Spoligotyping and drug resistance patterns of Mycobacterium tuberculosis isolates from five provinces of Iran

Abstract

Tuberculosis (TB) persists as a public health problem in Iran. Characterization of Mycobacterium tuberculosis isolates circulating in this area will contribute to understand and control the spread of the strains. The aims of this study were to understand the genetic diversity and drug susceptibility of M. tuberculosis isolates circulating in Iran and to analyze the relationship between genotype and drug resistance. A total of 291 M. tuberculosis isolates collected from TB patients were genotyped by spoligotyping. Drug susceptibility testing was performed using proportion method. Spoligotyping resulted in 75 distinct patterns. 86.2% of isolates were grouped in 35 clusters while the remaining isolates were unique. Ural was found to be the most predominant lineage (34.3%) followed by Central Asian strain (CAS) (24%), T (18.2%), Manu2 (7.5%) and Latin American-Mediterranean (LAM) (6.1%). The five largest clusters were Ural/Spoligotype International Type (SIT)127 (15.8%), CAS1/SIT26 (9.2%), T1/SIT53 (6.1%), T1/SIT284 (5.4%), and CAS1/SIT25 (4.4%). About 5% of isolates had multidrug resistance (MDR) and 10% had other resistance. MDR was significantly associated with Beijing strains, but not with Ural family. This study highlights dominance of Ural, CAS, and T families in Iran. Biogeographic specificity of CAS and T families to border provinces of Iran including Sistan-Baluchestan and Kermanshah, respectively, suggested that this family strains might be transmitted from these regions to other provinces of the country.

Molecular characterization of Mycobacterium tuberculosis isolates from Tehran, Iran by restriction fragment length polymorphism analysis and spoligotyping

“…The Ural lineage (formerly the H4 sub-lineage) has recently been excluded from the Haarlem family based on not harboring the mgtC545 (CGC→CAC) mutation (25) . Our results are in agreement with those of a study performed by Haeili et al (5) , who reported that the Ural (34%), CAS (24%), and T (18.2%) families were the first, second, and third most predominant families, respectively, in MTB isolates obtained from 5 different provinces in Iran between 2010-2012. In another study performed by Kazemian et al (26) , who studied the genetic diversity of MDR and extensively drug-resistant MTB isolates from Iran, the Beijing (32.5%), Ural (22.5%), and CAS (10%) families were found to be the most common.…”

“…Even though it is time-consuming, labor-intensive, and requires successive DNA purification, and despite the difficulty of analyzing strains with a low copy number of IS6110 (< 6 copies), it is still the gold standard method for typing MTB strains (5) (9) . The spoligotyping method, which is a rapid polymerase chain reaction (PCR)-based method requiring small amounts of genomic DNA, has not been used as widely as RFLP, but it is suitable for differentiating MTB complex and for identifying the Beijing strains of MTB.…”

“…Despite a promising decline in the incidence rate of TB in Iran from 36 cases per 100,000 people in 1990 to 17 cases per 100,000 people in 2010 (2) , TB continues to be a major public health concern in Iran. Risk factors such as drug addiction, human immunodeficiency virus (HIV) infection, drug-resistant Mycobacterium tuberculosis (MTB) strains, population ageing (3) , and sharing borders with 4 countries that have high rates of TB incidence, namely Afghanistan, Pakistan, Turkmenistan, and Iraq (4) (5) ,have contributed to a persistent problem of TB in Iran. According to a recent report, approximately 21 per 100,000 Iranians suffered from TB in 2013 (6) .…”

Genotyping of Mycobacterium tuberculosis Isolates from Hormozgan Province of Iran Based on 15-Locus MIRU-VNTR and Spoligotyping

“…The estimated degree of diversity was found to be 55 ( D = (21/38) ∗ 100) by spoligotyping and 73.6 ( D = (28/38) ∗ 100) by MIRU-VNTR. This high degree of diversity obtained for isolates from this province is comparably higher than that obtained for isolates from other provinces including 33 for Tehran (37 spoligopatterns between 110 isolates), 50 for Alborz (7 spoligopatterns between 14 isolates), 40 for Sistan-Baluchestan (36 spoligopatterns between 89 isolates), 43 for Hormozgan (20 spoligopatterns between 46 isolates), and 40 for Kermanshah (13 spoligopatterns between 32 isolates) calculated based on spoligotyping (unpublished data from [34]). This is also comparable to degree of diversity obtained for MTB isolates from other provinces calculated based on MIRU-VNTR method which was 57 for isolates from Tehran, 62 for isolates from Kermanshah, and 71 for isolates from Sistan-Baluchestan (unpublished data from [27]).…”

Laboratory cross-contamination of Mycobacterium tuberculosis in Northwest of Iran

“…Tuberculosis transmission recently has been increased in Iran [1] and specific strains are coming to be prevalent due to immigrations from neighbor countries [20]. Therefore, the number of referred patients to TB labs has been increased which causes higher possibility of cross-contamination, unless we prevent contaminations and detect possible cases.…”