Growth characteristics of microorganisms occurring in penicillin-treated Brucella abortus cultures.

Abstract

Summary and ConclusionsMicroorganisms capable of producing L-colonies were detected in penicillin-treated broth cultures of B. abortus, 3183, throughout a 7-day incubation period by subcultures made to agar plates containing penicillin. Isolation of comparable numbers of bacterial colonies from the same cultures when subcultures were made to antibiotic-free agar plates, and absence of L-colonies on the latter plates, indicates that most cell wall-defective forms capable of producing L-colonies were also capable of reverting to bacteria. Bacteria with increased resistance to penicillin were isolated from some treated broth cultures and after reversion of B. abortus L-phase variants. Failure to show an increase in the number of colony-forming organisms during 7 days of incubation in penicillin-treated broth cultures suggests that a steady state existed in these cultures. Persistence of B. abortus on the surface of agar plates containing penicillin points up the fact that survival of bacteria under inhibitor...