Molecular epidemiology of multi- and extensively-drug-resistant Mycobacterium tuberculosis in Ireland, 2001–2014. Issue 1 (January 2018)

• Record Type: Journal Article
• Authors: Roycroft, E.; O'Toole, R.F.; Fitzgibbon, M.M.; Montgomery, L.; O'Meara, M.; Downes, P.; Jackson, S.; O'Donnell, J.; Laurenson, I.F.; McLaughlin, A.M.; Keane, J.; Rogers, T.R.
• Is Part Of: Journal of infection. Volume 76:Issue 1(2018)
• Page Start: 55
• Page End: 67
• Publication Date: 2018-01
• Subjects: Tuberculosis -- Molecular epidemiology -- Drug resistance; Infection -- Periodicals; Bacterial Infections -- Periodicals; Communicable Diseases -- Periodicals; Electronic journals; 616.905
• DOI: 10.1016/j.jinf.2017.10.002
• Languages: English
• ISSNs: 0163-4453

Abstract

Highlights: Prevalence of MDR/XDR-TB in Ireland, while low, still poses a threat to Public Health. High lineage diversity was found among MDR/XDR-TB strains. "Cross-border" European Union strains have been found in Ireland. Evidence of in vivo micro-evolution of strains was found during the study. Putative transmission between an Irish-born patient and a non-Irish born patient was discovered. Summary: Objectives: The primary objective of this work was to examine the acquisition and spread of multi-drug resistant (MDR) tuberculosis (TB) in Ireland. Methods: All available Mycobacterium tuberculosis complex (MTBC) isolates (n = 42), from MDR-TB cases diagnosed in Ireland between 2001 and 2014, were analysed using phenotypic drug-susceptibility testing, Mycobacterial-Interspersed-Repetitive-Units Variable-Number Tandem-Repeat (MIRU-VNTR) genotyping, and whole-genome sequencing (WGS). Results: The lineage distribution of the MDR-TB isolates comprised 54.7% Euro-American, 33.3% East Asian, 7.2% East African Indian, and 4.8% Indo-Oceanic. A significant association was identified between the East Asian Beijing sub-lineage and the relative risk of an isolate being MDR. Over 75% of MDR-TB cases were confirmed in non-Irish born individuals and 7 MIRU-VNTR genotypes were identical to clusters in other European countries indicating cross-border spread of MDR-TB to Ireland. WGS data provided the first evidence in Ireland of in vivo microevolution of MTBC isolates from drug-susceptible to MDR, and from MDR to extensively-drug resistant (XDR). In addition, they found that the katG S315T isoniazid and rpoB S450L rifampicin resistance mutations were dominant across the different MTBC lineages. Conclusions: Our molecular epidemiological analyses identified the spread of MDR-TB to Ireland from other jurisdictions and its potential to evolve to XDR-TB.