IN-VITRO ACTIVITY OF A NEW FLUOROQUINOLON E, FLEROXACIN AGAINST HOSPITAL ISOLATES AND REGRESSION CURVE - A MULTICENTER STUDY

Minimal inhibitory concentrations (MICs) of fleroxacin (FLE) were dete rmined by agar dilution for 1261 bacterial strains isolated in 1992 in 4 university hospitals ; in addition, antibiograms by agar diffusion were performed with 5 mug disks. Activity of FLE against nalidixic aci d (NAL) susceptible (S) Enterobacteriaceae was close to that of other fluoroquinolones (FQ) (MIC 50 and 90 : 0.12-0.25 mug/ml) ; like for ot her FQ, this activity was reduced against NAL intermediate and resista nt (R) Enterobacteriaceae (4-32). MICs of FLE against P aeruginosa wer e between 1 and 128 (8-128). FLE had also a good activity against NAL- S A. baumannii (0.12-0.5) but this activity is reduced against NAL-R A cinetobacter (64-128). FLE was highly active against Haemophilus (0.06 -0.12), Gonococci (0.03-0.25), Meningococci (0.016-0.03) and B. catarr halis (0.12-0.25). FLE showed activity close to the currently availabl e FQ against methicillin susceptible Staphylococci (0.25-1) ; the resi stant strains (32->128) are usually methicillin resistant. FLE is less effective against Enterococci (4-128), Streptococci (8-16) and Pneumo cocci (4-8). The coefficient correlation of the regression curve is 0. 93; for MIC breakpoints of 1 and 4 mug/ml, zone diameter breakpoints s hould be 20 and 15 mm.