Comparative study of different methods of microscopy followed by a culture method in the detection of mycobacterium tuberculosis in clinically and radiologically suspected cases of pulmonary tuberculosis

Abstract

To compare the sensitivity of 2 microscopic methods for the diagnosis of Mycobacterium tuberculosis (M.tb) along with culture and drug susceptibility testing to first line drugs.: The cross-sectional study comprises 200 suspected cases of pulmonary tuberculosis both clinically and radiologically in KIMS, Bangalore over a period of 2 years. Samples (sputum/BAL fluid) were collected, processed and stained by Ziehl Neelson (ZN) and Fluorescent methods. Culture and drug susceptibilty testing was done for Streptomycin, Isoniazid, Rifampicin and Ethambutol by Mycobacterium growth indicator tube (MGIT) method after decontamination.Fischer’s test : 1. Out of 200 samples: 1.120 were male and 80 were female; 2. 18 were positive by Ziehl Neelson, 21 by Fluorescent and 28 by culture; 3. Majority of the patients belonged to age group 41-50 years (23%); 4. InMGIT, 26 were M.tb and 2 were Non-tubercular mycobacteria; 5. Out of 26 M.tb isolates, 4 were resistant to streptomycin, 6 to isoniazid, 2 to rifampicin and 9 to ethambutol.1. The sensitivity of Fluorescent staining (64.28%) is higher than that of Ziehl-Neelson (51.7%); 2. In MGIT, 26 were M.tb and 2 were Non tubercular mycobacteria; 3. 2 were Multi-drug resistant- tuberculosis (MDR-TB) This study made us aware of the need for prompt detection, identification and appropriate treatment of Tuberculosis due to the rising incidence of MDR-TB.