Investigations on in vitro survival and virulence of T. pallidum under aerobiosis.

Motility of pathogenic T. pallidum was maintained in aerobic in vitro cultures for several weeks using a special medium. The latter consisted of McCoy's 5a medium supplemented with glutathione, sodium pyruvate, HEPES buffer, gentamycin (garamycin), and fetal calf serum. The virulence of the organisms was lost in 5 to 6 days. No multiplication of the organisms was observed. Four antibiotics (viomycin, kanamycin, gentamycin (garamycin), and neomycin) were tested for their bactericidal action and possible toxicity to T. pallidum. Gentamycin proved to be superior to the other three antibiotics in being non-toxic to the treponemes and showing a possible stimulatory effect on their motility and longevity. Cultivation of T. pallidum in cultured cells in the presence of the enzymes, superoxide dismutase and catalase, in a special medium showed possibilities for future experimentation under monitored, reduced oxygen pressure with a continuous system to dismutate superoxide radicals.