KILLING KINETICS OF 4 QUINOLONES AGAINST GRAM-POSITIVE COCCI

Killing kinetics of four fluoroquinolones against Staphylococcus speci es were determined during the first 5 h of incubation in the presence of drug concentrations ranging from the MIC to 1,024 mug/ml. Additiona lly, the relationship between killing rate and drug concentration was established. Sparfloxacin and temafloxacin were the most active quinol ones assayed with greater lethal rates than ciprofloxacin and norfloxa cin. The relation was biphasic with a decrease of at least 1 log10 c.f .u./ml at high drug concentrations with respect to that obtained at th e optimal bactericidal concentration for all quinolone-microorganism c ombinations tested.