title: Comparison of adhesion and virulence of two predominant hospital-acquired methicillin-resistant Staphylococcus aureus clones and clonal methicillin-susceptible S. aureus isolates.
abstract: The virulence of SCCmec type IV hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates belonging to the major sequence type 8 (ST8 [Lyon clone]) and to a minor upcoming clone, ST5, was compared with that of methicillin-susceptible S. aureus (MSSA) isolates of matching sequence types. In vitro adhesion to human airway epithelial cells (HAECs) as an indicator of dissemination and mortality in a murine sepsis model as an indicator of virulence were evaluated. Ten MRSA isolates and 8 MSSA isolates of ST8 and 8 MRSA isolates and 8 MSSA isolates of ST5 were characterized with respect to multilocus sequence type; agr, spa, and capsule typing; in vitro doubling time; toxin and adhesin gene profiles; and adherence to HAECs. Adherence was significantly lower in the MRSA ST5 group than in the ST8 groups. Infections with MRSA and MSSA isolates ST8 and ST5 were compared. No change in virulence related to the presence of SCCmec was observed, since ST8 but not ST5 caused a significantly lower mortality in its presence. Despite their similar genetic backgrounds, individual clonal MRSA and MSSA isolates were heterogeneous in adherence and virulence. No one of these specific virulence factors determined in vitro was related to mouse mortality. In conclusion, in a bacteremic model, mortality was dependent on the ST and was differentially modulated by SCCmec; within an ST, clonality was not associated with a homogenous outcome.
authors.affiliation: Department of Biomedicine, University Hospital Basel, Hebelstrasse 20, 4031 Basel, Switzerland.
authors.forename: Hatice
authors.initials: H
authors.lastname: Karauzum
authors.forename: Tristan
authors.initials: T
authors.lastname: Ferry
authors.forename: Sophie
authors.initials: S
authors.lastname: de Bentzmann
authors.forename: Gérard
authors.initials: G
authors.lastname: Lina
authors.forename: Michèle
authors.initials: M
authors.lastname: Bes
authors.forename: François
authors.initials: F
authors.lastname: Vandenesch
authors.forename: Mathias
authors.initials: M
authors.lastname: Schmaler
authors.forename: Brigitte
authors.initials: B
authors.lastname: Berger-Bächi
authors.forename: Jerome
authors.initials: J
authors.lastname: Etienne
authors.forename: Regine
authors.initials: R
authors.lastname: Landmann
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion / Q000502:physiology*; D002999:Clone Cells; D003428:Cross Infection / Q000382:microbiology*; D004847:Epithelial Cells / Q000382:microbiology; D005838:Genotype; D006801:Humans; D008168:Lung / Q000166:cytology / Q000382:microbiology; D016106:Methicillin Resistance / Q000502:physiology*; D051379:Mice; D010641:Phenotype; D020545:Respiratory Mucosa / Q000382:microbiology; D013211:Staphylococcus aureus / Q000235:genetics* / Q000378:metabolism* / Q000472:pathogenicity*; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D037521:Virulence Factors
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