Histopathological changes in experimental escherichia infection caused by Escherichia coli exotoxins

Escherichia infection is a pressing problem for livestock farming. Pathogenic variants of Escherichia coli, having a wide range of virulence factors, when entering the body, can lead to complications and damage to various organ systems, including those outside the gastrointestinal tract. Histopathological studies contribute to a better understanding of the mechanisms of pathogenesis, host responses and interactions at the tissue level in various forms of Escherichia infection, as well as the development of preventive and therapeutic strategies. The purpose of research is to study the effect of exometabolites of pathogenic Escherichia coli on the histological picture of internal organs and systems in rabbits. The material for the study was pathogenic isolates of Escherichia coli and a mixture of their exometabolites. The work used molecular-genetic, bacteriological, serological, biological and histopathological research methods. As a result, characteristic histological signs associated with toxic infections of pathogenic Escherichia coli producing Shiga-like, heat-stable and heat-labile exotoxins were established. Destruction of microvilli in the distal small intestine and colon, thrombotic microangiopathy in the kidneys, which included endothelial edema, thrombosis in the glomerular capillaries, fibrin deposition, mesangiolysis and damage to the tubular epithelium were revealed. From the central nervous system, perivascular narrowing, inflammation of the meninges, neuronal necrosis and gliosis were observed. Pathohistological effects in the form of toxic liver dystrophy and pulmonary emphysema were also noted. Thus, specific patterns of histological tissue damage indicate mechanisms of interaction between different pathotypes of Escherichia coli, which may help improve strategies for the treatment and prevention of toxigenic escherichiosis.