Prevalence of non-tuberculous mycobactera isolated from patients referring to tuberculosis center of Kashan University of Medical Sciences.

Background and Aim: Nowadays, the importance of pathogenicity of non-tuberculosi s mycobacteria is well known. Generally, this group, in addition o the respiratory system can cause lymph nodes, skin, soft tissue and bone disorders. Ide ntification of Mycobacterium by culture and biochemical tests may take several weeks an d may not be useful for definitive diagnosis. PCR-RFLP (PRA) technique of the hsp65 gene using HaeI II and BstEII enzymes is a precise method for species differentiation, in compariso n to phenotypic methods. It is a quick and inexpensive method for detection of mycobacterial spe cies. This study aimed to assess the prevalence of non-tuberculous mycobacteria iso lated from the patients referring to tuberculosis center (TB) of Kashan University of Medical Sciences. Material and Method: The study included 106 patients who had been referring to TB Center of Kashan University of Medical Sciences, from 1391 to 1394. The samples were tested by biochemical diagnostic tests. At the same time identifica on of the strains was made by use of PRA. Amplification of 441-bp fragment was performed by PRA fo r detection of hsp65 gene. The PCR products were digested with HaeIII and BsteII enzymes and a n lysis was performed on the basis of electrophoresis. Results: Molecular analysis showed non-tuberculosis mycobacteria i n 4(8.3%) sputum samples,i.e. one positive sample (o.9 %) for every one of the fo llowing strains: M. abscessus , M. senegalense, M. fortuitum and M.kansasii. Conclusion: The results of this study showed that some cases of tuberculosis in Kashan are due to non-tuberculosis mycobacteria. Also use of PRA analysis of h p65 gene for clinical specimens is a rapid and useful tool for identification of species of mycobacterium which is helpful for early diagnosis, treatment and control of tuberculosis.