Impact of Helicobacter pylori eradication on the gastric microbiome

Background Helicobacter pylori (Hp) eradication has been used for many years. Yet, the impact of this eradication on the normal gastric microflora is not well understood. In this study, we explored the effect of eradication on the stomach microbial community and its recovery after successful Hp eradication. Methods Among the 89 included patients, 23, 17, 40, and 9 were included in the Hp-negative, Hp-positive, successful eradication, and failed eradication groups, respectively. Four subgroups were further determined according to disease status (Hp-negative chronic gastritis [N-CG], Hp-negative atrophic gastritis [N-AG], successful-eradication chronic gastritis [SE-CG], and atrophic gastritis with successful eradication [SE-AG]). During the endoscopic examination, one piece of gastric mucosa tissue was obtained from the lesser curvature side of the gastric antrum and gastric corpus, respectively. In addition, 16S rDNA gene sequencing was used to analyze the gastric mucosal microbiome. Results In the Hp-negative group, the gastric microbiota was dominated by five phyla: Firmicutes, Proteobacteria, Actinobacteria, Bacteroidetes, and Fusobacteria. After successfully eradicating Hp, the bacterial flora in the stomach recovered to a considerable extent. In the failed eradication group, the flora was similar to the flora in Hp-positive subjects based on the alpha and beta diversities. Among the groups, Curvibacter and Acinetobacter were enriched in the presence of Hp (i.e., failed eradication and Hp-positive groups), suggesting that these two genera could be used as biomarkers in the symbiotic flora in the presence of Hp. SE-CG was characterized by an increase in Firmicutes taxa and a decrease in Proteobacteria taxa compared with N-CG. SE-AG was characterized by a decrease in Firmicutes relative to N-AG. Finally, no differences were found in the pairwise comparisons of nitrate and nitrite reductase functions of the microflora among the four subgroups. Conclusions After Hp infection, the diversity and relative abundance of gastric microflora were significantly decreased. Yet, gastric microbiota could be partially restored to the Hp-negative status after eradication. Still, this effect was incomplete and might contribute to the long-term risks.

Impact of Helicobacter Pylori Eradication Therapy on Gastric Microbiome

Background: Helicobacter pylori (Hp) eradication therapy has been used in clinical practice for many years. Yet, the effect of this therapy on existing gastric microflora has not been well understood. In this study, we explored the effect of eradication therapy on the microbial community in the stomach and the specific recovery after the successful eradication therapy. Methods: Among the 89 included patients, 23, 17, 40, and 9 were enrolled into the Hp-negative, Hp-positive, Successful eradication, and Failed eradication groups, respectively. Four subgroups were further divided according to disease status (Hp-negative chronic gastritis [N-CG], Hp-negative atrophic gastritis [N-AG], successful-eradication chronic gastritis [SE-CG], and atrophic gastritis with successful eradication [SE-AG]). During the endoscopic examination, one piece of gastric mucosa tissue was obtained from the lesser curvature side of the gastric antrum and gastric corpus, respectively. 16S rRNA gene sequencing was used to analyze the gastric mucosal microbiome. Results: In Hp negative group, the gastric microbiota was dominated by five phyla: Firmicutes , Proteobacteria , Actinobacteria , Bacteroidetes, and Fusobacteria . Two Hp-related genera were selected as potential biomarkers: Curvibacter and Acinetobacter . After successfully eradicating Hp, the bacterial flora in the stomach recovered to a considerable extent, and the failure of eradication was almost unchanged compared with Hp positive subjects. SE-CG was characterized by an increase in Firmicutes taxa and a decrease in Proteobacteria taxa compared with N-CG. SE-AG was characterized by a decrease in Firmicutes relative to N-AG. Finally, no differences were found in pairwise comparisons of nitrate and nitrite reductase functions among the four subgroups. Conclusions: After Hp infection, the diversity and relative abundance of gastric microflora were significantly decreased. Yet, gastric microbiota could be partially restored to the Hp-negative status after eradication; however, this effect was incomplete and might contribute to the long-term risks.

Problematic issues of chronic gastritis studies

The article defines chronic gastritis as a polyetiological and polypathogenetic stomach disease with a chronic, slowly progressing course, which is based on a specific inflammatory process with lymphoplasmocytic infiltration of its mucosa and neutrophilic component indicating its activity, and with development of disregenerative, dystrophic changes, leading to its secretory insufficiency, manifested hypo- and achlorhydria and gastric achilia. The history of studying chronic gastritis from the beginning of the 19th century till present days is briefly described. It is proposed to distinguish between causal (Helicobacter pylori, etc.) and predisposing (alcohol, smoking, coarse food, etc.) factors in the development of chronic gastritis. The analysis of various classifications of gastritis is carried out: based on etiology, pathogenesis, functional features, clinic, endoscopic and histological characteristics. The Sydney, Houston classifications, the OLGA system are described. Particular attention is paid to diagnosis, biopsy technique of the gastric mucosa, ratio of diagnoses of chronic gastritis and functional dyspepsia, as well as the role of gastric microflora in development of gastritis. It is revealed that gastric microflora in chronic gastritis is represented by numerous types of bacteria (more often in the form of bacterial associations), moreover, Helicobacter pylori is not the dominant microorganism colonizing the stomach, and the mucosal microflora found in the stomach has adhesiveness, invasiveness and pathogenic properties, including its urease activity.

Kyoto consensus - the new etiological classification of chronic gastritis and its discussion

The main provisions and headings of the new etiological classification of chronic gastritis are discussed in the context of recent data on the true role of Helicobacter pylori infection in the development of this pathology. The methods and results of the authors ’ investigations into gastric microflora are presented along with information about the frequency of detection of its different forms, concentration of microbial forms in gastric mucosa, their pathogenic properties including urease activity, and possible contribution to chronic gastritis etiology. The possibility of alcoholic and chemical chronic gastritis is discussed along with the role of these conditions in the development of stomach cancer. Special emphasis is laid on the disagreement between the adopted consensuses and principles of evidence-based medicine.

Experimental model in the qualitative and quantitative assessment of non-Helicobacter gastric microflora under proton pump inhibitors action

PURPOSE: To evaluate models of gastric material collection from Wistar rats with and without using proton pump inhibitors(PPIs). METHODS: Twenty-four rats underwent intraperitoneal omeprazol treatment, and other 12 received similar treatment with 0.9% saline. All animals underwent collection of gastric material samples, after stomach removal, by either biopsies, or aspirates, or swabs. Samples were bacteriologically processed in order to identify species and strains. Values are described as natural logarithm of colony former units per mL [Ln(CFU/mL)]. Kruskal-Wallis and Mann-Whitney non-parametric tests were used, and p<0.05 was set as statistically significant. RESULTS: Significant difference was not seen for Ln (UFC/mL) values among the three methods of collection irrespective of using or not omeprazol. Also, significant difference was not seen in Ln (UFC/mL) values when comparing a method with each others, either using omeprazol or placebo. A significant increase of bacteria strains occurred when PPI was used, and this was seen on the three ways of collection, mainly in biopsy and swab. CONCLUSION: No difference occurred among the three methods of collecting bacteria samples from stomachs of rats, either when using placebo or omeprazol. A remarkable change is seen on animals bacterial microflora when PPIs are used, and bacteria are better identified when swab and biopsy are used.

Gut origin of sepsis: a prospective study investigating associations between bacterial translocation, gastric microflora, and septic morbidity

AIMSTo investigate the “gut origin of sepsis” hypothesis.METHODSProspective controlled study of 279 surgical patients in which cultures of nasogastric aspirates were compared with those obtained from mesenteric lymph nodes taken at laparotomy and the organisms cultured from subsequent septic complications. Bacterial translocation was confirmed if positive cultures were obtained from mesenteric lymph nodes. Postoperative sepsis was defined as any positive culture in the postoperative period. Bacterial species obtained in gastric microflora, mesenteric lymph nodes, and postoperative septic complications were compared.RESULTSOnly 85/279 patients (31%) had a sterile nasogastric aspirate; the most frequently identified organism was Candida spp. (54%) and the most common enteric organism cultured was E coli (20%). Multiple organisms were isolated in 39% and occurred more frequently in patients aged over 70 years, those undergoing non-elective surgery, and in those requiring proximal gastrointestinal surgery. Postoperative sepsis was more common in these patients. Bacterial translocation occurred in 21% and was significantly more frequent in those with multiple organisms in their nasogastric aspirates. E coli was the commonest organism isolated from the lymph node specimens (48%) and septic foci (53%). Fungal translocation did not occur. An identical genus was identified in the nasogastric aspirate and the septic focus in 30% of patients, in the nasogastric aspirate and the lymph node in 31%, and in the lymph node and a postoperative septic focus in 45%.CONCLUSIONSProximal gut colonisation is associated with both increased bacterial translocation and septic morbidity. The commonality of organisms identified supports the gut origin of sepsis hypothesis.