Helicobacter pylori and its relationship with variations of gut microbiota in asymptomatic children between 6 and 12 years

Helicobacter pylori and oral-gut microbiome: clinical implications

More than half of the world's population are colonized with H. pylori; however, the prevalence varies geographically with the highest incidence in Africa. H. pylori is probably a commensal organism that has been associated with the development of gastritis, ulcers, and gastric cancer. H. pylori alone is most probably not enough for the development of gastric carcinoma, but evidence for its association with the disease is high and has, therefore, been classified by the International Agency for Research on Cancer as a Class 1 carcinogen. Bacteroidetes and Fusobacteria positively coexisted during H. pylori infection along the oral-gut axis. The eradication therapy required to treat H. pylori infection can also have detrimental consequences for the gut microbiota, leading to a decreased alpha diversity. Therefore, therapy regimens integrated with probiotics may abolish the negative effects of antibiotic therapy on the gut microbiota. These eradication therapies combined with probiotics have also higher rates of eradication, when compared to standard treatments, and are associated with reduced side effects, improving the patient's compliance. The eradication therapy not only affects gut microbiome but also affects the oral microbiome with robust predominance of harmful bacteria. However, there have been reports of a protective role of H. pylori in Barrett's esophagus, esophageal adenocarcinoma, eosinophilic esophagitis, IBD, asthma, and even multiple sclerosis. Therefore, eradication therapy should be carefully considered, and test to treat policy should be tailored to specific communities especially in highly endemic areas. Supplementation of probiotics, prebiotics, herbals, and microbial metabolites to reduce the negative effects of eradication therapy should be considered. After failure of many eradication attempts, the benefits of H. pylori eradication should be carefully balanced against the risk of adverse effects especially in the elderly, persons with frailty, and intolerance to antibiotics.

Parasitosis by Fasciola hepatica and Variations in Gut Microbiota in School-Aged Children from Peru

(1) Background: Human fascioliasis is considered an endemic and hyper-endemic disease in the Peruvian Andean valleys. Our objective was to determine variations in the composition of the gut microbiota among children with Fasciola hepatica and children who do not have this parasitosis. (2) Method: A secondary analysis was performed using fecal samples stored in our biobank. The samples were collected as part of an epidemiological Fasciola hepatica cross-sectional study in children from 4 through 14 years old from a community in Cajamarca, Peru. (3) Results: In a comparison of the bacterial genera that make up the intestinal microbiota between the F. hepatica positive and negative groups, it was found that there are significant differences in the determination of Lactobacillus (p = 0.010, CI: 8.5-61.4), Bacteroides (p = 0.020, CI: 18.5-61.4), Clostridium (p < 0.001, CI: 3.5-36.0), and Bifidobacterium (p = 0.018, CI: 1.1-28.3), with each of these genera being less frequent in children parasitized with F. hepatica. (4) Conclusions: These results show that F. hepatica may be associated with direct or indirect changes in the bacterial population of the intestinal microbiota, particularly affecting three bacterial genera.

Seroprevalence of Helicobacter pylori infection among schoolchildren in southern Taiwan-A 20-year longitudinal follow-up

BACKGROUND

Helicobacter pylori infection is primarily acquired in childhood and can lead to peptic ulcer diseases and gastric cancer. The prevalence of H. pylori infection varies widely in different countries. The aim of this study was to explore the change of pediatric H. pylori seroprevalence in the past two decades and to investigate the risk factors for pediatric H. pylori seropositivity in southern Taiwan.

MATERIALS AND METHODS

This study enrolled children aged 7-12 years in Tainan City in 2018 and compared the result with our previous data in 1998, 2005, and 2010. Parents of the participants were invited to fill out questionnaires, including information of personal history, family history of peptic ulcer diseases, annual household income, and source of drinking water. Blood samples were analyzed for anti-H. pylori IgG by enzyme-linked immunosorbent assay.

RESULTS

A total of 391, 629, 618, and 488 elementary school students in Tainan City were enrolled in 1998, 2005, 2010, and 2018, respectively. There was a significant decline in H. pylori seroprevalence from 9.2% in 1998, 7.8% in 2005, 6.2% in 2010 to 4.7% in 2018 (p < 0.001). Neither gender difference nor age difference was found in H. pylori seropositivity in each year of enrollment. Low household income was significantly associated with pediatric H. pylori seropositivity.

CONCLUSIONS

The seroprevalence of H. pylori infection among elementary schoolchildren has remarkably declined in southern Taiwan in the past two decades. Low household income was a risk factor for pediatric H. pylori seropositivity.

Therapeutic Approach Targeting Gut Microbiome in Gastrointestinal Infectious Diseases

While emerging evidence highlights the significance of gut microbiome in gastrointestinal infectious diseases, treatments like Fecal Microbiota Transplantation (FMT) and probiotics are gaining popularity, especially for diarrhea patients. However, the specific role of the gut microbiome in different gastrointestinal infectious diseases remains uncertain. There is no consensus on whether gut modulation therapy is universally effective for all such infections. In this comprehensive review, we examine recent developments of the gut microbiome's involvement in several gastrointestinal infectious diseases, including infection of Helicobacter pylori, Clostridium difficile, Vibrio cholerae, enteric viruses, Salmonella enterica serovar Typhimurium, Pseudomonas aeruginosa Staphylococcus aureus, Candida albicans, and Giardia duodenalis. We have also incorporated information about fungi and engineered bacteria in gastrointestinal infectious diseases, aiming for a more comprehensive overview of the role of the gut microbiome. This review will provide insights into the pathogenic mechanisms of the gut microbiome while exploring the microbiome's potential in the prevention, diagnosis, prediction, and treatment of gastrointestinal infections.

Crosstalk between Helicobacter pylori and gastrointestinal microbiota in various gastroduodenal diseases-A systematic review

Gastroduodenal diseases have prevailed for a long time and more so due to dominance of gut bacteria Helicobacter pylori in most of the cases. But habitation by other gut microbiota in gastroduodenal diseases and the relationship between Helicobacter pylori and gastrointestinal microbiota in different gastroduodenal diseases is somewhat being unravelled in the current times. For this systematic review, we did a literature search of various gastroduodenal diseases and the effect on gut microbiota pertaining to it. A search of the online bibliographic databases PUBMED and PUBMED CENTRAL was carried out to identify articles published between 1977 and May 2022. The analysis of these selected studies highlighted the inhabitation of other gut microbiota such as Fusobacteria, Bacteroidetes, Streptococcaceae, Prevotellaceae, Fusobacteriaceae, and many others. Interplay between these microbiota and H. pylori have also been noted which suggested that gastroduodenal diseases and gut microbiota are intertwined by a symbiotic association regardless of the H. pylori status. The relationship between the gut microbiota and many gastroduodenal diseases, such as gastritis, gastric cancer, lymphomas, and ulcers, demonstrates the dysbiosis of the gut microbiota in both the presence and absence of H. pylori. The evolving ways for eliminating H. pylori are provided along with inhibiting qualities of other species on H. pylori. Most significant member of our gut system is Helicobacter pylori which has been associated with numerous diseases like gastric cancer, gastritis, duodenal ulcer.

Gastric juice microbiota in pediatric chronic gastritis that clinically tested positive and negative for Helicobacter pylori

Purpose

Helicobacter pylori (HP) infection is an identified risk factor for pediatric chronic gastritis (PCG), but its impact on gastric juice microbiota (GJM) remains to be further elucidated in PCG. This study aimed to analyze and compare the microbial communities and microbial interactive networks of GJM in PCG that clinically tested positive and negative for HP (HP+ and HP-, respectively).

Methods

A total of 45 PCG patients aged from 6 to 16 years were recruited, including 20 HP+ and 25 HP- patients tested by culture and rapid urease test. Gastric juice samples were collected from these PCG patients and subjected to high-throughput amplicon sequencing and subsequent analysis of 16S rRNA genes.

Results

While no significant change in alpha diversity, significant differences in beta diversity were observed between HP+ and HP- PCG. At the genus level, Streptococcus, Helicobacter, and Granulicatella were significantly enriched in HP+ PCG, whereas Campylobacter and Absconditabacteriales (SR1) were significantly enriched in HP- PCG. Network analysis showed that Streptococcus was the only genus positively correlated with Helicobacter (r = 0.497) in the GJM network of overall PCG. Moreover, compared to HP- PCG, HP+ PCG showed a reduction in microbial network connectivity in GJM. Netshift analysis identified driver microbes including Streptococcus and other four genera, which substantially contributed to the GJM network transition from HP- PCG to HP+ PCG. Furthermore, Predicted GJM function analysis indicated up-regulated pathways related to the metabolism of nucleotides, carbohydrates, and L-Lysine, the urea cycle, as well as endotoxin peptidoglycan biosynthesis and maturation in HP+ PCG.

Conclusion

GJM in HP+ PCG exhibited dramatically altered beta diversity, taxonomic structure, and function, with reduced microbial network connectivity, which could be involved in the disease etiology.

Exhaled Hydrogen after Lactulose Hydrogen Breath Test in Patient with Duodenal Ulcer Disease-A Pilot Study for Helicobacter-pylori-Associated Gastroduodenal Disease

OBJECTIVES

The precipitating mechanism(s) from the inactive to the active stage of duodenal ulcer disease (DU) is unclear. It has been shown that hydrogen gas from colonic fermentation provides an important energy source for Helicobacter pylori (Hp) colonization. The lactulose hydrogen breath test (LHBT) is a useful tool to assess the small intestinal and/or colon fermentation. This study examines the association(s) between the status of gastroduodenal disease and the result of a lactulose hydrogen breath test (LHBT).

MATERIALS AND METHODS

We enrolled Hp-positive active duodenal ulcer (aDU) patients, inactive DU (iDU) patients and patients with a positive Hp infection without structural gastroduodenal lesion, i.e., simple gastritis (SG Hp+). The patients with simple gastritis without Hp infection (SG Hp-) served as controls. Histological examinations of the gastric mucosa and lactulose hydrogen breath test (LHBT) were performed.

RESULTS

SG Hp+ patients tend to have advanced gastritis (pangastritis or corpus-predominant gastritis) compared with SG Hp- patients (7/29 vs. 0/14, p = 0.08). More iDU patients had advanced gastritis than either the SG Hp+ (7/9 vs. 7/29, p = 0.006) or aDU patients (7/9 vs. 6/24, p = 0.013). In comparison with the aDU patients, the iDU patients were also older (52.1 ± 12.6 vs. 42.2 ± 11.9 years, p = 0.02) and had a lower mean area under the curve value of the LHBT(AUC) (209.1 ± 86.0 vs. 421.9 ± 70.9, p = 0.023).

CONCLUSION

aDU patients with a positive Hp infection have a lower grade of gastric mucosa damage than iDU patients and tend to have a higher level of exhaled hydrogen after LHBT.

Helicobacter Pylori Infection Induces Intestinal Dysbiosis That Could Be Related to the Onset of Atherosclerosis

Cardiovascular diseases represent one of the first causes of death around the world, and atherosclerosis is one of the first steps in the development of them. Although these problems occur mainly in elderly, the incidence in younger people is being reported, and an undetermined portion of patients without the classic risk factors develop subclinical atherosclerosis at earlier stages of life. Recently, both the H. pylori infection and the intestinal microbiota have been linked to atherosclerosis. The mechanisms behind those associations are poorly understood, but some of the proposed explanations are (a) the effect of the chronic systemic inflammation induced by H. pylori, (b) a direct action over the endothelial cells by the cytotoxin associated gene A protein, and (c) alterations of the lipid metabolism and endothelial dysfunction induced by H. pylori infection. Regarding the microbiota, several studies show that induction of atherosclerosis is related to high levels of Trimethylamine N-oxide. In this review, we present the information published about the effects of H. pylori over the intestinal microbiota and their relationship with atherosclerosis and propose a hypothesis to explain the nature of these associations. If H. pylori contributes to atherosclerosis, then interventions for eradication and restoration of the gut microbiota at early stages could represent a way to prevent disease progression.

The interactions between oral-gut axis microbiota and Helicobacter pylori

In the human body, each microbial habitat exhibits a different microbial population pattern, and these distinctive microflorae are highly related to the development of diseases. The microbial interactions from host different niches are becoming crucial regulators to shape the microbiota and their physiological or pathological functions. The oral cavity and gut are the most complex and interdependent microbial habitats. Helicobacter pylori is one of the most important pathogens from digestive tract, especially the stomach, due to its direct relationships with many gastric diseases including gastric cancer. H. pylori infections can destroy the normal gastric environment and make the stomach a livable channel to enhance the microbial interactions between oral cavity and gut, thus reshaping the oral and gut microbiomes. H. pylori can be also detected in the oral and gut, while the interaction between the oral-gut axis microbiota and H. pylori plays a major role in H. pylori’s colonization, infection, and pathogenicity. Both the infection and eradication of H. pylori and its interaction with oral-gut axis microbiota can alter the balance of the microecology of the oral-gut axis, which can affect the occurrence and progress of related diseases. The shift of oral-gut axis microbiota and their interactions with H. pylori maybe potential targets for H. pylori infectious diagnosis and treatment.

Gut microbiota in various childhood disorders: Implication and indications

Gut microbiota has a significant role in gut development, maturation, and immune system differentiation. It exerts considerable effects on the child's physical and mental development. The gut microbiota composition and structure depend on many host and microbial factors. The host factors include age, genetic pool, general health, dietary factors, medication use, the intestine's pH, peristalsis, and transit time, mucus secretions, mucous immunoglobulin, and tissue oxidation-reduction potentials. The microbial factors include nutrient availability, bacterial cooperation or antagonism, and bacterial adhesion. Each part of the gut has its microbiota due to its specific characteristics. The gut microbiota interacts with different body parts, affecting the pathogenesis of many local and systemic diseases. Dysbiosis is a common finding in many childhood disorders such as autism, failure to thrive, nutritional disorders, coeliac disease, Necrotizing Enterocolitis, helicobacter pylori infection, functional gastrointestinal disorders of childhood, inflammatory bowel diseases, and many other gastrointestinal disorders. Dysbiosis is also observed in allergic conditions like atopic dermatitis, allergic rhinitis, and asthma. Dysbiosis can also impact the development and the progression of immune disorders and cardiac disorders, including heart failure. Probiotic supplements could provide some help in managing these disorders. However, we are still in need of more studies. In this narrative review, we will shed some light on the role of microbiota in the development and management of common childhood disorders.

Peptic Ulcer and Gastric Cancer: Is It All in the Complex Host-Microbiome Interplay That Is Encoded in the Genomes of "Us" and "Them"?

It is increasingly being recognized that severe gastroduodenal diseases such as peptic ulcer and gastric cancer are not just the outcomes of Helicobacter pylori infection in the stomach. Rather, both diseases develop and progress due to the perfect storms created by a combination of multiple factors such as the expression of different H. pylori virulence proteins, consequent human immune responses, and dysbiosis in gastrointestinal microbiomes. In this mini review, we have discussed how the genomes of H. pylori and other gastrointestinal microbes as well as the genomes of different human populations encode complex and variable virulome–immunome interplay, which influences gastroduodenal health. The heterogeneities that are encrypted in the genomes of different human populations and in the genomes of their respective resident microbes partly explain the inconsistencies in clinical outcomes among the H. pylori-infected people.

Relationship Between Helicobacter pylori IgG Seroprevalence and the Immune Response to Poliovirus Vaccine Among School-Age Children From a Population With Near-Universal Immunity Level

Objectives

To examine the association between Helicobacter pylori seroprevalence and serum pepsinogens (PGs) as markers of gastric inflammation), with high neutralizing antibody titers to poliovirus type 1 and 3 vaccine strains among children age 3–4 years, subsequent to sub-clinical infection acquired during a wild-type poliovirus type 1 outbreak in Israel.

Methods

A serosurvey was conducted among 336 children aged 5–17 years who were vaccinated with both inactivated polio vaccine and oral polio vaccines. H. pylori serum IgG antibodies and PG concentrations were measured using ELISA. Neutralizing antibodies to poliovirus vaccine strains were measured and children with a titer ≥1:8 were considered immune. High-level immunity was defined as having a serum NA titer >1:2048. Propensity score inverse weighting was used to account for confounders.

Results

Neutralizing antibodies titers ≥1:8 to poliovirus type 1 and 3 vaccine strains were found in 99.4 and 98.2% of the children, respectively. An inverse association was found between H. pylori seropositivity accompanied by PGI:PGII ratio ≤6.5 (marker of gastric inflammation) and high-level immunity to poliovirus type 1: OR 0.39 (95% CI 0.68–0.91), p = 0.027. The association between H. pylori seropositivity of CagA virulent phenotype and polio high immunity was not significant. The association between H. pylori seropositivity and high neutralizing antibodies to type 3 poliovirus was of low magnitude and not significant.

Conclusions

H. pylori seroprevalence accompanied by evidence of gastric inflammation was inversely correlated with high titers of neutralizing antibodies to poliovirus in children from a population with near universal polio immunity.

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.

Interplay and cooperation of Helicobacter pylori and gut microbiota in gastric carcinogenesis

Chronic Helicobacter pylori infection is a critical risk factor for gastric cancer (GC). However, only 1–3 % of people with H. pylori develop GC. In gastric carcinogenesis, non-H. pylori bacteria in the stomach might interact with H. pylori. Bacterial dysbiosis in the stomach can strengthen gastric neoplasia development via generating tumor-promoting metabolites, DNA damaging, suppressing antitumor immunity, and activating oncogenic signaling pathways. Other bacterial species may generate short-chain fatty acids like butyrate that may inhibit carcinogenesis and inflammation in the human stomach. The present article aimed at providing a comprehensive overview of the effects of gut microbiota and H. pylori on the development of GC. Next, the potential mechanisms of intestinal microbiota were discussed in gastric carcinogenesis. We also disserted the complicated interactions between H. pylori, intestinal microbiota, and host in gastric carcinogenesis, thus helping us to design new strategies for preventing, diagnosing, and treating GC.

Helicobacter pylori infection-induced changes in the intestinal microbiota of 14-year-old or 15-year-old Japanese adolescents: a cross-sectional study

OBJECTIVE

The relationship between Helicobacter pylori and the intestinal microbiota has not yet been clearly demonstrated in children and adolescents. The present study aimed at evaluating how H. pylori infection could affect the intestinal microbiota in adolescents using genetic analysis.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

We included subjects from a longitudinal project involving H. pylori screening and treatment of junior high school third-grade students (aged 14 or 15 years) in Saga Prefecture. The study included a control group (n=79) and an H. pylori group (n=80) tested negative and positive for the anti-H. pylori antibody in the urine and H. pylori antigen in stool specimens, respectively.

INTERVENTIONS

The intestinal microbiota was evaluated in stool specimens using 16S rRNA gene/DNA/amplicon sequencing with next-generation sequencing.

PRIMARY AND SECONDARY OUTCOME MEASURES

We assessed alpha and beta diversity, just as well as relative abundances within the bacterial composition at the genus level in both groups.

RESULTS

As shown by the alpha diversity of the 16S rRNA gene/DNA/amplicon sequence data, the control group exhibited lower microbial species richness with lower alpha diversity compared with the H. pylori group (p<0.001). The beta diversity of the intestinal microbiota profile also differed between the two groups (p<0.01). The relative abundance of the Prevotella genus was higher in the H. pylori group (p<0.01) concomitant with a gain in body mass index (BMI) in the H. pylori group (p<0.01) compared with the control group.

CONCLUSION

H. pylori infection significantly affected the intestinal microbiota in Japanese adolescents. In addition, the prevalence of the Prevotella genus is concomitantly increased along with the BMI in H. pylori-infected students.

TRIAL REGISTRATION NUMBER

UMIN000028721.

The role of gastrointestinal pathogens in inflammatory bowel disease: a systematic review

The inflammatory bowel diseases (IBD), comprising Crohn's disease (CD) and ulcerative colitis (UC), are chronic, progressive, inflammatory conditions of the gastrointestinal tract. Imbalance in the gut microbial community, or dysbiosis, and the subsequent immune response, represent the critical relationship between genetic susceptibility, microbes, and environment factors, that result in IBD. Gastrointestinal pathogens - a common cause of dysbiosis - have been implicated as an environmental trigger in new onset IBD, as well as flare of existing IBD. In this article, we systematically review clinical data regarding the association between specific gastrointestinal pathogens and IBD. Numerous bacteria, viruses, fungi, and parasites have been implicated in the pathogenesis of IBD, and exacerbations of existing disease. In this article, we will also specifically discuss the less recognized microbes that have an inverse association with IBD, including certain bacterial pathogens, such as Helicobacter pylori, and parasites, such as Trichuris species. Future prospective and experimental studies are required to establish causality and clarify potential mechanisms of enteric pathogens in modifying the risk and course of IBD.

Gut microbiota changes related to Helicobacter pylori eradication with vonoprazan containing triple therapy among adolescents: a prospective multicenter study

Currently, it is unclear whether treating Helicobacter pylori (H. pylori) infection is safe among adolescents. This study aimed to evaluate the safety of H. pylori eradication therapy by examining gut microbiota changes in adolescents 3 months after the therapy. H. pylori-infected adolescents were enrolled in this study. Their stool samples were collected at the following three time points: before treatment, 1-2 days after completion of treatment, and time of eradication successful judgment. We assessed the relative abundance, alpha-diversity, and beta-diversity of the gut microbiota and adverse events. The number of isolated Actinobacteria decreased immediately after eradication therapy in the 16 students included in the study, and it returned to pretreatment condition at the eradication judgment point. There was no change in the relative abundance at genus level. The alpha-diversity was lost immediately after eradication therapy; however, it recovered at the time of eradication judgment, and it was restored to pretreatment condition. Meanwhile, none of the participants experienced serious adverse events. H. pylori eradication therapy is safe for adolescents with respect to gut microbiota changes associated with H. pylori eradication therapy. Therefore, further long-term evaluations of gut microbiota changes following eradication therapy are warranted.

Gut Microbiota: The Missing Link Between Helicobacter pylori Infection and Metabolic Disorders?

Helicobacter pylori (H. pylori) is a gram-negative bacterium that infects approximately 4.4 billion individuals worldwide. Although the majority of infected individuals remain asymptomatic, this bacterium colonizes the gastric mucosa causing the development of various clinical conditions as peptic ulcers, chronic gastritis and gastric adenocarcinomas and mucosa-associated lymphoid tissue lymphomas, but complications are not limited to gastric ones. Extradigestive pathologies, including metabolic disturbances such as diabetes, obesity and nonalcoholic fatty liver disease, have also been associated with H. pylori infection. However, the underlying mechanisms connecting H. pylori with extragastric metabolic diseases needs to be clarified. Notably, the latest studies on the topic have confirmed that H. pylori infection modulates gut microbiota in humans. Damage in the gut bacterial community (dysbiosis) has been widely related to metabolic dysregulation by affecting adiposity, host energy balance, carbohydrate metabolism, and hormonal modulation, among others. Taking into account that Type 2 diabetic patients are more prone to be H. pylori positive, gut microbiota emerges as putative key factor responsible for this interaction. In this regard, the therapy of choice for H. pylori eradication, based on proton pump inhibitor combined with two or more antibiotics, also alters gut microbiota composition, but consequences on metabolic health of the patients has been scarcely explored. Recent studies from our group showed that, despite decreasing gut bacterial diversity, conventional H. pylori eradication therapy is related to positive changes in glucose and lipid profiles. The mechanistic insights explaining these effects should also be addressed in future research. This review will deal with the role of gut microbiota as the linking factor between H. pylori infection and metabolic diseases, and discussed the impact that gut bacterial modulation by H. pylori eradication treatment can also have in host's metabolism. For this purpose, new evidence from the latest human studies published in more recent years will be analyzed.

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.

Relationship between Helicobacter pylori infection and gastrointestinal microecology

Helicobacter pylori (H. pylori) is a common human bacterial pathogenh that infects more than 50% of the global natural population. In the absence of proper treatment, H. pylori will persist. H. pylori infection leads to changes in gastrointestinal flora, which is associated with a variety of gastrointestinal and extra-gastrointestinal diseases. In recent years, intestinal microecology has become a research hotspot, and the relationship between H. pylori infection and intestinal microecology has gradually attracted researchers' attention. H. pylori eradication leads to short-term changes in intestinal flora, but its long-term effects are unclear. The use of probiotics may have a positive impact on H. pylori eradication.

Duodenal microbiome in patients with or without Helicobacter pylori infection

BACKGROUND

Intestinal microbiota are recognized as an organ with important physiological functions whose alterations have been associated with common diseases including inflammatory intestinal conditions, malnutrition, type-2 diabetes, and cardiovascular diseases. The composition and function of the microbiota in the distal part of the intestine has been mainly described, while there is limited information on the small intestine microbiota. The objective of the present study was to describe the duodenal microbiome in individuals with dyspepsia in the presence or absence of Helicobacter pylori gastric infection.

MATERIALS AND METHODS

Thirty-eight biopsies from the proximal duodenum of uninfected and 37 from H pylori-infected individuals were analyzed. Microbiota composition was assessed by PCR amplification and sequencing of 16S rRNA and ITS genes; sequences were analyzed with QIIME2.

RESULTS AND CONCLUSIONS

At the phyla level, Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria, and Fusobacteria were predominant in the mucosal associated duodenal microbiota (MAM); at the genera level, we observed the predominance of Ralstonia, Streptococcus, Pseudomonas, Haemophilus, Herbaspirillum, Neisseria, and Veillonella. Microbiota α-diversity was higher in H pylori-infected individuals than in non-infected ones. In terms of β-diversity metrics, there was a statistically significant difference between groups. Also, relative abundance of Haemophilus, Neisseria, Prevotella pallens, Prevotella 7, and Streptococcus was greater in H pylori-infected patients. In infected patients, several types of H pylori were present in duodenal MAM. Finally, the majority of duodenal samples had fungi sequences; the most common taxa observed were Recurvomyces followed by Ascomycota and Basidiomycota.

Colonization by Pseudomonas aeruginosa and Staphylococcus aureus of Antral Biopsy Specimens from Gastritis Patients Uninfected with Helicobacter Pylori

Purpose

Roles and incidence of some microorganisms that transiently or permanently colonize the human stomach are still unknown despite advances in gastroenterology. We aimed to examine the incidence of four microorganisms, Helicobacter pylori, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis, in the antral biopsy specimens of patients with gastroduodenal conditions.

Patients and Methods

Patients (67 females, 33 males; mean age = 49.5 years) were initially examined and diagnosed by a gastroenterologist at the Mehrad Hospital, Tehran, Iran. We enrolled those who underwent the upper gastrointestinal endoscopy because of gastroduodenal conditions. Two antral biopsy samples were taken by endoscopy; the first sample was used for the “rapid urease test” to confirm H. pylori. The second was used for DNA extraction and PCR analyses with specific, corresponding primer sets to establish the presence of the four microorganisms. Our study was approved by the Ethics Committee at the Tarbiat Modares University, Tehran.

Results

Based on pathology and endoscopy findings, we divided the patients into three groups: 62 presented with gastritis, 18 with duodenal ulcer, and 20 gastric ulcer. The number of patients with P. aeruginosa but without H. pylori significantly differed from the number of those co-infected with both microorganisms (P = 0.03). Additionally, a similar significance was found between the incidence of S. aureus in patients without H. pylori and those with both infections (P = 0.04). Our results indicated that a significant number of patients with gastritis were colonized with P. aeruginosa or S. aureus without being co-infected with H. pylori (P < 0.001). Interestingly, the incidence of colonization by P. aeruginosa of patients without H. pylori (45/49, 91.8%) was higher than that by S. aureus (28/49, 57%).

Conclusion

The number of patients without H. pylori but with P. aeruginosa or with S. aureus infection significantly differed from that with both infections, respectively. Our study thus shows that patients without H. pylori infection are prone to be colonized by P. aeruginosa or S. aureus, indicating that targeted antibiotic regimens are necessary for clinically treating them.

Association between infection and delayed growth in children: A meta-analysis

Helicobacter pylori (H. pylori) infection is associated with extra-gastrointestinal diseases in children. The present study aimed to investigate the potential association between H. pylori infection and growth in children. The PubMed, Exerpta Medica dataBASE, Cochrane Library and Chinese Biomedical Literature Database databases were comprehensively searched for relevant publications dated between January 1st 1994 and January 1st 2019. Delayed childhood growth was defined according to the age-appropriate criteria in the World Health Organization Child Growth Charts (2006 edition). The odds ratios (ORs) and 95% CIs were pooled using the fixed-effects model and subgroup and sensitivity analyses were performed using Review Manager (version 5.3; Cochrane) and STATA (version 12.0; StataCorp LP) software. A total of 15 observational studies comprising 4,199 subjects were included in the present study. A higher frequency of delayed growth was observed in H. pylori-positive children compared with that in H. pylori-negative children (OR, 1.51; 95% CI, 1.28-1.78), particularly for linear growth (OR, 1.63; 95% CI, 1.32-2.00). The aforementioned association was only observed when H. pylori infection was detected using ¹³C-urea breath tests (OR, 1.72; 95% CI, 1.22-2.40) or serum IgG antibodies targeted against H. pylori (OR, 1.81; 95% CI, 1.35-2.44). H. pylori infection was also associated with delayed childhood growth in studies with a H. pylori prevalence of ≤30% (OR, 1.71; 95% CI, 1.31-2.23) or >30% but not >50% (OR, 1.43; 95% CI, 1.10-1.86). The association between infection and growth was only statistically significant in the cross-sectional (OR, 1.43; 95% CI, 1.18-1.73) and case-control (OR, 1.81; 95% CI, 1.23-2.67) studies. No significant heterogeneity among studies was identified in the present analysis. According to Begg's and Egger's linear regression methods for funnel plots and quantification assessments, no publication bias was identified. The trim and fill method further suggested that H. pylori-positive children were prone to delayed linear growth. Therefore, the present study suggested that preventing and detecting H. pylori infection in children may be critical to ensure normal growth and development during childhood.

Alzheimer's disease and gastrointestinal microbiota; impact of Helicobacter pylori infection involvement

Background: Alzheimer disease (AD) is a leading cause of global burden with great impact on societies. Although research is working intensively on promising therapy, the problem remains up-to-date. Among the various proposed hypotheses regarding causality and therapy, emerging evidence supports the hypothesis that gastrointestinal microbiota through the so-called 'gut-brain axis' interacts with immune system and brain and shape the balance between homeostasis and disease; the involvement of gastrointestinal microbiota in the pathophysiology of AD is less defined, even though the role of 'gut-brain axis' has been well verified for other neurodegenerative conditions.Methods: We performed a systematic review of PubMed/MEDLINE database from 1^st January 1990 to 17^th October 2018, to investigate the accessible literature regarding possible association between AD and gastrointestinal microbiota. Inclusion criteria were available full text in English language, original clinical papers implicating AD patients and any sort of gastrointestinal microbiota.Results: Through our query, an initial number of 241 papers has been identified. After removing duplicates and through an additional manual search, twenty-four papers met our inclusion criteria. The great majority of eligible publications supported a possible connection between AD and gastrointestinal microbiota. The most common investigated microorganism was Helicobacter pylori.Conclusion: Our own systematic review, showed a possible association between AD and gastrointestinal microbiota mainly including Helicobacter pylori, and thus further research is required for substantiation of causality as well as for the establishment of promising novel therapies.

Assessing the progression of gastric cancer via profiling of histamine, histidine, and bile acids in gastric juice using LC-MS/MS

Bile acid (BA) imbalance may be directly associated with gastric cancer and indirectly influence stomach carcinogenesis via overexpression of histidine decarboxylase (HDC), which converts histidine (His) into histamine (HIST). Moreover, the progression of gastric cancer, could change the gut microbiome, including bacteria spp. that produce secondary BAs. Gastric juice has various metabolites that could indicate gastric cancer-related stomach conditions. Therefore, profiling of HIST, His, and BAs in gastric juice is crucial for understanding the etiological mechanisms of gastric cancer. We used a profiling method to simultaneously determine targeted metabolites in gastric juice using liquid chromatography-tandem mass spectrometry (LC-MS/MS). We successfully analyzed 70 human gastric juice samples from patients with chronic superficial gastritis (CSG, n = 20), intestinal metaplasia (IM, n = 12), and gastric cancer (n = 38). Furthermore, we investigated the relevance between BA metabolism and gastric cancer. There were statistical differences in the metabolism of cholic acid (CA) into deoxycholic acid (DCA) based on the progression of CSG into IM and gastric cancer. Hence, the progression of gastric cancer might be related to the alterations in gut microbiome composition. We provide insight into the etiological mechanisms of the progression of gastric cancer and biomarkers to diagnose and treat gastric cancer.

Atrophic gastritis and chronic diarrhea due to Helicobacter pylori infection in early infancy: A case report

RATIONALE

Helicobacter pylori infection causes atrophic gastritis in childhood, but atrophic gastritis due to H pylori infection is extremely rare in infancy. The relationship between H pylori infection and chronic diarrhea without protein leakage remains controversial.

PATIENT CONCERNS

An 8-month-old male infant presented to our hospital with severe watery diarrhea, erythema, and failure to thrive from approximately 1 month after birth. Blood, stool, esophagogastroduodenoscopy, total colonoscopy, and H pylori urease analysis results were positive, thereby suggesting atrophic gastritis.

DIAGNOSES

Atrophic gastritis and chronic diarrhea due to H pylori infection.

INTERVENTIONS

We performed H pylori eradication therapy using triple therapy with vonoprazan (6 mg/kg), amoxicillin (300 mg/d), and clarithromycin (120 mg/kg) for 7 days.

OUTCOMES

From approximately 1 week after the H pylori eradication therapy, the frequency of defecation had decreased, stool shape had improved, and body weight had gradually increased.

LESSONS

H pylori infection can cause atrophic gastritis and chronic diarrhea even in infancy. Early eradication therapy for H pylori infection may be useful for prevention of gastric cancer and improvement in growth disorders.

Review: Helicobacter pylori in pediatrics

Despite a decrease in the prevalence of Helicobacter pylori infection, it still poses a significant health burden worldwide. This review summarizes important pediatric studies on H pylori published from April 2018 to March 2019. Epidemiologic studies have reported different prevalences in different parts of the world and have mainly confirmed traditional risk factors. Several studies on pathophysiology attempted to identify risk markers in childhood for gastric cancer development later in life. One of the most interesting studies evaluated the relationship between eosinophilic esophagitis and H pylori infection; however, an inverse relationship was not confirmed. The high resistance of H pylori and, consequently, low eradication rates, is still a major concern and susceptibility testing before treatment has again been highlighted. Potassium-competitive acid blockers are promising new acid-suppressant drugs but their role in H pylori eradication schemes is still to be determined.

Exploring the impact of Helicobacter pylori on gut microbiome composition

Helicobacter pylori (H. pylori) is known to colonize gastric mucosa, induce inflammation, and alter gastric microbiota resulting in a spectrum of gastric diseases. Likewise, changes in gut microbiota have recently been linked with various metabolic and inflammatory diseases. While extensive number of studies were published examining the relationship between H. pylori and gastric microbiota, little is known about the impact of H. pylori on downstream gut microbiota. In this study, we performed 16 S rRNA and ITS2-based microbial profiling analysis of 60 stool samples from adult individuals. Remarkably, the gut microbiota of H. pylori infected individuals was shown to be increased of members belonging to Succinivibrio, Coriobacteriaceae, Enterococcaceae, and Rikenellaceae. Moreover, gut microbiota of H. pylori infected individuals was shown to have increased abundance of Candida glabrata and other unclassified Fungi. These results links possible role for H. pylori-associated changes in the gut microbiota in intestinal mucosal barrier disruption and early stage colorectal carcinoma deployment. Altogether, the identified differences in bacterial and fungal composition provides important information that may eventually lead to the development of novel biomarkers and more effective management strategies.

Helicobacter pylori and nutrition: a bidirectional communication

Helicobacter pylori (HP) is a gram-negative flagellated pathogen acid-resistant bacterium; it belongs to the order Campylobacterales that is wide spread all over the world, infecting more than 50% of the world population. HP infection is etiologically associated with non-atrophic and atrophic gastritis, peptic ulcer and with 3 to 6-fold increased relative risk for developing gastric adenocarcinoma and mucosa-associated lymphoid tissue (MA LT) lymphoma. For this reason HP is recognized by the World Health Organization as a Class I human carcinogen. In the last years a lot of studies clarified the role of this pathogen in nutrition and metabolism; particularly, it has been shown that it is able to induce malabsorption of several nutrients like iron, cobalamin, vitamin C and vitamin E, with strong consequences on nutritional status. Interesting, this bacterium is able to produce different biological effects on hormones like ghrelin and leptin controlling both appetite and growth, mostly depending on the time of acquisition of the infection and of its treatment. In this review, the authors focused their attention on nutritional effects of HP infection and particularly on the role that diet, food, plants and specific nutrients can play in its treatment, considering that HP eradication rates, with standard triple-therapy, have fallen to a low level in the last years.

Exploring the impact of Helicobacter pylori on gut microbiome composition

Helicobacter pylori (H. pylori) is known to colonize gastric mucosa, induce inflammation, and alter gastric microbiota resulting in a spectrum of gastric diseases. Likewise, changes in gut microbiota have recently been linked with various metabolic and inflammatory diseases. While extensive number of studies were published examining the relationship between H. pylori and gastric microbiota, little is known about the impact of H. pylori on downstream gut microbiota. In this study, we performed 16 S rRNA and ITS2-based microbial profiling analysis of 60 stool samples from adult individuals. Remarkably, the gut microbiota of H. pylori infected individuals was shown to be increased of members belonging to Succinivibrio, Coriobacteriaceae, Enterococcaceae, and Rikenellaceae. Moreover, gut microbiota of H. pylori infected individuals was shown to have increased abundance of Candida glabrata and other unclassified Fungi. These results links possible role for H. pylori-associated changes in the gut microbiota in intestinal mucosal barrier disruption and early stage colorectal carcinoma deployment. Altogether, the identified differences in bacterial and fungal composition provides important information that may eventually lead to the development of novel biomarkers and more effective management strategies.