title: Novel methicillin resistance gene mecD in clinical Macrococcus caseolyticus strains from bovine and canine sources.
abstract: Methicillin-resistant Macrococcus caseolyticus strains from bovine and canine origins were found to carry a novel mecD gene conferring resistance to all classes of β-lactams including anti-MRSA cephalosporins. Association of β-lactam resistance with mecD was demonstrated by gene expression in S. aureus and deletion of the mecD-containing island in M. caseolyticus. The mecD gene was located either on an 18,134-bp M. caseolyticus resistance island (McRImecD-1) or a 16,188-bp McRImecD-2. Both islands were integrated at the 3' end of the rpsI gene, carried the mecD operon (mecD-mecR1m-mecIm), and genes for an integrase of the tyrosine recombinase family and a putative virulence-associated protein (virE). Apart from the mecD operon, that shared 66% overall nucleotide identity with the mecB operon, McRImecDislands were unrelated to any mecB-carrying elements or staphylococcal cassette chromosome mec. Only McRImecD-1 that is delimitated at both ends by direct repeats was capable of circular excision. The recombined excision pattern suggests site-specific activity of the integrase and allowed identification of a putative core attachment site. Detection of rpsI-associated integrases in Bacillus and S. aureus reveals a potential for broad-host range dissemination of the novel methicillin resistance gene mecD.
authors.affiliation: Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
authors.forename: Sybille
authors.initials: S
authors.lastname: Schwendener
authors.affiliation: Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Cotting
authors.affiliation: Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
authors.forename: Vincent
authors.initials: V
authors.lastname: Perreten
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000145:classification / Q000235:genetics; D001483:Base Sequence; D002417:Cattle; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004285:Dogs; D005798:Genes, Bacterial / Q000235:genetics*; D058507:Host Specificity; D016106:Methicillin Resistance / Q000235:genetics*; D009876:Operon; D010802:Phylogeny; D040141:Staphylococcaceae / Q000235:genetics* / Q000502:physiology; D013203:Staphylococcal Infections / Q000382:microbiology / Q000662:veterinary
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial