Characterization of pTS14, an IncF2:A1:B1 Plasmid Carrying (M) in a Isolate.

The objective of this study was to explore the genetic and biological features of the (M)-harboring plasmid pTS14 in strain S14 isolated from a chicken fecal sample. Plasmid pTS14 was identified by conjugation, S1-pulsed-field gel electrophoresis (PFGE), Southern hybridization, and plasmid sequencing. The biological characteristics of pTS14 were assessed via stability, growth kinetics, and starvation survival experiments. Strain S14, belonging to ST3007, harbored a 119-kb (M)-bearing IncF2:A1:B1 conjugative plasmid pTS14. The plasmid pTS14 contained a novel transposon Tn with the genetic structure IS---Δ--(M)--Δ-IS, and the resistance genes (B), (D), , , and . In addition, pTS14 was found to be highly stable in the recipient strain J53. The transconjugant TS14 exhibited a higher survival ratio than J53 under permanent starvation-induced stress. The (M)-bearing IncF2 epidemic plasmid lineage may accelerate the dissemination of (M) and other genes by coselection, which could constitute a potentially serious threat to clinical treatment regimens.