Use of 3,4-Dihydroxyphenylalanine Oxidation in the Identification of Mycobacterium leprae.

Identification of acid-fast bacteria failing to grow on artificial culture media under known conditions as Mycobacterium leprae now depends on the results of two time-consuming tests. At relatively low ambient temperatures, several thousand leprosy bacilli multiply within 6 to 9 months to maximal numbers of several million in the mouse footpad. Gross lesions or invasion of adjacent or remote tissues are absent (C. C. Shepard, J. Bacteriol. 90:1271, 1965). The other test requires intradermal injection of leprosy patients simultaneously with the heat-killed mycobacteria and with standard lepromin. (Shepard and Guinto, Intern. J. Leprosy 31:353, 1963). Leprosy bacilli are the only known mycobacteria failing to evoke dermal responses in Mitsudanegative leprosy patients. Both tests distinguish between the noncultivated species, M. leprae and M. lepraemurium. Since culture of M. leprae is