bioRxiv2018
The human gut microbiome plays an important role both in health and disease. The use of antibiotics can alter gut microbiota composition, which can cause complications of various kinds. Here we report a whole genome sequencing metagenomic study of the intestinal microbiota changes caused by Helicobacter pylori eradication therapy. We have found the decrease in taxonomic alpha-diversity due to the therapy. The changes observed were more extensive for patients with duodenal ulcer and female ones. As well across the patients under the therapy we have detected the shifts in the metabolic potential and resistome. Seven KEGG pathways associated with quorum sensing, genetic Information processing and environmental Information processing were increased, while metabolic pathways related with metabolism of cofactors and vitamins and glycan biosynthesis and metabolism decreased. Changes in the resistome profile have also been identified. We observed perturbations in intraspecies structures, which were higher in group of patients under the therapy than in control group of people without treatment. The Eubacterium rectale pangenome extracted from metagenomic data were changed. We also isolated and sequenced Enterococcus faecium strains from two patients before and after eradication therapy. After the therapy this bacterium increased as the antibiotic resistance in vitro, as well the number of ARGs to macrolides and tetracyclines and metagenomic relative abundance in comparison with strains before therapy. In summary, microbial community demonstrated shift to reduce metabolic potential and to increased mechanisms, which mediate more survival condition through intraspecies perturbations.\n\nImportanceThe human gut microbiome plays an important role both in health and disease. The use of antibiotics can alter gut microbiota composition, which can cause complications of various kinds. H. pylori eradication therapy causes multiple shifts and alterations (including intraspecies changes) of the intestinal microbiota structure and leads to the accumulation of genes which determine resistance to macrolides. Since these changes are not the same for patients with various diseases, patients with duodenal ulcer may be further paid special attention for reducing side effects, such as antibiotic-induced dysbiosis. Also, study of antibiotic treatment in terms of its impact upon the human gut microbiota allows shedding light on of the complex processes that cause accumulation and spread of antibiotic resistance. An identification and understanding of these complicated processes may help to constrain antibiotic resistance spread, which is of great importance for human health care.