The penetration of fleroxacin into intra-abdominal abscesses.

Using a recently developed, low mortality model of an intra-abdominal abscess in the Wistar rat, we have studied the penetration of fleroxacin into the abscess. Maximum serum concentration was 1.83 +/- 0.39 mg l and occurred 1 h after iv injection (20 mg/kg), but even at 4 h after administration the mean serum level was 1.21 +/- 0.27 mg/l. By contrast, levels in pus were 6.27 +/- 0.83 mg/l at 1 h rising steadily to a value of 12.7 +/- 3.69 mg/l at 4 h. The study has confirmed exceptional antibiotic penetration into the abscess, with levels at all time intervals between 0.5 and 8 h after administration in excess of the MIC50 for Escherichia coli, Proteus vulgaris and Clostridium perfringens.