Activity of clinafloxacin, trovafloxacin, quinupristin/dalfopristin, and other antimicrobial agents versus Staphylococcus aureus isolates with reduced susceptibility to vancomycin

Isolations of Staphylococcus aureus strains with reduced susceptibility to vancomycin are now being reported worldwide. In testing here by broth micro dilution according to NCCLS guidelines and applying vancomycin breakpoint c riteria (susceptible at 4 mu g/mL), two of three strains were susceptible ( MICs at 4 mu g/mL) rather than intermediate (MICs at 8 mu g/mL) as previous ly reported by other laboratories. Clinafloxacin was more active (MICs/MBCs at 0.5 to 2 mu g/mL) than ciprofloxacin, grepafloxacin, levofloxacin, oflo xacin, and sparfloxacin. Trovafloxacin, trimethoprim/sulfamethoxazole, and quinupristin/dalfopristin were the next most active agents, although quinup ristin/dalfopristin was bactericidal against only two of these three strain s. Amikacin, imipenem, oxacillin, and rifampin were less active. (C) 1999 E lsevier Science Inc.