A non-acid-fast coccoid precursor--possible cultivable phase of Mycobacterium leprae.

A non-acid-fast coccoid organism isolated from human leproma, and skin and nasal smears of leprosy patients shows tendency to revert to an acid-fast mycobacterial form during test tube passages. One of these coccoid isolates gave strong DOPA oxidase activity. There is also preliminary evidence of mycobacterial conversion from these coccoids in intraperitoneally inoculated mice. The possibility that these non-acid-fast coccoids could be a cultivable precursor phase of M. leprae has been raised and discussed.