Abstract
The objective of this study was to explore the genetic and biological features of the tet(M)-harboring plasmid pTS14 in Salmonella enterica 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 tet(M)-bearing IncF2:A1:B1 conjugative plasmid pTS14. The plasmid pTS14 contained a novel transposon Tn6709 with the genetic structure IS26-tnpA1-tnpA2-Δorf13-LP-tet(M)-tnpX-ΔtnpR-IS26, and the resistance genes tet(B), tet(D), strAB, sul2, and blaTEM–1b. In addition, pTS14 was found to be highly stable in the recipient strain E. coli J53. The transconjugant TS14 exhibited a higher survival ratio than E. coli J53 under permanent starvation-induced stress. The tet(M)-bearing IncF2 epidemic plasmid lineage may accelerate the dissemination of tet(M) and other genes by coselection, which could constitute a potentially serious threat to clinical treatment regimens.
Highlights
IntroductionThe tetracycline resistance gene tet(M) encodes a ribosomal protection protein that confers tetracycline resistance to a variety of bacterial species (Franke and Clewell, 1981; Roberts et al, 1986; Donhofer et al, 2012; Roberts and Schwarz, 2016), including genera of Gram-positive bacteria and genera of Gram-negative bacteria, with most associated with other tet genes, likely through the association with integrative and conjugative transposons located on the chromosome or conjugative plasmids, which facilitate horizontal transfer (Bryan et al, 2004; Jones et al, 2006; Tuckman et al, 2007; de Vries et al, 2009; Hu et al, 2013)
The results of the conjugation assay indicated that the tet(M) gene can be successfully transferred to Salmonella JS-500 and E. coli J53 at frequencies of 1.638 × 10−4 and 1.397 × 10−4, respectively, which were assigned as TS14-JS500 and TS14
S1-pulsed-field gel electrophoresis (PFGE) and Southern hybridization indicated that the tet(M) gene was located on a plasmid of ∼119 kb in size, designated as pTS14 (Supplementary Figure S1)
Summary
The tetracycline resistance gene tet(M) encodes a ribosomal protection protein that confers tetracycline resistance to a variety of bacterial species (Franke and Clewell, 1981; Roberts et al, 1986; Donhofer et al, 2012; Roberts and Schwarz, 2016), including genera of Gram-positive bacteria and genera of Gram-negative bacteria, with most associated with other tet genes, likely through the association with integrative and conjugative transposons located on the chromosome or conjugative plasmids, which facilitate horizontal transfer (Bryan et al, 2004; Jones et al, 2006; Tuckman et al, 2007; de Vries et al, 2009; Hu et al, 2013). In Gram-negative bacteria, the tet(M) gene was first reported in Escherichia coli in 2006 (Jones et al, 2006) and later described in Salmonella enterica isolates from chicken and pig feces in China in 2017 (Ma et al, 2017). There are relatively few reports of tet(M)-harboring IncF plasmids from Salmonella. We report the complete sequence of the tet(M)-harboring IncF2:A1:B1 plasmid pTS14 isolated from S. enterica. A novel transposon, Tn6709 harboring the tet(M) gene, as well as three other resistance modules, were located on the same plasmid, pTS14. The biological characteristics of plasmid pTS14 in Salmonella were further investigated
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
