In Vitro Isolation of Treponema pallidum subsp. pallidum From Fresh and Frozen Needle Aspirates of Primary Experimental Syphilis Lesions.

Isolation of Treponema pallidum subsp. pallidum strains still relies on rabbit intratesticular inoculation of clinical samples. In this article, we report an alternative isolation approach based on the inoculation of fresh and frozen needle aspirates of primary experimental lesions into culture plates suitable for in vitro propagation of the syphilis agent.