Viability of acid-fast bacilli from gamma-& UV-irradiated lepromatous armadillo tissues infected with Mycobacterium leprae.

Gamma-irradiated splenic homogenates of armadillos infected with M. leprae proved sterile by conventional tests and media. However, on media for chemoautotrophy, these could repeatedly grow as a single type of acid-fast nocardioform bacterium like the unirradiated specimens, although with a much reduced count. In the slide culture, transition from the initial AFB/coccoid bodies, to sporulating mycelia and granules in the final stage, could be observed sequentially. The gamma-irradiated tissue specimens failed to yield any other mycobacterium/corynebacterium tested according to standard protocols.