Purpose: The objective of this study was to investigate the prevalence of E. coli in the slaughterhouses and farms in S. Korea, and the genetic properties for the isolates were determined.
Methods: Samples were collected from the carcass (n=28) and feces (n=29) of cecum in six slaughterhouses, and from soil (n=20) and feces (n=63) in 20 cattle and pig farms in S. Korea. The samples were plated on E. coli/Coliform count plate incubated at 35°C for 24 h. Isolated colonies on the plates were identified by 16s rRNA analysis. To detect virulence genes in all E. coli isolates, PCR were performed using the primers specific to pathogenic genes (stx1, stx2, eaeA, inV, aggR, lt, and st) and to determine O antigen serotype. Antimicrobial susceptibility for the isolates were also examined. In addition, pulsed-field gel electrophoresis (PFGE) digested with XbaI restriction enzymes was conducted to compare the genetic correlations among the isolate.
Results: Of 140 E. coli isolates, 13 samples [9.3%; one feces and one carcass samples (3.5%) in slaughterhouse and 11 feces samples (13.3%) in farms] were verotoxin producing E. coli [stx1 (1), stx2 (9), and stx1+stx2 (3)]. Genetic characteristics for other pathogenic genes (eaeA, inV, aggR, lt, and st) and antimicrobial susceptibility were varied among the isolates. In PFGE patterns of E. coli, geographical correlation was observed, but low genetic correlation was observed among serotypes.
Significance: These results indicate that there is high prevalence of verotoxin producing E. coli in cattle and pig farms in S. Korea, and they have geographical correlations.