Persistent and transient Helicobacter pylori infections in early childhood

Global H. pylori recurrence, recrudescence, and re-infection status after successful eradication in pediatric patients: a systematic review and meta-analysis

BACKGROUND

Little information is available regarding global H. pylori recurrence, recrudescence, and re-infection in pediatric patients after successful eradication, nor are their influencing factors clear. We conducted a systematic review and meta-analysis to determine global H. pylori recurrence status and its influencing factors in children and adolescents to improve infection management and disease prevention.

METHODS

Published studies on H. pylori recurrence in children and adolescents were collected from major public databases until January 2023. H. pylori recurrences were determined using randomized-effect and fixed-effect models. Stratified analysis was performed based on various regions, countries, publication time, human development indexes (HDIs), and ages.

RESULTS

A total of 3310 relevant articles were screened, and 30 articles (1915 participants) were finally enrolled for analysis. The overall H. pylori recurrence rate was 19%, and the annual recurrence rate was 13%. In stratified analysis, H. pylori annual recurrence rate in Asian children was higher than that in Europe (17% vs. 6%) and higher in developing countries than in developed countries (18% vs. 5%). In children aged ≤ 5 years, ≤ 10 years, and 11-18 years, the H. pylori recurrence rates were 30%, 14%, and 8%, respectively. H. pylori recrudescence and re-infection rates were 6% and 10%, respectively, and its recurrence was inversely correlated with HDI.

CONCLUSIONS

These results provide insights into global H. pylori recurrence, annual recurrence, recrudescence, and re-infection status in pediatric population. The stratified analysis revealed the pattern and seriousness of infection, which requires further efforts to improve patient care.

The Most Recent Insights into the Roots of Gastric Cancer

Helicobacter pylori (H. pylori) is the most common bacterial infection worldwide, usually being acquired during childhood, and its persistence into adulthood represents one of the main contributors of gastric carcinogenesis. Based on these statements, it would be of great importance to know if the most early premalignant transformation occurs in children or later since, this would enable the development of effective anti-tumorigenesis strategies. The interplay between H. pylori virulence factors, the host's responses modified by this infection, and the gastric microecology are complex and eventually lead to the development of gastric cancer in susceptible individuals. Several biomarkers were identified as major contributors of this long-lasting process, such as pepsinogens, gastrin 17, lipid-, glucose- and iron-metabolism parameters, immunity players, aberrant bacterial DNA methylation, H. pylori virulence factors, and hallmarks of gastric dysbiosis. Several of these biomarkers were also identified in children with H. pylori infection, independently of the presence of premalignant lesions, which were also proven to be present in a subgroup of H. pylori-infected children, especially those carrying extremely virulent strains. Therefore, the most incipient premalignant gastric changes might indeed occur early during childhood, opening a promising research gate for further studies to delineate the border between infection and cancer.

Helicobacter pylori Infections in Children

In the context of epidemiology, host response, disease presentation, diagnosis, and treatment management, the manifestation of Helicobacter pylori (H. pylori) infection diverges between children and adults. H. pylori infection stands out as one of the most prevalent bacterial infections globally, and its prevalence in both children and adults is decreasing in many developing countries but some still struggle with a high prevalence of pediatric H. pylori infection and its consequences. The majority of infected children are asymptomatic and pediatric studies do not support the involvement of H. pylori in functional disorders such as recurrent abdominal pain. The pathophysiology of H. pylori infection relies on complex bacterial virulence mechanisms and their interaction with the host immune system and environmental factors. This interaction gives rise to diverse gastritis phenotypes, which subsequently influence the potential development of various gastroduodenal pathologies. In clinical settings, the diagnosis of this infection in childhood requires an upper gastrointestinal endoscopic exam with mucosal biopsy samples for histology and culture, or Polymerase Chain Reaction (PCR) at the very least. When warranted, eradication treatment should be given when good compliance is expected, and there should be systematic use of a treatment adapted to the antimicrobial susceptibility profile. To combat the burgeoning threat of multidrug resistance, vigilant surveillance of resistance patterns and strategic antibiotic management are paramount.

Intracellular presence and genetic relationship of Helicobacter pylori within neonates' fecal yeasts and their mothers' vaginal yeasts

Helicobacter pylori are transmissible from person to person and among family members. Mother-to-child transmission is the main intrafamilial route of H. pylori transmission. However, how it transmits from mother to child is still being determined. Vaginal yeast often transmits to neonates during delivery. Therefore, H. pylori hosted in yeast might follow the same transmission route. This study aimed to detect intracellular H. pylori in vaginal and fecal yeasts isolates and explore the role of yeast in H. pylori transmission. Yeast was isolated from the mothers' vaginal discharge and neonates' feces and identified by internal transcribed spacer (ITS) sequencing. H. pylori 16S rRNA and antigen were detected in yeast isolates by polymerase chain reaction and direct immunofluorescence assay. Genetic relationships of Candida strains isolated from seven mothers and their corresponding neonates were determined by random amplified polymorphic DNA (RAPD) fingerprinting and ITS alignment. The Candida isolates from four mother-neonate pairs had identical RAPD patterns and highly homologous ITS sequences. The current study showed H. pylori could be sheltered within yeast colonizing the vagina, and fecal yeast from neonates is genetically related to the vaginal yeast from their mothers. Thus, vaginal yeast presents a potential reservoir of H. pylori and plays a vital role in the transmission from mother to neonate.

The Importance of Accurate Early Diagnosis and Eradication in Helicobacter pylori Infection: Pictorial Summary Review in Children and Adults

Among the most widespread childhood infections, Helicobacter pylori (H. pylori) develops potentially life-threatening conditions in adults if not appropriately treated. Helicobacter pylori is a common human pathogen that was first described in the stomach many years ago. The discovery of H. pylori was crucial in gastroenterology; this bacterium is associated with chronic gastritis, peptic ulcers, gastric cancer, and lymphoid tissue lymphoma related to the gastric mucosa. Studies published so far estimate that approximately 10% of subjects infected with H. pylori develop a peptic ulcer, and 1-3% of subjects develop gastric cancer. The clinical manifestations are variable and characteristically depend on the individual factors of the host. Various methods of detection and diagnosis of H. pylori infection have been developed, each with advantages, disadvantages, and/or limitations. Available diagnostic tests are usually performed using invasive (endoscopy, biopsy, rapid urease test, cultures, and molecular tests) and noninvasive methods (urea breath test, stool antigen examination, and serological and molecular tests). Although there is extensive accessibility for diagnosing and treating H. pylori infection, the prevalence of antibiotic resistance is not negligible. Thus, numerous studies and meta-analyses are focused on a new orientation of gastroenterologists in diagnosing and treating H. pylori infections. A fascinating perspective hypothesis is the administration of probiotics to reduce H. pylori adhesion to gastric epithelial cells, preventing H. pylori colonization, especially in children, or reinfection with H. pylori in high-risk adult patients.

Changes in prevalence of Helicobacter pylori in Japan from 2008 to 2018: a repeated cross-sectional study

OBJECTIVES

To understand the recent prevalence and time trends of Helicobacter pylori infection rates in the Japanese population.

DESIGN

Repeated cross-sectional study.

PARTICIPANTS

A total of 22 120 workers (age: 35-65 years) from one Japanese company, who underwent serum H. pylori antibody tests in a health check-up between 2008 and 2018.

MEASURES

H. pylori infection rates among participants aged 35 years from 2008 to 2018, and participants aged 35, 40, 45, and 50-65 years in 2018, based on the results of serum antibody tests, were analysed. In the 2018 analysis, in addition to the antibody test results, all participants who had undergone eradication treatment for H. pylori were considered as infected. Trends were examined using joinpoint analysis.

RESULTS

H. pylori was detected in 1100 of 7586 male and 190 of 1739 female participants aged 35 years. Annual infection rates among those aged 35 years showed linear downward trends as follows: men, 17.5% in 2008 to 10.1% in 2018 (slope: -0.66); women, 12.3% in 2008 to 9.2% in 2018 (slope: -0.51) without joinpoints. In the 2018 analysis, 2432 of 9580 men and 431 of 1854 women were H. pylori positive. Infection rates tended to increase with older age (men: 11.0% (35 years) to 47.7% (65 years); women: 10.0% (35 years) to 40.0% (65 years)), and showed joinpoints in both sexes (men: 54 years; women: 45 years). Although both the first and second trends were upward, the second trend for both men and women was steeper than the first trend (p<0.05).

CONCLUSIONS

Our study demonstrated that in the previous 11 years, infection rates of H. pylori in 35-year-old male and female Japanese workers have constantly decreased, and furthermore, analysis of various age groups showed joinpoints around 50 years, suggesting a consistent declining trend in H. pylori infection rates in Japan.

Effect of Helicobacter pylori eradication therapy on clinical and laboratory biomarkers associated with gastric damage in healthy school-aged children: A randomized non-blinded trial

OBJECTIVES

Helicobacter pylori (H. pylori) is the primary cause of gastric cancer and eradication in healthy adults has proven effective in decreasing cancer incidence. H. pylori is acquired largely in early childhood, however, the benefits of eradication in children are controversial. We aimed to determine the effect of H. pylori eradication on clinical and laboratory markers associated with gastric damage in apparently healthy school-aged children.

METHODS

This was a pilot non-blinded trial including 61 children persistently infected with H. pylori who were randomized to eradication/no treatment and followed for at least 12 months, evaluating clinical and blood markers (Pepsinogen I (PGI) and II (PGII) determined by ELISA) associated with gastric damage. The treatment consisted of a sequential scheme including 7 days of omeprazole + amoxicillin followed by 7 days of omeprazole + clarithromycin + metronidazole; adherence and tolerance were surveyed. Eradication rates were assessed by stool antigen detection or urea breath test 1 month following treatment every 4 months thereafter to detect reinfection.

RESULTS

Eradication occurred in 30/31 treated children (median age: 8.8, range: 7.9-10.8) and in 0/30 non-treated controls (median age: 8.6, range: 7.9-11) (p < .001). Treatment was associated with mild transient symptoms (altered taste, nocturnal upper abdominal pain, nausea, and diarrhea). Baseline frequency of symptoms was low and eradication did not change symptoms compared to controls. PGI, PGII, and anti-H. pylori seropositivity were similar in both groups at baseline and significantly decreased only in eradicated patients; PGI (92.5 vs. 74.4, p < .001), PGII (15.2 vs. 8.9, p < .001) levels, and frequency of anti-H. pylori seropositivity (100 vs. 68%, p < .001) respectively. Four eradicated children (13%) were reinfected during follow-up.

CONCLUSIONS

H. pylori eradication therapy in apparently asymptomatic school-aged children was well tolerated and associated with decreased serum PGI and PGII levels. Future studies should expand on the middle-long-term effect of early H. pylori eradication, especially on preventing gastric cancer.

Prevalence of Helicobacter pylori among Patients with Gastrointestinal Tract (GIT) Symptoms: A Retrospective Study at Selected Africa Air Rescue (AAR) Clinics in Kampala, Uganda, from 2015 to 2019

Background

Helicobacter pylori (HP) infection is extremely common worldwide, with almost half of the world's population infected. In Uganda, no study has been done on the trends of the prevalence of H. pylori infection in the affluent population. Therefore, this retrospective cross-sectional study aimed at determining the trend of H. pylori prevalence among affluent patients presenting with gastrointestinal (GIT) symptoms whose stool samples were tested at selected AAR clinics in Kampala area. Patients were tested for Helicobacter pylori infection using the stool antigen test between January 2015 and December 2019.

Results

The overall 5-year H. pylori prevalence was 35.7% (1298/3634). The prevalence was higher in males (36.0% (736/2044)) than in females (35.4% (562/1590)), although not statistically significant (OR = 0.97, p = 0.680, 95% CI: 0.84–1.11). The prevalence of H. pylori infection was significantly higher (39.4%) among patients who belonged to the age group of 19–35 years (OR = 1.49, p < 0.001, 95% CI: 1.22–1.82). The prevalence for H. pylori among the age group of 19–35, the most productive age, could be attributed to work-related factors such as stress. The highest prevalence (43.4%) was recorded in 2018 and the lowest (21.4%) in 2015; however, the trend of H. pylori infection in the 5 years was fluctuating.

Conclusion

H. pylori infestation is a preserve of not only the poor but also the elites. Stressful factors, especially in the age group of 19–35 years, should be appropriately managed.

Persistent Helicobacter pylori infection for more than 3 years leads to elevated serum homocysteine concentration: A retrospective cohort study based on a healthy Chinese population

BACKGROUND AND AIM

The relationship between the Helicobacter pylori (H. pylori) infection and homocysteine is unclear. We evaluated the effect of H. pylori on serum homocysteine in a healthy Chinese population.

METHODS

A total of 21 184 individuals aged over 18 years underwent ¹³ C/¹⁴ C urease breath test (¹³ C/¹⁴ C-UBT) and blood tests and 5042 individuals with follow-up intervals greater than 6 months. Homocysteine levels are classified according to the Chinese expert consensus.

RESULTS

The rates of H. pylori infection of normal level, mild level, moderate level, and severe level were 40.9%, 43.8%, 45.8%, and 46.6%, respectively (P = 0.000). H. pylori infection increased the risk of higher homocysteine concentration (OR = 1.406, P = 0.000). In the case-control study, the rates of persistent negative, new infection, persistent infection, and eradication infection were 43.6%, 11.2%, 22.9%, and 22.3%, respectively. The percentage of changes in serum homocysteine levels varied significantly among the different H. pylori infection statuses only in mild level (P = 0.024). Mean changed homocysteine values were higher in the subgroup of persistent infection than in the persistent negative subgroup (P = 0.004) and the eradication infection subgroup (P = 0.034). Serum homocysteine values were elevated only in the subgroup with over 3 years interval time and persistent infection (n = 107, mean paired differences = 1.1 ± 4.6 μmol/L, P = 0.014).

CONCLUSIONS

There is a relationship between H. pylori and serum homocysteine, and persistent infection leads to elevation of the latter.

Temperatures Outside the Optimal Range for Helicobacter pylori Increase Its Harboring within Candida Yeast Cells

Simple Summary

Helicobacter pylori is associated with the development of diverse gastric pathologies. This bacterium has been shown to invade yeast to protect itself from environmental factors such as changes in pH, the presence of antibiotics or variations in nutrients that affect their viability. However, intra-yeast H. pylori has been reported from other sources, including food, or when the storage temperature is outside the optimal growth range for H. pylori, which is 30–37 °C. It is necessary to continue investigating the environmental factors that participate in the entry of the bacteria into yeast. In this work, it was evaluated whether temperature changes promote the entry of H. pylori into Candida and whether this endosymbiosis favors bacterial viability. It was observed that H. pylori significantly increased its invasiveness to yeast when these two microorganisms were co-cultured under 40 °C. The results support that H. pylori invades yeasts to protect itself from stressful environments, favoring its viability in these environments. In addition, it can be suggested that this microorganism would use yeast as a transmission vehicle, thereby contributing to its dissemination in the population. However, the latter still needs to be confirmed.

Abstract

Helicobacter pylori is capable of entering into yeast, but the factors driving this endosymbiosis remain unknown. This work aimed to determine if temperatures outside the optimal range for H. pylori increase its harboring within Candida. H. pylori strains were co-cultured with Candida strains in Brucella broth supplemented with 5% fetal bovine serum and incubated at 4, 25, 37 or 40 °C. After co-culturing, yeasts containing bacteria-like bodies (Y-BLBs) were observed by optical microscopy, and the bacterium were identified as H. pylori by FISH. The H. pylori 16S rRNA gene was amplified from the total DNA of Y-BLBs. The viability of intra-yeast H. pylori cells was confirmed using a viability assay. All H. pylori strains were capable of entering into all Candida strains assayed. The higher percentages of Y-BLBs are obtained at 40 °C with any of the Candida strains. H pylori also increased its harboring within yeast in co-cultures incubated at 25 °C when compared to those incubated at 37 °C. In conclusion, although H. pylori grew significantly at 40 °C, this temperature increased its harboring within Candida. The endosymbiosis between both microorganisms is strain-dependent and permits bacterial cells to remain viable under the stressing environmental conditions assayed.

Intracellular Presence of Helicobacter pylori and Its Virulence-Associated Genotypes within the Vaginal Yeast of Term Pregnant Women

BACKGROUND

Helicobacter pylori transmission routes are not entirely elucidated. Since yeasts are postulated to transmit this pathogen, this study aimed to detect and genotype intracellular H. pylori harbored within vaginal yeast cells.

METHODS

A questionnaire was used to determine risk factors of H. pylori infection. Samples were seeded on Sabouraud Dextrose Agar and horse blood-supplemented Columbia agar. Isolated yeasts were identified using and observed by optical microscopy searching for intra-yeast H. pylori. Total yeast DNA, from one random sample, was extracted to search for H. pylori virulence genes by PCR and bacterial identification by sequencing.

RESULTS

43% of samples contained yeasts, mainly Candida albicans (91%). Microscopy detected bacteria such as bodies and anti-H. pylori antibodies binding particles in 50% of the isolated yeasts. Total DNA extracted showed that 50% of the isolated yeasts were positive for H. pylori 16S rDNA and the sequence showed 99.8% similarity with H. pylori. In total, 32% of H. pylori DNA positive samples were cagA+ vacAs1a vacAm1 dupA-. No relationship was observed between possible H. pylori infection risk factors and vaginal yeasts harboring this bacterium.

CONCLUSION

H. pylori having virulent genotypes were detected within vaginal yeasts constituting a risk for vertical transmission of this pathogen.

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.

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

Background

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

Methodology

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

Principal findings

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

Conclusions

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

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

Gastric Damage and Cancer-Associated Biomarkers in Helicobacter pylori-Infected Children

Helicobacter pylori (H. pylori) is well-known to be involved in gastric carcinogenesis, associated with deregulation of cell proliferation and epigenetic changes in cancer-related genes. H. pylori infection is largely acquired during childhood, persisting long-term in about half of infected individuals, a subset of whom will go on to develop peptic ulcer disease and eventually gastric cancer, however, the sequence of events leading to disease is not completely understood. Knowledge on carcinogenesis and gastric damage-related biomarkers is abundant in adult populations, but scarce in children. We performed an extensive literature review focusing on gastric cancer related biomarkers identified in adult populations, which have been detected in children infected with H. pylori. Biomarkers were related to expression levels (RNA or protein) and/or methylation levels (DNA) in gastric tissue or blood of infected children as compared to non-infected controls. In this review, we identified 37 biomarkers of which 24 are over expressed, three are under expressed, and ten genes are significantly hypermethylated in H. pylori-infected children compared to healthy controls in at least 1 study. Only four of these biomarkers (pepsinogen I, pepsinogen II, gastrin, and SLC5A8) have been studied in asymptomatically infected children. Importantly, 13 of these biomarkers (β-catenin, C-MYC, GATA-4, DAPK1, CXCL13, DC-SIGN, TIMP3, EGFR, GRIN2B, PIM2, SLC5A8, CDH1, and VCAM-1.) are consistently deregulated in infected children and in adults with gastric cancer. Future studies should be designed to determine the clinical significance of these changes in infection-associated biomarkers in children and their persistence over time. The effect of eradication therapy over these biomarkers in children if proven significant, could lead to modifications in treatment guidelines for younger populations, and eventually promote the development of preventive strategies, such as vaccination, in the near future.

Helicobacter pylori infection in children

Helicobacter pylori infection affects more than half of the world population and it occurs generally in childhood. It is associated with gastroduodenal ulcer, gastric atrophy, intestinal metaplasia, gastric adenocarcinoma and lymphoid tissue-associated lymphoma. It is difficult to eradicate this bacterium due to its high antimicrobial resistance. In children, the infection is asymptomatic in the majority of cases and complications are less common. Probable inverse relationships with allergic diseases and inflammatory bowel diseases are being studied. These reasons mean that the decision to diagnose and treat the infection in children is only considered in specific circumstances in which it provides true benefits. This review focuses on some current considerations regarding epidemiology, diagnosis and treatment of childhood infection, emphasising outcomes and treatment schemes in children.

Helicobacter pylori Infection Aggravates Dysbiosis of Gut Microbiome in Children With Gastritis

Introduction:Helicobacter pylori infection consistently leads to chronic and low degree of inflammatory response in gastric mucosa and is closely related with gastrointestinal and extra-gastric diseases. Effects of local microbiome in the stomach have been studied in adults and children with H. pylori infection. It is, however, not known whether the intestinal microbial community differs in children with varying H. pylori infection. The aim of this study is to characterize the altered composition of microbiome induced by H. pylori infection and in gastritis.

Materials and Methods: This study involved 154 individuals, including 50 children affected by H. pylori-induced gastritis, 42 children with H. pylori-negative gastritis, and 62 healthy controls. Gut microbiome composition was analyzed using 16S rRNA gene-based pyrosequencing. Fecal bacterial diversity and composition were then compared.

Results: On the basis of an analysis of similarities and differences, we found that children with H. pylori-induced gastritis exhibited gut bacteria dysbiosis. The ratio of Firmicutes/Bacteroidetes (F:B) at the phylum level had dramatically decreased in H. pylori-positive gastritis group (HPG) and H. pylori-negative gastritis group (HNG), compared with the healthy control group (HCG). At the family and genus levels, relative abundance of Bacteroidaceae and Enterobacteriaceae was prevalent in HPG and HNG, whereas relative abundance of Lachnospiraceae, Bifidobacteriaceae, and Lactobacillaceae was seen in HCG. Prevalence of different taxa of gut microbiome at the class, order, family, and genus levels was also observed among the three groups.

Conclusions: Gastritis can cause changes in composition of fecal microbiome, which is exacerbated by H. pylori infection. These changes in gut microbiome may be related to drug resistance and development of chronic gastrointestinal diseases.

Immunity and Vaccine Development Against Helicobacter pylori

Helicobacter pylori is a highly-adapted gastrointestinal pathogen of humans and the immunology of this chronic infection is extremely complex. Despite the availability of antibiotic therapy, the global incidence of H. pylori infection remains high, particularly in low to middle-income nations. Failure of therapy and the spread of antibiotic resistance among the bacteria are significant problems and provide impetus for the development of new therapies and vaccines to treat or prevent gastric ulcer, and gastric carcinoma. The expansion of knowledge on gastric conventional and regulatory T cell responses, and the role of T_H17 in chronic gastritis from studies in mouse models and patients have provided valuable insights into how gastritis is initiated and maintained. The development of human challenge models for testing candidate vaccines has meant a unique opportunity to study acute infection, but the field of vaccine development has not progressed as rapidly as anticipated. One clear lesson learned from previous studies is that we need a better understanding of the immune suppressive mechanisms in vivo to be able to design vaccine strategies. There is still an urgent need to identify practical surrogate markers of protection that could be deployed in future field vaccine trials. Important developments in our understanding of the chronic inflammatory response, progress and problems arising from human studies, and an outlook for the future of clinical vaccine trials will be discussed.

Prevalence of Helicobacter pylori infection in Latin America and the Caribbean populations: A systematic review and meta-analysis

OBJECTIVE

To describe the prevalence of Helicobacter pylori (H. pylori) infection in Latin Americaand the Caribbean (LAC), through systematic review and meta-analysis by age groups and gender.

METHODS

Systematic review and meta-analysis of the population-based observational epidemiological studies carried out in LAC, focused on the prevalence of H. pylori and published until March, 2018. The databases utilized in the search were MEDLINE, SCIELO andPUBMED. The prevalence described in the meta-analysis and 95% confidence intervals were estimated by the random effects model, and weighted by the size of the study.

RESULTS

The 22 selected studies were carried out in 14 countries of LAC, and included 24,178 individuals. The studies were conducted between 1987 and 2012, and all were representative of at least one city. The prevalence of H. pylori infection was 57.57% (CI95%:50.43;64.72) for all ages; in children and adolescents the prevalence was 48.36% (CI95%:38.03;58.70) and in adults 69.26%(CI95%:64.54;76.99). No differences were observed regarding sex.

CONCLUSION

Prevalence of H. pylori infection in LAC is high for all age groups. These data reinforce the necessity of actions towards the prevention and treatment of H. pylori infection for all age groups. Treating H pylori infection in young ages probably will reduce gastric cancer incidence in the future.

High prevalence and low spontaneous eradication rate of Helicobacter pylori infection among schoolchildren aged 7-12 years

AIM

Helicobacter pylori infections mainly occur during childhood and may cause chronic diseases and persist for life unless they are treated. The aim of this study was to identify the prevalence and infection status of H. pylori infection among schoolchildren.

METHODS

We conducted a cross-sectional study of 867 children (52% male) aged 7-12 years in a primary school in the Minhang District of Shanghai, China, in 2014, and a one-year follow-up study of 352 subjects. The 13C-urea breath test was used to identify the H. pylori infection at baseline and one year later. A parental questionnaire provided information regarding the children's socioeconomic status and household environment.

RESULTS

The overall prevalence of the H. pylori infection was 24.1% (209/867), with a 95% confidence interval of 21.3% to 27.0%. The one-year follow-up study of 352 subjects found that 33.5% were positive for the infection at baseline and 66.5% were negative. We found that 27.1% of the positive cases recovered and 8.9% of the negative cases acquired the infection during the year. The spontaneous eradication rate was only 2.9% over the one-year period.

CONCLUSION

The prevalence of the H. pylori infection among Chinese schoolchildren aged 7-12 was high and spontaneous eradication was low.

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.

Detection of Helicobacter pylori in stool samples of young children using real-time polymerase chain reaction

BACKGROUND

The aims of this study were to develop and validate a multiplex real-time polymerase chain reaction (q-PCR) assay of Helicobacter pylori in stool samples of healthy children. Additionally, we determined the prevalence of clarithromycin resistance and cagA gene in H. pylori-positive samples.

MATERIALS AND METHODS

Archived stool samples from 188 children aged 6-9 years and 272 samples of 92 infants aged 2-18 months were tested for H. pylori antigens using enzyme immunoassay (EIA). A multiplex q-PCR assay was designed to detect H. pylori 16S rRNA and urease and the human RNase P gene as an internal control. Kappa coefficient was calculated to assess the agreement between q-PCR and EIA.

RESULTS

Laboratory validation of the q-PCR assay using quantitated H. pylori ATCC 43504 extracted DNA showed S-shaped amplification curves for all genes; the limit of detection was 1 CFU/reaction. No cross-reactivity with other bacterial pathogens was noted. Applying the multiplex q-PCR to DNA extracted from fecal samples showed clear amplification curves for urease gene, but not for 16S rRNA. The prevalence of H. pylori infection was 50% (95% CI 43%-57%) by q-PCR (urease cycle threshold <44) vs 59% (95% CI 52%-66%) by EIA. Kappa coefficient was .80 (P < .001) and .44 (P < .001) for children aged 6-9 years and 2-18 months, respectively. Sixteen samples were positive for cagA and three were positive for clarithromycin resistance mutation (A2143G) as confirmed by sequencing.

CONCLUSIONS

The developed q-PCR can be used as a cotechnique to enhance the accuracy of H. pylori detection in epidemiological studies and in clinical settings.

Helicobacter pylori Infection and Risk Factors in Relation to Allergy in Children

PURPOSE

To analyze presence of Helicobacter pylori infection and environmental risk factors among children with and without allergy.

METHODS

Parents of children at primary health care centres/kindergartens and allergologist consultation were asked to answer a questionnaire and to bring a faecal sample. H. pylori infection was detected by monoclonal stool antigen test. Prevalence of H. pylori infection and risk factors were compared between individuals with and without allergy using χ² test, ANOVA test and parameters and logistic regression.

RESULTS

Among 220 children (mean age, 4.7 years; ±standard deviation 2.3 years) H. pylori positivity was non-significantly lower among patients with allergy (n=122) compared to individuals without allergy (n=98): 13.9% (17/122) vs. 22.4% (22/98); p=0.106. In logistic regression analysis presence of allergy was significantly associated with family history of allergy (odds ratio [OR], 8.038; 95% confidence interval [CI], 4.067-15.886; p<0.0001), delivery by Caesarean section (OR, 2.980; 95% CI, 1.300-6.831; p=0.009), exclusive breast feeding for five months (OR, 2.601; 95% CI, 1.316-5.142; p=0.006), antibacterial treatment during the previous year (OR, 2.381; 95% CI, 1.186-4.782; p=0.015).

CONCLUSION

Prevalence of H. pylori infection did not differ significantly between children with and without allergy. Significant association of allergy with delivery by Caesarean section and antibacterial therapy possibly suggests the role of gastrointestinal flora in the development of allergy, while association with family history of allergy indicates the importance of genetic factors in the arise of allergy.

Review: Prevalence and dynamics of Helicobacter pylori infection during childhood

INTRODUCTION

Long-term persistent Helicobacter pylori infection has been associated with ulceropeptic disease and gastric cancer. Although H. pylori is predominantly acquired early in life, a clear understanding of infection dynamics during childhood has been obfuscated by the diversity of populations evaluated, study designs, and methods used.

AIM

Update understanding of true prevalence of H. pylori infection during childhood, based on a critical analysis of the literature published in the past 5 years.

METHODS

Comprehensive review and meta-analysis of original studies published from 2011 to 2016.

RESULTS

A MEDLINE^® /PubMed^® search on May 1, 2016, using the terms pylori and children, and subsequent exclusion, based on abstract review using predefined criteria, resulted in 261 citations. An Embase^® search with the same criteria added an additional 8 citations. In healthy children, meta-analysis estimated an overall seroprevalence rate of 33% (95% CI: 27%-38%). Seven healthy cohort studies using noninvasive direct detection methods showed infection prevalence estimates ranging from 20% to 50% in children ≤5 and 38% to 79% in children >5 years. The probability of infection persistence after a first positive sample ranged from 49% to 95%. Model estimates of cross-sectional direct detection studies in asymptomatic children indicated a prevalence of 37% (95% CI: 30%-44%). Seroprevalence, but not direct detection rates increased with age; both decreased with increasing income. The model estimate based on cross-sectional studies in symptomatic children was 39% (95% CI: 35%-43%).

CONCLUSIONS

The prevalence of H. pylori infection varied widely in the studies included here; nevertheless, model estimates by detection type were similar, suggesting that overall, one-third of children worldwide are or have been infected. The few cohort and longitudinal studies available show variability, but most studies, show infection rates over 30%. Rather surprisingly, overall infection prevalence in symptomatic children was only slightly higher, around 40%. Studies including only one positive stool sample should be interpreted with caution as spontaneous clearance can occur.

Helicobacter pylori cagA+ Is Associated with Milder Duodenal Histological Changes in Chilean Celiac Patients

HIGHLIGHTS

What is already known about this subject?

Celiac disease (CD) has a high clinical and histological diversity and the mechanisms underlying this phenomenon remain elusive.

H. pylori is a bacterium that chronically infect gastric and duodenal mucosa activating both a Th1/Th17 and T-reg pathways.

The role of H. pylori (and the effect of their virulence factors) in CD have not yet completely elucidated.

What are the new findings?

cagA+ H. pylori strains are associated to milder histological damage in infected CD patients.

In active-CD patients the presence of cagA+ H. pylori is associated to an increase in T-reg markers, contrasting with a downregulation in cagA+ infected potential-CD individuals.

How might it impact on clinical practice in the foreseeable future?

The identification of microbiological factors that could modulate inflammation and clinical expression of CD may be used in the future as preventive strategies or as supplementary treatment in patients that cannot achieve complete remission, contributing to the better care of these patients.

Background: Mechanisms underlying the high clinical and histological diversity of celiac disease (CD) remain elusive. Helicobacter pylori (Hp) chronically infects gastric and duodenal mucosa and has been associated with protection against some immune-mediated conditions, but its role (specifically of cagA+ strains) in CD is unclear.

Objective: To assess the relationship between gastric Hp infection (cagA+ strains) and duodenal histological damage in patients with CD.

Design: Case-control study including patients with active-CD, potential-CD and non-celiac individuals. Clinical presentation, HLA genotype, Hp/cagA gene detection in gastric mucosa, duodenal histology, Foxp3 positive cells and TGF-β expression in duodenal lamina propria were analyzed.

Results: We recruited 116 patients, 29 active-CD, 37 potential-CD, and 50 non-CD controls. Hp detection was similar in the three groups (~30–40%), but cagA+ strains were more common in infected potential-CD than in active-CD (10/11 vs. 4/10; p = 0.020) and non-CD (10/20; p = 0.025). Among active-CD patients, Foxp3 positivity was significantly higher in subjects with cagA+ Hp+ compared to cagA- Hp+ (p < 0.01) and Hp- (p < 0.01). In cagA+ Hp+ individuals, Foxp3 positivity was also higher comparing active- to potential-CD (p < 0.01). TGF-β expression in duodenum was similar in active-CD with cagA+ Hp+ compared to Hp- and was significantly downregulated in cagA+ potential-CD subjects compared to other groups.

Conclusion: Hp infection rates were similar among individuals with/without CD, but infection with cagA+ strains was associated with milder histological damage in celiac patients infected by Hp, and in active-CD cases with higher expression of T-reg markers. Results suggest that infection by cagA+ Hp may be protective for CD progression, or conversely, that these strains are prone to colonize intestinal mucosa with less severe damage.

Association between cagA, vacAi, and dupA genes of Helicobacter pylori and gastroduodenal pathologies in Chilean patients

In addition to the already known cagA gene, novel genetic markers have been associated with Helicobacter pylori (H. pylori) virulence: the dupA and vacAi genes. These genes might play an important role as specific markers to determine the clinical outcome of the disease, especially the vacAi gene, which has been expected to be a good marker of severe pathologies like gastric adenocarcinoma. In the present study, the association of cagA, dupA, and vacAi genes with gastroduodenal pathologies in Chilean patients was studied. One hundred and thirty-two patients positive for H. pylori were divided into two groups-non-severe and severe gastric pathologies-and investigated for the presence of cagA, dupA, and vacAi H. pylori virulence genes by PCR. The cagA gene was detected in 20/132 patients (15.2%), the vacAi1 gene was detected in 54/132 patients (40.9%), the vacAi2 gene was detected in 26/132 patients (19.7%), and the dupA gene was detected in 50/132 (37.9%) patients. Logistic regression model analysis showed that the vacAi1 isoform gene in the infected strains and the severity of the diseases outcome were highly associated, causing severe gastric damage that may lead to gastric cancer (p < 0.0001; OR = 8.75; 95% CI 3.54-21.64). Conversely, cagA (p = 0.3507; OR = 1.62; 95% CI 0.59-4.45) and vacAi2 (p = 0.0114; OR = 3.09; 95% CI 1.26-7.60) genes were not associated with damage, while the dupA gene was associated significantly with non-severe clinical outcome (p = 0.0032; OR = 0.25; 95% CI 0.09-0.65). In addition, dupA gene exerts protection against severe gastric pathologies induced by vacAi1 by delaying the outcome of the disease by approximately 20 years.

Detection of Helicobacter pylori by Real-Time PCR for 16s rRNA in Stools of NonInfected Healthy Children, Using ELISA Antigen Stool Test as the Gold Standard

BACKGROUND

We previously detected Helicobacter pylori infection by stool antigen ELISA assay in 33-41% of asymptomatic Chilean children between 2-3 years of age, of which 11-20% had a transient infection and 21-22% a persistent infection. A total of 88% of ELISA-positive samples were also rtPCR positive, while 37/133 (33%) of ELISA-negative stool samples were rtPCR positive. The significance of a ELISA-negative/rtPCR-positive sample requires clarification. We aimed to determine whether rtPCR is able to detect persistent infections not detected by ELISA.

MATERIALS AND METHODS

We selected 36 children with an ELISA-negative/rtPCR-positive stool sample, of which 25 were never H. pylori infected according to ELISA, and 11 had a transient infection with an ELISA-positive sample before or after the discordant sample. At least two additional consecutive ELISA-negative samples per child were tested in duplicate by rtPCR for the 16s rRNA gene.

RESULTS

A total of 14 of 78 (17.9%) rtPCR reactions were positive, but only 4/78 (5.1%) were positive in both duplicates, representing a total of 3/36 (8.3%) children with an additional rtPCR-positive sample, only one of whom was persistently negative by ELISA. One child with a transient infection had two positive rtPCR reactions despite negative ELISA samples.

CONCLUSIONS

In H. pylori noninfected or transiently infected children, as determined by stool ELISA, additional ELISA-negative/rtPCR-positive stool samples were found in 8.3% of children, but a possible persistent infection was only identified in 2.7% of children. Thus, the characterization of infection dynamics in children is not being misrepresented by application of stool ELISA. Furthermore, rtPCR does not significantly improve dynamic characterization.

Active efflux in dormant bacterial cells - New insights into antibiotic persistence

Bacterial persisters are phenotypic variants of an isogenic cell population that can survive antibiotic treatment and resume growth after the antibiotics have been removed. Cell dormancy has long been considered the principle mechanism underlying persister formation. However, dormancy alone is insufficient to explain the full range of bacterial persistence. Our recent work revealed that in addition to 'passive defense' via dormancy, persister cells employ 'active defense' via enhanced efflux activity to expel drugs. This finding suggests that persisters combine two seemingly contradictory mechanisms to tolerate antibiotic attack. Here, we review the passive and active aspects of persister formation, discuss new insights into the process, and propose new techniques that can facilitate the study of bacterial persistence.

Helicobacter pylori Infection Is Associated with Decreased Expression of SLC5A8, a Cancer Suppressor Gene, in Young Children

Background:Helicobacter pylori infects half of the world's population and causes gastric cancer in a subset of infected adults. Previous blood microarray findings showed that apparently healthy children, persistently infected with H. pylori have differential gene expression compared to age-matched, non-infected children. SLC5A8, a cancer suppressor gene with decreased expression among infected children, was chosen for further study based on bioinformatics analysis. Methods: A pilot study was conducted using specific qRT-PCR amplification of SLC5A8 in blood samples from H. pylori infected and non-infected children, followed by a larger, blinded, case-control study. We then analyzed gastric tissue from H. pylori infected and non-infected children undergoing endoscopy for clinical purposes. Results: Demographics, clinical findings, and family history were similar between groups. SLC5A8 expression was decreased in infected vs. non-infected children in blood, 0.12 (IQR: 0-0.89) vs. 1.86 (IQR: 0-8.94, P = 0.002), and in gastric tissue, 0.08 (IQR: 0.04-0.15) vs. 1.88 (IQR: 0.55-2.56; P = 0.001). Children who were both stool positive and seropositive for H. pylori had the lowest SLC5A8 expression levels. Conclusions:H. pylori infection is associated with suppression of SCL5A8, a cancer suppressor gene, in both blood and tissue samples from young children. Key Points: Young children, persistently infected with Helicobacter pylori show decreased expression of SLC5A8 mRNA in both blood and tissue samples as compared to non-infected children.

Helicobacter pylori in children

Helicobacter pylori infection in early childhood may differ in many aspects compared to infection in adulthood: the immune response in the gut, the type and prevalence of complications within and outside the stomach, and the impact on long-term health. In high prevalence countries, transient infections seem to be common in infants and toddlers, and the consequences of this phenomenon on the short- and long-term immune response are still unclear. Other controversial issues are related to the question of which H. pylori-infected children benefit from treatment and which is the best regimen to eradicate the infection in the presence of a worldwide increasing antibiotic resistance. The first large-scale randomized placebo-controlled vaccination trial in schoolchildren indicates that prevention of the infection may be possible.

[Infections and epigenetic changes in cancer]

The role of epigenetics and infectious diseases at early stages of life influence pre-malignant lesions of cancer, in particular, gastric cancer, one of the most frequent tumours in Chile, Latin America, and worldwide. This article examines the role of H.pylori and epigenetic alterations (i.e. DNA methylation) at early stages of gastric cancer and proposes, from the paediatric point of view, strategies for prevention and early detection.

The Long-Term Public Health Benefits of Breastfeeding

Breastfeeding has many health benefits, both in the short term and the longer term, to infants and their mothers. There is an increasing number of studies that report on associations between breastfeeding and long-term protection against chronic disease. Recent research evidence is reviewed in this study, building on previous authoritative reviews. The recent World Health Organization reviews of the short- and long-term benefits of breastfeeding concluded that there was strong evidence for many public health benefits of breastfeeding. Cognitive development is improved by breastfeeding, and infants who are breastfed and mothers who breastfeed have lower rates of obesity. Other chronic diseases that are reduced by breastfeeding include diabetes (both type 1 and type 2), obesity, hypertension, cardiovascular disease, hyperlipidemia, and some types of cancer.