Isolation and characterization of cultivable mycobacteria from leprosy skin

Attempts were made to isolate cultivable mycobacteria from 129 biopsies/slit-skin scrapings from the skin of leprosy patients (73 multibacillary-BB/BL/LL and 56 paucibacillary-TT/BT/I) as well as 50 healthy controls. Among the 19 isolates obtained, 17 were from specimens from leprosy cases whereas two were from healthy controls. 14 of the 17 isolates were from multibacillary cases and three were from paucibacillary patients. The mycobacteria isolated were: M.scrofulaceum (4 = all LL cases); M.avium (3 = 2 from LL cases and 1 from healthy control); M.avium-intracellulare complex (1 LL); M.gordonae (2 = 1 from BT and BB each); M.flavescens (1 BL); M.smegmatis (2 = both LL); M.phlei (4 = 1 LL, 1 BL, 1 BT and 1 healthy control); M.fortuitum (1 BL); and M.chelonei (1 BT relapse). The results of this study suggest a preferential colonization of skin of lepromatous leprosy cases by M.scrofulaceum and M.avium. As such isolates have been reported by the investigators from other parts of the world, independent confirmation of such trends in Indian patients is significant and casual relationship (if any) between such colonization and development of lepromatous disease merits further investigation.