Parissa Farnia - Mycobacteriology Research Center (MRC), National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran
Saman Ayoubi - Mycobacteriology Research Center (MRC), National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran
Poopak Farnia - Department of Biotechnology, School of Advanced Technology in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Jalaledin Ghanavi - Mycobacteriology Research Center (MRC), National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran
Jafar Aghajani - Mycobacteriology Research Center (MRC), National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran
Ali Akbar Velayati - Mycobacteriology Research Center (MRC), National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Introduction: The prevalence of non-tuberculous mycobacterial infections (NTM) in many countries, including Iran is a very serious and worrying problem. Among these non-tuberculous mycobacteria, Mycobacterium kansasii can cause pulmonary and extrapulmonary infections. Due to the high prevalenceof M. kansasii in Iran, unfortunately there is little information about the epidemiological aspects of M. kansasii infection. The aim of this study was to investigate the prevalence of Mycobacterium kansasii in patients referred to the National Tuberculosis Reference Laboratory of Iran between ۲۰۱۲ and ۲۰۲۲.Materials and methods: This descriptive study was performed on ۶۴۲۲ isolated samples with symptoms of pulmonary tuberculosis between ۲۰۱۲ and ۲۰۲۲ in the Mycobacteriology Research Center of the Iranian Tuberculosis and Pulmonary Disease Research Institute. The IS۶۱۱۰ gene and TB۱ and TB۲ primers were used to identify mycobacteria. Samples that had a negative PCR result based on IS۶۱۱۰ were analyzed for Mycobacterium kansasii and other non-tuberculous mycobacteria using the hsp۶۵ gene by PCR-RFLP. M. kansasii were also sequenced for the rpoB gene.Results: Based on sequence analysis of IS۶۱۱۰, rpoB and hsp۶۵ genes, out of ۶۴۲۲ samples, ۷۲۳ (۱۱.۲۶%) NTM strains and ۵۶۹۹ (۸۸.۷۴%) TB strains were identified. Also, out of ۷۲۳ (۱۱.۲۶%) NTM strains, ۳۱ (۴.۲۹%) Mycobacterium kansasii strains were isolated. Based on data analysis, it was foundthat Mycobacterium kansasii is prevalent in provinces such as Tehran, Tabriz, Lorestan, Qom, Golestan, Gilan, Mazandaran and Isfahan. The prevalence of this strain in Tehran (۲۰/۶۴.۵۲%) and Tabriz (۲/۶.۴۵%) provinces according to the information has increased significantly compared to otherprovinces. The results also showed that the prevalence of Mycobacterium kansasii in ۲۰۱۴ and ۲۰۲۱ (۷/۲۲.۵۸%) has increased significantly compared to other years. Conclusion: The results of this study showed that the prevalence of Mycobacterium kansasii in Iran is increasing, especially in industrial cities. The high prevalence of Mycobacterium kansasii may indicate the fact that this genotype has a special power to cause infection in humans. Therefore, more studies are needed to better understand the biology and pathogenicity of Mycobacterium kansasii. Also, according to the obtained results and considering that the treatment protocol for Mycobacterium kansasii is very different from Mycobacterium tuberculosis, so early diagnosis of this strain can have significant goals forphysicians.

Mycobacterium kansasii, Prevalence, diagnosis, Iran