ENTEROKOKI
- CZYNNIKI WIRULENCJI I CHOROBOTWÓRCZOŚĆ
Katarzyna Piekarska
Zakład Bakteriologii, Państwowy Zakład Higieny,
ul. Chocimska 24, 00-791 Warszawa
Wpłynęło we wrześniu 2005 r.
1. Wstęp. 2. Patogeneza zakażeń
enterokokowych. 3. Czynniki wirulencji sprzyjające kolonizacji. 3.1. Substancja agregująca - AS. 3.2. Białko wiążące kolagen - Ace. 3.3. Białko -
EfaA. 3.4. Białko powierzchniowe - Esp. 3.5. Antygen SagA. 4. Czynniki wirulencji oddziaływujące na
tkanki. 4.1. Cytolizyna - Cyl. 4.2. Żelatynaza - GelE, proteaza serynowa - SprE i locus fsr. 4.3. Hialuronidaza -
Hyl. 4.4. Zewnątrzkomórkowe nadtlenki (-O2-). 5. Oporność na
antybiotyki. 6. Chorobotwórczość enterokoków. 6.1. Infekcje układu
moczowego. 6.2. Bakteriemia. 6.3. Zapalenie wsierdzia. 7. Podsumowanie
Enterococci - virulence factors and pathogenicity
Abstract: Enterococci that form part of the commensal intestinal flora of healthy human and mammals, last years have emerged as a major opportunistic nosocomial pathogen. Generally, enterococcal infections occur inpatients with underlying conditions representing a wide spectrum of severity of illnes and immune modulation.The most important infections caused by
Enterococcus faecalis (80-90%) and Enterococcus faecium (5-15%) include urinary tract infections, bacteremias and endocarditis. The problem of nosocomial enterococcal infection is related to multiple antibiotic resistances. Many of the antibiotic resistance genes are located on mobile genetic
elements-plasmids and transposons. The emergence of resistance against almost all clinically available antibiotics and the ability to transfer these resistance determinants
to other pathogens demonstrates the urgency for an improved understanding of enterococcal yirulence mechanisms. Enterococci are not "virulent" in comparision with organisms such as
S. pneumoniae, S. pyogenes or S. aureus. Bacterial adherence to host tissues is a first step in the infection. There are few adhesive factors that are involved in colonization, for example aggregation substance (AS), collagen-binding protein (Ace), endocarditis antigen (EfaA), surface protein (Esp) and antigen SagA. Enterococci secrete several yirulence factors that damage host tissues like cytolisyn, gelatinase (GelE) and serine protease (SprE), hyaluronidase or extracellular superoxide. Some of E. faecalis seem to be able to translocate from gastrointestinal tract into the bloodstream. These organisms seem to be resistant against defense mechanisms of the host, too. This article presents major putative yirulence factors of enterococci, pathogenesis of enterococcal infections and enterococcal involvement in pathogenicity.
1. Introduction. 2. Pathogenesis of enterococcal infections. 3. Virulence factors favouring colonization. 3.1. Aggregation substance. 3.2. Collagen-binding protein - Ace. 3.3. Protein - EfaA. 3.4. Surface protein - Esp. 3.5. Antigen -
SagA. 4. Virulence factors influencing tissues. 4.1. Cytolisyn -
Cyl. 4.2. Gelatinase - GelE, serine protease - SprE and fsr locus. 4.3. Hyaluronidase -
Hyl. 4.4. Extracellular superoxides (-O2-). 5. Antibiotic resistance. 6. Pathogenicity of enterococci. 6.1. Urinary tract infections. 6.2. Bacteremia. 6.3. Endocarditis. 7. Summary
Słowa kluczowe: enterokoki, czynniki wirulencji, chorobotwórczość
Key words: enterococci, virulence factors, pathogenicity
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