title: Diversity of antimicrobial resistance pheno- and genotypes of methicillin-resistant Staphylococcus aureus ST398 from diseased swine.
abstract: OBJECTIVE
  Fifty-four methicillin-resistant Staphylococcus aureus (MRSA) ST398 isolates from unrelated diseased swine collected all over Germany were comparatively investigated for their antimicrobial resistance and virulence properties, and for their genomic relatedness.
  
  
  METHODS
  MICs of 30 antimicrobial agents were determined by broth microdilution. Resistance and virulence genes were detected via a diagnostic DNA microarray and specific PCRs. The genomic relationships were determined by ApaI-PFGE, spa typing and SCCmec typing.
  
  
  RESULTS
  Twenty-two distinct resistance patterns were observed. All 54 isolates were tetracycline resistant, mediated by tet(M), tet(K) and/or tet(L), with 14 isolates being only resistant to beta-lactam antibiotics and tetracyclines. Trimethoprim resistance, seen in 28 isolates, was mostly due to the gene dfrK or dfrG. Among the 24 macrolide/lincosamide-resistant isolates, the genes erm(A), erm(B) and/or erm(C) were detected. The two chloramphenicol/florfenicol-resistant isolates harboured the gene fexA. The eight gentamicin-resistant isolates carried the gene aacA/aphD. Fifty-three isolates harboured SCCmec type V elements while the remaining one carried mecA and ugpQ, but no recombinase genes. All isolates were PVL negative, but one and three isolates, respectively, were positive for the enterotoxin B and enterotoxin K and Q genes. Eight different spa types were identified with t011 being the most predominant. Six ApaI-PFGE clusters with up to nine individual patterns were detected.
  
  
  CONCLUSIONS
  MRSA ST398 isolates varied slightly in their virulence properties and spa types but differed distinctly in their antimicrobial resistance pheno- and genotypes as well as their ApaI-PFGE patterns. These data underline the ability of ST398 to acquire genetic material that might increase antimicrobial resistance and virulence.
authors.affiliation: Institute of Farm Animal Genetics, Friedrich-Loeffler-Institute (FLI), Neustadt-Mariensee, Germany.
authors.forename: Kristina
authors.initials: K
authors.lastname: Kadlec
authors.forename: Ralf
authors.initials: R
authors.lastname: Ehricht
authors.forename: Stefan
authors.initials: S
authors.lastname: Monecke
authors.forename: Ulrike
authors.initials: U
authors.lastname: Steinacker
authors.forename: Heike
authors.initials: H
authors.lastname: Kaspar
authors.forename: Joachim
authors.initials: J
authors.lastname: Mankertz
authors.forename: Stefan
authors.initials: S
authors.lastname: Schwarz
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D016521:Electrophoresis, Gel, Pulsed-Field; D014644:Genetic Variation; D005838:Genotype; D005858:Germany; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology; D046228:Microarray Analysis / Q000379:methods; D008826:Microbial Sensitivity Tests; D010641:Phenotype; D016133:Polymerase Chain Reaction / Q000379:methods; D013203:Staphylococcal Infections / Q000382:microbiology / Q000662:veterinary*; D013552:Swine / Q000382:microbiology*; D013553:Swine Diseases / Q000382:microbiology*; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D037521:Virulence Factors