Pathogenic potential of enterococci

Abstract

Pathogenicity as an integral characteristic of infectious agents is a polydeterminant property of microorganisms, which reflects their ability to form endogenous sources of infections, colonize organs and tissues, and initiate a pathological process in them. This ability is determined not by one, but by a complex of phenotypic characteristics, in other words, by their bioprofile. For many microbes, for example, for Escherichia coli (E. coli), the signs that characterize their persistence (antilysozyme activity, anticomplementary activity etc.) and are responsible for the survival of bacteria in the presence of effectors of the macroorganism's immunity are highly diagnostically informative. Significant qualitative and quantitative changes in the structure of infectious pathology are largely associated with changes in the pathogenicity of bacteria at the genetic level. Currently, the greatest importance is given to structural and regulatory genes that determine the pathogenicity of bacteria and are grouped into mobile clusters - "islands of pathogenicity", which contain genes that determine the key stages of interaction with the macroorganism. Some scientists believe that changes in pathogenicity, which occur according to this mechanism, lead to the formation of pathogenic variants of opportunistic microorganisms. The mobile nature of these genetic elements and the possibility of horizontal and vertical transfer to other strains was established, which largely dictates the nature and direction of selection in the processes of adaptive evolution of bacteria. Revision of the assessment of the role of enterococci in the pathogenesis of enterococcal infections was facilitated by the discovery of pathogenicity factors in them. However, this issue is not fully explored. The main argument in favor of their pathogenetic role is the high frequency of detection of pathogenicity factors in strains isolated during infectious processes, and their almost complete absence in strains isolated from the intestines of healthy individuals and from environmental objects. In connection with the growing etiopathogenetic significance of Enterococcus faecium (E. faecium) in the general structure of enterococcal infections, the interest of researchers in the detailed study of the pathogenic potential of this species of enterococci is also growing