Emerging resistant clone of Mycobacterium tuberculosis in west Asia
2016; Elsevier BV; Volume: 16; Issue: 12 Linguagem: Inglês
10.1016/s1473-3099(16)30460-1
ISSN1474-4457
Autores Tópico(s)Infectious Diseases and Tuberculosis
ResumoA clinical dimension has become recognised in the population structure of Mycobacterium tuberculosis: certain lineages, sublineages, or even clones are more medically significant than are others. Here, I would like to draw attention to one intriguing, but apparently underestimated M tuberculosis genotype. Until recently endemic in southern Iran, wider propagation has started in west and south Asia, already as a multidrug resistant (MDR) strain. Phylogenetically, the genotype is a part of the large Euro-American superlineage of M tuberculosis. Once consecutively misassigned to the Haarlem and Ural families, the genotype still holds an awkward designation of NEW-1. Its molecular signature derives from a characteristic spoligotyping profile with absent signals at positions 2, 29–31, and 33–36 (prototype spoligotype SIT127; figure). In my review in 2012,1Mokrousov I The quiet and controversial: Ural family of Mycobacterium tuberculosis.Infect Genet Evol. 2012; 12: 619-629Crossref PubMed Scopus (46) Google Scholar I suggested, first, NEW-1's phylogeographic specificity for Iran, more precisely, southern Iran, and second, its historical eastward propagation via the Silk Road. However, the dispersal pattern of this genotype in the past 15–20 years has undergone remarkable changes in both volume and content (figure). In Iran, in addition to the already high prevalence of NEW-1 in the south (25% of M tuberculosis cases) and northeast (10%), prevalence has increased substantially in the north (Tehran) from 0·2% to 20·5%.1Mokrousov I The quiet and controversial: Ural family of Mycobacterium tuberculosis.Infect Genet Evol. 2012; 12: 619-629Crossref PubMed Scopus (46) Google Scholar, 2Farnia P Masjedi MR Mirsaeidi M et al.Prevalence of Haarlem I and Beijing types of Mycobacterium tuberculosis strains in Iranian and Afghan MDR-TB patients.J Infect. 2006; 53: 331-336Summary Full Text Full Text PDF PubMed Scopus (63) Google Scholar, 3Khanipour S Ebrahimzadeh N Masoumi M et al.Haarlem 3 is the predominant genotype family in multidrug-resistant and extensively drug-resistant Mycobacterium tuberculosis in the capital of Iran: a 5-year survey.J Glob Antimicrob Resist. 2016; 5: 7-10Summary Full Text Full Text PDF PubMed Scopus (11) Google Scholar In refugees from Afghanistan in Tehran, prevalence of the genotype increased from 2% to 70% 2Farnia P Masjedi MR Mirsaeidi M et al.Prevalence of Haarlem I and Beijing types of Mycobacterium tuberculosis strains in Iranian and Afghan MDR-TB patients.J Infect. 2006; 53: 331-336Summary Full Text Full Text PDF PubMed Scopus (63) Google Scholar, 4Feyisa SG Haeili M Zahednamazi F et al.Molecular characterization of Mycobacterium tuberculosis isolates from Tehran, Iran by restriction fragment length polymorphism analysis and spoligotyping.Rev Soc Bras Med Trop. 2016; 49: 204-210Crossref PubMed Scopus (18) Google Scholar (although the Feyisa and colleagues' study could be affected by small sample size). In Pakistan, prevalence of NEW-1 remains modest, but has increased significantly (p<0·0001).5Tanveer M Hasan Z Siddiqui AR et al.Genotyping and drug resistance patterns of M. tuberculosis strains in Pakistan.BMC Infect Dis. 2008; 8: 171Crossref PubMed Scopus (66) Google Scholar, 6Ali A Hasan Z Jafri S et al.Mycobacterium tuberculosis Central Asian Strain (CAS) lineage strains in Pakistan reveal lower diversity of MIRU loci than other strains.Int J Mycobacteriol. 2014; 3: 108-116Crossref PubMed Scopus (13) Google Scholar What is worse, results from studies in northern Iran and Pakistan have shown a significant association between NEW-1 and MDR.3Khanipour S Ebrahimzadeh N Masoumi M et al.Haarlem 3 is the predominant genotype family in multidrug-resistant and extensively drug-resistant Mycobacterium tuberculosis in the capital of Iran: a 5-year survey.J Glob Antimicrob Resist. 2016; 5: 7-10Summary Full Text Full Text PDF PubMed Scopus (11) Google Scholar, 6Ali A Hasan Z Jafri S et al.Mycobacterium tuberculosis Central Asian Strain (CAS) lineage strains in Pakistan reveal lower diversity of MIRU loci than other strains.Int J Mycobacteriol. 2014; 3: 108-116Crossref PubMed Scopus (13) Google Scholar Furthermore, 10–15 years ago, NEW-1 strains in countries farther from Iran (eg, Bulgaria, Kazakhstan, Kyrgyzstan) were mainly or exclusively drug-susceptible. However, their situation is also changing. Data from a comprehensive longitudinal study in Bulgaria showed an increase from a single drug-susceptible isolate in 2006 to the circulation of MDR strains in 2009–11.7Panaiotov S Bachiyska E Yordanova S et al.Genetic biodiversity of drug sensitive and multidrug resistant strains of Mycobacterium tuberculosis in Bulgaria.Meditsinski Pregled. 2016; 52 (in Bulgarian).: 47-54Google Scholar Immigration from Afghanistan was suggested to be responsible for SIT127 transmission in Iran.4Feyisa SG Haeili M Zahednamazi F et al.Molecular characterization of Mycobacterium tuberculosis isolates from Tehran, Iran by restriction fragment length polymorphism analysis and spoligotyping.Rev Soc Bras Med Trop. 2016; 49: 204-210Crossref PubMed Scopus (18) Google Scholar On a global scale, current migration flows within and beyond this region in Asia, and especially, an ongoing immigration from Afghanistan, highlight an alarming possibility of the wider dissemination of these strains (appendix). In summary, the NEW-1 genotype of M tuberculosis (or its subtype) has increasing circulation in Iran and its neighbours and the capacity to rapidly acquire drug resistance. Certain refugee migration flows make this clone of particular epidemiological and clinical concern because of its potential ability to jeopardise tuberculosis control programmes in Iran and other countries. Consequently, an indepth pathogenomic and phylogeographic study of this epidemic and potentially pandemic clone would be highly relevant and pertinent. I acknowledge funding from the Russian Science Foundation (grant #14-14-00292). I declare no competing interests. Download .pdf (.62 MB) Help with pdf files Supplementary appendix
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