Comparison of primers for the detection of Salmonella enterica serovars using real-time PCR

To evaluate the specificity and sensitivity of PCR primers for the detection of Salmonella enterica in a real-time PCR assay using pure cultures.

Unenriched whole cells in sterile water were used as template for each PCR. SYBR Green dye was used for the nonspecific detection of dsDNA. The real-time PCR detection limits of five previously published primer sets used in conventional PCR applications were not below 3 x 10(3) CFU per reaction (rxn). A new primer set, Sen, was designed, which detected Salm. enterica Newport down to 6 CFU rxn(-1) in one case, and gave an average detection limit of 35 CFU rxn(-1) over three separate runs.

Primers originally designed for end-point PCR did not have adequate specificity or sensitivity compared with those specifically designed for real-time PCR.

This study emphasizes the importance of evaluating real-time PCR primer sets in pure cultures prior to testing in field samples. This study will benefit other researchers in selecting an appropriate primer set for real-time PCR detection of Salm. enterica.