Molecular identification of Mycobacterium bovis in patients with tuberculosis attending a tertiary care hospital in South India.

BACKGROUND

Mycobacterium (M.) bovis is a member of Mycobacterium tuberculosis complex (MTBC). Clinical infection caused by M. bovis is indistinguishable from other MTBC and could pose a potential challenge for control of TB epidemic due to its zoonotic nature. Availability of reliable molecular diagnostic methods such as Genotype MTBC based on line probe assay (LPA) paves way for reliable differentiation of M. bovis from other MTBC.

OBJECTIVE

To determine the proportion of Mycobacterium bovis among the Mycobacterium tuberculosis complex isolates from patients with tuberculosis.

METHODS

In our study, we analysed MGIT positive cultures and performed Line probe assay (LPA) for identification of MTBC isolates. Total of 206 patient samples were taken, 104 pulmonary and 102 from extrapulmonary sites.

RESULTS

M.tuberculosis/M.canettii was isolated in all pulmonary specimens (100%). Among 102 extrapulmonary samples, 99 % was identified as M.tuberculosis/M.canettii, and 1 % as M. bovis BCG.

CONCLUSION

Our study suggests that zoonotic TB by M. bovis may not be as prevalent in India and hence may not constitute a significant risk to public health in India.