title: DNA sequence and comparative genomics of pAPEC-O2-R, an avian pathogenic Escherichia coli transmissible R plasmid.
abstract: In this study, a 101-kb IncF plasmid from an avian pathogenic Escherichia coli (APEC) strain (APEC O2) was sequenced and analyzed, providing the first completed APEC plasmid sequence. This plasmid, pAPEC-O2-R, has functional transfer and antimicrobial resistance-encoding regions. The resistance-encoding region encodes resistance to eight groups of antimicrobial agents, including silver and other heavy metals, quaternary ammonium compounds, tetracycline, sulfonamides, aminoglycosides, trimethoprim, and beta-lactam antimicrobial agents. This region of the plasmid is unique among previously described IncF plasmids in that it possesses a class 1 integron that harbors three gene cassettes and a heavy metal resistance operon. This region spans 33 kb and is flanked by the RepFII plasmid replicon and an assortment of plasmid maintenance genes. pAPEC-O2-R also contains a 32-kb transfer region that is nearly identical to that found in the E. coli F plasmid, rendering it transferable by conjugation to plasmid-less strains of bacteria, including an APEC strain, a fecal E. coli strain from an apparently healthy bird, a Salmonella enterica serovar Typhimurium strain, and a uropathogenic E. coli strain from humans. Differences in the G+C contents of individual open reading frames suggest that various regions of pAPEC-O2-R had dissimilar origins. The presence of pAPEC-O2-R-like plasmids that encode resistance to multiple antimicrobial agents and that are readily transmissible from APEC to other bacteria suggests the possibility that such plasmids may serve as a reservoir of resistance genes for other bacteria of animal and human health significance.
authors.affiliation: Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, 1802 Elwood Drive, VMRI #2, Ames, IA 50011, USA.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Johnson
authors.forename: Kylie E
authors.initials: KE
authors.lastname: Siek
authors.forename: Sara J
authors.initials: SJ
authors.lastname: Johnson
authors.forename: Lisa K
authors.initials: LK
authors.lastname: Nolan
mesh_terms: D000818:Animals; D001482:Base Composition; D002645:Chickens / Q000382:microbiology*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D016680:Genome, Bacterial; D008826:Microbial Sensitivity Tests; D011815:R Factors; D017422:Sequence Analysis, DNA