Susceptibility of Staphylococcus species and subspecies to teicoplanin. Antimicrob. Agents Chemother

Twenty-four Staphylococcus species or subspecies were examined for their susceptibilities to the fluoroqui-nolone fleroxacin (Ro 23-6240) by disk diffusion (5-jig disk) and by agar dilution for the determination of MICs. Resistant strains were further tested for their susceptibilities to oxacillin and the fluoroquinolone ciprofloxacin. Reference strains of the novobiocin-resistant species (Staphylococcus saprophyticus, Staphylococcus cohnii, Staphylococcus xylosus, Staphylococcus arlettae, and Staphylococcus gallinarum) had an intrinsic intermediate susceptibility (MIC, 4,ug/ml) to fleroxacin. Fleroxacin resistance was not observed in the reference strains of the novobiocin-susceptible species (MIC, 0.5 to 2.0,uglml). Clinical isolates of coagulase-negative species were generally less susceptible to fleroxacin than were reference strains. Seven percent of the Staphylococcus epidermidis clinical strains were resistant (MIC,-8 jig/ml) to fleroxacin. Of these strains, 77 % were resistant to oxacillin and 50 % were resistant to ciprofloxacin. Thirty-four percent of the Staphylococcus haemolyticus clinical strains were resistant to fleroxacin, and 9 % had intermediate susceptibility. Of the resistant strains, 95 % were resistant to oxacillin and 77 % were resistant to ciprofloxacin, while 23 % had intermediate susceptibility to ciprofloxacin. Fleroxacin is an effective antimicrobial agent against most staphylococci. Fleroxacin (Ro 23-6240) is a new orally and intravenously administered trifluoroquinolone with a half-life of 9 to 10 h i