Failure of transformation in leptospira with two genetic markers of streptomycin resistance and the ability to grow in a synthetic medium.

Transformability of Leptospira was investigated with the two genetic markers, streptomycin (SM) resistance and the ability to grow in SHENBERG's synthetic medium. DNA was extracted from the two mutants of L. icterohaemorrhagiae strain Shibaura, which were SM-resistant and able to grow in SHENBERG's medium. Recipients were 5 strains of L. icterohaemorrhagiae and 1 strain of L. copenhageni. Studies taking careful consideration of the growth phase of the recipient cells, transformation medium, and incubation temperature did not produce the appearance of transformant. Transformation of L. kremastos with SM resistance also showed a negative result.