Protection of hamsters from mortality by reducing fecal moxifloxacin concentration with DAV131A in a model of moxifloxacin-induced Clostridium difficile colitis

Lowering the gut exposure to antibiotics during treatments can prevent microbiota disruption. We evaluated the effects of an activated charcoal-based adsorbent, DAV131A, on the fecal free moxifloxacin concentration and mortality in a hamster model of moxifloxacin-induced Clostridium difficile infection. A total of 215 hamsters receiving moxifloxacin subcutaneously (day 1 [D₁] to D₅) were orally infected at D₃ with C. difficile spores. They received various doses (0 to 1,800 mg/kg of body weight/day) and schedules (twice a day [BID] or three times a day [TID]) of DAV131A (D₁ to D₈). Moxifloxacin concentrations and C. difficile counts were determined at D₃, and mortality was determined at D₁₂. We compared mortality rates, moxifloxacin concentrations, and C. difficile counts according to DAV131A regimen and modeled the links between DAV131A regimen, moxifloxacin concentration, and mortality. All hamsters that received no DAV131A died, but none of those that received 1,800 mg/kg/day died. Significant dose-dependent relationships between DAV131A dose and (i) mortality, (ii) moxifloxacin concentration, and (iii) C. difficile count were evidenced. Mathematical modeling suggested that (i) lowering the moxifloxacin concentration at D₃, which was 58 μg/g (95% confidence interval [CI] = 50 to 66 μg/g) without DAV131A, to 17 μg/g (14 to 21 μg/g) would reduce mortality by 90%; and (ii) this would be achieved with a daily DAV131A dose of 703 mg/kg (596 to 809 mg/kg). In this model of C. difficile infection, DAV131A reduced mortality in a dose-dependent manner by decreasing the fecal free moxifloxacin concentration.