Sporadic clone E. coli ST615 as vector and reservoir for dissemination of crucial antimicrobial resistance genes

CARRERA PÁEZ LC; OLIVIER, M; GAMBINO AS; POKLÉPOVICH, T; AGUILAR, ANDREA; QUIROGA MP; CENTRÓN D

Front. Cell. Infect. Microbiol.

Frontiers in Cellular and Infection Microbiology Editorial Office

Lugar: Lausana; Año: 2024 vol. 14

2235-2988

There is scarce information concerning the role of sporadic clones in the dissemination of antimicrobial resistance genes (ARG) within the nosocomial niche. We confirmed that clinical E. coli M19736 ST615 strain, one of the first isolates of Latin America that harbors a plasmid with a mcr-1 gene, could receive crucial ARG by transformation and conjugation using as donors critical plasmids that harbor blaCTX-M-15, blaKPC-2, blaNDM-5, blaNDM-1, or aadB genes. E. coli M19736 acquired blaCTX-M-15, blaKPC-2, blaNDM-5, blaNDM-1, and aadB genes being only blaNDM-1, maintained at the 100% at the 10th day of subculture. In addition, when evolved MDR-E. coli M19736 acquired sequentially blaCTX-M-15 and blaNDM-1 genes, the pattern of maintenance along time of plasmids changed. In addition, when evolved XDR-E. coli M19736 acquired in an ulterior step the paadB plasmid, a different pattern of plasmid´s maintenance was found. Interestingly, evolved E. coli M19736 strains disseminated simultaneously the acquired conjugative plasmids in different combinations though selection was ceftazidime in all cases. Finally, we isolated and characterized the Extracellular Vesicles (EV) from native and evolved XDR-E. coli M19736 strains. Interestingly, EV from evolved XDR-E. coli M19736 harbored blaCTX-M-15 though the pDCAG1-CTX-M-15 was previously lost as shown by WGS and 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 relevant transitional link in the clinical dynamics and evolution to multidrug/extensively/pandrug phenotypes of superbugs within the nosocomial niche by acting simultaneously as vector and reservoir of multiple ARG which later could be disseminated.