Multiple distinct outbreaks of Panton–Valentine leucocidin-positive community-associated meticillin-resistant Staphylococcus aureus in Ireland investigated by whole-genome sequencing

BackgroundPanton–Valentine leucocidin (PVL)-positive community-associated meticillin-resistant Staphylococcus aureus (CA-MRSA) is increasingly associated with infection outbreaks.AimTo investigate multiple suspected PVL-positive CA-MRSA outbreaks using whole-genome sequencing (WGS).MethodsForty-six outbreak-associated isolates from 36 individuals at three separate Irish hospitals (H1–H3) and incidents involving families H2 were investigated by multi-locus sequence typing (wgMLST).FindingsTwo clusters (CH1 CH2) consisting of 8/10 6/6 t008 ST8-MRSA-IVa H1 H2, respectively, identified. Within each cluster, neighbouring separated ?5 allelic differences; however, ?73 differences identified between the clusters, indicating two independent outbreaks. Isolates H3 maternity unit formed (CH3–SCI CH3–SCII) composed four PVL-negative t4667 ST5-MRSA-V 14 t002 ST5-MRSA-IVc isolates, respectively. ?24 differences, whereas both 1822 distinct Eight t127 ST1-MRSA-V+fus t267 ST97-MRSA-V+fus H2-associated FC1 (N = 4) FC2 7) (FC1 (t127), (t127) (t267)). Neighbouring within closely related exhibited ?7 differences. Intrafamilial transmission was apparent, but detection ?48 indicated no interfamilial transmission.ConclusionThe frequent importation into healthcare settings, association a serious ongoing concern. WGS highly discriminatory, informative method for deciphering such conclusively. Panton–Valentine To (WGS). Forty-six (wgMLST). Two transmission. The