The primers were designed to specifically amplify a region of
hilA gene (216 bp), a highly conserved SPI-1 gene, from Salmonella.
Salmonella diverged from other enteric bacteria by acquiring
Salmonella Pathogenicity Island 1. This island is conserved among
the Salmonella serovars. hilA gene is absent from the other related
bacteria (pathogenic and non-pathogenic). Bioinformatic analysis
showed that hilA is conserved among all the Salmonella serovars
reported so far and is absent in non-Salmonella strains (Data not
shown).