FIG 6.

T. pallidum subsp. pallidum Nichols can be cultured effectively long-term in vitro in Brewer jars. A T. pallidum preparation was used to inoculate duplicate 6-well plates containing Sf1Ep cells and TpCM-2 medium. The cultures were incubated in parallel in a Brewer jar equilibrated with 1.5% O₂: 5% CO₂: balance N₂ or a tri-gas incubator containing the same gas mixture at 34°C and were passaged in the same manner at 7-day intervals. Results represent the average T. pallidum per culture and percent motility ± SEM for triplicate cultures in each environment.