Author
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Harmon, Karen |
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RANSOM, G - FSIS |
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Wesley, Irene |
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Submitted to: Food Safety Consortium Proceedings
Publication Type: Proceedings Publication Acceptance Date: 10/22/1996 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: A multiplex PCR assay using two primers sets for the identification and differentiation of C. coli and C. jejuni was designed. Primer set I amplifies a 450-bp fragment of the fla A gene which is present in both C. jejuni and C. coli but is absent in other thermotolerant campylobacters. Primer set II amplifies a 160-bp sequence unique to C. jejuni. Specificity yof the assay was determined using reference strains of thermotolerant campylobacters (C. coli, C. jejuni, C. lari, and C. upsaliensis). Amplification of C. coli yielded only the 450-bp fragment, whereas C. jejuni generated both the 160- and 450-bp amplicons. No product was seen when C. lari and C. upsaliensis were used as the template. In field trials, 85 poultry isolates were speciated both biochemically and via mPCR. Results agreed for 83 of the 85 isolates (97.6%). Two isolates which could not be identified using biochemical methods, were identified as C. coli by mPCR. Thus, PCR identified all of the field isolates. We next determined the feasibility of performing PCR directly from colonies grown on highly selective media. This would indicate the practicality of utilizing mPCR to estimate the prevalence of campylobacters in food animals. Of 1,057 swine fecal samples evaluated, 69% harbored C. coli and 0.28% contained C. jejuni. The mPCR assay is specific, simple to perform, easy to interpret and may be a useful adjunct to conventional biochemical testing for the identification of C. coli and C. jejuni. Performing a mPCR directly from colonies grown on selective agar provides an efficient method for large scale screening of livestock for campylobacters of potential food safety significance. |
