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. 2018 Jan 31:11:1-6.
doi: 10.1016/j.jctube.2018.01.001. eCollection 2018 May.

High genetic diversity among Mycobacterium tuberculosis strains in Tehran, Iran

Taher Azimi  1 , Mohammad Javad Nasiri  1 , Samin Zamani  2   3 , Ali Hashemi  1 , Hossein Goudarzi  1 , Abbas Ali Imani Fooladi  4 , Mohammad Mehdi Feizabadi  5 , Fatemeh Fallah  6
Affiliations

High genetic diversity among Mycobacterium tuberculosis strains in Tehran, Iran

Taher Azimi et al. J Clin Tuberc Other Mycobact Dis. .

Abstract

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 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%) 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: Genotyping; Iran; MIRU-VNTR; Mycobacterium tuberculosis; Tehran.

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Figures

Fig 1
Fig. 1
Genetic relationships of 80 isolates.
Fig 2
Fig. 2
Minimum spanning tree showed the 4 clonal complex.
See this image and copyright information in PMC

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