Sensitivity of Staphylococcus aureus, isolated from skin infections in 1994, to 19 antimicrobial agents

The most common pathogen causing skin infections is Staphylococcus aureus and the incidence of multiply resistant strains of S. aureus has been increasing. The in vitro susceptibility of 130 isolates of S. aureus to 19 antimicrobial agents : ampicillin (ABPC), methicillin, cefaclor, cefpodoxime proxetil, gentamicin, erythromycin, clindamycin, minocycline, vancomycin, fusidic acid, norfloxacin, ofloxacin, enoxacin, ciprofloxacin, lomefloxacin, tosufloxacin, sparfloxacin, nadifloxacin and grepafloxacin, was evaluated by agar dilution tests. The S. aureus isolates were isolated from 130 patients with skin infections in 1994. The proportion of methicillin-resistant S. aureus isolates among the strains isolated was 19.2%. The concentration needed to inhibit 50% of the isolates was 3.13 mg/ml or less for all of the drugs, but the concentration needed to inhibit 90% of isolates was over 12.5 μg/ml, except in the cases of minocycline, vancomycin, fusidic acid, tosufloxacin and nadifloxacin. Tosufloxacin and nadifloxacin had the lowest minimum inhibitory concentrations. None of the S. aureus strains was resistant to nadifloxacin.