title: Population structure and exotoxin gene content of methicillin-susceptible Staphylococcus aureus from Spanish healthy carriers.
abstract: The population structure of 111 methicillin-susceptible Staphylococcus aureus (MSSA), recovered in Spain from healthy and risk-free carriers was investigated using pulsed-field gel electrophoresis (PFGE), spa (staphylococcal protein A) typing, multi locus sequence typing (MLST) and the accessory gene regulator (agr). Results from the different techniques were highly concordant, and revealed twelve clonal complexes (CCs): CC30 (27%), CC5 (18.9%), CC45 (16.2%), CC15 (11.7%), CC25 (8.1%), CC1, CC9 (3.6% each), CC59, CC97 and CC121 (2.7% each), CC72 (1.8%) and CC8 (0.9%). Isolates with genetic backgrounds of hospital-acquired MSSA were detected and, consistent with the ability of diverse MSSA to act as recipients of the SCCmec cassette, a MSSA isolate from a healthy carrier shared the ST, spa-type and agr-type of a MRSA clone recovered in a hospital of the same region. All except two fragments of the PGFE-profiles of these isolates were identical, and the differential fragment of the MRSA carried mecA. Analyses of the exotoxin gene content of the nasal isolates revealed an increase in the number of exotoxin genes over time. This, together with the detection of lukPV and the high frequency of tst, exfoliatin and enterotoxin genes, is worrisome and requires further surveillance.
authors.affiliation: Department of Functional Biology (Microbiology Section), Faculty of Medicine, University of Oviedo, Julián Clavería 6, 33006 Oviedo, Spain.
authors.forename: M Angeles
authors.initials: MA
authors.lastname: Argudín
authors.forename: Virginia
authors.initials: V
authors.lastname: Argumosa
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Mendoza
authors.forename: Beatriz
authors.initials: B
authors.lastname: Guerra
authors.forename: M Rosario
authors.initials: MR
authors.lastname: Rodicio
mesh_terms: D002353:Carrier State / Q000453:epidemiology / Q000382:microbiology*; D016000:Cluster Analysis; D005098:Exotoxins / Q000235:genetics*; D005838:Genotype; D006801:Humans; D017720:Molecular Epidemiology; D058889:Molecular Typing; D013030:Spain / Q000453:epidemiology; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D037521:Virulence Factors / Q000235:genetics; D055815:Young Adult
chemical_list: D005098:Exotoxins; D037521:Virulence Factors