Genotypic and phenotypic trends in antibiotic resistant pathogenic Escherichia coli isolated from humans and farm animals in South Korea

South Korea uses more antibiotics for animal production than any other member of the OECD. The excessive use could potentially lead to a greater incidence of antibiotic resistant microorganisms, some of which may be pathogenic. In this study, we examined potential diarrheagenic and extraintestinal pathogenic E. coli (ExPEC) isolates using virulence gene profiling (eaeA, est, elt, ipaH, stx1 and stx2 as diarrheagenic and afa/dra, iutA, kpsMT II, papA/C, and sfa/foc as extraintestinal pathogenic virulence genes). A cluster analysis of DNA fingerprint data indicated that certain genotypes of chicken E. coli isolates are likely ExPEC. Moreover, our results showed 38 of the 60 potential diarrheagenic and ExPEC isolates obtained from animals and humans were also resistant to antibiotics, mostly to tetracycline groups, penicillin groups, and folate pathway inhibitors. Our results suggest that the use of antibiotics in agriculture should be controlled due to potential impacts on human health.