Exam 3 Lecture 24 Flashcards
Obligate anaerobes are killed by:
oxygen
Where are obligate anaerobes found?
everywhere: in our mouth, feces, ubiquitous in soil and silt
Clostridium causes 3 classical diseases, which are:
- gas gangrene
- botulism
- tetanus
Clostridium causes 2 enteric diseases, which are:
- food poisoning
2. antibiotic-associated colitis
Cl. perfringens causes:
- gas gangrene
2. food poisoning
Cl. botulinum causes:
botulism
Cl. tetani causes:
tetanus
Clostridioides difficile (C. diff) causes:
antibiotic-associated colitis
Clostridium natural reservoirs:
soil, intestinal tracts, skin of humans and animals
True or false: Clostridium forms endospores
True
Gram stain of Clostridium
gram positive rods, may see endospores
Why are Clostridium endospores significant?
endospores can survive in the presence of oxygen
Clostridial wound infections are caused by:
mixed clostridial infection following surgery or trauma (Cl. perfringens, other Cl. species)
Gas gangrene
toxins produced by Cl. perfringens causes infection and spreads to healthy muscle tissue; causes myonecrosis
True or false: in gas gangrene, bacteremia is common
false - systemic toxemia can result
What toxins does Cl. perfringens produce to cause gas gangrene?
exotoxins: alpha toxin and perfringolysin O (PFO)
Cl. perfringens alpha toxin is also called:
phospholipase C or lecithinase C
Cl. perfringens alpha toxin function
has phospholipase/spingomyelinase activity which leads to cell lysis (broad spectrum)
Cl. perfringens PFO function
pore forming toxin similar to streptolysin O/listeriolysin O; lyses cells
Cl. perfringens PFO is toxic specifically to:
heart muscle
Cl. perfringens PFO alters ___ ___
capillary permeability
True or false: Cl. perfringens PFO is the principal virulence factor for gas gangrene
false - alpha toxin is principal
Are there host defenses in gas gangrene?
not in necrotic tissues - thus hard to control gas gangrene infection
How is gas gangrene diagnosed?
clinically once typical lesions occur