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United States Department of Agriculture

Agricultural Research Service

Research Project: EPIDEMIOLOGY, ECOLOGY, AND MOLECULAR GENETICS OF ANTIMICROBIAL RESISTANCE IN PATHOGENIC AND COMMENSAL BACTERIA FROM FOOD ANIMALS Title: Evaluation of two commercial real-time PCR assays for detecting Campylobacter in broiler carcass rinses.

Authors
item Englen, Mark
item Berrang, Mark
item Meinersmann, Richard
item Cray, Paula

Submitted to: Journal of Food Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 12, 2009
Publication Date: February 1, 2010
Citation: Englen, M.D., Berrang, M.E., Meinersmann, R.J., Cray, P.J. 2010. Evaluation of two commercial real-time PCR assays for detecting Campylobacter in broiler carcass rinses. Journal of Food Safety. 30(2010):732-739.

Interpretive Summary: Traditional detection methods for Campylobacter are time consuming, requiring several days to complete. The recent introduction of commercial real-time PCR instruments for the identification of Campylobacter offer more rapid, simplified alternatives to standard culture-based techniques. The automated gene-based detection systems now available reduce assay time, data collection and analysis. Bio-Rad and DuPont Qualicon recently introduced Campylobacter assays for their real-timme PCR instruments. In this study, we evaluated the utility of these assays compared to standard plating and enumeration methods routinely used in our laboratory. Two replicates of 40 broiler carcass rinses collected before and after defeathering at a commercial processing plant were tested. All samples were positive for Campylobacter after incubation on agar plates spread with the rinses. The Bio-Rad assay was 60-72.5% positive with direct rinses; the Qualicon test produced 60-85% positives from direct rinses. Using 24 hr enrichment broth from rinses in the PCR assays significantly improved detection: the Bio-Rad test had 95-100% positive while the Qualicon assay found 90-95% positive. We conclude that both commercial assays show very promising results with direct rinses. With minor improvements to the assay chemistries, significantly better results with rinses are expected.

Technical Abstract: Traditional plating methods are reliable means for Campylobacter identification from poultry samples but automated gene-based detection systems now available can reduce assay time, data collection and analysis. Bio-Rad and DuPont Qualicon recently introduced Campylobacter assays for their real-time PCR instruments. We evaluated the utility of these assays compared to standard plating and enumeration methods routinely used in our laboratory. Two replicates of 40 broiler carcass rinses collected before and after defeathering at a commercial processing plant were tested. All samples were postitive for Campylobacter by direct plating of rinses: log10 values ranged from 0.24 - 4.61. In contrast, the Bio-Rad iQ-Check assay returened 60 - 72.5 positives on direct rinses; the Qualicon BAX Q7 test produced 60 - 85% positives with direct rinse samples. Using aliquots of 24 hr enrichment broth from rinses as in the real-time assays significantly improved detection: the Bio-Rad test had 95 - 100% positive while the Qualicon assay found 90 - 95% positive.

Last Modified: 10/30/2014
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