title: Transmission of methicillin-resistant Staphylococcus aureus in long-term care facilities and their related healthcare networks.
abstract: Long-term care facilities (LTCF) are potential reservoirs for methicillin-resistant Staphylococcus aureus (MRSA), control of which may reduce MRSA transmission and infection elsewhere in the healthcare system. Whole-genome sequencing (WGS) has been used successfully to understand MRSA epidemiology and transmission in hospitals and has the potential to identify transmission between these and LTCF.
  
  
  
  Two prospective observational studies of MRSA carriage were conducted in LTCF in England and Ireland. MRSA isolates were whole-genome sequenced and analyzed using established methods. Genomic data were available for MRSA isolated in the local healthcare systems (isolates submitted by hospitals and general practitioners).
  
  
  
  We sequenced a total of 181 MRSA isolates from the two study sites. The majority of MRSA were multilocus sequence type (ST)22. WGS identified one likely transmission event between residents in the English LTCF and three putative transmission events in the Irish LTCF. WGS also identified closely related isolates present in colonized Irish residents and their immediate environment. Based on phylogenetic reconstruction, closely related MRSA clades were identified between the LTCF and their healthcare referral network, together with putative MRSA acquisition by LTCF residents during hospital admission.
  
  
  
  These data confirm that MRSA is transmitted between residents of LTCF and is both acquired and transmitted to others in referral hospitals and beyond. Our data present compelling evidence for the importance of environmental contamination in MRSA transmission, reinforcing the importance of environmental cleaning. The use of WGS in this study highlights the need to consider infection control in hospitals and community healthcare facilities as a continuum.
authors.affiliation: Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Box 157, Hills Road, Cambridge, CB2 0QQ, UK. eh439@cam.ac.uk.
authors.forename: Ewan M
authors.initials: EM
authors.lastname: Harrison
authors.affiliation: London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
authors.forename: Catherine
authors.initials: C
authors.lastname: Ludden
authors.affiliation: Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Box 157, Hills Road, Cambridge, CB2 0QQ, UK.
authors.forename: Hayley J
authors.initials: HJ
authors.lastname: Brodrick
authors.affiliation: Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Box 157, Hills Road, Cambridge, CB2 0QQ, UK.
authors.forename: Beth
authors.initials: B
authors.lastname: Blane
authors.affiliation: National MRSA Reference Laboratory, St. James's Hospital, Dublin, Ireland.
authors.forename: Gráinne
authors.initials: G
authors.lastname: Brennan
authors.affiliation: Antimicrobial Resistance and Microbial Ecology (ARME) Group, School of Medicine, National University of Ireland, Galway, Ireland.
authors.forename: Dearbháile
authors.initials: D
authors.lastname: Morris
authors.affiliation: Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Box 157, Hills Road, Cambridge, CB2 0QQ, UK.
authors.forename: Francesc
authors.initials: F
authors.lastname: Coll
authors.affiliation: Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Box 157, Hills Road, Cambridge, CB2 0QQ, UK.
authors.forename: Sandra
authors.initials: S
authors.lastname: Reuter
authors.affiliation: Cambridge University Hospitals NHS Foundation Trust, Hills Road, Cambridge, CB2 0QQ, UK.|Public Health England, Clinical Microbiology and Public Health Laboratory, Addenbrooke's Hospital, Box 236, Hills Road, Cambridge, CB2 0QW, UK.
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Brown
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Holmes
authors.affiliation: National MRSA Reference Laboratory, St. James's Hospital, Dublin, Ireland.
authors.forename: Brian
authors.initials: B
authors.lastname: O'Connell
authors.affiliation: Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK.
authors.forename: Julian
authors.initials: J
authors.lastname: Parkhill
authors.affiliation: Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Box 157, Hills Road, Cambridge, CB2 0QQ, UK.|Cambridge University Hospitals NHS Foundation Trust, Hills Road, Cambridge, CB2 0QQ, UK.|Public Health England, Clinical Microbiology and Public Health Laboratory, Addenbrooke's Hospital, Box 236, Hills Road, Cambridge, CB2 0QW, UK.
authors.forename: M Estee
authors.initials: ME
authors.lastname: Török
authors.affiliation: Antimicrobial Resistance and Microbial Ecology (ARME) Group, School of Medicine, National University of Ireland, Galway, Ireland.
authors.forename: Martin
authors.initials: M
authors.lastname: Cormican
authors.affiliation: Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Box 157, Hills Road, Cambridge, CB2 0QQ, UK.|London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.|Cambridge University Hospitals NHS Foundation Trust, Hills Road, Cambridge, CB2 0QQ, UK.|Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK.
authors.forename: Sharon J
authors.initials: SJ
authors.lastname: Peacock
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control / Q000635:transmission*; D004269:DNA, Bacterial / Q000235:genetics*; D005260:Female; D006272:Health Facility Environment / Q000458:organization & administration; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D017053:Infection Control; D008134:Long-Term Care; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics* / Q000302:isolation & purification; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D011446:Prospective Studies; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control / Q000635:transmission*; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D004269:DNA, Bacterial
keywords: Long-term care facilities; MRSA; Molecular epidemiology; Nursing home; Staphylococcus aureus; Transmission; Whole-genome sequencing