Exotoxins of pathogenic Escherichia coli

Abstract

Escherichia coli is a representative of the natural normal microflora of humans and animals. At the same time, some variants may acquire pathogenic properties that contribute to the occurrence of intestinal and extraintestinal infections. In the pathogenesis of these diseases, the main role is played by exotoxins. Currently, along with the well-known and well-studied toxins of Escherichia coli, there is information about new toxoid structures detected in this pathogen, which play an important role in pathologies in humans and animals. Authors summarized current data on the toxigenic properties of Escherichia coli bacteria and established the role of exotoxins of pathogenic Escherichia coli in the mechanism of disease development. Scientific publications of mainly foreign researchers were used as a material for the review. It was found that cyclodomodulating exotoxins that affect the eukaryotic cell cycle were currently identified in Escherichia coli in addition to thermolabile, thermostable, shigalike, necrotizing toxins and hemolysin. Also Escherichia coli has a number of pore-forming toxins that destroy the epithelial barrier and overcome the protection of the host's immune cells due to the formation of pores in their membranes, and so-called repeated toxins, the prototype of which is а-hemolysin. Thus, it can be seen from the review that Escherichia coli, having a wide range of toxoid structures, can cause pathological changes in the human and animal body. The nature of these changes directly depends on the type of E. coli and the type of exotoxin produced by them. Most toxigenic strains of Escherichia coli have the ability to modulate the expression of proinflammatory cytokines, chemokines and other immune cells, which can be further used in the design of effective vaccines and biological products for the treatment and prevention of enterobacterial infections.