[In vitro antibacterial activity of a new fluoroquinolone, sparfloxacin, against nosocomial bacteria, and concordance curve]. / Activité anti-bactérienne in vitro d'une nouvelle fluoroquinolone, la sparfloxacine sur les bactéries hospitalières et courbe de concordance.

ABSTRACT

Minimal inhibitory concentrations (MICs) of sparfloxacin (SFX) were determined by agar dilution for 3,164 bacterial strains isolated in 10 university hospitals; in addition, antibiograms by agar diffusion were performed with 5 micrograms disks. Activity of SFX against nalidixic acid (NAL) susceptible (S) Enterobacteriaceae was close to that of other fluoroquinolones (FQ) (MIC 50 and 90 0.06-0.5 microgram/ml); like for other FQ, this activity was reduced against NAL intermediate and resistant (R) Enterobacteriaceae (2-16). MICs of SFX against P. aeruginosa were between 0.12 and 16 (1-32). SFX had also a good activity against NAL-S A. baumannii (CMI < or = 0.25) but this activity is reduced against NAL-R Acinetobacter (16). SFX was highly active against Haemophilus (0.016-0.06) gonococci (0.008), meningococci (0.008) and B. catarrhalis (0.008-0.03). SFX showed activity superior to the currently available FQ against methicillin susceptible staphylococci (0.06); the resistant strains [8] are usually methicillin resistant. SFX is more effective against enterococci (0.5), streptococci (0.25-0.5) and particularly pneumococci (0.25-0.5) including penicillin-resistant strains. The coefficient correlation of the regression curve is 0.876; for MIC breakpoints of 1 and 2 micrograms/ml, zone diameter breakpoints should be 20 and 16 mm.