In vitro activity of CI-934 compared with ciprofloxacin, enoxacin, norfloxacin, and vancomycin.

The in vitro activity of the quinolone CI-934 was compared with ciprofloxacin, norfloxacin, enoxacin, and vancomycin against 607 Gram-positive and -negative isolates. CI-934 inhibited 90% of the Enterobacteriaceae, Aeromonas hydrophila, and Acinetobacter spp. at 1 microgram/ml. Decreased activity was observed against Pseudomonas aeruginosa. Pseudomonas maltophilia, and other Pseudomonas spp. with CI-934 MIC90 greater than or equal to 8 micrograms/ml. CI-934 activity against Gram-positive organisms exceeded vancomycin and the other quinolones. MIC90 for Streptococcus faecalis, Listeria monocytogenes, and Corynebacterium spp. were less than or equal to 2 micrograms/ml. CI-934 was equally effective against oxacillin-susceptible and -resistant staphylococci with MIC90 of 0.5 micrograms/ml.

Activity of ciprofloxacin against resistant clinical isolates.

The in-vitro activity of ciprofloxacin, a new quinolone derivative, was determined by broth microdilution for 518 clinical isolates. The MICs for 90% of the organisms were 2 mg/l for Pseudomonas aeruginosa, 8 mg/l for P. maltophilia, 4 mg/l for other Pseudomonas spp., 1 mg/l for Acinetobacter anitratus, 0.03-0.5 mg/l for differing species of Enterobacteriaceae, 2 mg/l for Streptococcus faecalis, 0.25 mg/l for coagulase-negative Staphylococcus spp. and 2 mg/l for S. aureus. Furthermore, on a weight basis, the activity of ciprofloxacin was equivalent or superior to that of cefotaxime, ceftazidime, gentamicin, imipenem, latamoxef, piperacillin, oxacillin and vancomycin. In general, ciprofloxacin appears to be highly active against organisms resistant to many broad spectrum antimicrobials, including norfloxacin, gentamicin, cefotaxime, and ceftazidime, with MICs for 90% of organisms in the range of 0.03 to 16 mg/l.