DNA fingerprinting of Mycobacterium tuberculosis isolates from Agra region by IS 6110 probe

DNA fingerprinting using IS 6110 probe has been used all over the world quite successfully to characterize M. tuberculosis strains. The present study has been carried out to study the polymorphism among isolates of M. tuberculosis from Agra region from patients attending the clinics at SN Medical College and TBDTC, Agra. Sputa were collected in sterilized containers and brought to CJIL, Agra. Samples were processed and cultured on Lowenstein Jensen (LJ) slants. M. tuberculosis isolates were identified by standard biochemical tests. DNA from these isolates were purified by a physicochemical procedure, restricted with Pvu II enzyme and hybridized with PCR amplified and DIG labeled 245 bp IS 6110 probe. With a view to study IS 6110 polymorphism, M. tuberculosis isolates obtained from different geographical areas of Agra region were analyzed. Among the 60 isolates taken in study, 5 had no copy of IS 6110, 8 had 1-4 copies and 47 had multiple copies of IS 6110. DNA fingerprinting using this probe was found to be quite discriminating for typing of most of the strains (80%) which had multiple copies. RFLP profiles did not correlate with geographical areas, contacts or the resistance pattern of the strains. While this data shows the potential of IS 6110 based RFLP for strain characterization of M. tuberculosis in Agra, to understand the molecular epidemiology of tuberculosis in this region, a larger number of isolates from defined geographical areas need to be studied.