Tabriz University of Medical Sciences Medical Journal of Tabriz University of Medical Sciences 2783-2031 37 3 2015 08 05 Determining the Drug Susceptibility of Mycobacterium Tuberculosis Strains to the Pyrazinamide 56 62 EN Seyyed Reza Moaddab Keivan Amini Behzad Kazemi Haki Journal Article 2015 02 04 2015 04 11 Background and Objectives: Pyrazinamide (PZA) is an important first anti tuberculosis medication and PZA resistance can be affect the successful tuberculosis (TB) control program. The aim of this study was to determine the PZA resistance among Mycobacterium tuberculosis (MTB) isolated strains. Materials and Methods: These strains were isolated from foreigners and Iranian patients. 100 MTB strains collected at the research center for TB and Pulmonary diseases in Tabriz and for detections of PZA 7H10 agar medium by proportion method was used. Results: Out of 100 MTB strains, 60 isolated strains were resistant to at least one of the main drugs (isoniazid, rifampin, streptomycin, ehambuthol) and 40 isolated strains were susceptible to all of these drugs. One strain (2.5%) from 40 susceptible and 22 strains (36%) from 60 MTB resistant strains was found to be resistant to PZA. Out of 21 MDR (Multi Drug Resistant) strains, 11 isolates were resistant to PZA (57%) The most of the PZA resistant strains were isolated from the foreigner patients (72%). Conclusion: The rate of PZA resistance among East Azerbaijan province patients is low and the sensitivity test of this drug is not necessary as a routine method for MTB susceptible strains.