title: Evolution of sporadic isolates of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals and their similarities to isolates of community-acquired MRSA.
abstract: Forty-one methicillin-resistant Staphylococcus aureus (MRSA) hospital isolates that clearly differed from the six major pandemic clones of MRSA in pulsed-field gel electrophoresis type, mecA and Tn554 polymorphism, and epidemic behavior were selected from an international strain collection for more detailed characterization. SpaA typing, multilocus sequence typing, and SCCmec (staphylococcal cassette chromosome mec) typing demonstrated extensive diversity among these sporadic isolates both in genetic background and also in the structure of the associated SCCmec elements. Nevertheless, the isolates could be grouped into restricted clonal complexes by using the BURST (i.e., based upon related sequence types) program algorithm, which predicted that most sporadic MRSA isolates evolved from pandemic MRSA clones. Several of the sporadic MRSA resembled community-acquired MRSA isolates in properties that included a relatively limited multiresistance pattern, faster growth rates, diversity of genetic backgrounds, and a frequent association with SCCmec type IV.
authors.affiliation: Laboratório de Genética Molecular, Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa, Oeiras, Portugal.
authors.forename: M
authors.initials: M
authors.lastname: Aires de Sousa
authors.forename: H
authors.initials: H
authors.lastname: de Lencastre
mesh_terms: D000465:Algorithms; D000595:Amino Acid Sequence; D001208:Asia; D017714:Community-Acquired Infections / Q000382:microbiology*; D003428:Cross Infection / Q000382:microbiology*; D005060:Europe; D019143:Evolution, Molecular; D006801:Humans; D016106:Methicillin Resistance; D010446:Peptide Fragments / Q000737:chemistry; D015995:Prevalence; D013020:South America; D013203:Staphylococcal Infections / Q000175:diagnosis* / Q000453:epidemiology; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics*
chemical_list: D010446:Peptide Fragments