Pulsed-field gel electrophoresis typing of oxacillin-resistant Staphylococcus aureus isolates from the United States: establishing a national database.
Oxacillin-resistant Staphylococcus aureus (ORSA) is a virulent pathogen responsible for both health care-associated and community onset disease. We used SmaI-digested genomic DNA separated by pulsed-field gel electrophoresis (PFGE) to characterize 957 S. aureus isolates and establish a database of PFGE patterns. In addition to PFGE patterns of U.S. strains, the database contains patterns of representative epidemic-type strains from the United Kingdom, Canada, and Australia; previously described ORSA clonal-type isolates; 13 vancomycin-intermediate S. aureus (VISA) isolates, and two high-level vancomycin-resistant, vanA-positive strains (VRSA). Among the isolates from the United States, we identified eight lineages, designated as pulsed-field types (PFTs) USA100 through USA800, seven of which included both ORSA and oxacillin-susceptible S. aureus isolates. With the exception of the PFT pairs USA100 and USA800, and USA300 and USA500, each of the PFTs had a unique multilocus sequence type and spa type motif. The USA100 PFT, previously designated as the New York/Tokyo clone, was the most common PFT in the database, representing 44% of the ORSA isolates. USA100 isolates were typically multiresistant and included all but one of the U.S. VISA strains and both VRSA isolates. Multiresistant ORSA isolates from the USA200, -500, and -600 PFTs have PFGE patterns similar to those of previously described epidemic strains from Europe and Australia. The USA300 and -400 PFTs contained community isolates resistant only to beta-lactam drugs and erythromycin. Noticeably absent from the U.S. database were isolates with the previously described Brazilian and EMRSA15 PFGE patterns. These data suggest that there are a limited number of ORSA genotypes present in the United States.
McDougal
Linda K
LK
Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. lkm1@cdc.gov
Steward
Christine D
CD
Killgore
George E
GE
Chaitram
Jasmine M
JM
McAllister
Sigrid K
SK
Tenover
Fred C
FC
D016208:Databases, Factual; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods; D006801:Humans; D008826:Microbial Sensitivity Tests; D010068:Oxacillin / Q000494:pharmacology*; D010802:Phylogeny; D015183:Restriction Mapping; D012703:Serotyping / Q000379:methods*; D013203:Staphylococcal Infections / Q000382:microbiology; D013211:Staphylococcus aureus / Q000145:classification* / Q000187:drug effects / Q000302:isolation & purification*; D014481:United States
D010068:Oxacillin