Antibacterial activity of trovafloxacin against nosocomial Gram-positive and Gram-negative isolates.

A total of 1132 clinical isolates from 952 patients with nosocomial infections were tested against the fluoroquinolone trovafloxacin by the agar dilution method. They comprised 285 staphylococci, 111 streptococci, 94 enterococci and 470 isolates of Enterobacteriaceae, 92 Pseudomonas aeruginosa, 27 Stenotrophomonas maltophilia, 28 Haemophilus influenzae and 25 Acinetobacter calcoaceticus. The in-vitro activity of trovafloxacin was compared with that of ciprofloxacin, norfloxacin, beta-lactam and aminoglycoside agents. Over 96% of Enterobacteriaceae were susceptible to trovafloxacin with an MIC of <0.03-4 mg/L. It also inhibited 97% and 100% clinical isolates of P. aeruginosa and S. maltophilia, respectively. All staphylococci, including 51 strains of methicillin-resistant Staphylococcus aureus, were susceptible to trovafloxacin, which also had excellent activity against streptococci and enterococci, inhibiting all 111 strains of the former and 94% of the latter. Trovafloxacin had a greater activity against both Gram-positive and Gram-negative bacteria than ciprofloxacin, norfloxacin, penicillins, cephalosporins and the aminoglycosides tested.