title: Throat and rectal swabs may have an important role in MRSA screening of critically ill patients.
abstract: OBJECTIVE
  Methicillin-resistant Staphylococcus aureus (MRSA) is a major problem in intensive care units (ICU). International guidelines recommend screening patients for MRSA on admission, although consensus on sites required for optimum detection has not been reached. Our aim was to determine whether throat and rectal swabs identified a significant number of additional MRSA-colonised patients not captured by swabbing at keratinized skin carriage sites (anterior nares, perineum and axillae).
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  30-Bed medical and surgical ICU in a tertiary teaching hospital.
  
  
  METHODS
  One thousand four hundred and eighty adult patients consecutively admitted over 15 months.
  
  
  RESULTS
  Swabs from carriage sites (anterior nares, perineum, axillae, throat and rectum), wounds and clinical samples taken within 48 h of ICU admission were analysed to identify patients admitted with MRSA. A complete set of carriage swabs were received from 1,470 patients. 105 (7%) patients were admitted with MRSA of which 63 (60%) were detected by a pooled keratinized skin swab (anterior nares, perineum, axillae). A further 36 (34%) patients were detected only by throat or rectal swabs. Indeed, throat and rectal swabs combined had a higher sensitivity than pooled keratinised skin swabs (76 vs. 60% P = 0.0247). Swabs from all carriage sites together detected 95% (100) of MRSA positive patients, with five patients being positive at wound sites only.
  
  
  CONCLUSIONS
  The throat and rectum are important and potentially hidden sites of MRSA carriage in critically ill patients. These findings prompt the need for larger studies to determine the most cost-effective screening strategy for MRSA detection.
  
  
  BACKGROUND
  Non-pulmonary nosocomial infections.
authors.affiliation: Department of Infection, Guy's and St. Thomas' National Health Service Foundation Trust, Lambeth Palace Road, London, SE1 7EH, UK. rahul.batra@gstt.nhs.uk
authors.forename: Rahul
authors.initials: R
authors.lastname: Batra
authors.forename: Alice C
authors.initials: AC
authors.lastname: Eziefula
authors.forename: Duncan
authors.initials: D
authors.lastname: Wyncoll
authors.forename: Jonathan
authors.initials: J
authors.lastname: Edgeworth
mesh_terms: D002353:Carrier State / Q000175:diagnosis*; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data; D008403:Mass Screening / Q000379:methods*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification*; D010614:Pharynx / Q000382:microbiology*; D011446:Prospective Studies; D012007:Rectum / Q000382:microbiology*; D012867:Skin / Q000382:microbiology; D014947:Wounds and Injuries / Q000382:microbiology