2020 Volume 37 Issue 2 Pages 61-68
We isolated and investigated Shiga toxin (Stx)-producing Escherichia coli (STEC) from feces of captured wild boars in the Toyama Prefecture. For detection of STEC, which were not grown in STEC-selective medium, we cultured fecal samples in a non-STEC selective medium and screened the samples by stx-PCR. Out of fecal samples obtained from 76 wild boars, stx was detected in 12 samples (15.8%) and STEC strains were isolated from seven stx-positive fecal samples (9.2%). The STEC isolates harbored the following serotype and stx: Og8 : H19 (stx2e), Og148 : H10 (stx2g), Og105 : H7 (stx2f), and Og4 : H27 (stx2g). Except for Og105 : H7, the isolates were LEE (locus for enterocyte effacement)-negative STEC, which did not harbor the eae gene. Also, these isolates were not grown in STEC-selective medium. The wild boars harboring STEC were distributed in particular regions and STEC Og8 : H19 isolated from four wild boars captured from the same region were found to harbor the same DNA pattern by pulse-field gel electrophoresis (PFGE) analysis. Og148 : H10 and Og4 : H27 harbored virulence-associated genes, EAST-1 and heat-stable enterotoxin gene. The findings of our study indicate that wild boars are the carriers of LEE-negative STEC harboring virulence-associated genes that are different from those of the serotype O157 : H7, which was prevalent STEC in humans.
