Virulence-resistance plasmids ( pUO-StVR 2-like ) in meat isolates of 1 Salmonella enterica serovar Typhimurium 2 3 4 5 6

25 During a screening of Salmonella enterica in foods of animal origin four isolates of serovar 26 Typhimurium carrying hybrid virulence-resistance plasmids were detected. Three of them, 27 one from pork and two from chicken meat, contained pUO-StVR2, a derivative of the 28 pSLT virulence plasmid with the blaOXA-1, catA1, aadA1, sulI and tet(B) genes, which 29 confer resistance to ampicillin, chloramphenicol, streptomycin-spectinomycin, 30 sulfonamides and tetracycline, respectively. The fourth isolate harboured a pUO-StVR2 31 variant (termed ν8) with an additional dfrA10 gene responsible for resistance to 32 trimethoprim. This gene is part of the orf513-dfrA10-qacEΔ1-sul1 element 33 characteristically found in complex class 1 integrons. Pulsed-field gel electrophoresis 34 identified two XbaI-BlnI combined profiles: X2-B2 generated from the three pUO-StVR2 35 isolates, and X12-B17 shown by the pUO-StVR2-ν8 isolate. The same profiles have also 36 been found in clinical and ill pig isolates, supporting chicken and pork meat as vehicles for 37 transmission of Typhimurium carrying pUO-StVR2-like plasmids. 38 39 40 41 42 43 44 45 46 47