Characterization of the ends and target site of a novel tetracycline resistance-encoding conjugative transposon from Enterococcus faecium 664.1H1.
Enterococcus faecium 664.1H1 is multiply antibiotic resistant and mercury resistant. In this study, the genetic support for the tetracycline resistance of E. faecium 664.1H1 was characterized. The tet(S) gene is responsible for tetracycline resistance, and this gene is located on the chromosome of E. faecium 664.1H1, on a novel conjugative transposon. The element is transferable to Enterococcus faecalis, where it integrates into a specific site. The element was designated EfcTn1. The integrase of EfcTn1 is related to the integrase proteins found on staphylococcal pathogenicity islands. We show that the transposon is flanked by an 18-bp direct repeat, a copy of which is also present at the target site and at the joint of a circular form, and we propose a mechanism of insertion and excision.
Roberts
Adam P
AP
Division of Microbial Diseases, UCL Eastman Dental Institute, University College London, University of London, 256 Gray's Inn Road, London WC1X 8LD, United Kingdom. aroberts@eastman.ucl.ac.uk
Davis
Ian J
IJ
Seville
Lorna
L
Villedieu
Aurelie
A
Mullany
Peter
P
D000595:Amino Acid Sequence; D002876:Chromosomes, Bacterial / Q000235:genetics; D003227:Conjugation, Genetic; D004251:DNA Transposable Elements / Q000235:genetics; D016984:Enterococcus faecium / Q000187:drug effects / Q000235:genetics; D005798:Genes, Bacterial; D019426:Integrases / Q000235:genetics; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D013752:Tetracycline / Q000494:pharmacology; D013753:Tetracycline Resistance / Q000235:genetics*
D004251:DNA Transposable Elements; D019426:Integrases; D013752:Tetracycline