Identification and Discrimination of Salmonella Enteritidis, S. Pullorum, S. Gallinarum and S. Dublin Using Salmonella Specific Genomic Regions Amplification Assay

Background: DNA amplification method has been developed for identifying and discriminating Salmonella serovars, using specific primers at the genus and serovar levels and to identify the S. Enteritidis, S. Dublin, S. Gallinarum and S. Pullorum. Objectives: This study was conducted for molecular identification and discrimination among some important Salmonella serovars. Methods: Fifty isolates of Salmonella were assayed. The PCR assay was designed to amplify DNA fragments from six Salmonella genes, invA (284 bp), tcpS (882 bp), lygD (339 bp), flhB (155 bp), SlgC (252 bp), and speC (174 bp). Results: The results showed invA and tcpS genes presence in all four Salmonella serovars, whereas the lygD gene only exists in S. Enteritidis and is not found in S. Dublin, S. Gallinarum and S. Pullorum. The flhB gene is only present in S. Enteritidis and S. Dublin whereas it does not exist in S. Gallinarum and S. Pullorum. The SlgC gene exists in both S. Gallinarum and S. Pullorum, the SpeC gene is specifically present in S. Gallinarum, whereas SlgC and SpeC genes are not found in S. Enteritidis and S. Dublin. Salmonella Dublin serovar amplification assay successfully identified three selected serovar specific genomics regions (SSGRs) and hut gene. The results identify hut gene (495 bp), DSR1 (Dublin-specific genomics region1) (105 bp), DSR2 (Dublin-specific genomics region2) (203 bp), and DSR3 (Dublin-specific genomics region3) (296 bp). Conclusions: Amplification techniques on Salmonella serovars specific genomics regions are able to identify and discriminate clinically significant Salmonella serovars, and therefore, have the possibility to be used as a useful and rapid screening assay and support conventional biochemical and serological examinations