Evaluation of rapid detection and investigation of the presence of spv operon virulence genes in Salmonella isolates using simplex PCR and multiplex PCR molecular methods

The traditional methods of diagnosing Salmonella which are time-consuming and sometimes problematic, are still used to identify Salmonella serotypes in clinical and food samples, but with the invention of rapid molecular detection methods, these problems have been largely eliminated. The present study aimed to rapidly detect different Salmonella isolates based on invA chromosomal gene search and also to identify acute isolates containing spv operon virulence genes. To this end, 20 human isolates of Salmonella were obtained from hospitals in Tabriz and 20 isolates of this bacterium were isolated from traditional cheese available on Tabriz consumer market. The molecular confirmation of isolates was first evaluated using specific primers of invA gene by simplex PCR method. Then, in order to evaluate the acute strains of the bacterium based on the presence of operon spv, the presence of spvA, B, C and R genes was examined by multiplex PCR using the relevant specific primers. The results showed that firstly, all isolates had molecular confirmation. Secondly, all 40 tested isolates had 3 spvA, C and R genes, but none of them had spvB gene. It seems that due to the limitations and problems in the traditional laboratory examination of Salmonella, PCR can be used as a rapid method to detect Salmonella infection. Also, the presence of 3 out of 4 virulence genes of opron spv in different Salmonella isolates in Tabriz region should be considered an undesirable finding, which emphasizes the need to further observe principles of control and prevention in animal and human communities.