Preventive antibacterial treatment improves the general medical and neurological outcome in a mouse model of stroke

Background and Purpose - Epidemiological studies have demonstrated a high incidence of infections after severe stroke and their prominent role in morbidity and mortality in stroke patients. In a mouse model, it has been shown recently that stroke is coupled with severe and long-lasting immunosuppression, which is responsible for the development of spontaneous systemic infections. Here, we investigated in the same model the effects of preventive antibiotic treatment on survival and functional outcome of experimental stroke. Methods - Mice were subjected to experimental stroke by occlusion of the middle cerebral artery (MCAO) for 60 minutes. A group of mice received moxifloxacin ( 6 x 100 mg/kg body weight every 2 hours over 12 hours) either immediately or 12 hours after MCAO. Control animals received the vector only. Behavior, neurological deficit, fever, survival, and body weight were monitored over 14 days. In a subgroup, infarct volume was measured 4 days after MCAO. Microbiological assessment was based on cultures of lung tissue, blood, and feces of animals 3 days after stroke. For a dose-response study, moxifloxacin was given immediately after MCAO in different doses and at different time points. Results - Microbiological analyses of blood and lung tissue demonstrated high bacterial burden, mainly Escherichia coli, 3 days after stroke. Accordingly, we observed clinical and histological signs of septicemia and pneumonia. Moxifloxacin prevented the development of infections and fever, significantly reduced mortality, and improved neurological outcome. Conclusions - Preventive antibiotic treatment may be an important new therapeutical approach to improve outcome in patients with severe stroke.