Major pathogenicity factors of <i>Streptococcus pyogenes</i>

Abstract

Streptococcal diseases and their complications are among the global problems of international health. S. pyogenes (group A streptococci — GAS) is a pathogen that causes significant morbidity in different countries and different age groups of the population, occurring both sporadically and epidemically. Due to ineffective antibacterial therapy or its absence, 3–5% of people who have had streptococcal infection may develop complications such as acute rheumatic fever, rheumatic heart disease, acute post-streptococcal glomerulonephritis and invasive complications: necrotizing fasciitis and myositis, septicemia and toxic shock syndrome, highly lethal due to the rapid development of the process and systemic organ damage. According to recent estimates, at least 517 000 deaths occur annually in the world due to diseases caused by GAS. The diverse arsenal of pathogenic factors of this pathogen is manifested in a combination of joint or sequential reactions in the process of microbial colonization of tissue, formation of the focus of infection and overcoming the host's defense mechanisms. It is an important point in the process of studying the pathogenesis of diseases caused by these microbes. The pathogenic factors of GAS can be divided into extracellular and associated with the microbial cell, predominantly with its cell wall. The spectrum activity of pathogenicity factors can be quite wide (M proteins, pyrogenic exotoxins, superantigens) or limited (serine and cysteine proteinases, streptokinase). Information about the specificity of pathogenicity factors, their properties, relationships, regulation and specific function in pathology is the task of scientific, as well as complex researches, leading to understanding the pathogen-host interaction. An integrated approach to the investigation of GAS pathogenicity factors is needed to study the pathogenicity of streptococci, since pathogenicity factors do not manifest themselves in isolation and are not always independently regulated. In many cases, regulators control the expression of more than one of them. S. pyogenes has been studied for about 150 years, but a number of issues related to their pathogenicity remain unknown to this day. Some factors need more in-depth study: for example, endo-β-N-acetylglucosaminidase, arginine deiminase. Immunoglobulin-degrading enzymes require special attention due to their possible participation in the genesis of immunopathological processes of streptococcal etiology. This review summarizes the literature data about most of the pathogenicity factors of S. pyogenes and their role in the infectious process.

Keywords

• streptococcus pyogenes
• streptococcal cell structure
• cell-associated pathogenic factors
• extracellular pathogenic factors