title: Identification of major clonal complexes and toxin producing strains among Staphylococcus aureus associated with atopic dermatitis.
abstract: Staphylococcus aureus promotes the onset and severity of atopic dermatitis (AD), which is exacerbated by superantigen toxins SEB and SEC. The genetic identity of these isolates, and their relationship to common hospital- or community-associated methicillin resistant S. aureus (HA-MRSA and CA-MRSA) has not been defined. We conducted spa typing, partial multi-locus sequence typing (MLST), and toxin profiling (seb, sec, lukS-PV) of S. aureus from 119 pediatric and 40 adult AD patients. MLST clonal complexes CC45, CC5, CC15, CC1, CC8 and CC30 accounted for 79% of isolates, representing the same major groups reported for nosocomial S. aureus in hospital intensive care units. The highest disease severity was associated with CC1, which was significantly greater relative to CC15 (p = 0.017) or CC30 (p = 0.040), but with no significant difference relative to CC45, CC5 or CC8. Although there were two few lukS-PV, seb or sec isolates to infer a role in disease severity, CC45 was identified as a source of SEC producing strains, and lukS-PVL was associated with a small number of CC5 pediatric isolates. CC1 harbored the only CA-MRSA that was identified, and was a source of isolates that expressed both seb and sec, and closely resembled the USA400 strain of CA-MRSA.
authors.affiliation: Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S1A8, Canada.
authors.forename: Melinda
authors.initials: M
authors.lastname: Yeung
authors.forename: Alexandra
authors.initials: A
authors.lastname: Balma-Mena
authors.forename: Neil
authors.initials: N
authors.lastname: Shear
authors.forename: Andrew
authors.initials: A
authors.lastname: Simor
authors.forename: Elena
authors.initials: E
authors.lastname: Pope
authors.forename: Scott
authors.initials: S
authors.lastname: Walsh
authors.forename: Martin J
authors.initials: MJ
authors.lastname: McGavin
mesh_terms: D000328:Adult; D002648:Child; D002999:Clone Cells; D003428:Cross Infection / Q000382:microbiology*; D003876:Dermatitis, Atopic / Q000382:microbiology*; D005098:Exotoxins / Q000378:metabolism; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology; D012720:Severity of Illness Index; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D018089:Superantigens / Q000378:metabolism
chemical_list: D005098:Exotoxins; D018089:Superantigens