Abstract

The aim of the study was to evaluate the automated mycobacteria growth ındicator tube (MGIT) for drug susceptibility testing of Mycobacterium tuberculosis and to determine resistance patterns. We used BACTEC MGIT 960 System to determine the susceptibility of M. tuberculosis complex isolates to major anti tuberculous agents. Patients with single and first positive isolates were enrolled in the study. We have performed our drug susceptibility study between January 2005 and December 2010 for monitoring of drug resistance patterns in six years. A total of 1240 (77.16%) of the 1607 isolates were susceptible to all four of the antimycobacterial agents while 369 (22.96%) were found to be resistant to one or more of the drugs. The rate of isolates resistant to streptomycin (SM) was 6.84%, the other rates were 17.17% to isoniazid (INH), 5.28% to rifampicin (RIF) and 4.10% to ethambutol (ETM). Single drug resistance rates were found to be 12.13% for INH, 0.99% for RIF, 5.6% for SM, and 1.74% for ETM. The ratio of resistant isolates to all four drugs was 0.74% (n=12) and the prevalence of multidrug resistant isolates was 3.92% (n=63). It was concluded that resistance to INH and RIF continues almost in a straight line in the present study. Monitoring of drug resistance patterns is essential for accurate drug regimen in management of tuberculosis.

Key words: Mycobacterium tuberculosis complex, primary resistance, ısoniazid, rifampicin.