Vancomycin exposure caused opportunistic pathogens bloom in intestinal microbiome by simulator of the human intestinal microbial ecosystem (SHIME).

Antibiotics are emerging organic pollutants posing high health risks to humans by causing human intestinal microbial disorders with increasing abundances of opportunistic pathogens, and fecal microbiota transplantation (FMT) has been confirmed to restore the dysbiosis of gut flora in many kinds of intestinal disease. However, to date, few studies have focused on the bloomed opportunistic pathogens associated human disease-related pathways as well as antibiotic resistance genes (ARGs) after vancomycin exposure, and there is limited information on using FMT for restoration of intestinal microbiome affected by antibiotics. Therefore, this study investigated effects of vancomycin on the opportunistic pathogens, human disease-related pathways as well as ARGs in human gut, and the restoration of intestinal microbiome by FMT. Results indicated that vancomycin treatment substantially increased human disease-related pathways and decreased abundances of ARGs. Besides, the bloomed opportunistic pathogens including Achromobacter, Klebsiella, and Pseudomonas, caused by vancomycin exposure, were positively correlated with human disease-related pathways. The microbiota abundance and genes of human disease-related pathways and antibiotic resistance showed a remarkable return towards baseline after FMT, but not for natural recovery. These findings suggest that impacts of vancomycin on human gut are profound and FMT will be a promising strategy in clinical application that can restore the dysbiosis of gut microbiota, which may be valuable for directing future work.