Activity of ciprofloxacin (BAYo 9867) against Pseudomonas aeruginosa and ampicillin-resistant Enterobacteriaceae.

We studied the in vitro activity of ciprofloxacin against 570 strains of ampicillin-resistant Enterobacteriaceae and 286 Pseudomonas aeruginosa strains. 95.26% of the Enterobacteriaceae and 53.45% of the P. aeruginosa were inhibited by 0.1 mg/l of ciprofloxacin. 2 mg/l of ciprofloxacin inhibited all of the Enterobacteriaceae strains and 4 mg/l all of the P. aeruginosa. We compared the activity of ciprofloxacin with that of temocillin in the Enterobacteriaceae strains. In the P. aeruginosa strains, classified according to their susceptibility to carbenicillin and gentamicin, we compared the activity of ciprofloxacin with that of ceftazidime. In the strains studied, the in vitro activity of ciprofloxacin is superior to that of temocillin against the Enterobacteriaceae and to that of ceftazidime against the P. aeruginosa strains.