A real-time PCR assay for detection and quantification of Lactococcus garvieae

Aims: To develop a rapid, sensitive, specific tool for the detection and quantification of Lactococcus garvieae in food and environmental samples. Methods and Results: A real-time quantitative PCR (qPCR) assay with primers for CAU12F and CAU12R based on the 16S rRNA gene of L. garvieae was successfully established. The limit of detection for L. garvieae genomic DNA was 1 ng DNA in conventional PCR and 32 fg with a mean C(T) value of 36 center dot 75 in qPCR. Quantification of L. garvieae vegetative cells was linear (R2 = 0 center dot 99) over a 7-log-unit dynamic range down to ten L. garvieae cells. Conclusions: This method is highly specific, sensitive and reproducible for the detection of L. garvieae compared to gel-based conventional PCR assays, thus providing precise quantification of L. garvieae in food and natural environments. Significance and Impact of the Study: This work provides efficient diagnostic and monitoring tools for the rapid identification of L. garvieae, an emerging pathogen in aquaculture and an occasional human pathogen from other members of the genus Lactobacillus.