title: A novel methicillin-resistance cassette in community-acquired methicillin-resistant Staphylococcus aureus isolates of diverse genetic backgrounds.
abstract: Until recently, it has been unclear whether community-acquired (CA) methicillin-resistant Staphylococcus aureus (MRSA) isolates represent the spread of hospital MRSA isolates into the community. In 2 CA-MRSA isolates, a novel genetic element, designated staphylococcal cassette chromosome mec (SCCmec) type IV, was found; it differs from SCCmec types I-III in its small size and absence of non-beta-lactam genetic-resistance determinants. To study the prevalence of type IV SCCmec, polymerase chain reaction characterization of SCCmec was performed on DNA from 12 CA-MRSA isolates. The 12 CA-MRSA isolates were from diverse genetic backgrounds, as evidenced by their stratification into 5 pulsed-field gel electrophoresis types, 4 coagulase types, and 2 ribotypes. Eleven of the 12 isolates contained the novel SCCmec type IV element. Ten were resistant only to beta-lactam antibiotics. SCCmec type IV is present on the genome of CA-MRSA isolates. Its relatively small size and presence in isolates of diverse genetic backgrounds suggest that it may spread among S. aureus isolates.
authors.affiliation: Department of Pediatrics, University of Chicago, Chicago, Illinois 60637, USA. rdaum@peds.bsd.uchicago.edu
authors.forename: Robert S
authors.initials: RS
authors.lastname: Daum
authors.forename: Teruyo
authors.initials: T
authors.lastname: Ito
authors.forename: Keiichi
authors.initials: K
authors.lastname: Hiramatsu
authors.forename: Farid
authors.initials: F
authors.lastname: Hussain
authors.forename: Kanokporn
authors.initials: K
authors.lastname: Mongkolrattanothai
authors.forename: Mantana
authors.initials: M
authors.lastname: Jamklang
authors.forename: Susan
authors.initials: S
authors.lastname: Boyle-Vavra
mesh_terms: D017714:Community-Acquired Infections / Q000635:transmission*; D003428:Cross Infection / Q000635:transmission; D006801:Humans; D016106:Methicillin Resistance / Q000235:genetics*; D016133:Polymerase Chain Reaction; D013203:Staphylococcal Infections / Q000635:transmission*; D013211:Staphylococcus aureus / Q000145:classification / Q000187:drug effects / Q000235:genetics*