Virulence Factors and Toxins Flashcards
(12 cards)
This binds to the Fc region if immunoglobulins
Protein A
Binding of the Fc region of immunoglobulins is the mechanism of action of the virulence factor protein A, which is expressed by S. aureus and prevents effective opsonization and phagocytosis of microbial pathogens.
This toxin inactivates the 60S ribosome
Shiga toxin
Inactivation of the 60S ribosome is the mechanism of action of Shiga toxin (produced by Shigella species), and Shiga-like toxin (produced by EHEC).
What toxin over activates adenylate cyclase?
Heat Labile toxin from ETEC, cholera toxin from vibrio cholerae, and pertussis toxin from B. Pertusses.
What virulence factor cleaves secretory immunoglobulins to better increase their chances of colonizing their target tissue?
IgA protease produced by hemophilus, strep pneump, neisseria gon, neisseria mening (think of mucosal infections)
What toxin inactivates elongation factor?
Wither Diptheria toxin or exotoxin A.
C diptheriae and P aeruginosa
Bacillus cereus is a gram-positive bacillus that forms heat-stable spores and produces two different enterotoxins. What are they and what do they do?
One enterotoxin (cereulide) causes severe nausea and emesis 1–3 hours after ingestion of typically reheated starch-containing foods (e.g., rice), while the other results in watery, non-bloody diarrhea 8–16 hours after ingestion.
This toxin increases intracellular cAMP and causes electrolyte (chloride) and water secretion into the intestine. This results in profuse, non-bloody diarrhea, often described as rice-water stools. The organism is non-lactose fermenting.
vibrio cholerae
Heat stabile increases ___________________ while heat labile increases ____________________ in ETEC.
heat-stable toxin increases cGMP via activation of guanylate cyclase, heat-labile toxin causes overactivation of adenylate cyclase, which increases cAMP.
Enterotoxin that binds to the brush border of enterocytes and alters fluid secretion into the intestinal lumen, resulting in diarrhea.
Toxin A c diff
Cutotoxin that depolymerizes actin filaments and alters the cytoskeleton of enterocytes, resulting in diarrhea.
Toxin B from c diff
What virulence factor is crucial for n meningitidis to infect an individual?
Pili and certain proteins, e.g., opacity proteins, are important virulence factors for N. meningitidis as they allow the bacterium to adhere to and invade epithelial and endothelial cells. Colonization of the nasal epithelium is considered the first crucial step leading to clinically apparent infection.
What does Phospholiase C do?
An enzyme that cleaves phospholipids. Functions as part of the IP3/DAG pathway to cleave PIP2 into IP3 and DAG (e.g., in autonomic signaling). Also a virulence factor produced by several bacteria (including Pseudomonas aeruginosa, gardnerella) that degrades cell membranes.
