Sensitivity of mycobacteria to dapsone.

Dapsone sensitivity was tested on Loewenstein-Jensen medium on 164 mycobacterial strains belonging to 32 different species. A minimum inhibitory concentration as low as that of M. leprae, as determined "in vivo" was never observed. The most sensitive strains belong to the species M. kansasii, M. ulcerans, M. gordonae, M. szulgai and M. gastri with minimal inhibitory concentrations varying between 0.3 and 0.1 microgram/ml, still approximately 10 times the value known for wild strains of M. leprae.