Prevalence of drug resistance in Mycobacterium tuberculosis in a teaching hospital of Kanchipuram District , Tamilnadu, south India .

Makeshkumar, V.; Madhavan, R.; Narayanan, S.

American Journal of Microbiological Research; 2014; 2; 35-40.

Abstract: Objectives: To study the prevalence of drug resistance in Mycobacterium tuberculosis isolated from patients with pulmonary and extrapulmonary tuberculosis.

Materials and Methods : A total of 178 extra pulmonary clinical specimens were collected from patients suspected with extrapulmonary tuberculosis (EPTB) and again 2,048 sputum samples from 1030 patients with clinical evidence of pulmonary tuberculosis (PTB) were collected in SRM Hospital and Research Centre of Kanchipuram District. Both pulmonary and extrapulmonary specimens were stained by Ziehl-Neelsen (ZN) method. All sputum AFB smear positive specimens and 178 extrapulmonay clinical specimens were cultured in Lowenstein Jensen (LJ) medium. All Mycobacterial isolates were identified by standard protocols and were tested by conventional drug susceptibility method using absolute concentration method.

Results: Out of 1030 clinically suspected pulmonary tuberculosis patients, 125 (12.13%) patients were smear positive for AFB. Among these 125, 76 (54.4%) were positive for Mycobacterium species cultured on LJ medium. Out of 76 mycobacterial isolates, 68 (89.4%) were M.tuberculosis and 8 (10.52%) were non tuberculous mycobacteria (NTM). Of 178 extrapulmonary clinical specimens, 10 (5.6%) were direct AFB smear positive and 6 (3.37%) were positive for M. tuberculosis on LJ medium. All 74 M.tuberculosis isolates (68 pulmonary isolates and 6 extrapulmonary isolates) were tested for first line anti-TB drugs by conventional drug susceptibility method. Three (4.05%) M.tuberculosis isolates were resistant to rifampicin, isoniazid and ethambutol. All the three multidrug resistance tuberculosis (MDR - TB) strains were isolated from pulmonary tuberculosis patients.

Conclusion: In this hospital area, 4.05 percentage of MDR - TB isolates were reported in culture positive PTB cases.

Keywords: prevalence of drug resistance; pulmonary and extra pulmonary tuberculosis; absolute concentration method; Middle brook 7H10 agar; first line anti-tb drugs

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