Molecular epidemiology of multi- and extensively-drug-resistant Mycobacterium tuberculosis in Ireland, 2001-2014.

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.

Tuberculosis incidence in the Irish Traveller population in Ireland from 2002 to 2013.

The health status of the Irish Traveller ethnic minority is low compared to the general population in Ireland in terms of infant mortality rates and life expectancies. Respiratory disease is an area of health disparity manifested as excess mortalities in Traveller males and females. In this study, we examined the available data with regard to tuberculosis (TB) notifications in Ireland from 2002 to 2013. We found an increase in TB notifications in Irish Travellers from 2010 onwards. This resulted in a crude incidence rate for TB in Irish Travellers that was approximately threefold higher than that of the white Irish-born population in 2011 and 2012. An outbreak of TB in Irish Travellers in 2013 increased this differential further, but when outbreak-linked cases were excluded, a higher incidence rate was still observed in Irish Travellers relative to the general population and to white Irish-born. The mean age of a TB patient was 26 years in Irish Travellers compared to 43 years in the general population, and 49 years in white Irish-born. Based on available data, Irish Travellers exhibit a higher incidence rate and younger age distribution of TB compared to white Irish-born and the general population. These observations emphasize the importance of routine use of ethnicity identifiers in the management of TB and other notifiable communicable illnesses in Ireland. They also have implications for the orientation of preventive services to address health disparities in Irish Travellers and other ethnic minority groups.

Phylogenetic lineages of tuberculosis isolates in New Zealand and their association with patient demographics.

SETTING: In New Zealand, the lineage genotypes of Mycobacterium tuberculosis clinical isolates and their role in the epidemiology of tuberculosis (TB) are currently unknown. OBJECTIVE: 1) To measure the relative frequency of each phylogenetic lineage of the M. tuberculosis complex in New Zealand, and 2) to examine its relationship with patient demographics and multidrug-resistant TB (MDR-TB). METHODS: All non-duplicate M. tuberculosis complex isolates recovered in 2010 and 2011 underwent large sequence polymorphism and/or single nucleotide polymorphism analyses. Mycobacterial interspersed repetitive units (MIRU) profiling was also performed for cluster identification. RESULTS: New Zealand isolates were dominated by lineage 4 (Euro-American: 37.8%, 95%CI 33.6-42.2), followed by lineage 1 (Indo-Oceanic: 22.6%, 95%CI 19.1-26.5), lineage 2 (East Asian: 19.5%, 95%CI 16.2-23.3) and lineage 3 (East-African Indian, which included Central Asian: 17.7%, 95%CI 14.5-21.3). Lineage 2 accounted for 58.1% of MDR-TB cases from 2002 to 2011. Among immigrants, the predominant lineages corresponded to high prevalence lineages in the country of origin. In New Zealand-born individuals, Maori and NZ Europeans share the same predominant lineage, lineage 4, with a higher proportion of non-unique MIRU types observed in Maori cases. Lineage 3 was more prevalent in Maori than in NZ Europeans. CONCLUSION: In New Zealand, M. tuberculosis complex phylogenetic lineage is associated with TB epidemiology in terms of ethnicity, country of origin and MDR-TB.