[In vitro antibacterial activity of a new fluoroquinolone, enoxacin against hospital bacteria and regression curve]. / Activité antibactérienne in vitro d'une nouvelle fluoroquinolone, l'énoxacine sur les bactéries hospitalières et courbe de concordance.

ABSTRACT

Minimal inhibitory concentrations (MICs) of enoxacin (ENX), a new fluoroquinolone indicated for the treatment of urinary tract infections, was determined by agar dilution for 703 bacterial strains isolated in 1993 in 3 university hospitals in order to study its activity against urinary pathogens; in addition, antibiograms by agar diffusion were performed with 5 micrograms disks to calculate the regression curve and the breakpoints for sensitivity testing. Activity of ENX against nalidixic acid (NAL) susceptible (S) Enterobacteriaceae was close to that of other fluoroquinolones (FQ) (MIC 50 and 90 0.25-0.5 microgram/ml); like for other FQ, this activity was reduced against NAL intermediate and resistant (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 NAL-S A. baumannii (0.06-2) but this activity is reduced against NAL-R Acinetobacter (0.5- > 128). ENX showed activity close to the currently available FQ against methicillin susceptible Staphylococci (0.5-8); the resistant strains (32- > 64) are usually methicillin resistant. ENX is less effective against Enterococci (4-128). The coefficient correlation of the regression curve is 0.906. For MIC breakpoints of 1 and 2 micrograms/ml, zone diameter breakpoints should be 22 and 19 mm.