IN-VITRO EVALUATION OF DRUG SUSCEPTIBILITIES OF BABESIA DIVERGENS ISOLATES

The susceptibilities of three bovine and two human Babesia divergens i solates to antimicrobial agents were evaluated in vitro by a tritiated hypoxanthine incorporation assay. The MICs at which 50% of isolates a re inhibited (MIC(50)s) for mefloquine (chlorhydrate), chloroquine (su lfate), quinine (chlorhydrate), clindamycin (phosphate), pentamidine ( isethionate), phenamidine (isethionate) plus oxomemazine (chlorhydrate ), lincomycin (chlorhydrate monohydrate), and imidocarb (dipropionate) were determined. Except for imidocarb, the MIC(50)s observed for the different isolates were close. Imidocarb and the combination of phenam idine plus oxomemazine exhibited the highest in vitro activity, while antimalarial agents such as mefloquine, choroquine, and quinine were i nactive. Other drugs had intermediate activities. The data support fur ther in vitro evaluation of antimicrobial agents active against B. div ergens for the improvement of therapeutic strategies.