Enzyme-Linked Immunosorbent Assay (Elisa) for the Detection of the K88 Antigen of Escherichia Coli in Porcine Faeces

The purpose of this study was to evaluate an enzyme-linked immunosorbent assay (ELISA) and an immunoblot procedure for detection and isolation of Shiga toxin-producing Escherichia coli (STEC) from beef, and to correlate the presence of STEC in beef with E. coli and total coliform counts. A total of 120 samples of boneless beef supplied to a meat processor in southern Ontario were tested for the presence of STEC, E. coli, and total coliforms. Following enrichment in modified tryptic soy broth, samples were screened for Shiga toxin (Stx) by a Stx-ELISA and a Vero cell assay (VCA). Samples that were positive in the Stx-ELISA were subjected to the Stx-immunoblot for STEC isolation. Overall, 33.3% of samples were positive in the VCA, and 34.2% were positive in the Stx-ELISA. There was almost complete agreement between the Stx-ELISA and the VCA results (kappa = 0.98). The sensitivity and specificity of the Stx-ELISA with respect to the VCA were 100% and 98.75%, respectively. STEC were isolated by the Stx-immunoblot from 87.8% of the samples that were positive in the Stx-ELISA. The STEC isolates belonged to 19 serotypes, with serotype O113:H21 accounting for 10 of 41 isolates. No STEC of serotype O157:H7 were isolated. There was a significant correlation between E. coli counts and total coliform counts (Spearman correlation coefficient = 0.68, P < 0.01). The E. coli count was positively correlated with detection of STEC by both the Stx-ELISA and the VCA (P < 0.01).

Download Full-text

Comparison of a monoclonal antibody-based capture/enrichment sandwich enzyme linked immunosorbent assay with immunomagnetic bead separation for the detection of attachment effacement Escherichia coli O26 strains from cattle faeces

Journal of Applied Microbiology ◽

10.1111/j.1365-2672.2006.02889.x ◽

2006 ◽

Vol 100 (5) ◽

pp. 1141-1146 ◽

Cited By ~ 2

Author(s):

D. Finlay ◽

C. Bell ◽

H.J. Ball

Keyword(s):

Escherichia Coli ◽

Monoclonal Antibody ◽

Immunosorbent Assay ◽

Enzyme Linked Immunosorbent Assay ◽

Immunomagnetic Bead ◽

Cattle Faeces

Download Full-text

Evaluation of Three Commercially Available Enzyme-Linked Immunosorbent Assay Kits for Detection of Shiga Toxin

Journal of Food Protection ◽

10.4315/0362-028x-72.4.741 ◽

2009 ◽

Vol 72 (4) ◽

pp. 741-747 ◽

Cited By ~ 34

Author(s):

JOHN WILLFORD ◽

KENNETH MILLS ◽

LAWRENCE D. GOODRIDGE

Keyword(s):

Escherichia Coli ◽

Immunosorbent Assay ◽

Shiga Toxin ◽

Screening Method ◽

Enzyme Linked Immunosorbent Assay ◽

Microplate Assay ◽

E Coli ◽

Elisa Kit ◽

Pure Cultures ◽

Order Of Magnitude

Three commercially available Shiga toxin (Stx) enzyme-linked immunosorbent assay (ELISA) kits were evaluated for their ability to detect Stx in pure cultures of Stx-producing Escherichia coli (specificity). The detection limits (sensitivity) of each ELISA kit were also evaluated. Seventy-eight Stx-producing E. coli (STEC) isolates that produced Stx1, Stx2, or Stx1 and Stx2 variants were examined in this study. The specificities of the tests were comparable, and the sensitivities of two of the tests (Premier EHEC and rBiopharm Ridascreen Verotoxin Enzyme Immunoassay) were within the same order of magnitude. The ProSpecT Shiga Toxin E. coli Microplate Assay was approximately 10-fold less sensitive. The inability of all three tests to detect the Stx2d and Stx2e variants indicated that some STEC strains may not be detected by Stx ELISA. The ability of the Premier EHEC ELISA to detect toxin in artificially inoculated bovine fecal samples (following enrichment) indicated that this kit may be used to screen cattle for the presence of Stx as an indicator of the presence of STEC. In particular, such a screening method could be useful during the summer, when the number of STEC-positive animals and the number of STEC that they shed increase.

Download Full-text