Vancomycin-resistant Enterococcus faecium (VREfm) is a leading cause of nosocomial infections globally. Ireland has the highest prevalence of VREfm bloodstream infections (BSIs) in Europe but little is known about VREfm molecular epidemiology in Irish hospitals because traditional typing methods are poorly discriminatory. Currently, at-risk patients are routinely screened rectally for VREfm, with subsequent isolation/cohorting of VREfm-positive patients incurring extensive healthcare costs. Little is known about the prevalence of VREfm carriage beyond these at-risk groups or how this contributes to the nosocomial burden of VREfm. This study aims to investigate the true prevalence of VREfm carriage among patients in a large acute Irish hospital and the molecular epidemiology of nosocomial VREfm in Ireland using whole-genome sequencing (WGS) typing methods that provide robust typing of VREfm. Rectal screening swabs will be obtained from patients on all wards of St. James’s Hospital Dublin, over 10-months, together with contemporaneous environmental and air samples. VREfm screening isolates will also be obtained from six additional Irish hospitals during a two-week period, as well as vancomycin-susceptible E. faecium (VSEfm) and VREfm from BSIs in all hospitals involved over a 12-month period. Isolates and samples will be investigated for VREfm or confirmed as VREfm/VSEfm by PCR, followed by culturing on Oxoid Brilliance VRE agar and CHROMagar Orientation media. All isolates will undergo Illumina MiSeq short-read WGS and core-genome MLST and single nucleotide variant analysis for population and preliminary vancomycin-resistance encoding transposon analysis. Approximately 5% of VREfm isolates, representing vancomycin-resistance transposon differences identified following the alignment of MiSeq reads, will undergo Oxford Nanopore MinION long-read WGS, to determine the genetic organisation of the transposons. The study’s findings will provide a robust evidence base to inform infection prevention and control strategies to minimise the spread of VREfm and provide invaluable data on the emergence, spread and evolution of VREfm.
