Dysbiosis in the gastric microenvironment of patients with follicular gastropathy initially associated to Helicobacter pylori infection.. Dysbiosis in the gastric microenvironment of patients with follicular gastropathy initially associated to Helicobacter pylori infection.

Dysbiotic events play an important role in the establishment of bacterial infections in the gastric mucosa, especially the ones induced by Helicobacter pylori. International guidelines for treatment of H. pylori suggest a standard triple therapy (STT) In review which includes clarithromycin. Nevertheless, due to the increasing resistance rates to clarithromycin, metronidazole has been widely considered in several countries. Non-justified administration of antibiotics induces dysbiosis in the target organ. We characterized the gastric microbiota of patients diagnosed with follicular gastropathy and evaluated the effect of the STT administered for eradication of H. pylori infection in their microbial community composition and structure. Thirty-six gastric corpus biopsies were obtained from six patients diagnosed with follicular gastropathy initially attributed to H. pylori infection. The samples were processed for histopathological evaluation, microbiological and molecular diagnosis, and metagenomic analysis. H. pylori infection was confirmed in only three pre-treatment patients by microbiological and molecular determinations. However, histopathological evaluation revealed several degrees of histological injure in both pre-treatment and posttreatment patients. The metagenomic analysis revealed several dysbiotic events in pre-treatment patients, such as significant relative abundances of genera Tsukamurella, Cutibacterium, and Methylobacterium. Significant posttreatment alterations in relative abundances of pathobiont bacteria of clinical interest associated the lifestyle of the host and pathogenic processes were observed as well, e.g., diminishment of C. acnes relative abundances, significant increase of genera Staphylococcus, Pseudomonas, and Klebsiella relative abundances, suggesting the multifactoriety of the disease. Other gastrointestinal bacteria can be associated to the initiation and development of gastric diseases, such as pathobiont Cutibacterium acnes.