Propidium monoazide (PMA) real-time PCR amplification for viable Salmonella species and S. Heidelberg in pork

Salmonella enterica serovar Heidelberg causes foodborne infections and is a major threat to the food chain and public health. In this study, we aimed to develop a rapid molecular typing approach to identify S. enterica serovar Heidelberg. Using comparative genomics, four serovar-specific gene fragments were identified, and a real-time polymerase chain reaction (PCR) combined with propidium monoazide (PMA) pretreatment method was developed for simultaneous detection of viable Salmonella sp. (invA) and S. Heidelberg(SeHA C3258). The assay showed 100% specificity for all strains tested. The assay was able to effectively distinguish viable or dead cell using PMA . The detection limit was 2.4 CFU/mL following a 6-h incubation in enrichment LB medium, and the assay could detect 1.7 Ă 102 CFU/mL in the presence of pork background flora. In artificially contaminated pork, real-time PCR detected inoculum levels of 1.15 CFU/25 g of pork after a 6-h enrichment. Thus, our findings indicated that this comparative genomics approach could be used to screen for serovar-specific fragments and that real-time PCR with PMA was a simple and reliable method for detecting viability of Salmonella species and S. Heidelberg.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author