Ciprofloxacin- and methicillin-resist ant Staphylococcus aureus susceptible to moxifloxacin, levofloxacin, teicoplanin, vancomycin and linezolid

In order to determine the comparative efficacy of vancomycin, teicoplanin, levofloxacin, moxifloxacin, and linezolid against methicillin- and ciproflo xacin-resistant Staphylococcus aureus, each agent was tested against 65 gen etically different strains using the microbroth dilution method. All of the isolates were typed using the enterobacterial repetitive intergenic consen sus polymerase chain reaction to exclude multiple isolates of epidemic clon es. Susceptibility testing revealed that all of the isolates were susceptib le to vancomycin and teicoplanin. Linezolid exhibited minimum inhibitory co ncentration (MIQ levels ranging from 1 to 4 mg/l (MIC90, 4 mg/l). The MICs of moxifloxacin and levofloxacin ranged from 0.01 to 8 mg/l (MIC90, 8 mg/l) and 0.25 to 32 mg/l (MIC90, 16 mg/l), respectively. Thus, linezolid is act ive against methicillin- and ciprofloxacin-resistant Staphylococcus aureus, whereas moxifloxacin may need to be administered at a dose higher than rec ommended in order to successfully treat serious infections.