title: Molecular epidemiology of methicillin-resistant Staphylococcus aureus, rural southwestern Alaska.
abstract: USA300 is the dominant strain responsible for community-associated (CA) methicillin-resistant Staphylococcus aureus (MRSA) infections in most of the United States. We examined isolates from outbreaks of MRSA skin infections in rural southwestern Alaska in 1996 and 2000 (retrospective collection) and from the hospital serving this region in 2004-2006 (prospective collection). Among 36 retrospective collection isolates, 92% carried Panton-Valentine leukocidin (PVL) genes; all carried staphylococcal chromosomal cassette mec (SCCmec) type IV. None belonged to clonal complex (CC) 8, the CC associated with USA300; 57% were sequence type (ST) 1, and 26% were ST30; 61% were clindamycin resistant. In the prospective collection, 42 isolates were PVL+ and carried SCCmec type IV; 83.3% were ST1, 9.5% were ST30, and 7.1% were ST8. Among 120 prospective isolates, 57.5% were clindamycin resistant. CA-MRSA epidemiology in southwestern Alaska differs from that in the lower 48 states; ST8 strains were rarely identified and clindamycin resistance was common.
authors.affiliation: Department of Pediatrics, University of Chicago, 5841 S Maryland Ave, MC 6054, Chicago, IL 60637, USA. mdavid@medicine.bsd.uchicago.edu
authors.forename: Michael Z
authors.initials: MZ
authors.lastname: David
authors.forename: Karen M
authors.initials: KM
authors.lastname: Rudolph
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Hennessy
authors.forename: Susan
authors.initials: S
authors.lastname: Boyle-Vavra
authors.forename: Robert S
authors.initials: RS
authors.lastname: Daum
mesh_terms: D000413:Alaska / Q000453:epidemiology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001427:Bacterial Toxins / Q000235:genetics; D002876:Chromosomes, Bacterial; D002981:Clindamycin / Q000494:pharmacology; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000382:microbiology; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005098:Exotoxins / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics; D006801:Humans; D007956:Leukocidins / Q000235:genetics; D016106:Methicillin Resistance / Q000235:genetics; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D012189:Retrospective Studies; D012424:Rural Population; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D013207:Staphylococcal Skin Infections / Q000453:epidemiology* / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D001427:Bacterial Toxins; D005098:Exotoxins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin; D002981:Clindamycin