EVALUATION OF A COMMERCIAL DIAGNOSTIC PCR FOR THE IDENTIFICATION OF CAMPYLOBACTER JEJUNI AND CAMPYLOBACTER COLI

Authors: Englen, Mark; Cray, Paula

Submitted to: Letters in Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/26/2002
Publication Date: 7/23/2002
Citation: Englen, M.D., Cray, P.J. 2002. Evaluation of a commercial diagnostic pcr for the identification of campylobacter jejuni and campylobacter coli. Letters in Applied Microbiology. V. 35. P. 353-356.

Interpretive Summary: The development of improved methods for the identification of major food borne pathogens such as Campylobacter is an important step in the process of designing intervention control strategies, and implementing better food safety standards. As part of a collaborative effort with DuPont Qualicon, in this study we evaluated the Campylobacter BAX System PCR, a new DNA-based assay for the identification of C. jejuni and C. coli. We compared test results for the BAX PCR to those obtained with a standard PCR assay, using Campylobacters isolated from poultry as the test group. For the majority of isolates, the BAX assay results were identical to those obtained using the standard PCR. An important and unexpected finding involved a small percentage of the well-characterized test isolate group that were found to be mixed cultures, containing both C. jejuni and C. coli. We are conducting further investigations on the phenomenon of mixed cultures with Campylobacter. Overall, the new BAX PCR provides the same test accuracy as standard methods, while offering significant improvements, including simplified design and ease of use. It is particularly well suited to applications involving large numbers of samples.

Technical Abstract: DuPont Qualicon has recently developed a new BAX System PCR assay for the identification of Campylobacter jejuni and Campylobacter coli. We evaluated the BAX PCR study against a PCR method already in use in our laboratory. A group of 133 Campylobacter isolates from poultry carcass rinse samples were screened using both the BAX PCR and the standard PCR. Identical results were found for 89.5% (119/133) of the isolates. However, 10.5% (14/133) gave conflicting results suggesting mixed cultures. These 14 strains were retested by both PCR methods. Of these, 78.6% (11/14) showed identical results for both PCR methods after retesting; the results for the remaining 21.4% (3/14) again indicated mixed cultures. We conclude that the Qualicon Campylobacter BAX PCR is a rapid and accurate alternative to standard PCR methods, and is ideal for applications with high throughput requirements. Our results also demonstrate the prevalence of mixed cultures among Campylobacter isolates.