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United States Department of Agriculture

Agricultural Research Service

Title: Immunomagnetic-Electrochemiluminescent Detection of Escherichia Coli 0157 in Ground Beef after Pre-Enrichment in Brilliant Green Bile Broth, Modified Escherichia Coli Broth with Or Without Novobiocin, Or Gram Negative Broth

Authors
item Feder, Ingrid
item Wijey, Chandi
item Paoli, George
item Crawford, Claude
item Tu, Shu-I

Submitted to: Journal of Rapid Methods and Automation in Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 24, 2006
Publication Date: January 30, 2007
Citation: Feder, I.E., Wijey, C., Paoli, G., Crawford, C.G., Tu, S. 2007. Immunomagnetic-electrochemiluminescent detection of escherichia coli 0157 in ground beef after pre-enrichment in brilliant green bile broth, modified escherichia coli broth with or without novobiocin, or gram negative broth. Journal of Rapid Methods and Automation in Microbiology. 15:92-106.

Interpretive Summary: Escherichia coli O157:H7 is the leading cause of hemolytic uremic syndrome (HUS). As few as 2 E. coli O157:H7 cells can cause HUS, a potentially fatal kidney disease, particularly in children and immunocompromised individuals. Additionally, E. coli O157:H7 infection can result in a bloody or a non-bloody diarrhea. In the past two decades, disease due to E. coli O157:H7 has been increasing. Cattle feces have been shown to be the most significant reservoir of E. coli O157:H7 with ground beef being the most common means of human infection. To improve the detection of Escherichia coli O157:H7 in ground beef, a procedure was developed for rapid analysis of Escherichia coli O157:H7 in ground beef using an immunomagnetic separation (IMS)/electrochemiluminescent (ECL) procedure. In less than 8 hours, IM-ECL could detect as few as 1 cell of E. coli O157:H7 in ground beef that had been pre-enriched in Brilliant Green Bile broth. IM-ECL could also detect as few as 1 cell of E. coli O157:H7 in ground beef samples that had been pre-enriched in mEC broth but typically not within 8 hours. The results from this study indicate that the BGB pre-enrichment/ IM-ECL procedure can rapidly detect low numbers of E. coli O157:H7 in ground beef. This assay can be recommended as an excellent E. coli O157:H7 screening method for use by the food industry.

Technical Abstract: A procedure was developed for rapid analysis of Escherichia coli O157:H7 in ground beef samples using an immunomagnetic separation (IMS)/electrochemiluminescent (ECL) procedure following pre-enrichment. Ground beef was spiked with E. coli O157:H7 and pre-enriched in brilliant green bile 2% broth (BGB), modified E. coli broth with novobiocin (mEC), mEC without novobiocin (mEC w/o N), or Gram negative broth, Hajna containing vancomycin, cefixime, and cefsuludin (GN) Samples were concentrated by IMS and assayed using ECL. In less than eight hours, IM-ECL could detect as few as 1 colony forming unit (cfu) of E. coli O157:H7 in ground beef samples that had been pre-enriched in BGB; IM-ECL detected E. coli O157:H7 in all of the samples spiked with 10 or 100 colonies after a 6 h incubation in BGB. IM-ECL could also detect as few as 1 cfu of E. coli O157:H7 in samples that had been pre-enriched in mEC, but suspensions obtained from mEC required considerable filtration time to remove meat particles. IM-ECL detected E. coli O157:H7 in all of the samples spiked with 10 or 100 colonies after a 6 h incubation in mEC. The results from this study indicate that the BGB pre-enrichment/IM-ECL procedure can rapidly detect low numbers of E. coli O157:H7 in ground beef samples. This assay can be recommended as an excellent E. coli O157:H7 screening method for use by the food industry.

Last Modified: 8/30/2014
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