Effects of treatment with three antibiotics, vancomycin, neomycin, and AVNM on gut microbiome in C57BL/6 mice

Higher organisms, especially mammals, harbor diverse microbiota in the gut that plays a major role in maintaining health and physiological homeostasis. Perturbation of gut flora helps identifying their roles. Antibiotics are potent perturbing agents of microbiome. Select antibiotics like vancomycin, neomycin, and AVNM (an antibiotic cocktail containing ampicillin, vancomycin, neomycin, and metronidazole) were used to perturb the gut microbiota of C57BL/6 male mice to understand their roles in host immunity and metabolism. The current study revealed that the resulting gut microbial composition was different, and diversity (at the phylum and genus level) was reduced differentially following each antibiotic treatment. Vancomycin treatment caused a significant increase in Verrucomicrobia and Proteobacteria phyla. The treatment with neomycin yielded an increase in the Bacteroidetes phylum, while the treatment with AVNM led to an increase in Proteobacteria phylum with lowest diversity of microbiome in the gut. The current results also revealed that the different antibiotics treatment caused variation in the cecal index, expression of immune genes (TNF-, IL-10, IFN-{gamma}) in the colon, and short-chain fatty acids (SCFA) level in the blood of mice. A strong correlation was observed for antibiotic-induced differential dysbiosis patterns of gut microbiota and the altered immune and SCFA profile of the host. The outcome of the present study could be clinically important.