Antibiotics Induce Dysbiosis in Oral and Gut Microbiota of Mice

Objectives: The antibiotic have a great contributed in treatment for infectious diseases. At the same time, it will cause great disturbance to host microbiota. The differences existing in different antibiotics-induced changes in host-microbiota are relatively short of study. The aim of this research was to investigate the changes in oral and gut microbiota which induced by different antibiotics administration. The possible alteration of gut resistance to pathogens after antibiotics treatment was also detected.
Methods: The mice experiment was conducted by administrating two kinds of antibiotics (vancomycin and ampicillin) to mice respectively. The saliva and stool samples of mice were collected and subjected to 16S rRNA gene sequencing in order to detail oral and gut microbiota alterations after treatments. Then, mice were infected by pathogens after antibiotics treatment, the post-infection bacteria burden in mice gut was counted by the colony forming units (CFU) assay.
Results: Gut and oral microbiota show the different response to the different antibiotic. Gut microbiota underwent dramatic change after both vancomycin and ampicillin treatment, the alpha diversity sharply decreased and the beta diversity presented significant difference. However, there was a recovery in gut microbiota within 4 weeks while stopping antibiotics usage, although the recovery was incomplete. The oral microbiota didn`t show the same significant alteration as that of the gut for there is no obvious change in both alpha diversity and beta diversity. The bacteria burden of gut in the control group of mice was significantly lower than antibiotic-treated mice, but this difference was only lasted for the first 4 days after infection.
Conclusions: The obvious variation existed in the response that gut and oral microbiota showed due to antibiotics administration. The descending of colonization resistance in gut would take place at the early stage after dose of antibiotics and would reverse in the later stage.