Fleroxacin: in-vitro activity worldwide against 20,807 clinical isolates and comparison to ciprofloxacin and norfloxacin

: By June 1987 worldwide investigators from 37 centres in 12 countries had completed epidemiological susceptibility testing studies comparing the in-vitro activity of fleroxacin with that of ciprofloxacin, norfloxacin and other antibacterials. In this paper the results of these studies, expressed primarily as MIC90S, are reviewed and analysed for centre to centre variability. Twenty thousand eight hundred and seven strains were evaluable for comparative analysis. All three quinolones exhibited high in-vitro activity against Enterobacteriaceae (MIC90 less than or equal to 0.125-2 mg/l), other common aerobic Gram-negative bacilli or coccobacilli (MIC90 less than or equal to 0.125-1 mg/l) and staphylococci, including selected resistant isolates (MIC90 less than or equal to 0.5-4 mg/l), and moderate to weak activity against streptococci and anaerobes (MIC90 = 1- greater than or equal to 8 mg/l). The activity of fleroxacin and norfloxacin was quite similar, but was usually inferior to that of ciprofloxacin. Comparison of data from the various investigating centres showed divergent results for many bacterial species, the MIC90S for the same quinolone varying by two to four dilution steps or more from centre to centre.