Abstract
To probe into the mechanism of antibiotic-associated diarrhea (AAD), the bacterial diversity and composition in the intestinal mucosa of AAD mice were investigated. Twelve specific pathogen-free Kunming mice were divided into control group and model group. The mouse model of AAD was established by gavaging with antibiotics (mixture of gentamycin sulfate and cefradine) at a total dose of 23.33 ml kg(-1) day(-1) for 5 days continuously, twice a day. The mice in the control group were given with an equal amount of sterile water. Then, the intestinal mucosa DNA was extracted for 16S rRNA gene sequence analysis by high-throughput sequencing. The results showed that the alpha diversity of the two groups did not differ significantly from each other, while the composition of intestinal mucosa bacteria differed dramatically between the two groups. The model group showed a higher abundance of Proteobacteria and Actinobacteria. More importantly, Lactobacillus was significantly less abundant (p = 0.000), while Enterococcus was significantly more abundant (p = 0.019) in the model group than in the control group. Furthermore, antibiotic treatment increased the abundance of Citrobacter, Stenotrophomonas, and Glutamicibacter,whereas antibiotics decreased the abundance of Mycoplasma and Helicobacter. In addition, 6 and 11 unique genera were found in the control group and model group, respectively. The combination of gentamycin sulfate and cefradine changed the intestinal mucosa bacterial composition, reduced colonization resistance and damaged the intestinal mucosal barrier by reducing the abundance of Lactobacillus.