title: Diversity of plasmids encoding virulence and resistance functions in Salmonella enterica subsp. enterica serovar Typhimurium monophasic variant 4,[5],12:i:- strains circulating in Europe.
abstract: Plasmids encoding resistance and virulence properties in multidrug resistant (MDR) Salmonella enterica (S.) serovar Typhimurium monophasic variant 4,[5],12:i:- isolates recovered from pigs and humans (2006-2008) in Europe were characterised. The isolates were selected based on the detection by PCR-amplification of S. Typhimurium virulence plasmid pSLT genes and were analysed by multi-locus sequence typing (MLST). The resistance genes present in the isolates and the association of these genes with integrons, transposons and insertion sequences were characterised by PCR-sequencing, and their plasmid location was determined by alkaline lysis and by S1-nuclease pulsed-field gel electrophoresis (PFGE) Southern-blot hybridisation. Plasmids were further analysed by replicon typing, plasmid MLST and conjugation experiments. The 10 S. 4,[5],12,i:- selected isolates belonged to ST19. Each isolate carried a large plasmid in which MDR with pSLT-associated virulence genes were located. After analysis, eight different plasmids of three incompatibility groups (IncA/C, IncR and IncF) were detected. Two IncA/C plasmids represented novel variants within the plasmid family of the S. 4,[5],12:i:- Spanish clone, and carried an empty class 1 integron with a conventional qacEΔ1-sul1 3' conserved segment or an In-sul3 type III with estX-psp-aadA2-cmlA1-aadA1-qacH variable region linked to tnpA440-sul3, part of Tn2, Tn21 and Tn1721 transposons, and ISCR2. Four newly described IncR plasmids contained the resistance genes within In-sul3 type I (dfrA12-orfF-aadA2-cmlA1-aadA1-qacH/tnpA440-sul3) and part of Tn10 [tet(B)]. Two pSLT-derivatives with FIIs-ST1+FIB-ST17 replicons carried cmlA1-[aadA1-aadA2]-sul3-dfrA12 and blaTEM-1 genes linked to an In-sul3 type I integron and to Tn2, respectively. In conclusion, three emerging European clones of S. 4,[5],12:i:- harboured MDR plasmids encoding additional virulence functions that could contribute significantly to their evolutionary success.
authors.affiliation: Department of Functional Biology, Area of Microbiology, University of Oviedo, Oviedo, Asturias, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: García
authors.affiliation: Antimicrobial Resistance and Healthcare Associated Infections Reference Unit, Public Health England (PHE), London, United Kingdom.
authors.forename: Katie L
authors.initials: KL
authors.lastname: Hopkins
authors.affiliation: Department of Functional Biology, Area of Microbiology, University of Oviedo, Oviedo, Asturias, Spain.
authors.forename: Vanesa
authors.initials: V
authors.lastname: García
authors.affiliation: Department of Biological Safety, Federal Institute for Risk Assessment (BfR), Berlin, Germany.
authors.forename: Janine
authors.initials: J
authors.lastname: Beutlich
authors.affiliation: Department of Functional Biology, Area of Microbiology, University of Oviedo, Oviedo, Asturias, Spain.
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Mendoza
authors.affiliation: Antimicrobial Resistance and Healthcare Associated Infections Reference Unit, Public Health England (PHE), London, United Kingdom.
authors.forename: John
authors.initials: J
authors.lastname: Threlfall
authors.affiliation: Department of Bacteriology and TSEs, Central Veterinary Institute (CVI), Lelystad, The Netherlands.
authors.forename: Dik
authors.initials: D
authors.lastname: Mevius
authors.affiliation: Department of Biological Safety, Federal Institute for Risk Assessment (BfR), Berlin, Germany.
authors.forename: Reiner
authors.initials: R
authors.lastname: Helmuth
authors.affiliation: Department of Functional Biology, Area of Microbiology, University of Oviedo, Oviedo, Asturias, Spain.
authors.forename: M Rosario
authors.initials: MR
authors.lastname: Rodicio
authors.affiliation: Department of Biological Safety, Federal Institute for Risk Assessment (BfR), Berlin, Germany.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Guerra
mesh_terms: D000818:Animals; D004251:DNA Transposable Elements; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D005060:Europe; D006801:Humans; D032023:Integrons / Q000235:genetics; D010957:Plasmids / Q000235:genetics*; D012480:Salmonella Infections / Q000235:genetics*; D012481:Salmonella Infections, Animal / Q000235:genetics; D012486:Salmonella typhimurium / Q000235:genetics*; D013552:Swine; D014774:Virulence / Q000235:genetics
chemical_list: D004251:DNA Transposable Elements