Pathogenesis and clinical forms of human listeriosis

Abstract

Listeriosis is a saprozoonotic infection caused in humans mainly by the species Listeria monocytogenes. Its source can be objects of the external environment (soil and water of open reservoirs with a high content of organic compounds, plants) and more than 90 species of animals. The high metabolic activity of listeria and resistance to adverse factors create the possibility of an easy transition from a saprophytic to a parasitic type of metabolism when ingested by the host. A variety of transmission routes and "entrance gates" cause the emergence of a variety of primary localized forms of infection, the most common of which is gastrointestinal. Invasive forms of listeriosis develop mainly in people with immunological insufficiency. "Risk groups" are pregnant women, newborns, people with comorbid conditions, over 60 years old, drug addicts, etc. They are characterized by polymorphism of symptoms, the absence of specific manifestations. Pathogenicity factors of L. are important in the pathogenesis of infection. monocytogenes, providing their incomplete phagocytosis, intracellular parasitism, high rate of colonization of neighboring healthy cells, the formation of antibiotic resistance. The pathological expression of changes caused by listeria in cells is the formation of small granulomas — listeriomas. The "diversity" of listeriosis, the high mortality rate (up to 50% or more) and the low alertness of doctors regarding this infection create difficulties in making a diagnosis, and therefore the improvement of microbiological diagnostic methods is of particular importance.