Polymerase chain reaction method for the rapid detection of virulent Shigella spp.

Bacillary dysentery, or shigellosis, is a disease of humans in which the colonic epithelium is invaded by bacteria and subjected to inflammatory destruction. The aim of this study was to develop a polymerase chain reaction(PCR) test for detection of virulent Shigella spp.. For this purpose, the primers were designed to amplify a 526-bp internal region of the Shigella spp. icsA gene, which encodes IcsA (intracellular spread)/VirG protein, a 116-kDa surface exposed outer membrane protein that mediates actin polymerization to aid bacterial movement inside the cell. The use of PCR to amplify a specific icsA gene fragment serves as a highly specific and sensitive method to detect virulent bacteria of the genus Shigella. Specific DNA band was obtained by using isolated plasmid DNA of Shigella and a bacterial suspension. Amplification of extracted DNA from all other genera of the family Enterobacteriaceae and various other gram-positive bacteria yielded negative results. Therefore this PCR method, can serve as a routine protocol for detecting and identifying virulent Shigella spp. from clinical samples.