Meticillin-resistant Staphylococcus aureus in elderly residents of care homes: Colonization rates and molecular epidemiology

C. Horner*, P. Parnell, D. Hall, Angela Kearns, J. Heritage, M. Wilcox

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

Background: Meticillin-resistant . Staphylococcus aureus (MRSA) is a significant cause of mortality and morbidity in healthcare and community settings; however, there is a paucity of large-scale, longitudinal studies monitoring the occurrence of MRSA in the care home setting. Aim: To determine the molecular epidemiology of MRSA colonizing elderly residents of care homes. Methods: Residents in 65 care homes in Leeds, UK, were screened for MRSA nasal colonization in four consecutive years (2006-2009). Isolates were characterized using antibiotic susceptibility testing, detection of the Panton-Valentine leucocidin (PVL) locus, accessory gene regulator allotyping, characterization of the staphylococcal cassette chromosome . mec element, . spa-typing and pulsed-field gel electrophoresis. Findings: MRSA was recovered from 888 nasal swabs of 2492 residents and prevalence was similar (19-22%) throughout the study. Resistance to ≥3 antibiotic classes was common (34%), but resistance to only β-lactam agents was rare (3%); no PVL-positive isolates were identified. Most isolates were related to healthcare-associated epidemic-MRSA type 15 (EMRSA-15, ST22-IV); such isolates decreased in prevalence during the study (86-72%; P < 0.0001, χ2-test). The remainder belonged to five different multi-locus sequence type clonal complexes (CC). Most notably, CC59 strains increased in prevalence (10-25%; P < 0.0001, χ2-test) and were associated with high-level mupirocin resistance. Conclusions: The molecular epidemiology of MRSA in care homes is complex and dynamic. There was a high, consistent prevalence of MRSA nasal colonization, dominated by healthcare-associated strains. Vigilance is recommended; however, as high-level mupirocin resistance was associated with a single clonal group (CC59) that significantly increased in prevalence during the study.

Original languageEnglish
Pages (from-to)212-218
Number of pages7
JournalJournal of Hospital Infection
Volume83
Issue number3
DOIs
Publication statusPublished - Mar 2013

Bibliographical note

Funding Information:
This work was funded by the Policy Research Programme in the Department of Health. The views expressed are not necessarily those of the Department.

Copyright:
Copyright 2013 Elsevier B.V., All rights reserved.

Keywords

  • Care home
  • Colonization
  • Elderly
  • Meticillin-resistant Staphylococcus aureus

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