Effect of Antibiotic Class on Stroke Outcome.

BACKGROUND AND PURPOSE Infections are common after stroke and associated with worse outcome. Clinical trials evaluating the benefit of prophylactic antibiotics have produced mixed results. This study explores the possibility that antibiotics of different classes may differentially affect stroke outcome. METHODS Lewis rats were subjected to transient cerebral ischemia (2 hours) and survived for 1 month. The day after stroke they were randomized to therapy with ceftiofur (a β-lactam antibiotic), enrofloxacin (a fluoroquinolone antibiotic), or vehicle (as controls) and underwent the equivalent of 7 days of treatment. Behavioral tests were performed weekly until euthanization. In a subset of animals, histology was done. RESULTS There were no differences in outcomes at 24 hours or 1 week after stroke among the different groups. At 1 month after stroke, however, performance on the rotarod was worse in enrofloxacin-treated animals when compared with control animals. CONCLUSIONS Independent of infection, the antibiotic enrofloxacin was associated with worse stroke outcome. These data echo the clinical observations to date and suggest that the secondary effects of antibiotics on stroke outcome should be considered when treating infection in subjects with stroke. The mechanism by which this antibiotic affects outcome needs to be elucidated.