Influence of Intestinal Indigenous Microbiota on Intrafamilial Infection by Helicobacter pylori in Japan

Factors associated with treatment failure, and possible applications of probiotic bacteria in the arsenal against Helicobacter pylori

INTRODUCTION

Helicobacter pylori is a widespread helical Gram-negative bacterium, which causes a variety of stomach disorders, such as peptic ulcer, chronic atrophic gastritis, and gastric cancer. This microbe frequently colonizes the mucosal layer of the human stomach and survives in the inhospitable microenvironment, by adapting to this hostile milieu.

AREAS COVERED

In this extensive review, we describe conventional antibiotic treatment regimens used against H. pylori including, empirical, tailored, and salvage therapies. Then, we present state-of-the-art information about reasons for treatment failure against H. pylori. Afterward, the latest advances in the use of probiotic bacteria against H. pylori infection are discussed. Finally, we propose a polymeric bio-platform to provide efficient delivery of probiotics for H. pylori infection.

EXPERT OPINION

For effective probiotic delivery systems, it is necessary to avoid the early release of probiotics at the acidic stomach pH, to protect them against enzymes and antimicrobials, and precisely target H. pylori bacteria which have colonized the antrum area of the stomach (basic pH).

Helicobacter pylori may participate in the development of inflammatory bowel disease by modulating the intestinal microbiota

Inflammatory bowel disease (IBD) is a non-specific inflammatory disease of the gastrointestinal (GI) tract that is generally accepted to be closely related to intestinal dysbiosis in the host. GI infections contribute a key role in the pathogenesis of IBD; however, although the results of recent clinical studies have revealed an inverse correlation between Helicobacter pylori (H. pylori) infection and IBD, the exact mechanism underlying the development of IBD remains unclear. H. pylori, as a star microorganism, has been a focus for decades, and recent preclinical and real-world studies have demonstrated that H. pylori not only affects the changes in the gastric microbiota and microenvironment but also influences the intestinal microbiota, indicating a potential correlation with IBD. Detailed analysis revealed that H. pylori infection increased the diversity of the intestinal microbiota, reduced the abundance of Bacteroidetes, augmented the abundance of Firmicutes, and produced short-chain fatty acid-producing bacteria such as Akkermansia. All these factors may decrease vulnerability to IBD. Further studies investigating the H. pylori-intestinal microbiota metabolite axis should be performed to understand the mechanism underlying the development of IBD.

The interplay between Helicobacter pylori and gastrointestinal microbiota

The complex population of microbes in the human gastrointestinal (GI) tract interacts with itself and with the host, exerting a deep influence on health and disease development. The development of modern sequencing technology has enabled us to gain insight into GI microbes. Helicobacter pylori colonization significantly affects the gastric microenvironment, which in turn affects gastric microbiota and may be correlated with colonic microbiota changes. Crosstalk between H. pylori and GI commensal flora may play a role in H. pylori-related carcinogenicity and extragastric manifestations. We review current knowledge on how H. pylori shapes GI microbiota with a specific focus on its impact on the stomach and colon. We also review current evidence on colonic microbiota changes attributed to eradication therapy based on the clinical studies performed to date.

Helicobacter pylori and the intestinal microbiome among healthy school-age children

BACKGROUND

Helicobacter pylori (H. pylori) infection is acquired during childhood and causes chronic gastritis that remains asymptomatic in most infected people. H. pylori alters the gastric microbiota and causes peptic ulcer disease. Evidence on the relationship between asymptomatic H. pylori infection and children's gut microbiota remains elusive.

AIM

We characterized the relationship between H. pylori infection and the intestinal microbiome of healthy children, adjusting for known inter-personal and environmental exposures.

MATERIALS AND METHODS

This cross-sectional study included stool samples obtained from 163 Israeli Arab children aged 6-9 years from different socioeconomic strata. Sociodemographic information was collected through maternal interviews. H. pylori infection was determined using monoclonal antigen detection stool enzyme immunoassay. The gut microbiome was characterized by implementing 16S rRNA gene sequencing of the V4 region and a multivariate downstream analysis.

RESULTS

Overall, 57% of the participants were positive for H. pylori infection and it was significantly associated with low socioeconomic status. There was no significant association between H. pylori infection and bacterial richness of fecal microbiome. H. pylori infection was significantly associated with intestinal bacterial composition, including a strong association with Prevotella copri and Eubacterium biforme. Moreover, socioeconomic status was strongly associated with bacterial composition.

DISCUSSION AND CONCLUSIONS

H. pylori infection in healthy children was significantly associated with altered intestinal microbiome structure. Socioeconomic determinants exhibit a strong effect, related to both H. pylori infection and intestinal diversity and composition in childhood. These findings are clinically important to the understanding of the role of H. pylori infection and other intestinal microbes in health and disease.

Sex-dependent differences in the gut microbiota following chronic nasal inflammation in adult mice

A growing body of evidence suggests a relationship between olfactory dysfunction and the pathogenesis of mental disorders. Our previous studies indicated that chronic nasal inflammation caused loss of olfactory sensory neurons and gross atrophy of the olfactory bulb, which may lead to olfactory dysfunction. Simultaneously, increasing numbers of reports have elucidated the importance of gut microbiota to maintain brain function and that dysbiosis may be associated with neuropsychiatric disorders. Here we examined whether chronic nasal inflammation perturbed gut microbiota and whether there were sex differences in this pattern. Eight-week-old C57BL/6 mice repeatedly received bilateral nasal administration of lipopolysaccharide (LPS) 3 times/week to cause chronic nasal inflammation or saline as a control. At 9 weeks, cecal feces were used for 16S metagenomic analysis and whole blood and fresh tissue of spleen were used for ELISA analyses. Microbiome analysis demonstrated a remarkable change of the gut microbiota in male mice with chronic nasal inflammation which was different from that in female mice. In both mice, systemic inflammation did not occur. This has shown for the first time that chronic nasal inflammation correlates with sex-dependent changes in the gut microbiota. The detailed mechanism and potential alteration to brain functions await further studies.

A gut dysbiotic microbiota-based hypothesis of human-to-human transmission of non-communicable diseases

Non-communicable diseases (NCDs) have replaced communicable diseases as the leading cause of premature death worldwide over the past century. Increasing numbers of studies have reported a link between NCDs and dysbiotic gut microbiota. Some gut microbiota, such as Helicobacter pylori, have been implicated in person-to-person transmission. Based on these reports, we develop a hypothesis regarding dysbiotic microbiota-associated NCDs, and explore how the presence of communicable NCDs could be confirmedexperimentally. We have also reviewed reports on environmental factors, including a high-fat diet, alcohol, smoking, exercise, radiation and air pollution, which have been associated with dysbiotic microbiota, and determined whether any of these parameters were also associated with NCDs. This review discusses the potential mechanism by which dysbiotic microbiota induced by environmental factors are directly or indirectly involved in person-to-person transmission. The hypothetical interplay between the environment, gut microbiota and host can be tested through high-throughput sequencing, animal models, and cell studies, although each of these modalities presents specific challenges. Confirmation of a causative association of dysbiotic microbiota with NCDs would represent a paradigm shift in efforts to prevent and control these diseases, and should stimulate additional studies on the associations among environmental factors, gut microbiota, and NCDs.

Assessment of real-time PCR for Helicobacter pylori DNA detection in stool with co-infection of intestinal parasites: a comparative study of DNA extraction methods

Background

Many studies reported high prevalence of H. pylori infection among patients co-infected with intestinal parasites. Molecular approach for the DNA detection of those microbes in stool have been proposed. However there are a few reports that evaluated the effect of bead-beating in relation to the H. pylori outcome. Therefore, we developed and evaluated two TaqMan-based real-time PCR (rt-PCR) qualitative assays for the detection of ureC (glmM) and cagA of Helicobacter pylori on DNA extracted by three procedures.

Results

The two PCRs were analysed on 100 stool samples from patients who were screened for intestinal parasites. Three DNA extraction procedures were used: 1) automation with bead beating, 2) automation without bead beating and 3) hand column. The specificity of the new assays was confirmed by sequencing the PCR products and by the lack of cross-reactivity with other bacteria or pathogens DNA. Rt-PCR assays showed a detection limit of 10^4 bacteria/200 mg stool. The ureC_PCR with bead beating process was compared to conventional stool antigen test (SAT), with 94.12 and 93.75% of respectively sensitivity and specificity. However, the discordant samples were confirmed by DNA sequencing suggesting a potential higher sensitivity and specificity of PCR.

Conclusions

Our findings showed that the automation with bead-beating –suggested procedure for intestinal parasitic infections- can reach highly sensitive results in H. pylori detection on stool compared also with SAT. Thus, this work can provide new insights into the practice of a clinical microbiology laboratory in order to optimize detection of gastro-intestinal infections. Further studies are needed to better define the clinical value of this technique.

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.

Epidemiology, Diagnosis and Risk Factors of Helicobacter pylori Infection

Helicobacter pylori is a human-specific pathogen, which leads to gastric pathologies including gastric cancer. It is a highly unique bacterium considered as a carcinogenic agent. H. pylori remains a major human health problem, responsible for ~90% of the gastric cancer cases. Approximately four billion individuals have been detected for H. pylori infection worldwide in 2015. At the turn of the twenty-first century, the prevalence of H. pylori has been declining in highly industrialized countries of the Western world, whereas prevalence has plateaued at a high level in developing and newly industrialized countries. However, the infection status remains high in immigrants coming from countries with high prevalence of H. pylori infection. H. pylori can be diagnosed both by invasive and non-invasive methods. Urea breath test and stool antigens detection are among the most commonly used non-invasive ones. Although the way H. pylori is transmitted remains still not fully clear, the level of contamination is strongly dependent on the familial and environmental context, with a drastic impact of living conditions with poor hygiene and sanitation. However, familial socioeconomic status is the main risk factor for H. pylori infection among children. In addition, food and water source have a high impact on the prevalence of H. pylori infection worldwide. This chapter highlights the latest knowledge in the epidemiology of H. pylori infection, its diagnosis and critical risk factors responsible for its high prevalence in some populations and geographic areas.

Review: Epidemiology of Helicobacter pylori infection

This review summarizes recent publications on the epidemiology of Helicobacter pylori. Two major systemic analyses, from Malaysia and Ethiopia, were published. The Brazilian Consensus Conference has stated that H pylori infection is an infectious disease with an indication for antimicrobial therapy. A continuous decrease in H pylori prevalence was reported from many regions worldwide, including Korea, China, Iran, and Austria. A cross-sectional H pylori prevalence study conducted in the United Arab Emirates found 41% prevalence in a group of healthy children and adults. Several studies from Asia addressed H pylori prevalence in adults undergoing regular checkup. The largest of such studies, performed in Korea, involved 24 471 subjects and reported 41.5% seroprevalence. A relatively smaller study from East China on 3252 subjects reported 27.5% prevalence. In contrast, a study from Spain reported 87.2% seroprevalence. A report on the association between smoking and H pylori seropositivity was published on behalf of the Stomach Cancer Pooling (StoP) Project-a consortium of epidemiological studies of gastric cancer. Also, other potential risk factors, including occupational risk factors, water supply, and food were analyzed. Gastroesophageal reflux and sexual partners has been associated with a higher risk for H pylori acquisition, and gut microbiota was suggested to play a role in intrafamilial transmission of H pylori. Finally, in a few studies (from Mexico and Japan), the catalytic model for predicting the potential risk of acquiring H pylori infection in the future was used. As anticipated, a further decline in H pylori-related disease was demonstrated by applying the modeling.

Considering gut microbiota disturbance in the management of Helicobacter pylori infection

Helicobacter pylori (Hp) infection produces drastic changes in the gastric microenvironment, which, in turn, influence the gastric microbiota composition and might be correlated with large intestinal microbiota changes. This excellent perturbing actor could trigger important modifications in the homeostatic functions exerted by gut commensals leading to a new gastrointestinal balance. At the same time, the therapeutic strategies used to eradicate Hp can modulate this physiological symbiosis, but can be also conversely affected by its properties. Area covered: The purpose of this review is to explore the reciprocal interplay between Hp infection and gut microbiota and analyze how microbial changes can influence the management of Hp eradication therapies. Expert commentary: While many studies have described Hp-dependent gut microbiota alterations, their clinical implications are only partially clear, as well as the mechanism of actions that sustain these processes. This represents a clear challenge for future research projects that will also need to understand which role is exerted by viruses, parasites, and yeasts.

Helicobacter pylori and some aspects of gut microbiota in children

Helicobacter pylori infection in children differs from infection in adults in many aspects. The rate of infection, epidemiology, clinical presentations and complications, the applicability of diagnostic tests, antibiotic resistance, treatment options, and success rates differ significantly. Due to all these differences, management guidelines for children and adults differ also substantially. In 2017, the Updated ESPGHAN and NASPGHAN Guidelines on the management of H. pylori infection in children were published, emphasizing the differences in clinical presentation and indications for treatment, stating that the primary goal of clinical investigation in children is to identify the cause of upper gastrointestinal symptoms rather than the presence of H. pylori infection. Therefore, the diagnosis should be based on upper endoscopy, and the "test and treat strategy" should not be used in children. Due to an increasing rate of antibiotic resistance worldwide, the updated guidelines recommend broader use of antimicrobial susceptibility testing for H. pylori strains in order to tailor eradication treatment accordingly. Moreover, treatment in children should be prescribed only when indicated and should be based on the rate of eradication in local populations aiming for treatment success above 90%. During the last two decades there has been a steady decrease in the rate of H. pylori infection in both children and adults in the Western world. Two recent publications studying the incidence of H. pylori infection confirmed that early childhood is a time for acquisition of infection both in industrialized and nonindustrialized countries. In addition, they showed that H. pylori could be acquired outside the family. In respect to the inverse association between H. pylori and allergy, a longitudinal study demonstrated that early exposure to H. pylori at any age was inversely associated with atopy and allergic conditions.