mother and child during the first years of life.

Helicobacter pylori, clinical, laboratory, and noninvasive biomarkers suggestive of gastric damage in healthy school-aged children: A case-control study

BACKGROUND

Helicobacter pylori is acquired largely in early childhood, but its association with symptoms and indirect biomarkers of gastric damage in apparently healthy children remains controversial. We aimed to relate persistent H. pylori infection in apparently healthy school-aged children with clinical, laboratory, and noninvasive biomarkers suggestive of gastric damage using a case-control design.

MATERIALS AND METHODS

We followed up 83 children aged 4-5 years with persistent H. pylori infection determined by stool antigen detection and/or a urea breath test and 80 noninfected matched controls from a low-income to middle-income, periurban city in Chile for at least 3 years. Monitoring included clinical visits every 4 months and annual assessment by a pediatric gastroenterologist. A blood sample was obtained to determine laboratory parameters potentially associated with gastric damage (hemogram and serum iron and ferritin levels), biomarkers of inflammation (cytokines, pepsinogens I and II, and tissue inhibitor metalloproteinase 1), and expression of cancer-related genes KLK1, BTG3, and SLC5A8.

RESULTS

Persistently infected children had higher frequency of epigastric pain on physical examination (40% versus 16%; P = 0.001), especially from 8 to 10 years of age. No differences in anthropometric measurements or iron-deficiency parameters were found. Persistent infection was associated with higher levels of pepsinogen II (median 12.7 ng/mL versus 9.0 ng/mL; P < 0.001); no difference was observed in other biomarkers or gene expression profiles.

CONCLUSIONS

H. pylori infection in apparently asymptomatic school-aged children is associated with an increase in clinical symptoms and in the level of one significant biomarker, pepsinogen II, suggesting early gastric involvement.

Probiotics-Containing Yogurt Ingestion and H. pylori Eradication Can Restore Fecal Faecalibacterium prausnitzii Dysbiosis in H. pylori-Infected Children

This study investigated the compositional differences in fecal microbiota between children with and without H. pylori infection and tested whether probiotics-containing yogurt and bacterial eradication improve H. pylori-related dysbiosis. Ten H. pylori-infected children and 10 controls ingested probiotics-containing yogurt for 4 weeks. Ten-day triple therapy plus yogurt was given to the infected children on the 4th week. Fecal samples were collected at enrollment, after yogurt ingestion, and 4 weeks after successful H. pylori eradication for cytokines and microbiota analysis using ELISA and metagenomic sequencing of the V4 region of the 16S rRNA gene, respectively. The results showed H. pylori-infected children had significantly higher levels of fecal TGF-β1 than those who were not infected. Eight of 295 significantly altered OTUs in the H. pylori-infected children were identified. Among them, the abundance of F. prausnitzii was significantly lower in the H. pylori-infected children, and then increased after yogurt ingestion and successful bacterial eradication. We further confirmed probiotics promoted F. prausnitzii growth in vitro and in ex vivo using real-time PCR. Moreover, F. prausnitzii supernatant significantly ameliorated lipopolysaccharide-induced IL-8 in HT-29 cells. In conclusions, Probiotics-containing yogurt ingestion and H. pylori eradication can restore the decrease of fecal F. prausnitzii in H. pylori-infected children.

Individual and household correlates of Helicobacter pylori infection among Young Ethiopian children in Ziway, Central Ethiopia

Background

Investigating distinct individual- and household-level risk factors for acquiring Helicobacter pylori (H. pylori) infection can inform disease prevention efforts and implicate possible routes of transmission. This study determined the magnitude of H. pylori infection among schoolchildren in Ziway, central Ethiopia and identified personal and household correlates of H. pylori infection in young Ethiopian children.

Methods

A total of 434 schoolchildren participated in this cross-sectional study. Infection status was assessed using antigen and antibody rapid tests. Demographic and lifestyle information was obtained from parents via an interviewer-led questionnaire. Univariate and multivariate logistic regressions were performed to assess the relationships between potential individual- and household-level risk factors and H. pylori infection.

Results

The prevalence of H. pylori infection was 65.7% (285/434). Of the personal variables assessed, the age group 10–14 years was found to be significantly associated with higher odds of H. pylori infection in univariate analysis (COR = 2.22, 95% CI: 1.06–4.66, p = 0.03) and remained positively correlated after adjusting for confounding factors. Of the household-level factors explored, having a traditional pit or no toilet was found to be significantly associated with 3.93-fold higher odds of H. pylori infection (AOR = 3.93, 95% CI: 1.51–10.3, p = 0.01), while the presence of smokers in the household was associated with 68% lower odds of infection (AOR = 0.32, 95% CI: 0.11–0.89, p = 0.03).

Conclusion

This study from a developing country provides additional evidence for older age as a personal risk factor for H. pylori infection and identifies correlations between socioeconomic and sanitation household factors and positive childhood infection status. The associations reported here support the hypothesized fecal-oralroute of transmission for H. pylori.

Prevalence of Helicobacter pylori among Alaskans: Factors associated with infection and comparison of urea breath test and anti-Helicobacter pylori IgG antibodies

BACKGROUND

Helicobacter pylori is one of the most common human infections in the world, and studies in Alaska Native people, as well as other Indigenous peoples, have shown a high prevalence of this gastric infection. This study was undertaken to determine the prevalence of H. pylori infection by urea breath test (UBT) and anti- H. pylori IgG among Alaskans living in four regions of the state and to identify factors associated with infection.

METHODS

A convenience sample of persons > 6 months old living in five rural and one urban Alaskan community were recruited from 1996 to 1997. Participants were asked about factors possibly associated with infection. Sera were collected and tested for anti- H. pylori IgG antibodies; a UBT was administered to participants > 5 years old.

RESULTS

We recruited 710 people of whom 571 (80%) were Alaska Native and 467 (66%) were from rural communities. Rural residents were more likely to be Alaska Native compared with urban residents (P < .001). Of the 710 people, 699 (98%) had a serum sample analyzed, and 634 (97%) persons > 5 years old had a UBT performed. H. pylori prevalence was 69% by UBT and 68% by anti- H. pylori IgG. Among those with a result for both tests, there was 94% concordance. Factors associated with H. pylori positivity were Alaska Native racial status, age ≥ 20 years, rural region of residence, living in a crowded home, and drinking water that was not piped or delivered.

CONCLUSIONS

Helicobacter pylori prevalence is high in Alaska, especially in Alaska Native persons and rural residents. Concordance between UBT and serology was also high in this group. Two socioeconomic factors, crowding and drinking water that was not piped or delivered, were found to be associated with H. pylori positivity.

Epidemiology, clinical impacts and current clinical management of Helicobacter pylori infection

Helicobacter pylori infection is a major cause of morbidity and mortality worldwide. More than 50% of the global population is estimated to be infected. Differences in prevalence exist within and between countries, with higher prevalence seen among people with lower socio-economic status. Most transmission of infection occurs early in life, predominantly from person to person in the family setting. H. pylori is the cause of most peptic ulcer disease, gastric cancer and gastric mucosa-associated lymphoid tissue (MALT) lymphoma and causes symptoms in a subset of patients with functional dyspepsia. Choice of diagnostic test depends on the clinical context; urea breath tests and endoscopy with biopsy are the major diagnostic tools. Evidence-based indications for eradication of H. pylori infection are well documented. The most widely used and recommended eradication therapy in Australia is triple therapy comprising a proton pump inhibitor, amoxycillin and clarithromycin, usually for 1 week. Effective alternative regimens are available for patients with proven allergy to penicillin. Antimicrobial resistance is the major determinant of the outcome of eradication therapy. Trends in antibiotic resistance need to be monitored locally, but individual patient susceptibility testing is not usually necessary as it rarely guides the choice of therapy. The outcome of treatment should be assessed not less than 4 weeks after therapy. This is usually done with a urea breath test if follow-up endoscopy is not required. When first-line therapy fails, several proven second-line therapies may be used. Repeat first-line therapy and ad hoc regimens should be avoided. Overall cumulative eradication rates should approach 99%.

Extremely low Helicobacter pylori prevalence in North Sulawesi, Indonesia and identification of a Maori-tribe type strain: a cross sectional study

Background

Sulawesi in Indonesia has a unique geographical profile with assumed separation from Sundaland. Studies of Helicobacter pylori in this region are rare due to the region’s rural location and lack of endoscopy equipment. Indirect methods are, therefore, the most appropriate for measuring H. pylori infection in these areas; with the disposable gastric brush test, we can obtain gastric juice as well as small gastric tissue samples for H. pylori culture. We investigated the prevalence of H. pylori infection and evaluated human migration patterns in the remote areas of North Sulawesi.

Methods

We recruited a total of 251 consecutive adult volunteers and 131 elementary school children. H. pylori infection was determined by urine antibody test. A gastric brush test was used to culture H. pylori. We used next-generation and polymerase chain reaction based sequencing to determine virulence factors and multi-locus sequence typing (MLST).

Results

The overall H. pylori prevalence was only 14.3% for adults and 3.8% for children, and 13.6% and 16.7% in Minahasanese and Mongondownese participants, respectively. We isolated a single H. pylori strain, termed -Manado-1. Manado-1 was East Asian type cagA (ABD type), vacA s1c-m1b, iceA1 positive/iceA2 negative, jhp0562-positive/β-(1,3) galT-negative, oipA “on”, and dupA-negative. Phylogenetic analyses showed the strain to be hspMaori type, a major type observed in native Taiwanese and Maori tribes.

Conclusions

Our data support that very low H. pylori infection prevalence in Indonesia. Identification of hspMaori type H. pylori in North Sulawesi may support the hypothesis that North Sulawesi people migrated from north.

Seroconversion rates of Helicobacter pylori infection in Korean adults

BACKGROUND

Studies on seroconversion and its reversion rate in Korean adults with Helicobacter pylori infection are very rare. The purpose of this study was to evaluate the overall seroprevalence, seroconversion rate, and seroreversion rate of H. pylori infection in an adult population.

MATERIALS AND METHODS

We performed this retrospective cohort study on healthy adults who had visited our health screening center at Asan Medical Center more than twice between January 2000 and December 2010. We reviewed the anti- H. pylori Ab IgG profiles of the enrolled people and their family members and the results of esophagogastroduodenoscopies and a self-reported questionnaire.

RESULTS

A total of 67,212 people were enrolled in this study. The mean follow-up duration was 4.6 years, and each participant visited the center for a mean of 3.8 visits. The overall proportions of participants demonstrating persistent seropositivity, persistent seronegativity, seroconversion, and seroreversion were 53.1%, 32.5%, 4.3%, and 10.1%, respectively. The annual seroconversion rate was 2.79%. The annual crude and spontaneous seroreversion rates of the entire study population were 3.64% and 2.42%, respectively. According to multivariate logistic regression, old age (HR = 1.015), smoking (HR = 1.216), alcohol consumption more than four times per week (HR = 1.263), marriage (HR = 2.735), and living with H. pylori-infected family members (HR = 1.525) were identified as statistically significant risk factors associated with seroconversion.

CONCLUSION

The annual seroconversion rate was 2.79% in our study population. Marriage and living with H. pylori-infected family members were important risk factors affecting seroconversion in our adult population.

Eradication of Helicobacter pylori increases childhood growth and serum acylated ghrelin levels

AIM: To determine whether Helicobacter pylori (H. pylori)-infected children have reduced body weight (BW) and height (BH) growth, and if H. pylori eradication may restore growth while improving serum acylated ghrelin.

METHODS: This longitudinal cohort study with one-year follow-up enrolled 1222 children aged 4 to 12 years old into an observation cohort (18 with and 318 without H. pylori) and intervention cohort (75 with and 811 without). The 7-d triple therapy was used for eradication in the intervention cohort. The net increases of BW and BH as well serum acylated ghrelin after one-year follow-up were compared between successful eradicated H. pylori-infected children and controls.

RESULTS: In the observation cohort, the H. pylori-infected children had lower z score of BW (-1.11 ± 0.47 vs 0.35 ± 0.69, P = 0.01) and body mass index (BMI) (0.06 ± 0.45 vs 0.44 ± 0.73, P = 0.02) at enrollment and lower net BW gain after one-year follow-up (3.3 ± 2.1 kg vs 4.5 ± 2.4 kg, P = 0.04) than the non-infected controls. In the intervention cohort, the H. pylori-infected children had lower z score of BMI (0.25 ± 1.09 vs 0.68 ± 0.87, P = 0.009) and serum acylated ghrelin levels (41.8 ± 35.6 pg/mL vs 83.6 ± 24.2 pg/mL, P < 0.001) than the non-infected controls. In addition to restoring decreased serum ghrelin levels (87.7 ± 38.0 pg/mL vs 44.2 ± 39.0 pg/mL, P < 0.001), the H. pylori-infected children with successful eradication had higher net gains (P < 0.05) and increase of z scores (P < 0.05) of both BW and BH as compared with non-infected controls after one-year follow-up.

CONCLUSION: H. pylori-infected children are associated with low serum acylated ghrelin and growth retardation. Successful eradication of H. pylori restores ghrelin levels and increases growth in children.

Reinfection rate of Helicobacter pylori after eradication treatment: a long-term prospective study in Japan

BACKGROUND

We previously reported that the reinfection rate with Helicobacter pylori in Japan was low despite a high prevalence of infection. In the present study, we extended our previous work to more accurately determine the reinfection rate.

METHODS

We enrolled 1625 patients (219 women and 1406 men, mean age 50.8 years) who had received H. pylori eradication therapy. After documentation of eradication, bacterial culture and urea breath test were carried out yearly. H. pylori strains were analyzed by using random amplification of polymorphic DNA fingerprinting.

RESULTS

A total of 1609 patients were followed for up to 12.5 years (mean 4.7 years); H. pylori became re-positive in 26 patients. In 13 of the 26 patients, H. pylori became positive at the first-year follow up. Stored H. pylori isolates were available for analysis from ten of the 13 patients; four of the isolates were genetically different from the initial strain, but the other six were identical to the initial strain. In the other 13 patients, H. pylori became positive at later follow up (mean 4.8 years; range 1.8-8.0 years). In all of the four of these patients whose isolates could be analyzed, the H. pylori strains were different from the initial strain. Assuming that reinfection occurred in the four patients positive for different strains of H. pylori at the first-year follow up and in the 13 positive at later follow up, the reinfection rate was 0.22% per year.

CONCLUSIONS

When probable recrudescence (H. pylori positivity with identical strains) was excluded, the reinfection rate of H. pylori in this Japanese population was very low, but we note that reinfection can occur over many years.

Seroprevalence of Helicobacter pylori in female Vietnamese immigrants to Korea

AIM: To investigate the seroprevalence of Helicobacter pylori (H. pylori) and its relationship to nutritional factors in female Vietnamese immigrants to Korea.

METHODS: A total of 390 female immigrants from Vietnam and 206 Korean male spouses participated in the study. Blood samples from 321 female immigrants and 201 Korean male spouses were analyzed for H. pylori antibodies. Data on age, sex, alcohol consumption, smoking status, dietary nutritional factors and gastrointestinal symptoms were collected using questionnaires. The daily intakes of the following nutrients were estimated: energy, protein, niacin, lipid, fiber, calcium, iron, sodium, potassium, zinc, folate, cholesterol, and vitamins A, B1, B2, B6, C and E.

RESULTS: The prevalence of H. pylori positivity was lower in the immigrants than in age-matched Korean females (55.7% vs 71.4%, respectively; P < 0.0001) and the domestic population of Vietnam. The prevalence of H. pylori positivity among married couples was 31.7% for both spouses. There were no statistically significant differences in the incidence of smoking, amount of alcohol consumed, or nutritional factors between the H. pylori-positive and negative groups.

CONCLUSION: The prevalence of H. pylori positivity was lower among female Vietnamese immigrants than among Korean females. Nutritional factors did not differ between the H. pylori-positive and negative groups.

Seroprevalence rates of Helicobacter pylori and viral hepatitis A among adolescents in three regions of the Kingdom of Saudi Arabia: is there any correlation?

BACKGROUND

The seroprevalence rate of Helicobacter pylori in the Kingdom of Saudi Arabia (KSA) was reported to be in the range of 50-80% among mostly symptomatic patients in non-community-based studies. However, the seroprevalence of viral hepatitis A (HAV) underwent a marked decline in the last two decades from over 50% in 1989 to 25% in 1997 among Saudi children under the age of 12 years. The aim of this paper was to study seroprevalence rates of H. pylori and HAV among the adolescent population in three regions of KSA and to determine whether there was any correlation between them.

MATERIALS AND METHODS

We randomly selected 1200 16-18-year-old students from three regions around KSA. Demographic data, including socioeconomic status (SES), were recorded, and each student was tested for the presence of H. pylori-IgG antibodies and anti-HAV-IgG.

RESULTS

The results indicate a high H. pylori infection rate (47%) among this age group. Boys had a higher prevalence than girls (p = .03), and the Al-Qaseem region had the highest prevalence (51%, p = .002). SES did not contribute to the high prevalence rates (p = .83). A cross-tabulation of data showed that 88 (8%) of the teenagers were seropositive and that 512 (44%) were negative for both H. pylori and HAV antibodies (χ(2) = 0.03, OR = 0.97, CI = 0.70-1.34). The agreement between H. pylori and HAV seropositivity was lower than would be predicted by chance (κ = -0.03). The variables that were independently associated with seropositivity to H. pylori were being female (OR = 0.75, 95% CI = 0.60-0.95) and living in the Madinah region (OR = 0.72, 95% CI = 0.55-0.94).

CONCLUSION

The prevalence of H. pylori in this group of adolescents was high. However, there was no correlation between H. pylori and HAV infection rates. Hence, factors contributing to the transmission source and route seem to be different.

Development of vaccines against Helicobacter pylori

Helicobacter pylori is a Gram-negative, microaerophilic bacterium adapted to survive in the stomach of humans where it can cause peptide ulcers and gastric cancer. Although effective antibiotic treatment exists, there is a consensus that vaccines are necessary to limit the severity of this infection. Great progress has been made since its discovery 25 years ago in understanding the virulence factors and several aspects of the pathogenesis of the H. pylori gastric diseases. Several key bacterial factors have been identified: urease, vacuolating cytotoxin, cytotoxin-associated antigen, the pathogenicity island, neutrophil-activating protein, and among others. These proteins, in their native or recombinant forms, have been shown to confer protection against infectious challenge with H. pylori in experimental animal models. It is not known, however, through which effector mechanisms this protection is achieved. Nevertheless, a number of clinical trials in healthy volunteers have been conducted using urease given orally as a soluble protein or expressed in bacterial vectors with limited results. Recently, a mixture of H. pylori antigens was reported to be highly immunogenic in H. pylori-negative volunteers following intramuscular administration of the vaccine with aluminium hydroxide as an adjuvant. These data show that vaccination against this pathogen is feasible. More research is required to understand the immunological mechanisms underlying immune-mediate protection.

[Helicobacter pylori infection in children]

Knowledge about Helicobacter pylori infection in children continues to advance. While its prevalence appears to be falling in developed countries, it remains a major problem in developing nations. Its transmission pathway remains highly controversial. It has not yet been definitively elucidated, although the oral-oral route seems most probable. Infection is most often intrafamilial. Risk factors for infection are associated with low socioeconomic level, including overcrowding, unhygienic conditions, sharing beds in childhood, low maternal educational level. Infection in children differs from that in adults in three respects: symptoms, endoscopic appearance of the gastric mucosa, and histologic appearance of lesions. No study has established a clear association between recurrent abdominal pain and H. pylori infection. Nonetheless, in proven infections, recurrent abdominal pain is the most common marker. More recently, an association has been reported between H. pylori infection and iron deficiency anemia. The endoscopic aspect most suggestive of H. pylori infection in children is micronodular gastritis, but it is not specific to H. pylori infection. In children as in adults, H. pylori infection is always associated with histologic gastritis. Many questions about H. pylori remain unanswered, and numerous studies are still needed.

Helicobacter pylori infection in pediatrics

During the last year, epidemiologic studies have shown that spontaneous clearance of Helicobacter pylori infection has a less significant role in countries with high prevalence and, in contrast to adults, there is no male predominance of H. pylori infection in children. Early acquisition of H. pylori may play a role in the development of recurrent abdominal pain in children less than 5 years of age. In this very young age group, the adequate performance of stool antigen test and (13)C urea-breath test demonstrated satisfactory sensitivity and specificity as non-invasive methods to diagnose H. pylori infection. In the current paper, the most relevant pediatric studies on H. pylori infection published between April 2006 and March 2007 are reviewed.

A prospective study for the association of Helicobacter pylori infection to a multidimensional measure for recurrent abdominal pain in children

BACKGROUND

There is a controversial association between Helicobacter pylori infection and recurrent abdominal pain (RAP) in childhood and inconsistent information on specific symptomatology of the infection.

AIMS

To examine the prevalence of H. pylori infection among children with RAP compared to asymptomatic children.

METHODS

Two prospective studies were conducted. The first study enrolled 223 children diagnosed with RAP from two pediatric gastroenterology clinics in Houston, Texas. Children were qualified if they were identified by their physician as having RAP. A new multidimensional measure for RAP (MM-RAP) consisting of four scales (pain intensity scale, symptoms scale, disability scale, and satisfaction scale) was administered to each child/parent. The second study enrolled 330 asymptomatic children from the same community who did not have any upper gastrointestinal symptoms. Symptomatic and asymptomatic children underwent (13)C-urea breath testing.

RESULTS

In the first study, the prevalence of H. pylori in children with RAP was 11% and fell with age from 20% at age < or = 5 years to 7% for children > 10 years (OR = 2.7, 95% CI = 0.7-11.2). There was no association between the mother's educational level and H. pylori prevalence; (12% among children whose mothers completed college versus 11% among those who had elementary school, p = .8). No relationship was found between H. pylori and mean scores of the RAP scales. In the second study, the prevalence of H. pylori in asymptomatic children was 17% and increased with age from 11% for children < or = 5 years to 40% for children > 10 years (OR = 5.4, 95% CI = 2.0-13.8). The mother's educational level was inversely correlated with H. pylori (OR = 3.0, 95% CI = 2.2-6.1, p < .01).

CONCLUSIONS

The epidemiologic patterns of H. pylori infection differed significantly between symptomatic and asymptomatic children. Younger children suffering from RAP are more likely to be infected with H. pylori than older children with the same complaint, suggesting that early acquisition may manifest in symptoms that lead to clinic visits.

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

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

History of breastfeeding and Helicobacter pylori infection in children: results of a community-based study from northeastern Brazil

The aim of this study was to evaluate the role of breastfeeding and the infection status of the mother in the acquisition of Helicobacter pylori infection in a poor urban community in northeastern Brazil. Helicobacter pylori status was evaluated by 13C-urea breath test in individuals under the age of 14 years and by ELISA in the mothers. The prevalence of H. pylori infection was 55.8% (197/353) in the children and it increased with age (P<0.0001). Of the children in whom breastfeeding status was known, 93.2% (316/339) were breastfed. The H. pylori prevalence did not differ between breastfed and never breastfed children (55% vs. 52%) even when children were breastfed for >6 months. The prevalence of infection was much higher in children whose mothers were H. pylori infected than in children whose mothers were not infected, resulting in a crude odds ratio (OR) of 3.11 (95% CI 1.57-6.19) and 2.40 after adjustment for potential confounders (95% CI 1.12-5.15). This study suggests that breastfeeding does not protect against acquisition of H. pylori in northeastern Brazil; conversely, an infected mother may have an important role in transmission of the disease to the child.

A conceptual model of water's role as a reservoir in Helicobacter pylori transmission: a review of the evidence

Helicobacter pylori infection plays a role in the development of chronic gastritis, peptic ulcer and gastric cancer, yet the route of transmission into susceptible hosts remains unknown. Studies employing microbiological techniques have demonstrated that H. pylori has the ability to survive when introduced into water and that H. pylori is present in water and other environmental samples all over the world. Epidemiological studies have shown that water source and exposures related to water supply, including factors related to sewage disposal and exposure to animals, are risk factors for infection. This review describes the microbiological and epidemiological evidence for, and proposes a model of, waterborne H. pylori transmission outlining important features in the transmission cycle. In the model, humans and animals shed the bacteria in their faeces and the mechanisms for entry into water, and for survival, ingestion and infection are dependent upon a range of environmental influences. Verification of the proposed model pathways has important implications for public-health prevention strategies.

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.

Prevalence of Helicobacter pylori infection, endoscopic gastric findings and dyspeptic symptoms among a young Japanese population born in the 1970s

BACKGROUND

With the prevalence of Helicobacter pylori (H. pylori) infection rapidly decreasing in Japan, endoscopic findings and dyspeptic symptoms need to be re-evaluated.

METHODS

In a health check-up program, endoscopy was performed on 530 young Japanese subjects (371 men and 159 women) born in the 1970s. Helicobacter pylori infection was evaluated using serology and a rapid urease test. Endoscopic gastritis was classified according to the Sydney classification system, in addition to nodular gastritis. Dyspeptic symptoms were also recorded before endoscopy.

RESULTS

Of the 530 subjects, 87 (16.4%) were H. pylori positive. Of the 443 H. pylori-negative subjects, 349 (78.8%) were considered to have endoscopically normal gastric mucosa. However, of the 87 H. pylori-positive subjects, only 19 (21.8%) tested normal (P < 0.001). The prevalence of several types of gastritis was significantly higher in H. pylori-positive subjects compared with H. pylori-negative subjects: atrophic gastritis (37.9% vs 1.1%, P < 0.001), flat erosive gastritis (29.9% vs 7.2%, P < 0.001), rugal hyperplastic gastritis (12.6% vs 0.0%, P < 0.001), and nodular gastritis (13.8% vs 0.0%, P < 0.001). Other types of gastritis were not related to H. pylori status. The prevalence of subjects with dyspeptic symptoms was significantly higher in H. pylori-positive subjects compared with H. pylori-negative ones (28.7% vs 6.5%, P < 0.001).

CONCLUSION

It is suggested that in consideration of its recent low prevalence and the slow increase in its infection, the prevalence of H. pylori-related gastritis will gradually decrease in Japan. Further studies will be required to ascertain if there is a need for H. pylori eradication in this young population.

Seroconversion of Helicobacter pylori in Korean male employees

OBJECTIVE

Helicobacter pylori infections are acquired primarily during childhood, but also occur in adults. As no published estimates are available on the seroconversion rate of H. pylori in the Korean population, the purpose of this study was to evaluate the incidence and prevalence of H. pylori infection in male Korean employees.

MATERIAL AND METHODS

Levels of anti-H. pylori IgG were measured by ELISA, and gastroscopic findings were checked in 588 employees of the Subway Corporation (aged 40-60 years, male) in 1997, 1998, 1999, 2000, and 2003. Questionnaire responses concerning socio-economic state, education level, and type of job were analyzed versus serologic test results.

RESULTS

Out of the 588 subjects, 455 (77.4%) were positive for anti-H. pylori IgG. Multivariate analysis showed that abnormal gastroscopic findings, especially duodenal ulcers, were more frequent in the H. pylori-positive group (17.6) than in the initially H. pylori-negative group (9.0%) (OR: 1.71, 95% CI: 1.07-2.81). Among the multiple questionnaires, only the proportion of white-collar workers was significant; that is, it was lower in the H. pylori-positive group (44/6) than in the initial H. pylori-negative group (57.9%) (OR: 0.62, 95% CI: 0.41-0.92). Seventeen of 133 subjects (12.8%) who were initially seronegative underwent seroconversion during a 6-year follow-up period, a seroconversion rate of 2.13%/annum.

CONCLUSIONS

The seroprevalence of H. pylori infection in this study group was 77.4% and duodenal ulcer was more frequent in H. pylori-positive subjects, thus confirming the relationship between H. pylori infection and duodenal ulcer. Seroconversion of H. pylori infection in the Korean male employees was determined to be 2.13% per year, suggesting that new infections occur continuously even during late adulthood.

Cellular mucosal defense during Helicobacter pylori infection: a review of the role of glutathione and the oxidative pentose pathway

Helicobacter pylori is the primary cause of gastritis and peptic ulcer disease and is known to infect greater than 50% of the world's population. It is also known to lead to the onset of gastric cancer and unless treated, lasts throughout life in most individuals. Mouse models of H. pylori infection have improved our ability to study this organism and can be used to investigate the host mucosal response to the infection, particularly the early events postinoculation. Previous studies have shown that H. pylori infection leads to an increased production of reactive oxygen species within the gastric mucosa which are thought to play a major role in the mediation of associated disease. Recent studies have shown differences in the availability of an important antioxidant, glutathione, during chronic H. pylori infection. The availability of glutathione is primarily controlled by the activity of the oxidative pentose pathway. This review proposes that the severity of inflammation and damage associated with H. pylori infection is dependent on the ability of mucosal cells to counteract the increased load of reactive oxygen species. It is hypothesized that the oxidative pentose pathway and glutathione availability are important factors modulating this response. It is suggested that the therapeutic regulation of glutathione availability could provide a novel method for preventing or reducing the damage caused during H. pylori infection.

Children of Helicobacter pylori-infected dyspeptic mothers are predisposed to H. pylori acquisition with subsequent iron deficiency and growth retardation

BACKGROUND

We tested whether Helicobacter pylori-infected dyspeptic mothers had a higher rate of H. pylori infection in their children, and whether such H. pylori-infected children were predisposed to iron deficiency or growth retardation.

MATERIALS AND METHODS

A total of 163 children from 106 dyspeptic mothers (58 with and 48 without H. pylori infection) were enrolled to evaluate body weight, height, hemoglobin, serum ferritin, and H. pylori infection using the 13C-urea breath test. A questionnaire was used to evaluate demographic factors of each child.

RESULTS

The rate of H. pylori infection in children with H. pylori-infected dyspeptic mothers was higher than that of children with noninfected mothers (20.5% vs. 5.3%; p<.01, OR: 4.6, 95% CI: 1.5-14.2). The rate of H. pylori infection in children elevated as the number of their H. pylori-infected siblings increased (p<.01). For children below 10 years of age, H. pylori infection was closely related to low serum ferritin and body weight growth (p<.05).

CONCLUSION

The children of H. pylori-infected dyspeptic mothers had an increased risk for such infection. The risk further increased once their siblings were infected. H. pylori infection in pre-adolescent children may determine iron deficiency and growth retardation.

Well water--one source of Helicobacter pylori colonization

Helicobacter pylori (H. pylori) is one of the world's most widespread microorganisms. Its acquisition in humans remains poorly understood, however, epidemiological studies have identified drinking water as reservoir for the bacterium. The aim of this study was to investigate the prevalence of H. pylori infection among individuals using or drinking previously H. pylori tested well water. Applying household cluster sampling, a total of 91 subjects, all using or drinking well water (13 of either H. pylori positive or negative wells), were screened for their H. pylori status. The group was comprised of 73 adults and 19 children under the age of 18. H. pylori infection was determined using the [13C]urea breath test. A self-administered or parent-completed questionnaire provided information on living conditions and lifestyle habits including the use or drinking of well water. Logistic regression analyses associated the drinking of H. pylori positive well water with a positive colonization status [Odds Ratio (OR) 8.3; 95% confidence interval (95% CI) 2.4-29]. In summary, the use or drinking of H. pylori contaminated well water appears associated with the acquisition of a H. pylori infection. This study is based on a relatively small and inhomogeneous population sample and should be repeated to confirm the results.

Transmission of Helicobacter pylori infection in families of preschool-aged children from Minas Gerais, Brazil

We evaluated the role of the family in the transmission of Helicobacter pylori infection in preschool-aged children from a rural district in the State of Minas Gerais, Brazil. Sixty-six families (66 index children, 63 mothers, 60 fathers and 134 siblings), defined as at least one parent living in the same household with at least one offspring up to 8 years old, were studied. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by logistic regression controlling for age, gender, number of children in household and H. pylori status of the father, mother and siblings. The prevalence of the infection was 69.7% (469 of 673) and it increased with age (P < 0.001). Positive mothers were a strong and independent risk factor for infection (OR 22.70; 95% CI 2.31-223.21). Positive siblings were also positively associated with infection (OR 1.81; 95% CI 1.01-3.30).

Seroepidemiology of Helicobacter pylori and hepatitis A virus and the mode of transmission of infection: a 9-year cohort study in rural Japan

We compared the seroepidemiologic patterns of Helicobacter pylori and hepatitis A virus (HAV) infections among participants in 2 independent cross-sectional studies conducted in Japan in 1986 and 1994. Subgroups were monitored with successive blood sampling. H. pylori and HAV infection status was defined by results of enzyme-linked immunosorbent assay. In 1986, the prevalence of H. pylori infection and HAV infection, respectively, were 80% and 70% among adults and 31% and 5% among children. The prevalence of both infections increased with age. Concordant infections were found in 74.5% of adults (kappa=0.2) versus 2% of children (kappa=0.05). During the 9-year study period, the incidence of H. pylori infection was 1.1% among adults and 2% among children. The seroprevalence of HAV remained constant. The disparity between the increase in prevalence of H. pylori and HAV infection with age is likely associated with improvements in hygienic practices. The discordance between the presence of the infections among younger persons is evidence against a common source and/or vehicle for transmission.

Human leukocyte antigen class II genes and Helicobacter pylori infection: does genotype overwhelm environmental exposure?

OBJECTIVE

We investigated associations between human leukocyte antigen class II genes, environmental exposures, and Helicobacter pylori infection.

METHODS

Sixty-eight subjects with histologically confirmed H. pylori and intestinal metaplasia (cases) and 70 healthy subjects without H. pylori (controls) matched for age, sex, and year of birth were included in this study. All patients answered a detailed questionnaire designed to collect sociodemographic characteristics, smoking, alcohol drinking, and dietary habits. Human leukocyte antigen class II genes were typed with genomic DNA. The cytotoxins CagA and VacA were investigated with serology. Odds ratios and corresponding 95% confidence intervals were estimated from multivariate conditional logistic regression. Multiple correspondence analysis was used to represent the interrelationships of a multiple contingency table.

RESULTS

Human leukocyte antigen DRB1, DQA1, and DQB1 genotypes were not significantly associated with H. pylori infection and intestinal metaplasia. No significant association with blood group or Lewis antigen system was found. However, multiple correspondence analysis clearly associated H. pylori with environmental exposure: the control group largely consumed olive oil, fresh fruits, and vegetables and histories of never or formerly smoking and the case group (those positive for H. pylori and metaplasia) largely consumed eggs, meat and butter and had histories of smoking cigarettes.

CONCLUSIONS

These findings suggested that H. pylori infection is not influenced by a genetic compound and confirmed the relevance of environmental exposure.

Prevalence and risk factors associated with Helicobacter pylori infection in native populations from Brazilian Western Amazon

We evaluated the prevalence of, and factors associated with, Helicobacter pylori infection in 222 subjects from 3 distinct communities of native populations (Uru-Eu-Wau-Wau Indians and 2 riverine communities living on the banks of the Machado river and in Portuchuelo) living in isolation in the rainforest of Brazilian Western Amazon. The overall prevalence was 78.8% (95% CI 72.7-83.9). The prevalence was higher in the Machado river community compared with Portuchuelo (chi2 = 3.84, P = 0.05), but no significant difference was observed between the Machado river community and the Uru-Eu-Wau-Wau Indians. Logistic regression showed that residential crowding and age were factors associated with the presence of H. pylori infection. Acquisition of the bacterium started early in life and by the age of 2 years 50% of children were infected. The prevalence increased with age, reaching near universal levels during adulthood (97.9%). Residential crowding was high with a global index of 3.3 persons/room (SD = 1.8), varying significantly between the 3 communities (P = 0.001). These data provide further evidence supporting direct person-to-person spread of the bacterium.

[Seroconversion and seroreversion rate of Helicobacter pylori infection in women attended at hospital for delivery]

BACKGROUND AND OBJECTIVE

Helicobacter pylori infections are acquired primarily during childhood. Nevertheless, infections also develop in the adult population and it is not clear how the cumulative effect of these infections occurs throughout life. With the aim to contribute to the current data on the evolution of H. pylori infection in the adult population of Spain, the incidence and prevalence rates in a population of women who went to the hospital for delivery were studied.

SUBJECTS AND METHOD

The study considered the sero-conversion and sero-reversion of H. pylori antibodies in 1441 women from Gipuzkoa (Basque Country, Spain), between 15 and 41 years-old (mean 28.5 [3.4]). These women delivered after September 1989 and had a second childbirth 2 to 8 years later. A serum sample was obtained at the time of each childbirth. Results were determined by enzymoimmunoanalysis (Pyloriset EIA-G New, Finland).

RESULTS

H pylori antibodies were detected in the first serum specimen of 648 women (45.0% prevalence). Twenty-four out of the 793 women who were initially seronegative underwent a seroconversion in successive years, and an annual infection rate of 0.77% (95% CI 0.49-1.14) was estimated. Twenty-six women, who were initially seropositive, yielded negative result in the second serum specimen, which led to an annual sero-reversion rate of 1.03% (95% CI 0.67-1.50).

CONCLUSIONS

These results suggest that in our environment, infections by H. pylori occur with a moderate frequency in adults. The fact that the sero-reversion rate is similar to or higher than the sero-conversion one suggests that the prevalence of H. pylori infection in the adult population is currently decreasing.

Tracing clonality of Helicobacter pylori infecting family members from analysis of DNA sequences of three housekeeping genes (ureI, atpA and ahpC), deduced amino acid sequences, and pathogenicity-associated markers (cagA and vacA)

Helicobacter pylori, a Gram-negative bacterium, is a causal agent of peptic ulcers and is estimated to infect the gastric mucosa of at least half of the world's population. As primary infections are acquired mainly by household contact, studies on family clusters provide a model for investigating transmission and the natural history of initial infection. Here, sequence typing exploiting genetic variation in core fragments of three key housekeeping loci (ureI, atpA and ahpC) was used to determine clonal descent amongst isolates of ten members of four families in Northern Ireland and a family with three generations in central England. Phylogenetic analysis of each locus for 73 strains of H. pylori from 11 countries indicated high background intraspecific diversity, apart from identical paired isolates from five unrelated patients and strains with identical sequence types (STs) detected in adult members of two families. In several families carrying strains with different STs, evidence of residual clonal descent was detected at one or two loci by comparison of nucleotide and amino acid sequences. Pathogenicity-associated genotypes were heterogeneous with respect to ST and amino acid type. Analysis of these three housekeeping genes provides unique evidence for precise tracing of clonal descent in isolates of H. pylori in family groups.

Helicobacter pylori: resurrection of the cancer link

Helicobacter pylori is one of the most common pathogenic bacterial infections, colonizing an estimated half of all humans. In a subset of individuals, the infection leads to serious gastroduodenal disease such as peptic ulcers and gastric adenocarcinoma. The factors contributing to skewing this, in most cases benign, relationship into disease development are largely unknown. However, factors emanating from the bacterium, host and the environment have been shown to affect the risk for disease, although no factor can be singled out to be most important. The known factors are associated with affecting the risk of disease, and are not absolute. Virulence of H. pylori is affected by the existence and regulation of certain genes present in the bacterial population in a stomach. The effects of H. pylori on gastric cancer development have been challenged and the risk associated with infection with virulent (i.e. Cag PAI positive) H. pylori has likely been underestimated.

Helicobacter pylori interactions with host serum and extracellular matrix proteins: potential role in the infectious process

Helicobacter pylori, a gram-negative spiral-shaped bacterium, specifically colonizes the stomachs of humans. Once established in this harsh ecological niche, it remains there virtually for the entire life of the host. To date, numerous virulence factors responsible for gastric colonization, survival, and tissue damage have been described for this bacterium. Nevertheless, a critical feature of H. pylori is its ability to establish a long-lasting infection. In fact, although good humoral (against many bacterial proteins) and cellular responses are observed, most infected persons are unable to eradicate the infection. A large body of evidence has shown that the interaction between H. pylori and the host is very complex. In addition to the effect of virulence factors on colonization and persistence, binding of specialized bacterial proteins, known as receptins, to certain host molecules (ligands) could explain the success of H. pylori as a chronically persisting pathogen. Some of the reported interactions are of high affinity, as revealed by their calculated dissociation constant. This review examines the binding of host proteins (serum and extracellular matrix proteins) to H. pylori and considers the significance of these interactions in the infectious process. A more thorough understanding of the kinetics of these receptin interactions could provide a new approach to preventing deeper tissue invasion in H. pylori infections and could represent an alternative to antibiotic treatment.

Reinfection rate following effective therapy against Helicobacter pylori infection in Japan

BACKGROUND AND AIM

In developed countries, reinfection of Helicobacter pylori (H. pylori) after eradication of the bacterium is unusual, while the reinfection rate in developing countries is variable. In this study, we determined the reinfection rate after successful H. pylori eradication in Japan, a country with a high prevalence of H. pylori infection.

METHODS

After successful eradication, 377 patients were followed up by endoscopy and urea breath test annually. In reinfected patients, H. pylori strains isolated initially and after reinfection were compared by using random amplification of polymorphic DNA fingerprinting.

RESULTS

H. pylori became positive in four of 337 patients (1.2) 1 year after eradication and in two of 133 patients (1.5) 2 years after eradication. One patient experienced an ulcer relapse 2 years after eradication therapy. Random amplification of polymorphic DNA fingerprinting of the isolated strains from four of the six patients showed two had identical strains (at 1 year) while the other two had different strains (one at 1 year and one at 2 years). When infection in the two patients reinfected with identical strains is considered a recrudescence, the true reinfection rate is < 0.8 per patient year.

CONCLUSIONS

The reinfection rate after eradication of H. pylori is low in Japan despite the country's high prevalence of H. pylori infection.

The design of vaccines against Helicobacter pylori and their development

Helicobacter pylori is a gram negative, spiral, microaerophylic bacterium that infects the stomach of more than 50% of the human population worldwide. It is mostly acquired during childhood and, if not treated, persists chronically, causing chronic gastritis, peptic ulcer disease, and in some individuals, gastric adenocarcinoma and gastric B cell lymphoma. The current therapy, based on the use of a proton-pump inhibitor and antibiotics, is efficacious but faces problems such as patient compliance, antibiotic resistance, and possible recurrence of infection. The development of an efficacious vaccine against H. pylori would thus offer several advantages. Various approaches have been followed in the development of vaccines against H. pylori, most of which have been based on the use of selected antigens known to be involved in the pathogenesis of the infection, such as urease, the vacuolating cytotoxin (VacA), the cytotoxin-associated antigen (CagA), the neutrophil-activating protein (NAP), and others, and intended to confer protection prophylactically and/or therapeutically in animal models of infection. However, very little is known of the natural history of H. pylori infection and of the kinetics of the induced immune responses. Several lines of evidence suggest that H. pylori infection is accompanied by a pronounced Th1-type CD4(+) T cell response. It appears, however, that after immunization, the antigen-specific response is predominantly polarized toward a Th2-type response, with production of cytokines that can inhibit the activation of Th1 cells and of macrophages, and the production of proinflammatory cytokines. The exact effector mechanisms of protection induced after immunization are still poorly understood. The next couple of years will be crucial for the development of vaccines against H. pylori. Several trials are foreseen in humans, and expectations are that most of the questions being asked now on the host-microbe interactions will be answered.

Helicobacter pylori intrafamilial infections: change in source of infection of a child from father to mother after eradication therapy

Biopsy specimens of the antrum and corpus were obtained from four Helicobacter pylori-infected members of a family and from the same boy (son 1) in whom the infection reappeared after simultaneous successful eradication treatment of three family members, excluding the mother. A total of 18 to 60 H. pylori isolates were obtained from each specimen and subjected to rRNA gene restriction pattern analysis. The father's isolates and the initial isolates from son 1 showed the same HindIII type, which was divided into three HaeIII subtypes. Isolates from the mother and a brother (son 2) and posttreatment isolates from son 1 showed a distinct HindIII type (with one minor subtype), which was divided into six HaeIII subtypes. All subtypes of the initial isolates from son 1 were present in the father's isolates, and all subtypes of the posttreatment isolates from son 1 were present in the mother's isolates but not in son 2's. Electron microscopic analysis of the biopsy specimens demonstrated extremely high levels of H. pylori colonization in the father's gastric mucosa. H. pylori adherence with a ruffle formation was also demonstrated. The findings suggest that son 1 was infected initially with the H. pylori strain of the father and son 2 was infected with the H. pylori strain of the mother and that after eradication therapy son 1 was reinfected with the H. pylori strain of the mother, who did not undergo eradication therapy.

Rapid detection of anti-Helicobacter pylori IgG in urine using immunochromatography

BACKGROUND

Non-invasive methods to detect the presence of H. pylori infection continue to be refined.

AIM

To evaluate a new 20-min immunochromatography method (RAPIRUN H. pylori Antibody) for the presence of anti-H. pylori IgG in urine.

METHODS

We used the (13)C-urea breath test to establish H. pylori status. We evaluated the urine test among 104 subjects including 43 with H. pylori infection confirmed by repeatedly positive urea breath tests and 61 H. pylori-negative subjects with repeatedly negative urea breath tests. Forty-one of the 43 subjects with H. pylori infection had a positive rapid urine test with two false negative tests. There were two false positive tests among the 61 with repeatedly negative urea breath tests. The sensitivity, specificity, positive and negative predictive values for the rapid urine test were 95.3%, 96.7%, 95.3%, and 96.7%, respectively. The kit was easy to use and required no special equipment.

CONCLUSIONS

The rapid immunochromatography method for determination of anti-H. pylori IgG proved to be reliable with excellent sensitivity and specificity and is likely to be useful for both clinical and epidemiological studies.