title: Molecular analysis of a mobilizable theta-mode trimethoprim resistance plasmid from coagulase-negative staphylococci.
abstract: The Staphylococcus epidermidis plasmid pSK639 is the prototype of a newly described family of small plasmids identified in clinical staphylococcal isolates. pSK639 is 8 kb in length and possesses a composite structure consisting of an IS257-flanked segment mediating trimethoprim resistance (Tpr), and regions responsible for replication and mobilization of the plasmid. Comparative sequence analysis suggests that a pSK639-like plasmid may represent a progenitor of previously identified staphylococcal Tpr determinants related to the transposon-like structure, Tn4003. In contrast to the small staphylococcal plasmids characterized to date that all utilize a rolling circle mode of replication, the replication region of pSK639 was found to contain features typical of an iteron-controlled theta-mode replicon. pSK639 is the first small plasmid of this type to be identified in the staphylococci.
authors.affiliation: School of Biological Sciences, University of Sydney, Sydney, New South Wales, 2006, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Apisiridej
authors.forename: A
authors.initials: A
authors.lastname: Leelaporn
authors.forename: C D
authors.initials: CD
authors.lastname: Scaramuzzi
authors.forename: R A
authors.initials: RA
authors.lastname: Skurray
authors.forename: N
authors.initials: N
authors.lastname: Firth
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003227:Conjugation, Genetic / Q000235:genetics; D004261:DNA Replication; D004251:DNA Transposable Elements / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D019143:Evolution, Molecular; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D011815:R Factors / Q000235:genetics*; D012093:Replicon / Q000235:genetics; D016415:Sequence Alignment; D013212:Staphylococcus epidermidis / Q000235:genetics*; D014296:Trimethoprim Resistance / Q000235:genetics*
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial