Nontuberculous Mycobacteria are opportunist pathogens which have specific role in lymphadenitis, skin and
respiratory infections. Treatment of the disease due to these bacteria is difficult since these bacteria are resistant to
a large scale of antibiotics. On the other hand, most kinds of these Mycobacteria cannot be identified, so they are
mistreated under anti-tuberculosis cure. The aim of this research is to investigate the frequency of nontuberculous
Mycobacteria in patients suspected to tuberculosis in Golestan province, the most prevalent region of tuberculosis
in Iran. This cross-sectional study was carried on 3336 patients suspected to tuberculosis referred to hospitals and
health care centres in Golestan province during 2010-2011, 319 positive culture cases were collected. Identification
of species by using biochemical tests was done on the samples recognized as nontuberculous Mycobacteria; after
DNA extraction by boiling, 16S rRNA PCR was done and the species were identified by NCBI BLAST software.
Among 319 culture positive samples, 16 (%5.01) cases were diagnosed as nontuberculous Mycobacteria and 3
samples as Nocardia. Most of them were isolated from patients belonging to age groups 16-24 and older than 65
years old. The most common species in this research were M.simiae (6 cases) and M. fortuitum (4 cases). The
frequency of nontuberculous Mycobateria in our region (Golestan province) is less than other studied areas in Iran.
Frequency of Mycobacterium simiae and M.fortuitum ,which are resistant to first line of anti-tuberculosis drugs,
maybe one of the reasons of failure in the tuberculosis treatment in this province. Therefore, identification of species