FIG. 1.

Sensitivity of the fluorogenic 5′ nuclease assay for detecting pathogenic Y. enterocolitica in disposable 96-well optical reaction plates (PE Applied Biosystems). Tenfold dilutions of Y. enterocolitica serotypes O:3 (□) and O:9 (⧫) were made in PSBB in triplicate. One-milliliter aliquots from each dilution were subjected to DNA extraction using the PrepMan method, and 2.5 μl of the recovered DNA solution was PCR-amplified using the Pr2a and Pr2c primers in the presence of the Yer-prb fluorogenic probe. Detection and analysis were completed with the ABI Prism sequence detection system. All amplification and detection reactions were completed in 96-well optical reaction plates. The average ΔRQ values for each dilution were plotted against the average number of CFU per milliliter as determined by plating each dilution on CIN agar. The adjusted ΔRQ threshold value was calculated to be 4.44 (dashed horizontal line). Error bars indicate the standard deviations of the means.