The postantibiotic suppressive effect of L-ofloxacin, an optically active isomer of ofloxacin.

The postantibiotic suppressive effect (PAE) of L-ofloxacin was studied and compared with those of ciprofloxacin and norfloxacin. The PAE of L-ofloxacin was observed against all Gram-positive organisms tested: Staphylococcus aureus, S. epidermidis, and Enterococcus faecalis. At the achievable serum concentrations L-ofloxacin showed a longer PAE than ciprofloxacin and norfloxacin. Exposure of organisms to 4 micrograms/ml of L-ofloxacin for 2 hr produced a 3.1 and 4.2 hr PAE for methicillin-sensitive and methicillin-resistant staphylococci, respectively. Against E. faecalis and S. epidermidis, the PAEs of L-ofloxacin were 1.9 and 1.6 hr, respectively.