Browsing tag: wewnątrzkomórkowe bakterie

Wewnątrzkomórkowe bakterie względnie chorobotwórcze w zakażeniach górnych dróg oddechowych i ucha

Intracellular opportunistic bacteria in upper respiratory tract and ear infections
E. A. Trafny
1. Wprowadzenie. 2. Czy komórki nabłonkowe i limfoidalne migdałków stanowią rezerwuar patogenów wywołujących nawracające zakażenia górnych dróg oddechowych (GDO) i ucha? 3. Adhezyny umożliwiające przyleganie patogenów GDO do komórek gospodarza. 3.1. Adhezyny bakterii Gram-ujemnych. 3.2. Adhezyny ziarenkowców Gram-dodatnich. 3.3. Wpływ niskiej temperatury na ekspresję genów kodujących adhezyny u patogenów GDO. 4. Mechanizmy internalizacji patogenów do komórek gospodarza. 5. Sposoby przetrwania patogenów GDO wewnątrz komórek ssaków. 6. Wrażliwość wewnątrzkomórkowych patogenów GDO na antybiotyki i chemioterapeutyki.
Abstract: The pathogens commonly causing the upper respiratory tract infections: Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, nontypeable Haemophilus influenzae and Moraxella catarrhalis are able to exist within host cells in human upper respiratory tract. They may be found both in homogenates of the adenoids and tonsils and inside epithelial and monocyte/macrophage cells isolated from these tissues. The bacteria also invade epithelium of middle ear mucosa. They are alive and can multiply in the cytoplasm. Numerous adhesins are responsible for a tight attachment of bacterial cells to epithelial and endothelial cells as well as to lymphocytes. These adhesins mediate bacterial internalization by human cells. Some bacteria, e.g. S. aureus, are able to persist viable within host cell compartments for several days in high numbers. Bacterial persistence in the cellular interior allows evading immunological defences and bactericidal activity of antimicrobials, thereby creating an intercellular reservoir of pathogenic and/or opportunistic bacteria. Antibacterial agents, even when are applied in doses exceeding the MIC values, do not eradicate these bacteria from the intracellular compartment. This feature of intracellular bacteria resembles the characteristic attributes of biofilms, i.e. their increased tolerance to bactericidal antimicrobials.
1. Introduction. 2. Do epithelial and lymphoid cells constitute a reservoir of pathogens causing recurrent infections of upper respiratory tract (URT) and ear? 3. Adhesins that facilitate attachment of UTR pathogens to host cells. 3. Adhesins of Gram-negative bacteria. 3.2. Adhesins of Gram-positive coccal bacteria. 3.3. The effect of low temperature on the expression of the genes encoding adhesins of URT pathogens. 4. The internalization mechanisms of URT pathogens into host cells. 5. Bacterial strategies to persist within mammalian cells. 6. Susceptibility of the intracellular URT pathogens toward antibiotics.