| Summary: | <p>Abstract</p> <p>Background</p> <p><it>Campylobacter </it>spp., especially <it>Campylobacter jejuni </it>(<it>C. jejuni</it>) and <it>Campylobacter coli </it>(<it>C. coli</it>), are recognized as the leading human foodborne pathogens in developed countries. Livestock animals carrying <it>Campylobacter </it>pose an important risk for human contamination. Pigs are known to be frequently colonized with <it>Campylobacter</it>, especially <it>C. coli</it>, and to excrete high numbers of this pathogen in their faeces. Molecular tools, notably real-time PCR, provide an effective, rapid, and sensitive alternative to culture-based methods for the detection of <it>C. coli </it>and <it>C. jejuni </it>in various substrates. In order to serve as a diagnostic tool supporting <it>Campylobacter </it>epidemiology, we developed a quantitative real-time PCR method for species-specific detection and quantification of <it>C. coli </it>and <it>C. jejuni </it>directly in faecal, feed, and environmental samples.</p> <p>Results</p> <p>With a sensitivity of 10 genome copies and a linear range of seven to eight orders of magnitude, the <it>C. coli </it>and <it>C. jejuni </it>real-time PCR assays allowed a precise quantification of purified DNA from <it>C. coli </it>and <it>C. jejuni</it>. The assays were highly specific and showed a 6-log-linear dynamic range of quantification with a quantitative detection limit of approximately 2.5 × 10<sup>2 </sup>CFU/g of faeces, 1.3 × 10<sup>2 </sup>CFU/g of feed, and 1.0 × 10<sup>3 </sup>CFU/m<sup>2 </sup>for the environmental samples. Compared to the results obtained by culture, both <it>C. coli </it>and <it>C. jejuni </it>real-time PCR assays exhibited a specificity of 96.2% with a kappa of 0.94 and 0.89 respectively. For faecal samples of experimentally infected pigs, the coefficients of correlation between the <it>C. coli </it>or <it>C. jejuni </it>real-time PCR assay and culture enumeration were R<sup>2 </sup>= 0.90 and R<sup>2 </sup>= 0.93 respectively.</p> <p>Conclusion</p> <p>The <it>C. coli </it>and <it>C. jejuni </it>real-time quantitative PCR assays developed in this study provide a method capable of directly detecting and quantifying <it>C. coli </it>and <it>C. jejuni </it>in faeces, feed, and environmental samples. These assays represent a new diagnostic tool for studying the epidemiology of <it>Campylobacter </it>by, for instance, investigating the carriage and excretion of <it>C. coli </it>and <it>C. jejuni </it>by pigs from conventional herds.</p>
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