Isolation and characterization of mycobacterium tuberculosis in respiratory specimens

Background & Objectives: Tuberculosis in India is one of the largest public health problems of immense consequence, with an estimate one death per minute. It is caused by bacteria Mycobacterium tuberculosis. Lung is most commonly affecting site, hence we aimed to isolate, and characterize Mycobacterium tuberculosis from respiratory specimens by conventional methods. Materials and Methods: A total of 117 respiratory samples were included in the study. These specimens were subjected to Ziehl-Neelsen staining, culture on Lowenstein-Jensen medium, LJ with PNB and biochemical tests of Niacin, Nitrate reduction and heat stable catalase tests were performed. Results: Out of 117 samples, 104 (88%) was smear positive, on LJ medium 104 showed growth and 3 was resistant to PNB, Niacin test was positive in 71(71%) isolates, Nitrate reduction in 79(75%) and catalase was negative in 100 (100%) of isolates. Conclusion: The identification of Mycobacterium to the species level plays an important role in providing adequate patient management. Classical culture and biochemical tests when properly applied, detects M.tuberculosis in clinical samples with reasonable sensitivity.