A New Era in Treponema pallidum Cultivation: Current Advances and Future Directions.

Although long-term in vitro cultivation of the syphilis agent, Treponema pallidum subspecies pallidum, was introduced less than a decade ago, it has revolutionized and accelerated research with this difficult pathogen. Moreover, it is allowing for the exploration of topics that could not easily be pursued when propagation in the rabbit model was the only possible method for the expansion of treponemes. This report, based on talks presented at the Shanghai International Syphilis Symposium 2025, provides an overview of how in vitro cultivation is currently being applied to syphilis research.