Comparative Genetic Characterization of Pathogenic Escherichia coli Isolated from Patients and Swine Suffering from Diarrhea in Korea

The aim of this study was to compare the virulence factors and antimicrobial resistance of the most common pathogenic Escherichia coli strains in swine and patients with diarrhea in Korea. We examined virulence genes and antimicrobial susceptibility in 85 and 61 E. coli strains isolated from swine and patients with diarrhea, respectively. The most prevalent pathogen in swine was enterotoxigenic E. coli (ETEC) (47.1%), followed by Shiga toxin-producing E. coli (STEC) (32.9%). Similarly, the majority of the patient isolates (50.8%) were proven to be STEC, the most common pathotype, followed by ETEC (23.0%). We found that swine isolates had significantly higher resistance than patient isolates, especially to fluoroquinolones (ciprofloxacin: 37.5% and 16.1%; norfloxacin: 29.7% and 16.1%, respectively). Additionally, sequence type (ST) 100 (swine: 21; patients: 4), ST 1 (swine: 21, patients: 2), ST 10 (swine: 8; patients: 6), ST 641 (swine: 3, patients: 2), and ST 88 (swine: 2, patients: 11) were detected in both swine and humans. In addition, we confirmed that isolates from swine and patients had similar virulence traits and were phylogenetically similar. According to these findings, swine and humans are susceptible to cross infection and the transfer of antimicrobial resistance.

Automated summary

The study compared virulence factors and antibiotic resistance among the most common pathogenic Escherichia coli strains in swine and patients with diarrhea in Korea. The prevalence of enterotoxigenic E. coli (ETEC) was highest in swine (47.1%), followed by Shiga toxin-producing E. coli (STEC) (32.9%). Similarly, the majority of patient isolates were STEC (50.8%), followed by ETEC (23.0%). Swine isolates showed significantly higher resistance to fluoroquinolones compared to patient isolates. Several sequence types (ST) were detected in both swine and humans, indicating susceptibility to cross infection. The study highlights the potential transfer of antimicrobial resistance between swine and humans.