Susceptibility of Mexican brucella isolates to moxifloxacin, ciprofloxacin and other antimicrobials used in the treatment of human brucellosis.

Brucellosis is a disease of domestic and wild animals that is transmitted to humans and exists worldwide. We assessed the in vitro activity of moxifloxacin, ciprofloxacin, tetracycline, doxicycline, rifampin, streptomycin and trimethoprim-sulfamethoxazole (TMP/SMX) against 97 Brucella strains isolated from clinical samples, animals and dairy products in Mexico. Fluoroquinolones showed an antibacterial activity similar to that of tetracyclines (MIC(90) 0.5). Other drugs commonly used against brucellosis were less active, such as rifampin (MIC(90) 2.0 microg/ml) and streptomycin (MIC(90) 4.0 microg/ml). TMP/SMX showed the poorest activity (MIC(90) 8.0 microg/ml). Fluoroquinolones, either first-generation or the newer 8-methoxi derivatives, might be useful in the therapy of brucellosis, which remains to be assessed in clinical trials.