Year: 2017 | Month: May | Volume: 4 | Issue: 5 | Pages: 161-180
Multi Drug Resistant Tuberculosis: An Emerging Disease in Today’s Scenario of Kashmir (J&K), India
Zafar Nowshad1, Vandana Shrivastava2, Abhishek Mathur3, Ruchita4
1Dept. of Microbiology, Himalayan University, Arunachal Pradesh, India,
2Dept. of Microbiology, ITS Dental College, Ghaziabad, UP, India,
3National Centre of Fungal Taxonomy (NCFT) & EBEC, New Delhi, India,
4Hindu College of Pharmacy, Sonepat, Haryana, India.
Corresponding Author: Zafar Nowshad
Multidrug-resistant tuberculosis (MDR-TB) poses a formidable challenge to TB control due to its complex diagnostic and treatment challenges. The annual global MDR-TB burden is estimated at around 490,000 cases, or 5% of the global TB burden, however, less than 5% of existing MDR-TB patients are currently being diagnosed as a result of serious laboratory constraints. Alarming increase in MDR-TB, the emergence of extensively drug resistant TB (XDR-TB), potential institutional transmission, and rapid mortality of MDR-TB and XDR-TB patient with HIV co-infection, have highlighted the urgency for rapid screening, methods. Conventional methods for myco-bacteriological culture and drug susceptibility testing are slow and cumbersome, requiring sequential procedures for isolation of mycobacterium from clinical specimens, identification of Mycobacterium tuberculosis complex, and in vitro testing of strains susceptibility to anti-TB drugs. Rifampicin is a first line anti Tuberculosis drug active against bacilli in logarithmic and stationary phase, which interferes with RNA synthesis by binding to bacterial RNA polymerase. Tuberculosis bacilli achieve resistance to rifampicin by accumulation of mutations in a short-81bp region of the rpoB gene. Among many mutations identified in the rpo B gene, few were verified by molecular genetic methods as responsible for resistance to rifampicin. In this study, 8-different mutations were identified in an 81-bp section of a “hot spot” region of rpoB gene of rifampicin resistant strain of Mycobacterium tuberculosis. The clinical strains were evaluated in respect to drug resistance. It was found that the mutations in positions 526 (H/D) 516 (D/V) and 531(S/L) codons result in high level resistance to rifampicin. Mutations in position 516(D/Y) 515(M/I) 510 (Q/H) or a double mutation in codons 512(S/I) and 516 (D/G) relates to low level of resistance. 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.
Key words: MDR TB, Kashmir valley, first line treatment, drug resistanc, solid/LJ media, liquid/BACTEC-GIT-960 media.[PDF Full Text]