Cultivation requirements for Treponema pallidum, Mycobacterium leprae and other microbial and mammalian microaerophilic cells.

Atmospheric and biological evolution progressed simultaneously and today certain cell types flourish only at oxygen tensions which were ambient 600 million years ago, i.e., at 5 to 10 mm Hg. In man, a continuous oxygen flow at these pressures is supplied in the skin where Treponema pallidum, Mycobacterium leprae and members of the genus Rickettsia grow best. In vitro studies support the microaerophilic status of these organisms and of certain other microbial and mammalian cells. Vigorous growth in pure culture will await the development of techniques which can maintain these low oxygen tensions at the cell walls of the microbes as they replicate and consume increasing amounts of oxygen. Continuing failure to consistently isolate microbes from active lesions in patients with rheumatoid arthritis or systemic lupus erythematosus may reflect the universal absence of suitable methods for isolation of microaerophilic microbes.