Original Articles: 2016 Vol: 8 Issue: 4
Isolation pattern and drug susceptibility scenario in Mycobacterium tuberculosis isolates from infected patients of Kashmir Valley, India: A comparative study
Abstract
The present study was performed in order to compare the isolation and drug sensitivity testing (DST) methods for
Mycobacterium tuberculosis culture using solid media (Lowenstein-Jensen/LJ) and liquid media (BACTEC
Mycobacterium growth indicator Tube-MGIT 960). This was a cross-sectional survey of adults who visited
Intermediate Reference Laboratory, Srinagar (J&K), India with new diagnosis of pulmonary tuberculosis (TB) or
failing the first- line TB treatment. Patients were requested to provide two sputum specimens for smear- microscopy
and culture on solid and liquid media. Amongst 854 samples, 642 (75.17%) were positive, 211(25%) were found
negative and 1(0.1%) were non-tuberculosis mycobacterium (NTM) when isolated through solid/LJ media while 735
(86.06%) were positive, 100 (12%) were negative and 19 (2.22%) were found NTM when isolated through
liquid/BACTEC-GIT-960 media. Amongst the two media for isolation of Mycobacterium in random screening
procedures, liquid media/BACTEC-MGIT-960 increases diagnosis of TB-positive samples and specifically those
with MDR-TB. The choice of culture method should also depend on local availability, cost and test performance
characteristics. It was found that, positive cultures of TB were found to be most resistant against streptomycin and
most sensitive to ethambutol. The pattern of resistance against drugs in Mycobacterium tuberculosis as per the
study follows the order viz. streptomycin>isoniazid>rifampicin>ethambutol. The pattern of sensitivity follows the
order viz. ethambutol>rifampicin>isoniazid>streptomycin.