Publication:

A study on mutation in genes associated with rifampicin and isoniazid resistance in Mycobacterium tuberculosis complex using line probe assay

Background The term tuberculosis describe a clinical illness, which is predominantly caused by Mycobacterium tuberculosis and less common by other species. Infection is transmitted by infected droplets through respiratory route. Early diagnosis and appropriate management is the only way to control the spread of infection. The available diagnostic tools include, smear microscopy, culture and molecular methods. Culture is the gold standard, but it takes around 2-8 weeks to get the result and smear microscopy having less sensitivity. Molecular technique especially Line probe assay can be better option because of high sensitivity and specificity, and directly clinical sample can be used, and result will be made available within same day with sensitivity pattern. Present study was designed to use of LPA for early diagnosis.

Methods Laboratory based observational study conducted in department of microbiology, IGIMS Patna and TBDC, Patna. Sputum specimens were collected from clinically suspected cases of pulmonary tuberculosis, and subjected to smear microscopy, culture and LPA.

Results During the study period, 2841 patients were diagnosed as pulmonary tuberculosis. Strain of Mycobacterium tuberculosis complex in, 12% (347) patients were rifampicin and isoniazid resistant, 4% (117) and 3% (86) patients were rifampicin and isoniazid mono-resistant respectively. We found that rpoB MUT3 was the most common mutation in gene associated with rifampicin resistant and katG MUT1gene associated with isoniazid resistant.

Conclusions Present study support the use of LPA for early diagnosis of smear positive as well as smear negative pulmonary tuberculosis cases. Resulting early diagnosis and appropriate management of patients.