Comparison between ImmunoCard STAT!® and real-time PCR as screening tools for both O157:H7 and non-O157 Shiga toxin-producing Escherichia coli in Southern Alberta, Canada

Real-Time PCR Assay for Detection and Differentiation of Shiga Toxin-Producing Escherichia coli from Clinical Samples

“…Molecular testing for STEC is not routinely used in clinical settings, despite supportive data (10)(11)(12). PCR assays have routinely used stx 1 and stx 2 as targets but cannot, by themselves, distinguish O157 from non-O157 STEC, although stx 1 -positive signals are unlikely to originate from O157 STEC unless stx 2 is also detected (13,14).…”

Evaluation of Enzyme Immunoassays and Real-Time PCR for Detecting Shiga Toxin-Producing Escherichia coli in Southern Alberta, Canada

“…Conventional culture methods focus mainly on the O157 serotype, and non-O157 STEC serotypes are underreported (30). The Centers for Disease Control and Prevention guidelines from October 2009 recommend simultaneous culture of stool samples and detection of Shiga toxins and/or their genes for all STEC isolates (31).…”

“…The Centers for Disease Control and Prevention guidelines from October 2009 recommend simultaneous culture of stool samples and detection of Shiga toxins and/or their genes for all STEC isolates (31). Amplification and enzyme immunoassay (EIA) kits for STEC detection are commercially available (30,(32)(33)(34).…”

“…Stool samples were directly tested for STEC using both EIAs (Shiga Toxin Chek and Shiga Toxin Quik Chek). Stool culture enrichment was performed by inoculating 4.5 ml of MacConkey broth with 200 l of watery/mucoid stool or a pea-sized solid/semiformed stool and incubating it for 16 to 24 h at 37°C (30). The culture was not treated with antibiotics.…”

“…A 200-l aliquot of the broth culture was used for the EIAs, and DNA extraction for real-time PCR. DNA template was prepared (35) and amplified as described previously (30,36). Positive-and negative-control STEC stool samples were included for extraction and amplification; and positive DNA and water controls were incorporated for amplification.…”