Objective: Tuberculosis is one of the oldest diseases known throughout history. Infections caused by drug-resistant Mycobacterium tuberculosis strains represent a serious public health problem in recent years. The aim of this study was to investigate isoniazid, rifampicin, streptomycin and ethambutol resistance rates of Mycobacterium tuberculosis complex strains isolated from various clinical specimens.

Materials and Methods: Clinical specimens were inoculated in BACTEC™ 460TB System and Löwenstein-Jensen media between 2001-2006 and in BACTEC MGIT 960 System (Becton Dickinson, USA) and also Löwenstein-Jensen media between 2007-2008.

Results: A total of 1039 M. tuberculosis complex strains were isolated. Single isolate of each patient were enrolled in the study. Susceptibility testing was performed for 905 M. tuberculosis isolates. Among all isolates, 84.7% (767/905) were susceptible to all of the agents tested, 15.2% (138/905) were resistant to at least one of the four agents and 0.5% (5/905) were resistant to all of them. Total rates of resistance to isoniazid, rifampicin, streptomycin, and ethambutol were determined as 11.7%, 5.7%, 5.2% and 4.9%, respectively. Multidrug resistance was determined as 4% (36/905).

Conclusion: The resistance rates of M. tuberculosis complex strains to the primary antituberculosis drugs were in concordance with the average rates of resistance reported by the Department of Tuberculosis Control, Turkish Ministry of Health. This study carries importance by reflecting the drug resistance patterns of M. tuberculosis complex in our region and also should be considered as an initial study for the organisation of further more comprehensive surveys.