title: Differences between methicillin-resistant Staphylococcus aureus bacteremic isolates harboring type IV and type V staphylococcal cassette chromosome mec genes based on prior patient healthcare exposure.
abstract: This observational study enrolled adult patients with bacteremia due to methicillin-resistant Staphylococcus aureus (MRSA) who were treated at the emergency department of a teaching hospital from 2001 to 2007. MRSA isolates with type IV and type V staphylococcal cassette chromosome mec (SCCmec) genes (SCC IV/V-MRSA) were included in the final analysis. Healthcare-associated SCC IV/V-MRSA (HA-SCC IV/V-MRSA) and community-acquired SCC IV/V-MRSA (CA-SCC IV/V-MRSA) were defined as the identification of an SCC IV/V-MRSA isolate from a patient with and without healthcare-associated risk factors, respectively. Thirty-four cases of CA-SCC IV/V-MRSA (20 SCCmec type IV, 14 SCCmec type V) and 81 cases of HA-SCC IV/V-MRSA (59 SCCmec type IV, 22 SCCmec type V) bacteremia were identified. Vascular device-associated infections were a significant infection source in HA-SCC IV/V-MRSA bacteremia cases. SCCmec type IV HA-SCC IV/V-MRSA isolates (3.4%) were significantly less likely to carry the Panton-Valentine leukocidin (PVL) gene than SCCmec type IV CA-SCC IV/V-MRSA isolates (35.0%, p = 0.001). The 90-day cumulative probability of survival was 76% for patients with CA-SCC IV/V-MRSA bacteremia and 66% for patients with HA-SCC IV/V-MRSA bacteremia (p = 0.247, by the Wilcoxon rank-sum test). Significant differences in antimicrobial susceptibility were observed between bacterial isolates from patients with CA-SCC IV/V-MRSA bacteremia and HA-SCC IV/V-MRSA bacteremia.
authors.affiliation: Department of Emergency Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan, Republic of China.
authors.forename: S-Y
authors.initials: SY
authors.lastname: Chen
authors.forename: J-L
authors.initials: JL
authors.lastname: Wang
authors.forename: T H-H
authors.initials: TH
authors.lastname: Chen
authors.forename: W-C
authors.initials: WC
authors.lastname: Chiang
authors.forename: J-T
authors.initials: JT
authors.lastname: Wang
authors.forename: S-C
authors.initials: SC
authors.lastname: Chen
authors.forename: S-C
authors.initials: SC
authors.lastname: Chang
authors.forename: P-R
authors.initials: PR
authors.lastname: Hsueh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016470:Bacteremia / Q000453:epidemiology / Q000382:microbiology*; D002876:Chromosomes, Bacterial / Q000235:genetics; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000382:microbiology*; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology*; D005260:Female; D006785:Hospitals, University; D006801:Humans; D008297:Male; D016106:Methicillin Resistance / Q000235:genetics; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification* / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D013624:Taiwan / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents