Enterohaemorrhagic Escherichia coli (EHEC) infections: A threat to public health

Escherichia coli O157:H7 (EHEC - enterohemorrhagic Escherichia coli) is one of the most important foodborne and waterborne human pathogens. EHEC O157:H7 was described for the first time in 1977. Pathogenic E. cola can be classified into 4 main groups: diarrheagenic E. coli, uropathogenic E. coli, meningitis/sepsis E. coli and avian E. coli. The most important are the first three groups, which can cause human illness. The processes of genome dynamics, such as gene transfer, genome reduction and point mutations, contribute to the adaptation of bacteria to different environments. The genome of EHEC consists of prophage sequences (mobile elements such as transposon, pathogenicity islands (PM) and genomic islands (GEI)). Enterohemorrhagic Escherichia coli possesses specific virulence factors, such as Shiga toxins (Stx1 and Stx2), LEE motif, intimin (adhesion protein), enterohemolysin and others, which have not been fully described. PCR-based methods and PCR modifications (e.g. real time PCR) are usually used for rapid and specific detection of this pathogen in different samples and are often used in epidemiological investigation. Each pathogenic group contains specific serogroups, which in specific conditions may acquire pathogenicity factors, such as Shiga toxins. EHEC may be transmitted not only by various animal species, but also by insects present on vegetables and fruits. Infection is manifested by diarrhea (bloody diarrhea), fever, stomach pain and renal failure. Use of antibiotics in the treatment of EHEC infections is controversial. Therapy is based on hemofiltration and the transfusion of packed erythrocytes sometimes a renal transplant is needed. There is no vaccine against EHEC, and therefore good hygiene and prevention is necessary to avoid EHEC infections. EHEC O157:H7, responsible for many outbreaks around the world, is a serious threat to public health. One of the described prevention methods is the maintenance of good hygiene by both manufactures and restaurants.