Abstract

Objective: To characterize the Mycobacterium tuberculosis (M. tuberculosis) isolates by spoligotyping and mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) typing to understand how M. tuberculosis strains transmit among the study population. Methods: Spoligotyping and MIRU-VNTR were used to genotype M. tuberculosis isolates obtained from three distinct population groups in Sri Lanka. General population suspected of having tuberculosis attending the Chest Clinic, Kandy (n = 78), patients having tuberculosis in Bogambara prison, Kandy (n = 22) and estate workers having tuberculosis in the Central Province, Sri Lanka (n = 50), from January 2012 to April 2014 were included in the study. Results: Among 150 isolates, a total of 19 distinct families were observed including 6 major spoligotyping-based families; East-African-Indian (39.33%), Haarlem (20%), Beijing (8.6%), Central European family T (6.5%), European family X (5.2%) and Central and Middle Eastern Asian (0.6%). Beijing strains were only identified among the general population. MANU strains were significant (36.36%) among the prisoners who had clustered with the MANU strains of the general population indicating contact cases and a possible transmission index within a particular geographical area. Haarlem 3 (34%) was the predominant strain among the estate workers. There was a close epidemiological relationship between the prisoners and the estate workers in the population. Conclusions: The first insight of 15 loci MIRU-VNTR typing in conjunction with spoligotyping in a population in Sri Lanka demonstrated the feasibility and the applicability of these techniques to differentiate strains, their heterogeneity and the predominance of several worldwide distributed spoligotypes.

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