title: Transcriptional analysis of antibiotic resistance and virulence genes in multiresistant hospital-acquired MRSA.
abstract: The staphylococcal chromosome cassette mec cannot solely explain the multiresistance phenotype or the relatively mild virulence profile of hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA). This study reports that several multiresistant HA-MRSA strains differently expressed genes that may support antibiotic resistance, modify the bacterial surface and influence the pathogenic process. Genes encoding efflux pumps (norA, arsB, emrB) and the macrolide resistance gene ermA were found to be commonly expressed by HA-MRSA strains, but not in the archetypal MRSA strain COL. At equivalent cell density, the agr system was considerably less activated in all MRSA strains (including COL) in comparison with a prototypic antibiotic-susceptible strain. These results are in contrast to those observed in recent community-acquired MRSA isolates and may partly explain how multiresistant HA-MRSA persist in the hospital setting.
authors.affiliation: Département de Biologie, Centre d'Étude et de Valorisation de la Diversité Microbienne, Faculté des Sciences, Université de Sherbrooke, QC, Canada.
authors.forename: Mireille
authors.initials: M
authors.lastname: Pruneau
authors.forename: Gabriel
authors.initials: G
authors.lastname: Mitchell
authors.forename: Hélène
authors.initials: H
authors.lastname: Moisan
authors.forename: Emilie
authors.initials: E
authors.lastname: Dumont-Blanchette
authors.forename: Christian L
authors.initials: CL
authors.lastname: Jacob
authors.forename: François
authors.initials: F
authors.lastname: Malouin
mesh_terms: D003428:Cross Infection / Q000382:microbiology; D024901:Drug Resistance, Multiple, Bacterial; D020869:Gene Expression Profiling; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D013203:Staphylococcal Infections / Q000382:microbiology; D037521:Virulence Factors / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D037521:Virulence Factors