Uptake of ciprofloxacin and ofloxacin by 2 Brucella strains and their fluoroquinolone-resistant variants under different conditions. An in vitro study.

The existence of an efflux-mediated mechanism involved in the drug accumulation process of the 2 resistant Brucella strains was investigated; 2 susceptible Brucella strains, Brucella melitensis biovar abortus 2308 (S2308) and AFbortus 3196 (S3196) strains, were the reference strains cultured on trypticase soy agar (TSA) medium and incubated to gradient concentrations of ciprofloxacin and ofloxacin antibiotics. The uptake level of 2 antibacterial agents in 2 susceptible and their fluoroquinolones-resistant variants of Brucella strains obtained in vitro at neutral (pH 7) and acidic (pH 4.5) media, in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP), was analyzed spectrophotometrically.