IN-VITRO ACTIVITY OF NEW FLUOROQUINOLONE, ENOXACIN, AGAINST HOSPITAL ISOLATES AND REGRESSION CURVE - A MULTICENTER STUDY

Minimal inhibitory concentrations (MICs) of enoxacin (ENX), a new fluo roquinolone indicated for the treatment of urinary tract infections, w as determined by agar dilution for 703 bacterial strains isolated in 1 993 in 3 university hospitals in order to study its activity against u rinary pathogens; in addition, antibiograms by agar diffusion were per formed with 5 mu g disks to calculate the regression curve and the bre akpoints for sensitivity testing. Activity of ENX against nalidixic ac id (NAL) susceptible (S) Enterobacteriaceae was close to that of other fluoroquinolones (FQ) (MIC 50 and 90: 0,25-0,5 mu g/ml); like for oth er FQ, this activity was reduced against NAL intermediate and resistan t (R) Enterobacteriaceae (8-64) MICs of ENX against P. aeruginosa were between 0,5 and 128 (2->128). ENX had also a good activity against NA L-S A, baumannii (0,06-2) but this activity is reduced against NAL-R A cinetobacter (0,5->128). ENX showed activity close to the currently av ailable FQ against methicillin susceptible Staphylococci (0,5-8); the resistant strains (32->64) are usually methicillin resistant. ENX is l ess effective against Enterococci (4-128). The coefficient correlation of the regression curve is 0,906. For MIC breakpoints of 1 and 2 mu g /ml, zone diameter breakpoints should be 22 and 19 mm.