Sporadic clone E. coli ST615 as vector and reservoir for dissemination of crucial antimicrobial resistance genes
There is scarce information concerning the role of sporadic clones in the dissemination of antimicrobial resistance genes ARG within the nosocomial niche through the of Horizontal Genetic Transfer mechanisms. We confirmed that clinical E. coli M19736 ST 615 strain, one of the first isolated of Latin America that harbor a plasmid with mcr-1 gene, could receive crucial ARG by transformation and conjugation using as donors critical plasmids that harbors blaCTX-M-15, blaKPC-2, blaNDM-5, blaNDM-1, and aadB genes. We isolated and characterized the EV from native and evolved XDR-E. coli M19736 by transmission electron microscopy, and dynamic light scattering that showed particles with a size 193 nm for E. coli M19736 and 174,7 nm for evolved XDR-E. coli M19736 in diameter. By Liquid chromatography-MS-MS we studied the proteins that are inside of the EV from native E. coli M19736. We found 338 proteins including the presence of the MCR-1 protein. EV from evolved XDR-E. coli M19736 harbored blaCTX-M-15 though the pDCAG1-CTX-M-15 was previously lost as shown by other experiments along time, suggesting that EV could be relevant reservoir of ARG for susceptible bacteria. These results evidenced the genetic plasticity of a sporadic clone of E. coli such as ST615 that could play a very important transitional link in the clinical dynamics and evolution to multidrug-extensively-pandrug phenotypes of superbugs within the nosocomial niche by acting as vector and reservoir of multiple ARG which later could be disseminated.