Antibiotic intervention diversity of bacteria in the lower respiratory tract under ozone exposure

To further explore the LRT microbial response mechanisms, mice received intranasal administrationof an antibiotic cocktail , containing ampicillin (1 mg mL-1), vancomycin (0.5 mgmL-1), metronidazole (1 mg/mL), and neomycin (1 mg/mL), every 48 hours prior to O3 exposure to deplete LRT symbiotic microbiota. After antibiotic treatment, mice immediately were exposed to O3 (0.5 ppm, 2h). To distinguish the effects of antibiotic intervention from those of O3 exposure on LRT microbiota, this phase was extended to 14 days. Following the final O3 exposure in this 14 day regimen, we included a 6 hour invasive window to assess the dynamic response of the LRT microbiota to sustained community imbalance induced across treatment groups.