Molecular epidemiology of multi- and extensively-drug-resistant Mycobacterium tuberculosis in Ireland, 2001–2014 Academic Article uri icon


  • 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.


  • Roycroft, E
  • O'Toole, Ronan F
  • Fitzgibbon, MM
  • Montgomery, L
  • O'Meara, M
  • Downes, P
  • Jackson, S
  • O'Donnell, J
  • Laurenson, IF
  • McLaughlin, AM
  • Keane, J
  • Rogers, TR

publication date

  • 2018