A snapshot of genetic lineages of Mycobacterium tuberculosis in Ireland over a two-year period, 2010 and 2011.
Mycobacterial interspersed repetitive-unit-variable-number tandem repeat typing alone was used to investigate the genetic lineages among 361 Mycobacterium tuberculosis strains circulating in Ireland over a two-year period, 2010 and 2011. The majority of isolates, 63% (229/361), belonged to lineage 4 (Euro-American), while lineages 1 (Indo-Oceanic), 2 (East-Asian) and 3 (East-African–Indian) represented 12% of isolates each (42/361, 45/361, and 45/361, respectively). Sub-lineages Beijing (lineage 2), East-African–Indian (lineage 1) and Delhi/central-Asian (lineage 3) predominated among foreign-born cases, while a higher proportion of Euro-American lineages were identified among cases born in Ireland. Eighteen molecular clusters involving 63 tuberculosis (TB) cases were identified across four sub-lineages of lineage 4. While the mean cluster size was 3.5 TB cases, the largest cluster (involving 12 Irish-born cases) was identified in the Latin American–Mediterranean sub-lineage. Clustering of isolates was higher among Irish-born TB cases (47 of 63 clustered cases), whereas only one cluster (3/63) involved solely foreign-born individuals. Four multidrug-resistant cases identified during this period represented lineages 2 and 4. This study provides the first insight into the structure of the M. tuberculosis population in Ireland.
Irish Mycobacteria Reference Laboratory, St. James Hospital, Dublin, Ireland. MFitzgibbon@STJAMES.IE
M M
MM
Fitzgibbon
N
N
Gibbons
E
E
Roycroft
S
S
Jackson
J
J
O'Donnell
D
D
O'Flanagan
T R
TR
Rogers
D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000235:genetics*; D004586:Electrophoresis; D060005:Genotyping Techniques / Q000379:methods; D006801:Humans; D007494:Ireland / Q000453:epidemiology; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000302:isolation & purification*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011159:Population Surveillance; D015995:Prevalence; D020080:Tandem Repeat Sequences; D014376:Tuberculosis / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology*
D004269:DNA, Bacterial