COMPARATIVE ACTIVITY OF THE NEW FLUOROQUINOLONE RUFLOXACIN (MF-934) AGAINST CLINICAL ISOLATES OF GRAM-NEGATIVE AND GRAM-POSITIVE BACTERIA

The antibacterial activity of the new fluoroquinolone rufloxacin (MF 9 34) was evaluated against 1095 clinical isolates and compared with tha t of other quinolones and various commonly used antibiotics. Rufloxaci n was highly effective against members of the Enterobacteriaceae, inhi biting 98 % of the isolates at a concentration of 1 mg/l. Ninety-two p ercent of Aeromonas hydrophila and 65 % Acinetobacter strains tested w ere inhibited by 1 mg/l of rufloxacin, whereas 98 % of methicillin-sus ceptible and 87 % of methicillin-resistant Staphylococcus aureus strai ns and 76 % of coagulase-negative staphylococci strains required 4 mg/ l for growth inhibition. The MIC values of rufloxacin for most bacteri a were 4-16 times higher than those of ciprofloxacin and norfloxacin. Rufloxacin had little activity against xanthomonads, pseudomonads and enterococci. Approximately 95-96 % of isolates of Pseudomonas aerugino sa were inhibited by 2 mg/l of ciprofloxacin and norfloxacin as compar ed to 29 % inhibited by rufloxacin at this concentration.