Shiga toxin-producing Escherichia coli (STEC): principal virulence factors and epidemiology

Abstract

Shiga toxin producing Escherichia coli is an important food borne pathogen, mainly beef products, and is associated to mild and severe bloody diarrhea. In some individuals, STEC infection can progress to hemolytic-uremic syndrome (HUS), a sequela characterized by renal failure, and thrombotic thrombocytopenic purpura (TTP), with possible central nervous system involvement. Cattle, usually healthy, is the principal reservoir of STEC, although these strains have also been isolated from other domestic animals: sheep, goats, dogs, cats and pigs. The principal virulence feature, the production of Shiga toxins, is not enough to cause diseases, and other factors are considered important, as enterohemolysin and fimbrial and afimbrial adhesions production. Although human diseases associated to STEC have not been frequently reported in Brazil, their presence is frequent in cattle, as well as the correlation between serotypes found in these animals and human patients.