Cultivation of pathogenic treponema in tissue cultures of SflEp cells.

Recently, the successful in vitro cultivation of the Nichols strain of Treponema pallidum was achieved. Afterward, attempts were made to cultivate three other strains of T. pallidum and two strains of T. pertenue. The cultivation of the KKJ, Mexico A, and Bosnia A strains of T. pallidum was somewhat successful; the average increases were 10.8, 9.1, and 7.5-fold, respectively. The range of growth for each of these strains varied dramatically from experiment to experiment. The KKJ strain varied from 14.4 to 8.0-fold; the Mexico A strain from 12.8 to 5.4-fold; and the Bosnia A strain from 11.3 to 3.6-fold. However, the attempts to cultivate the Gauthier and the FB strains of T. pertenue were unsuccessful. The average increases were 1.7 and 1.9-fold, respectively. Although the maximum growth observed was about threefold with either of these strains of T. pertenue, over 50% of the treponemes remained motile for 10 d. These results suggest that although each of these strains of T. pallidum and T. pertenue has been shown to be genetically identical, they are very diverse biologically even among strains of the same species.