Determination of Distribution of icsA gene and Icsfl Protein Bands between ShigelIa flexneri Isolated from 3 Hospitals in Tehran

Introduction: shigella is a facultative intracellular pathogen that uses thehost actin cytoskeleton protein for intra- and intercellular spread. the aim ofthis study was to determine the distribution of icsa gene and icsa expressedprotein bands among shigella flexneri strains isolated from 3 clinical centersin tehran.material and methods: two hundred and seventy five isolated shigellaflexneri strains were identified by standard microbiological and biochemicalmethods. ona isolation was performed using sodium perchlorate method.hot start-pcr was done with 2 pairs of primers and the products wereseparated through agarose gel (0.8%) in tae buffer. ona fragments werevisualized by ethidium bromide staining under uv illumination. wholemembrane preparation was used to examine the protein profiles andidentification of probable icsa (120-kda) protein band by sos-page.results: from 100 isolated shigella flexneri strains, both bands of 1600 bpand 1709 bp were detected in 46 isolates (46%). a 120 koa band whichseems to be related to icsa protein was detected in 46 isolates (46%). theprotein bands varied between 30 and 150 koa.discussion: icsa is both necessary and sufficient for actin assembly inshigella flexneri. since icsa gene and icsa protein band were not found inall shigella strains, it seems that not all strains have the same pathogenesis.on the other hand, since the demonstration of icsa gene by pcr in allshigella strains (46%) corresponded to the presence of a 120 koa proteinband by sos-page (46%), it seems that both tests may confirm each other.however, the pcr may be more accurate than sos-page.