Prevalence of Shiga toxin genes and intimin genes in uropathogenic Escherichia coli

Shiga toxin-producing Escherichia coli (E. coli) strains (STEC) are most important food borne pathogenic bacteria. STEC are agents of serious illnesses such as food poisoning, dysentery, hemorrhagic colitis and hemolytic–uremic syndrome (HUS). Most of the cases in hemorrhagic colitis, HUS and sudden death in all ages are related to 0157:H7 serotypes that are considered as the most important serotypes of STEC[1,2]. In many cases, other Shiga toxin-producing serotypes such as non-0157:H7 serotypes were reported as outbreak or sporadic pathogens and also agents of HUS. Isolation of non-0157:H7 serotypes from pathogens has increased[3]. However, less reports are for isolation of extraintestinal STEC[4]. Verotoxigenic E. coli discharge a toxin that is able to kill vero cells, verotoxin and it is similar to Shiga enterotoxin which is discharged by Shiga dysentery type 1, called a toxin similar to STEC[5]. Verotoxin-producing gene is set on the genome of bacteriophage and enter the E. coli by phage conversion[5]. Verotoxins are categorized in two groups: stx2 and stx1. Verotoxin play a role by effecting on RNA ribosomal, preventing synthesis of the protein[6,7]. The pathogenicity of E. coli O157:H7 for sever illnesses of human is due to discharge of Shigalike toxin I and varieties of such toxins[8]. The other pathogen is a protein named intimin that is a 94-kDa outer membrane protein and coded by E. coli attaching and effacing (eae) gene. The protein is responsible for close link of bacteria with intestinal epithelial cells and damage through special mechanisms called attaching and effacing[8]. Pollution with E. coli O157:H7 is often because of ingestion of infected food such as types of meat and mince, meat sandwiches, raw milk, and infected posturized milk, yogurt, chesses, hamburger, sausage, vegetables and fruit juices, water, contact person to person and animals[9]. Bovine is the main source of these bacteria. Also animals such ARTICLE INFO ABSTRACT