Genetic Lineages of Mycobacterium tuberculosis Isolates in Isfahan, Iran

Abstract

In this study, we aimed to identify the genetic lineages of Mycobacterium tuberculosis isolates in Isfahan via the mycobacterial interspersed repetitive-unit-variable number tandem repeat typing method based on 15 loci. Forty-nine M. tuberculosis isolates were collected between 2013 and 2015 from Tuberculosis patients in Mollahadi Sabzevari Tuberculosis Center in Isfahan. All isolates were typed by 15-locus MIRU-VNTR typing. The highest percentage of isolates, 44.89 % (22/49), belonged to the Euro-American lineage, while the frequencies of the East-African-Indian, East-Asian, and Indo-Oceanic lineages were 28.57 % (14/49), 24.4 % (12/49), and 2.04 % (1/49), respectively. Among the 22 isolates of the Euro-American lineage, those belonging to the NEW-1 sub-lineage were most prevalent (24.4 %). Approximately, the same proportion of isolates belonging to the Delhi/CAS, Beijing, and NEW-1 sub-lineages were identified in Iranian and Afghan immigrant patients. The Delhi/CAS and Beijing sub-lineage isolates were prevalent among patients who had been previously treated for TB. Results showed that all of the 49 MIRU-VNTR patterns were unique and the clustering rate of the 15-locus MIRU-VNTR was 0.0 (minimum recent transmission). The results of this study show that the lineages of M. tuberculosis isolates in Isfahan are similar to those reported in the Eastern Mediterranean region (indicative of the epidemiological relationship between the countries in the region). The low clustering rate in our results reveals that transmission of tuberculosis in Isfahan is, in most cases, a reactivation of previous tuberculosis infection and the role of recently transmitted disease is minor.

Genotyping of Mycobacterium tuberculosis complex isolated from humans and animals in northeastern Iran

“…In other studies conducted in Iran, the clustering ratio varied between 0.0 and 75%. The major reason for such discrepancies is the number of loci used; as the number of loci increases, the clustering ratio decreases due to the increased discriminatory power 17 , 19 , 34 , 35 , 48 , 49 . In our study, we established a high discriminatory power for MIRU-VNTR typing of 0.998 (HGDI).…”

“…There have been three previous studies regarding the circulation of Beijing genotype in Iran, ranging from 1.7 to 24%. Additionally, this genotype has been located in the northern neighboring countries of Iran, including Kazakhstan, Georgia, Russia, as well as countries in Central and East Asia [34][35][36][37][38][39][40][41] . This indicates that the Beijing genotype is spreading across the region, and highlights the importance of further research into its circulation and how it can be better managed.…”

Genetic diversity of drug-resistant Mycobacterium tuberculosis clinical isolates from Khuzestan province, Iran

“…For example, of the total isolates surveyed recently, 59.1% in northern India (Sharma et al 2017 ), 53.4% in Pakistan (Bakuła et al 2019 ), and 41.8% in Iraq (Ahmed et al 2014 ) belonged to the Delhi/CAS sub-lineage. In reviewing the articles, we did not find an independent study from Afghanistan, but Delhi/CAS was the most prevalent (36.4%) sub-lineage among Afghan refugee patients living in Iran (Riyahi Zaniani et al 2017 ). The Delhi/CAS prevalence varies in different parts of Iran, although it seems to be more common in the central provinces.…”

Fingerprinting of Mycobacterium tuberculosis isolates by MIRU-VNTR genotyping and detection of isoniazid resistance by real-time PCR

“…Similarly, low clustering rates, 2 % and 2.6 %, were observed in two previous studies from Ecuador [69, 70] respectively. Another Iranian study [71] reported that the clustering rate of the 15-locus MIRU-VNTR was 0.0 (0 %). On the other hand, a Ghanaian study [72] estimated a high clustering rate of 41.2 %, which indicates high recent TB transmission and subsequent occurrence of unsuspected outbreaks in Ghana.…”