COMPARATIVE ACTIVITY OF THE NEW FLUOROQUINOLONE BAY Y3118 AGAINST 177PENICILLIN-SUSCEPTIBLE AND RESISTANT PNEUMOCOCCI

The activity of a new fluoroquinolone, Bay y3118, was evaluated in com parison to three quinolones (ciprofloxacin, ofloxacin, lomefloxacin) a nd four broad-spectrum oral cephalosporins (cefpodoxime, cefuroxime, c efaclor, cefixime) against 49 penicillin-susceptible pneumococci, 77 p neumococci with intermediate resistance and 51 penicillin-resistant pn eumococci. Quinolone activity was not affected by the penicillin susce ptibility status of the organisms. Bay y3118 was very active against a ll strains, with an MIC90 of 0.015 mu g/ml. Other quinolones were less active, with MIC90s of 4 mu g/ml (ciprofloxacin and ofloxacin) and 8 mu g/ml (lomefloxacin). Cephalosporin MICs rose parallel to those of p enicillin. Cefuroxime and cefpodoxime were the most active cephalospor ins, with MIC90s for strains showing susceptibility, intermediate resi stance and resistance of 0.125-0.25, 2-4 and 4 mu g/ml, respectively. Cefaclor and cefixime were less active, with correspending MIC90s of 1 -2, 8-16 and > 16 mu g/ml, respectively.