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Title: DETECTION AND POTENTIAL IDENTIFICATION OF ESCHERICHIA COLI 0157:H7 USING A MICROPARTICLE-BASED CHEMILUMINESCENT IMMUNOASSAY

Author
item Gehring, Andrew
item Albin, David
item Irwin, Peter
item Tu, Shu I

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/11/2006
Publication Date: 6/20/2006
Citation: Gehring, A.G., Albin, D.M., Irwin, P.L., Tu, S. 2006. Detection and potential identification of escherichia coli 0157:H7 using a microparticle-based chemiluminescent immunoassay. Biosensors p. 101.

Interpretive Summary:

Technical Abstract: Numerous cases of foodborne illnesses have been associated with the major foodborne pathogen, Escherichia coli O157:H7. Multiple screening methods have been developed to rapidly detect the presence of this bacterium in order to circumvent timely plate culture techniques. Unfortunately, many rapid methods are presumptive and do not claim to confirm the presence of E. coli O157:H7. The sandwich immunoassay-based method, enzyme-linked immunomagnetic chemiluminescence (ELIMCL), has been improved upon to allow for fewer incidences of false positives when used to detect E. coli O157:H7 in the presence of mixed cultures. The key feature of this assay is that it combines the highly selective synergism of both anti-O157 and anti-H7 antibodies in the sandwich immunoassay format that uses paramagnetic microparticles as a solid support. This work presents application of this new, now semi-automated version of ELIMCL to the detection of E. coli O157:H7 in pristine buffered saline yielding detection limits of approx. 1 e5 to 1 e6 of live cells per mL. ELIMCL was further demonstrated to detect E. coli O157:H7 inoculated into artificially contaminated ground beef at ca. 400 CFU/g after a 5 h enrichment and about 1.5 h assay time for a total detection time of about 6.5 h. ELIMCL was further compared with USFDAs BAM confirmation method for E. coli O157:H7 in a double blind study. Using McNemar’s treatment, the two methods were determined to be statistically similar for the detection and apparent identification of E. coli O157:H7 in ground beef inoculated with mixed cultures of select bacteria.