J Korean Med Sci.  2011 May;26(5):604-611. 10.3346/jkms.2011.26.5.604.

Molecular Epidemiologic Analysis of Methicillin-Resistant Staphylococcus aureus Isolates from Bacteremia and Nasal Colonization at 10 Intensive Care Units: Multicenter Prospective Study in Korea

• Kwon JC
• Kim SH
• Park SH
• Choi SM
• Lee DG
• Choi JH
• Park C
• Shin NY
• Yoo JH

• KMID: 1777857
• DOI: http://doi.org/10.3346/jkms.2011.26.5.604

Abstract

We investigated molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) isolated at 10 intensive care units (ICUs) in Korea. MRSA isolates from bacteremia and nasal colonization were collected prospectively from October 2008 through May 2009 at 10 University-affiliated hospital ICUs. A total of 83 and 175 MRSA strains were isolated from bacteremia and nasal colonization, respectively. Acquired group accounted for 69.9% (n = 58) of bacteremia and 73.1% (n = 128) of nasal colonization. Pulsed-field gel electrophoresis (PFGE) type B (SCCmec type II/ST5) was dominant in the acquired group followed by PFGE type D (SCCmec type IVA/ST72; a community genotype). Seven of 58 (12.1%) acquired bacteremia and 15 of 128 (11.8%) acquired nasal colonizations had SCCmec type IVA/ST72 genotype, which indicated that the community genotype had already emerged as a cause of ICU acquired MRSA infection or colonization. Antibiotic resistance rates to ciprofloxacin, tetracycline, clindamycin and trimethoprim/sulfamethoxazole were 84.4%, 67.1%, 78.1%, and 12.0%, respectively. Susceptibility to ciprofloxacin best predicted a community genotype (sensitivity 96.5%; specificity 96.9%; odds ratio 861; 95% confidence interval 169-4,390, P < 0.001) and the positive predictive value was 90.2%. Among 23 nasal re-colonized strains, 7 MRSA strains (30.4%) were different from the originally colonized strains on the basis of PFGE types.

Keyword

Methicillin-Resistant Staphylococcus aureus; Intensive Care Units; Bacteremia; Molecular Epidemiology

MeSH Terms

Adolescent
Adult
Aged
Aged, 80 and over
Bacteremia/*epidemiology/microbiology
Cross Infection/epidemiology/genetics
Drug Resistance, Multiple, Bacterial
Electrophoresis, Gel, Pulsed-Field
Female
Genotype
Humans
*Intensive Care Units
Male
Methicillin-Resistant Staphylococcus aureus/*genetics/isolation & purification
Microbial Sensitivity Tests
Middle Aged
Molecular Epidemiology
Molecular Typing
Nasal Lavage Fluid/*microbiology
Prospective Studies
Republic of Korea/epidemiology
Staphylococcal Infections/*epidemiology/genetics/microbiology

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