[Sensitivity and adaptation of various Brucella species to acid shock]

The sensitivity to acid shock (pH 2.5, 2.8, 3.0, and 3.3) and the capacity to adaptive acid tolerance response (ATR) is studied in the reference Brucella strains differing by the origin, biological, and virulent properties. The ability of Brucella to survive under conditions of acid pH depended on the medium composition, growth phase, and preliminary adaptation at pH 5.6. B. suis biovar 1 and B. melitensis biovar 3 were more resistant to low pH than other Brucella species. Adaptation by overnight growth at pH 5.6 (stationary phase) induced ATR to the acid shock (pH 3.3-3.0) in all Brucella species except B. abortus biovar 1. ATR induced in B. melitensis biovar 2, B. canis, and B. neotomae was more marked, with more than an 100-fold increase in survival of adapted cultures, while adapted B. suis biovar 1, B. melitensis biovars 1 and 2 showed a 2-24-fold increase in survival rates. The detected differences in acid sensitivity and ATR of various Brucella species may be useful for identification and characterization of Brucella strains.