Mycobacterium simiae: a possible emerging pathogen in Iran.

Mycobacterium simiae has been reported worldwide, particularly from the Middle East. This organism has been recognized as a causative agent of pulmonary and disseminated infections. In this study, we used molecular methods to detect this organism from patients who were suspected of having tuberculosis. A total of 117 isolates of mycobacteria were evaluated from different regions of Iran. Isolates were identified using phenotypic methods and gene sequencing of 16S rRNA, rpoB, hsp65, and ITS. Of the 117 isolates, 12 M. simiae isolates (10.2%) were identified from different clinical samples, including bronchoalveolar lavage and sputum (n = 8), blood (n = 3), and lymph node biopsy (n = 1). Three isolates (3/12, 25%) were recovered from blood samples of HIV cases when the CD4(+) count was less than 50/μl. There was no significant relationship between infection and age or gender. Infection with nontuberculous mycobacteria (NTM), including M. simiae, is the major problem among immunocompromised patients. The results of this study illustrated the importance of molecular methods for accurate and rapid detection of NTM infections in the treatment of nonresponding patients with suspected tuberculosis.