TABLE 2.
Sample (no. of samples) | stx genotype | Conventional assaysa | Immuno-PCR detection of Stxb
|
||
---|---|---|---|---|---|
Undiluted | 1:10 | 1:100 | |||
STEC low producers (6) | stx2dc | − | + | + | − |
stx2ed | − | + | + | − | |
STEC controls (4) | stx2de | + | + | + | + |
stx2ef | + | + | + | + | |
stx1, stx2g | + | + | + | + | |
Nonproducers (20) | —h | − | − | − | − |
Stool samples (3) | stx2 | − | + | ND | ND |
Stool samples (10) | — | − | − | ND | ND |
Conventional assays include the Vero cell cytotoxicity assay, the Stx enzyme immunoassay (R-Biopharm), the latex agglutination assay (VTEC-RPLA; Denka Seiken, Coventry, United Kingdom), and Stx colony immunoblotting (Sifin). +, positive result; −, negative result. Identical results were obtained with all of the conventional assays for each strain.
Immuno-PCR detection response to various supernatant dilutions. +, PCR product present; −, PCR product absent; ND, not done.
Serotypes O40:H8 (three samples), O86:H−, and Orough:HNT.
Serotype ONT (not typeable):H−.
Serotypes O91:H− and ONT:H12.
Serotype ONT:H−.
Strain EDL933 serotype O157:H7.
—, no stx gene was detected.