Study on Mycobacterium tuberculosis: the primary drug resistance pattern

The study was carried out to investigate the primary drug resistance pattern of tubercle bacilli isolated from the pulmonary tuberculosis patient attended in Shyamoli TB clinic, Dhaka. Sputum from 961 suspected tuberculous patients were randomly collected and stained by Ziehl-Neelsen (Z.N) stain. 135 were microscopically positive for Acid Fast Bacilli (AFB). Among them 30 patients were excluded from the study as they received antitubercular treatment before. So only 105 microscopically positive cases were cultured on Lowenstein-Jensen (L-J) media and 100 showed pure growth and rest 5 were contaminated with fungus. These 100 cases were studied on 4 antitubercular drugs. Out of these 100 isolates, 91 were M. tuberculosis and rest 9 in the nonchromogen group of mycobacteria other than tuberculosis (MOTT) species. Among 91 M. tuberculosis species, 89 (97.80%) to Isoniazid (INH), 73 (80.21%) to Rifampicin (RMP) and 91 (100%) to Streptomycin (SM) and Ethambutol (ETHM) were sensitive. Of the 9 MOTT species, 4 (44.44%) to SM, 7 (77.78%) to ETHM were sensitive and all (100%) were resistant to INH and RMP. Among the 100 isolates, 27 (18 M. tuberculosis and 9 MOTT) were resistant to 4 drugs either single or in combination. Of the 18 (66.67%) M. tuberculosis species, 16 (59.26%) to RMP, and 2 (7.41%) to RMP and INH were resistant. Of the 9 (33.33%) MOTT species, 4 (14.81%) to RMP and INH, 3 (11.11%) to RMP, INH and SM and 2 (7.41%) to RMP, INH, SM and ETHM were resistant.