In-vitro activity of pefloxacin compared with six other quinolones.

The in-vitro antimicrobial activity of pefloxacin was compared with that of three of the newer fluorated quinoline derivates: ciprofloxacin, norfloxacin and enoxacin, as well as with those of the earlier analogues: nalidixic acid, pipemidic acid and cinoxacin, against almost 750 recent patient isolates of medically important bacteria. MIC90S of pefloxacin were less than or equal to 2 mg/l for Enterobacteriaceae, less than or equal to 8 mg/l for Pseudomonas aeruginosa, less than or equal to 4 mg/l for other nonfermenters and 0.5 mg/l for Staphylococci. Most streptococcal strains were resistant to pefloxacin. Of all the fluorated quinolones, ciprofloxacin was overall the most active compound. The older non-fluorated quinolone analogues had activity against the Enterobacteriaceae only at levels achievable in urine.