title: Novel Structure of Enterococcus faecium-Originated ermB-Positive Tn1546-Like Element in Staphylococcus aureus.
abstract: We determined the resistance determinants in 274 erythromycin-resistant methicillin-susceptible Staphylococcus aureus (MSSA) isolates during a 13-year period, 2000 to 2012. The resistance phenotypes, inducible macrolide-lincosamide-streptogramin (iMLS), constitutive MLS (cMLS), and macrolide-streptogramin (MS) resistance phenotypes, were examined by a double-disk diffusion D test. The ermB gene was more frequent (35%; 97/274) than ermC (27%; 75/274) or ermA (21%; 58/274). All 97 ermB-positive isolates harbored Tn551 and IS1216V The majority (89/97) of ermB-positive isolates displayed the cMLS phenotype and carried mobile element structure (MES)-like structures, which has been previously reported in sequence type 59 (ST59) methicillin-resistant S. aureus (MRSA). The remaining 8 ermB-carrying isolates, belonging to ST7 (n = 4), ST5 (n = 3), and ST59 (n = 1), were sasK intact and did not carry MES-like structures. Unlike a MES-like structure that was located on the chromosome, the ermB elements on sasK-intact isolates were located on plasmids by S1 nuclease pulsed-field gel electrophoresis (PFGE) analysis and conjugation tests. Sequence data for the ermB-containing region (14,566 bp) from ST59 NTUH_3874 revealed that the best match was a Tn1546-like element in plasmid pMCCL2 DNA (GenBank accession number AP009486) of Macrococcus caseolyticus Tn1546 is recognized as an enterococcal transposon and was known from the vancomycin resistance gene cluster in vancomycin-resistant Enterococcus (VRE). So far, acquisitions of Tn1546 in S. aureus have occurred in clonal complex 5 (CC5) MRSA, but not in MSSA. This is the first report that MSSA harbors an Enterococcus faecium-originated ermB-positive Tn1546-like element located on a plasmid.
authors.affiliation: Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Tsai-Wen
authors.initials: TW
authors.lastname: Wan
authors.affiliation: Department of Microbiology and Immunology, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Wei-Chun
authors.initials: WC
authors.lastname: Hung
authors.affiliation: Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan Division of Neurosurgery, Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Jui-Chang
authors.initials: JC
authors.lastname: Tsai
authors.affiliation: Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Yu-Tzu
authors.initials: YT
authors.lastname: Lin
authors.affiliation: Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Hao
authors.initials: H
authors.lastname: Lee
authors.affiliation: Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Po-Ren
authors.initials: PR
authors.lastname: Hsueh
authors.affiliation: Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Tai-Fen
authors.initials: TF
authors.lastname: Lee
authors.affiliation: Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan ljteng@ntu.edu.tw.
authors.forename: Lee-Jene
authors.initials: LJ
authors.lastname: Teng
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002876:Chromosomes, Bacterial / Q000737:chemistry; D003227:Conjugation, Genetic; D004251:DNA Transposable Elements; D052978:Disk Diffusion Antimicrobial Tests; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D016521:Electrophoresis, Gel, Pulsed-Field; D016984:Enterococcus faecium / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D015870:Gene Expression; D022761:Gene Transfer, Horizontal; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D055231:Lincosamides / Q000494:pharmacology; D018942:Macrolides / Q000494:pharmacology; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D025361:Streptogramins / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D007527:Isoenzymes; D055231:Lincosamides; D018942:Macrolides; D025361:Streptogramins; D008780:Methyltransferases; C431709:ErmA protein, Bacteria; C035181:rRNA (adenosine-O-2'-)methyltransferase