Cultivation in vitro of acid-fast nocardioform chemoautotrophic bacteria from mouse foot-pads infected with human strains of leprosy bacillus

Four acid-fast nocardioform bacteria could be isolated and cultivated as pure cultures in vitro from mouse foot-pads (MFP), which were infected with serially passaged strains of human leprosy bacillus; the liquid mineral medium, such as paraffin urea minimal (PUM), paraffin gelatin minimal (PGM), gelatin minimal (GM), and GM agar (GMA) slants containing only simple sources of C and N were used, just like the human and the armadillo isolates of these organisms reported earlier. Morphologically, metabolically and enzymologically, these were closely related to the previous ones and were also chemoautotrophic in nature. Serologically there appears to be a heterogenicity in these isolates, i.e., some of them showing higher affinity to nocardioforms while others showing significant binding to several mycobacteria. Normal (uninfected) mouse foot-pad harvests were not found to harbour such organisms.