[Br. ovis sensitivity to antibiotics]

Irrespective of their geographical origin the cultures of Br. ovis are highly sensitive to tetracycline and streptomycin. The bactericidal concentrations of tetracycline for 86.6 per cent of the strains and streptomycin for 93.20 per cent of the strains were 0.02--0.04 and 0.1--0.4 gamma/ml respectively. The bactericidal effect of morphocycline, kanamycin, benzyl-penicillin, lincomycin and monomycin was less pronounced. Polymyxin M had no bactericidal effect on the Brucella even in concentrations of 200 gamma/ml. Antibiotic sensitivity of S-subcultures of Br. ovis and the initial R-variants was studied comparatively. It was found that genetically related S-subcultures of Br. ovis were more resistant to the antibiotics than the initial R-strains.