title: Characterization of novel conjugative multiresistance plasmids carrying cfr from linezolid-resistant Staphylococcus epidermidis clinical isolates from Italy.
abstract: OBJECTIVE
  The objective of this study was to investigate the genetic environment of the cfr gene from two linezolid-resistant clinical isolates of Staphylococcus epidermidis from Italy.
  
  
  METHODS
  The two strains (SP1 and SP2) were phenotypically and genotypically characterized. Transferability of cfr was assessed by electrotransformation and conjugation. The genetic contexts of cfr were investigated by PCR mapping, sequencing and comparative sequence analyses.
  
  
  RESULTS
  SP1 and SP2 belonged to ST23 and ST83, respectively. In both strains, the cfr gene was located on a plasmid, which could be transferred to Staphylococcus aureus by transformation and conjugation. In isolate SP1, linezolid resistance mediated by mutations in 23S rRNA and the L3 ribosomal protein was also detected. pSP01, the cfr-carrying plasmid from strain SP1, had a larger number of additional resistance genes and was sequenced (76 991 bp). It disclosed a distinctive mosaic structure, with four cargo regions interpolated into a backbone 95% identical to that of S. aureus plasmid pPR9. Besides cfr, resistance genes distributed in the cargo regions included blaZ, lsa(B), msr(A) and aad, and a gene cluster for resistance to heavy metals. A closely related cfr plasmid (pSP01.1, ∼ 49 kb), differing from pSP01 by the lack of a large cargo region with some resistance genes, was detected in strain SP2.
  
  
  CONCLUSIONS
  The conjugative multiresistance plasmid pSP01 is the first cfr-carrying plasmid to be sequenced in Italy. This is the first time cfr has been found: (i) in association with blaZ, msr(A) and heavy metal resistance genes; and (ii) in an S. epidermidis strain (SP2) belonging to ST83.
authors.affiliation: Unit of Microbiology, Department of Biomedical Sciences and Public Health, Polytechnic University of Marche Medical School, Ancona, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Brenciani
authors.affiliation: Unit of Microbiology, Department of Biomedical Sciences and Public Health, Polytechnic University of Marche Medical School, Ancona, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Morroni
authors.affiliation: Department of Medical Biotechnologies, University of Siena, Siena, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Pollini
authors.affiliation: Unit of Microbiology, Department of Biomedical Sciences and Public Health, Polytechnic University of Marche Medical School, Ancona, Italy.
authors.forename: Erika
authors.initials: E
authors.lastname: Tiberi
authors.affiliation: Unit of Microbiology, Department of Biomedical Sciences and Public Health, Polytechnic University of Marche Medical School, Ancona, Italy.
authors.forename: Marina
authors.initials: M
authors.lastname: Mingoia
authors.affiliation: Unit of Microbiology, Department of Biomedical Sciences and Public Health, Polytechnic University of Marche Medical School, Ancona, Italy pe.varaldo@univpm.it.
authors.forename: Pietro E
authors.initials: PE
authors.lastname: Varaldo
authors.affiliation: Department of Medical Biotechnologies, University of Siena, Siena, Italy Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy Clinical Microbiology and Virology Unit, Florence Careggi University Hospital, Florence, Italy.
authors.forename: Gian Maria
authors.initials: GM
authors.lastname: Rossolini
authors.affiliation: Unit of Microbiology, Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Giovanetti
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016000:Cluster Analysis; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D006801:Humans; D007558:Italy; D000069349:Linezolid / Q000494:pharmacology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010957:Plasmids / Q000032:analysis*; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013203:Staphylococcal Infections / Q000382:microbiology*; D013212:Staphylococcus epidermidis / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D000069349:Linezolid