Real-time PCR detection of Salmonella species using a novel target: the outer membrane porin F gene (ompF)

Abstract

To evaluate the outer membrane porin F gene (ompF) for the specific detection of Salmonella species by real-time PCR assay. Two hundred and eighteen isolates belonging to Salmonella enterica (subspecies I-VI) and Salmonella bongori were examined using primers designed to detect the ompF gene. The DNA of the bacteria was extracted from pure culture. The target was present in all the 218 Salmonella isolates including all the subspecies of Salm. enterica and Salm. bongori. The ompF gene was absent in 180 non-Salmonella strains tested. The limit of detection was determined to be three colony forming units per reaction in pure culture. In artificially contaminated food experiments with ten or less colony forming units per 25 g, the assay was successful in identifying the target in 100% of the samples after 22- to 24-h incubation in enrichment broth. Based on this study, the ompF gene is 100% inclusive for Salmonella species and 100% exclusive for non-Salmonella species for the strains tested. ompF gene was present in all the Salmonella strains tested and has the potential to be a good target for the rapid molecular identification of Salmonella.