Plasmid-mediated cephalosporin resistance in CMY-2-producing Escherichia coli isolated from ready-to-eat cilantro.

​An increasing number of global reports on the high prevalence of multidrug-resistant (MDR) strains in the environment underscoring the role of food as a reservoir for both commensal and pathogenic Escherichia coli capable of transmitting drug resistance genes. Due to how they are consumed and the possibility of poor washing and disinfection processes, vegetables have been frequently associated with the presence of multidrug-resistant strains. This study describes the resistome, virulome, and plasmidome of E. coli strains A65EC and A134EC that were isolated from ready-to-eat cilantro. Both strains were phenotypically characterized as MDR and AmpC-type β-lactamase producers, a capacity associated with the presence of the blaCMY-2 gene on an IncI1 and p0111 plasmid, respectively. In addition, A65EC belonging to ST746 presented three additional plasmids characterized as conjugative or mobilizable, harboring the resistance genes aadA2, blaTEM-103, sul1, dfrA12, dfrA14, tetA and qacEΔ1. Meanwhile, A134EC corresponding to ST10 showed three conjugative plasmids and one mobilizable plasmid carrying the genes aadA5, aac(3)-Ild, dfrA17, qacEΔ1, sul3, mefB, floR, estT and fosA2. described19 virulence genes were described, of which nine (aslA, fimH, nlpl, iss, sitA, terC, hlyE, cia, and anr) were shared in both strains. This is the first report of blaCMY-2-bearing strains isolated from green leafy vegetables, and we describe the presence of the fosA2 gene harbored on a conjugative plasmid. The detection of multidrug-resistant strains with the genetic potential to transfer resistance determinants in fresh produce is a concerning finding. It underscores the urgent need for surveillance and monitoring systems in vegetables to better elucidate the transmission pathways of resistance and virulence genes across diverse ecological niches.