No abstract

Fecal samples from 720 healthy, domestic animals representing seven different species (cattle, sheep, goats, pigs, chickens, dogs, and cats) were investigated for verotoxin (VT [Shiga-like toxin])-producing Escherichia coli (VTEC). VTEC were isolated from 208 animals (28.9%), most frequently from sheep (66.6% VTEC carriers), goats (56.1%), and cattle (21.1%). VTEC were isolated less frequently from pigs (7.5%), cats

Out of 174 bovine Shiga toxin-producing Escherichia coli (STEC) strains isolated from diarrheic calves in Germany and Belgium, 122 strains (70.1%) were selected because of their reactivity with the eae (E. coli attaching and effacing gene) probe ECW1-ECW2. One hundred seven of these eae-positive strains (87.7%) harbored stx1 genes, 13 strains (10.7%) had stx2 genes, and 2 strains (1.6%) had both stx genes. The strains displayed 17 different O types, the majority (97 strains [79.5%]) belonging to O5 (5 strains), O26 (21 strains), O111 (13 strains) O118 (36 strains), O145 (9 strains), and O157 (13 strains). In the HEp-2 cell adhesion assay, 99 strains (81.1%) showed a localized adhesion, and 80 strains (65.6%) stimulated actin accumulation, as determined in the fluorescence actin staining test. None of the strains harbored genes coding for bundle-forming pili (bfpA), clearly differentiating them from enteropathogenic E. coli. espB gene sequences were only detectable in 23 (18.9%) of the eae-positive bovine STEC strains. Three different PCRs were established, differentiating between eae sequences of enteropathogenic E. coli strain E2348/69 (O127:H6) and STEC strain EDL933 (O157: H7). Primers matching in the more heterologous downstream eae sequences gave amplicons in only 8 of the 17 O types (O84:

Aims:  To evaluate the suitability of the commercially distributed Ridascreen® Verotoxin enzyme immunoassay (EIA) for detection of known genetic types of the Vero (Shiga) toxins 1 (Stx1) and 2 (Stx2) families and to determine its relative sensitivity and specificity. Methods and Results:  The Ridascreen‐EIA was compared with the Vero cell assay, a P1‐glycoprotein receptor EIA and with stx gene‐specific PCs for detection of Stx with 43 Shiga toxin‐producing strains of Escherichia coli (STEC) reference strains and with 241 test strains. The Ridascreen‐EIA detects strains producing Stx1 and variants Stx1c and Stx1d, as well as Stx2 and variants Stx2d1, Stx2d2, Stx2e, Stx2d, Stx2‐O118 (Stx2d‐ount), Stx2‐NV206, Stx2f and Stx2g. The assay showed a relative sensitivity of 95·7% and a relative specificity of 98·7%. Some of the Stx2‐O118‐, Stx2e‐ and Stx2g‐producing STEC were not detected with the Ridascreen‐EIA probably because of low amount of toxin produced by these strains. Conclusions:  The Ridascreen‐EIA is able to detect all known types of Stx and is applicable for routine screening of bacterial isolates owing to its high specificity. It is less applicable for testing samples where low amounts of Stx are expected, such as mixed cultures and certain Stx2 variants. Significance and Impact of the Study:  This study presents a first comprehensive evaluation of the Ridascreen‐EIA, a rapid standardized STEC screening test for routine diagnostic laboratories. Data are presented on the type of the spectrum of Stx that are detected with this immunoassay and its advantages and limits for practical use.