Growth of Mycobacterium leprae in thyroxine treated culture medium--a preliminary report

A new approach in cultivation of Mycobacterium leprae in thyroxine treated Lowenstein-Jensen media is reported. The method has been proved to be successful as the organisms multiplied and remained viable in the thyroxine solution added at the bottom of the culture vial, for a period of 18 to 20 weeks of incubation at 37 degrees C. This has been possible due to metabolic stimulating action of thyroxine sodium solution as well as diffusion of nutrients into this solution from the medium. Intracutaneous inoculation of culture fluid on the surface of foot pad in cortisone treated mouse helped in rapid appearance of the specific lesion at the site within 20 days after injection. Both the intracutaneous method of inoculation and treatment of mouse with high doses of cortisone may play some role in shortening the period of development of such lesion.