In vitro Activity of Fleroxacin (Ro23-6240), a New Fluorinated 4-Quinolone against Isolates from Cancer Patients

Abstract

The in vitro activity of Fleroxacin (Ro23-6240; AM 833), a new fluorinated 4-quinolone, was compared to that of ciprofloxacin, enoxacin and A-56620, against 747 isolates from cancer patients. Fleroxacin inhibited more than 90% of Enterobacteriacea isolates at a concentration of ≤ 0.25 μg/ml. It was also extremely active against Aeromonas hydrophila and Haemophilus influenzae isolates with MIC₉₀ values of 0.12 and 0.06 μg/ml, respectively. The MIC₉₀ for Acinetobacter spp. was 1.0 μg/ml, for Pseudo-monas aeruginosa and Pseudomonas fluorescens 4.0 μg/ml, and for other Pseudomonas spp., 8.0 μg/ml. Staphylococcus aureus isolates including methicillin-resistant strains were inhibited by ≤ 1.0 μg/ml. The MIC₉₀ for three different species of coagulase-nega-tive Staphylococci was 1.0 μg/ml. Streptococcal species required 8–16 μg/ml for inhibition. Fleroxacin was also active against group JK-diphtheroids and Bacillus cereus. The overall activity of fleroxacin was similar to that of enoxacin and less than that of A-56620 and ciprofloxacin.

In vitro susceptibility of Xanthomonas (Pseudomonas) maltophilia to newer antimicrobial agents

“…None of the isolates tested was susceptible to the aminocyclitol, trospectomycin. Other investigators have demonstrated the activity of some of the 4-quinolone agents against X. maltophilia, with ciprofloxacin being the most active agent (1,3,9,10). Our results are in ANTIMICROB.…”