Predominant VNTR family of strains of Mycobacterium tuberculosis isolated from South Asian patients

Abstract

Setting: Despite the low incidence of tuberculosis in the UK, some minority ethnic groups, particularly those originating from South Asia, experience very high incidence rates.

Objective: Comparison of the variable number tandem repeat (VNTR) profiles of strains of Mycobacterium tuberculosis circulating in an immigrant community in the UK with those found in the country of ethnic origin.

Design: Isolates of M. tuberculosis were collected from samples obtained from patients attending clinics in Leeds and Bradford, UK and Rawalpindi, Pakistan. Strains were compared using VNTR analysis and mixed-linker PCR.

Results: Comparison of VNTR profiles found that one profile (42235) represented 37% of patient isolates from Rawalpindi and 23% of patient isolates in Leeds and Bradford, where it was associated exclusively with patients with South Asian names. A second profile (02235) represented 15% of patient isolates in Leeds and Bradford, and was also exclusively associated with the South Asian community. These profiles could be subdivided by mixed-linker PCR analysis.

Conclusion: The VNTR profile 42235 may represent a family of strains commonly found in communities associated with South Asia.