High genetic diversity among Mycobacterium tuberculosis strains in Tehran, Iran

High genetic diversity among Mycobacterium tuberculosis strains in Tehran, Iran

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Introduction: Tuberculosis (TB) still remains an important public health problem in Iran.The genotyping of Mycobacterium tuberculosis isolates is expected to lead to a better understanding of M.tuberculosis transmission in Tehran, the most populated city of Iran.Materials and Methods: A total of 2300 clinical specimens were obtained from TB suspected patients who were referred to a TB center in Tehran from Jan 2014 to Dec 2016.Identification was performed using both conventional and molecular methods.

The presence of resistance to rifampicin was examined by the GeneXpert MTB/RIF.The standard 15-locus mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) typing method was applied to genotype of clinical isolates.Results: Of 2300 specimens, 80 isolates were identified Tees as M.tuberculosis by using biochemical and molecular tests.Of 80 M.

tuberculosis isolates, 76 (95%) had unique genotypic profiles and 4 (5%) shared a profile with one or more other strains.Based on single loci variation (SLV) 4 clonal complexes were observed.NEW-1 was found to be the most predominant lineage (22.5%) console tv cover followed by West African (1.25%), Central Asian (CAS)/Delhi (1.

25%), Bovis (1.25%), H37Rv (1.25%) and multiple matches (1.25%).Loci MIRU10, MIRU26, MTUB21 and QUB26 were found as highly discriminative.

No mutation was detected in the hotspot region of rifampicin by using GeneXpert MTB/RIF.Conclusions: Our study findings show that there was considerable genotypic diversity among M.tuberculosis isolates in Tehran.The 15-locus MIRU-VNTR showed high HGDI and could be used as a first-line genotyping method for epidemiological studies.Keywords: Mycobacterium tuberculosis, Genotyping, MIRU-VNTR, Tehran, Iran.