Evaluation of the growth properties of M. bovis isolates. Isolates obtained from animals with tuberculosis, strains MP287/03 and B2, and reference M. tuberculosis strain H37Rv, were used for infection of BMDM in vitro (A) or cultured in Middlebrook 7H9 broth (B). Growth rates of mycobacteria inside MΦ infected at MOI of 1 were determined using the colony count method. Intracellular CFU numbers were quantified immediately after infection (day 0) or at 3 or 6 days after infection (A). Growth rates of mycobacteria in 7 H9 Middlebrook broth were monitored by measurement of OD of the mycobacterial cultures by spectrophotometry. The growth curves of the mycobacterial strains within a 12 day period of incubation are presented. (B). Values are the means ± SD of three independent experiments with samples in triplicate.