title: Carriage rates of methicillin-resistant Staphylococcus aureus (MRSA) depend on anatomic location, the number of sites cultured, culture methods, and the distribution of clonotypes.
abstract: The present study was carried out to determine how active surveillance for methicillin-resistant Staphylococcus aureus (MRSA) could be improved by the use of enrichment broth and the inclusion of extra-nasal sites with nares cultures. Molecular typing was also performed to identify colonization by single or multiple strains. Surveillance cultures for MRSA were obtained from 650 patients on admission to a medical and surgical intensive care unit (ICU) in Taiwan. MRSA was detected on directly plated vs. broth-enrichment cultures in any site at 10.0% vs. 24.2%, nares 8.2% vs. 17.5%, throat 4.8% vs. 13.4%, axilla 1.2% vs. 9.1%, and perineum 1.8% vs. 9.5%, respectively. Nares cultures alone detected only 81.5% and 72.5% of all colonized patients by direct and broth-enriched cultures, respectively. The molecular typing of 68 isolates from 17 patients revealed that multisite isolates were largely indistinguishable within each patient, but four patients had multiple subtypes and another three patients had different clonotypes. The detection of MRSA carriers was considerably enhanced by broth-enrichment cultures at multiple anatomic sites and simultaneous colonization by multiple strains at different sites can occur. Epidemiological studies are needed to determine the likelihood of subsequent nosocomial infection among colonized patients detected via direct nasal versus broth-enriched cultures from multiple sites.
authors.affiliation: Division of Infectious Diseases, National Health Research Institutes, 35 Keyan Road, Zhunan, Taiwan.
authors.forename: T-L Y
authors.initials: TL
authors.lastname: Lauderdale
authors.forename: J-T
authors.initials: JT
authors.lastname: Wang
authors.forename: W-S
authors.initials: WS
authors.lastname: Lee
authors.forename: J-H
authors.initials: JH
authors.lastname: Huang
authors.forename: L C
authors.initials: LC
authors.lastname: McDonald
authors.forename: I-W
authors.initials: IW
authors.lastname: Huang
authors.forename: S-C
authors.initials: SC
authors.lastname: Chang
mesh_terms: D001365:Axilla / Q000382:microbiology; D001431:Bacteriological Techniques; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology*; D003470:Culture Media; D006786:Hospitals, Urban; D006801:Humans; D007362:Intensive Care Units; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D009296:Nasal Cavity / Q000382:microbiology*; D010502:Perineum / Q000382:microbiology; D010614:Pharynx / Q000382:microbiology; D011159:Population Surveillance / Q000379:methods; D013183:Sputum / Q000382:microbiology; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology; D013624:Taiwan / Q000453:epidemiology
chemical_list: D003470:Culture Media
references.citation: J Clin Microbiol. 2007 Jun;45(6):2011-3
references.pmid: 17428926
references.citation: Emerg Infect Dis. 2005 Nov;11(11):1760-3
references.pmid: 16318733
references.citation: Clin Infect Dis. 1994 Dec;19(6):1123-8
references.pmid: 7888543
references.citation: J Clin Microbiol. 2000 Mar;38(3):1008-15
references.pmid: 10698988
references.citation: Clin Infect Dis. 2005 Feb 1;40(3):405-9
references.pmid: 15668864
references.citation: Am J Infect Control. 2007 Dec;35(10):631-7
references.pmid: 18063126
references.citation: Infect Control Hosp Epidemiol. 1988 May;9(5):204-5
references.pmid: 3286750
references.citation: J Clin Microbiol. 2003 Jul;41(7):3163-6
references.pmid: 12843058
references.citation: Infect Control Hosp Epidemiol. 2007 Mar;28(3):249-60
references.pmid: 17326014
references.citation: Antimicrob Agents Chemother. 1995 Sep;39(9):2169
references.pmid: 8540742
references.citation: Eur J Clin Microbiol Infect Dis. 2009 Apr;28(4):363-9
references.pmid: 18855028
references.citation: Clin Infect Dis. 2008 May 1;46(9):1368-73
references.pmid: 18419438
references.citation: Clin Infect Dis. 2008 Nov 1;47(9):1237-8
references.pmid: 18831703
references.citation: Bacteriol Rev. 1963 Mar;27:56-71
references.pmid: 14000926
references.citation: Clin Infect Dis. 2008 Nov 1;47(9):1238-9; author reply 1239-40
references.pmid: 18831705
references.citation: J Hosp Infect. 2004 Apr;56(4):321-5
references.pmid: 15066745
references.citation: J Clin Microbiol. 1989 Jul;27(7):1471-6
references.pmid: 2768437
references.citation: Eur J Clin Microbiol Infect Dis. 2009 Feb;28(2):115-27
references.pmid: 18688664
references.citation: J Clin Microbiol. 2009 Oct;47(10):3326-8
references.pmid: 19675216
references.citation: J Clin Microbiol. 2003 Nov;41(11):5113-20
references.pmid: 14605147
references.citation: J Med Microbiol. 2007 Apr;56(Pt 4):491-494
references.pmid: 17374889
references.citation: Clin Infect Dis. 2008 Jun 1;46(11):1717-25
references.pmid: 18494098
references.citation: J Clin Microbiol. 2006 Nov;44(11):4234-6
references.pmid: 16957041
references.citation: Emerg Infect Dis. 2007 Mar;13(3):494-7
references.pmid: 17552111
references.citation: J Hosp Infect. 2005 Oct;61(2):155-61
references.pmid: 16026896
references.citation: J Clin Microbiol. 1995 Sep;33(9):2233-9
references.pmid: 7494007
references.citation: N Engl J Med. 2001 Jan 4;344(1):11-6
references.pmid: 11136954
references.citation: Infect Control Hosp Epidemiol. 2006 Oct;27(10):1063-7
references.pmid: 17006813
references.citation: Clin Microbiol Rev. 1997 Jul;10(3):505-20
references.pmid: 9227864
references.citation: Antimicrob Agents Chemother. 2007 Jan;51(1):264-74
references.pmid: 17043114