Characterization of an IncA/C Multidrug Resistance Plasmid in Vibrio alginolyticus

Area of Science:

• Microbiology
• Genetics
• Food Safety

Background:

• Vibrio alginolyticus is a marine bacterium that can cause infections in humans and animals.
• Cephalosporin resistance in V. alginolyticus is a growing concern, particularly in food products.
• Beta-lactamases, such as blaPER-1, blaVEB-1, and blaCMY-2, are key enzymes conferring resistance to cephalosporins.

Purpose of the Study:

• To characterize the genetic basis of cephalosporin resistance in Vibrio alginolyticus isolated from food.
• To determine the complete sequence of a multidrug resistance plasmid involved in cephalosporin resistance.
• To investigate the potential origin and dissemination of the resistance plasmid.

Main Methods:

• Isolation and identification of Vibrio alginolyticus from food samples.
• Antimicrobial susceptibility testing, including cephalosporin resistance profiling.
• Whole-genome sequencing of the multidrug resistance plasmid pVAS3-1.
• Bioinformatic analysis to identify resistance genes and plasmid backbone homology.

Main Results:

• Cephalosporin-resistant Vibrio alginolyticus strains were identified in food products.
• The blaCMY-2 gene was identified as a major mechanism of cephalosporin resistance.
• The complete sequence of the multidrug resistance plasmid pVAS3-1 was determined, revealing the presence of blaCMY-2 and qnrVC4 genes.
• Plasmid pVAS3-1 shares genetic homology with IncA/C plasmids commonly found in Enterobacteriaceae.

Conclusions:

• The study identified specific beta-lactamase genes responsible for cephalosporin resistance in foodborne Vibrio alginolyticus.
• The sequencing of plasmid pVAS3-1 provides insights into the genetic elements driving multidrug resistance.
• The genetic relatedness of pVAS3-1 to Enterobacteriaceae plasmids suggests potential inter-species transfer and highlights a One Health concern.