Rapid Detection of Salmonella typhimurium Strains Isolated from Clinical Cases

Salmonellosis is the most common type of food poisoning that can cause a wide range of human diseases. Housekeeping genes are typically constitutive genes that are required for the maintenance of basic cellular function، and are expressed in all cells of an organism under normal conditions. The purpose of this study was to use the housekeeping genes for screening of Salmonella typhimurium strains isolated in Tehran’s hospitals. Bacterial samples were collected from various clinical specimens in several hospitals in Tehran. The bacterial isolates were detected and identified as Salmonella using standard microbiological and biochemical tests. Of all Salmonella isolates 22 strains were belonged to S. typhimurium. Then the PCR method using primers hem D، dnaN، and hisD was used to molecular screen of Salmonella typhimurium strains. PCR produced the bands of 567-633 bp for hemD gene، 635 bp for dnaN gene and 561 bp for hisD gene in all tested Salmonella typhimurium. Any positive reaction was seen on control strains including E. coli and Shigella indicating that the specificity of the PCR is good. This study showed that housekeeping genes are appropriate targets for molecular screening of Salmonella enterica serotype typhimurium.