Fig 4.
Analysis of the in vitro growth rates of B. burgdorferi strains in BSKII medium at 35°C. Strains were grown to the mid-exponential phase and diluted in triplicate to 2.5 × 105 spirochetes/ml. Spirochetes were enumerated by dark-field microscopy, and the mean and standard deviation are displayed as calculated by PRISM software. Spirochetes from the mixed culture (C12 plus A3) were plated and screened using lp28-3-specific primers. The ratio of lp28-3-deficient to wild-type spirochetes grown in the mixed culture remained constant throughout all growth phases and is plotted on the right y axis.