Marcus Ho-Yin Wong1,2, Edward Wai-Chi Chan1,2, Sheng Chen1,2. 1. Shenzhen Key Laboratory for Food Biological Safety Control, Food Safety and Technology Research Centre, The Hong Kong PolyU Shenzhen Research Institute, Shenzhen, P. R. China. 2. State Key Laboratory of Chirosciences, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Abstract
Objectives: To characterize a novel virulence-resistance plasmid pSE380T carried by a Salmonella enterica serotype Enteritidis clinical strain SE380. Methods: The plasmid pSE380T was conjugated to Escherichia coli strain J53 and sequenced by PacBio RSII, followed by subsequent annotation and genetic analysis. Results: Sequence analysis of this plasmid revealed that the entire Salmonella Enteritidis-specific virulence plasmid, pSEN, had been incorporated into an IncHI2 MDR plasmid, which comprises the cephalosporin and fosfomycin resistance determinants blaCTX-M-14 and fosA3. Based on BLAST analysis and scrutiny of insertion footprints, the insertion event was found to involve a replicative transposition process mediated by IS26, an IS element frequently detected in various resistance plasmids. The resulting pSE380T plasmid also comprises backbone elements of IncHI2 and IncFIA plasmids, producing a rare fusion product that simultaneously encodes functional features of both, i.e. virulence, resistance and high transmissibility. Conclusions: This is a novel hybrid plasmid mediating MDR and virulence from a clinical Salmonella Enteritidis strain. This plasmid is likely to be transmissible amongst various serotypes of Salmonella and other Enterobacteriaceae species, rendering a wide range of bacterial pathogens resistant to cephalosporins and fosfomycin, and further enhancing their virulence potential. It will be important to monitor the spread and further evolution of this plasmid among the Enterobacteriaceae strains.
Objectives: To characterize a novel virulence-resistance plasmid pSE380T carried by a Salmonella enterica serotype Enteritidis clinical strain SE380. Methods: The plasmid pSE380T was conjugated to Escherichia coli strain J53 and sequenced by PacBio RSII, followed by subsequent annotation and genetic analysis. Results: Sequence analysis of this plasmid revealed that the entire Salmonella Enteritidis-specific virulence plasmid, pSEN, had been incorporated into an IncHI2 MDR plasmid, which comprises the cephalosporin and fosfomycin resistance determinants blaCTX-M-14 and fosA3. Based on BLAST analysis and scrutiny of insertion footprints, the insertion event was found to involve a replicative transposition process mediated by IS26, an IS element frequently detected in various resistance plasmids. The resulting pSE380T plasmid also comprises backbone elements of IncHI2 and IncFIA plasmids, producing a rare fusion product that simultaneously encodes functional features of both, i.e. virulence, resistance and high transmissibility. Conclusions: This is a novel hybrid plasmid mediating MDR and virulence from a clinical Salmonella Enteritidis strain. This plasmid is likely to be transmissible amongst various serotypes of Salmonella and other Enterobacteriaceae species, rendering a wide range of bacterial pathogens resistant to cephalosporins and fosfomycin, and further enhancing their virulence potential. It will be important to monitor the spread and further evolution of this plasmid among the Enterobacteriaceae strains.