L21 Clostridium Flashcards
Clostridium
Gram
oxygen
Special
Gram +
Strict anaerobe
Produce endospores
Clostridum difficile
Leading cause of
Nosocomial diarrhea
Clostridium difficile
Characteristics
Pseudomembranous colits (Yellow plaques containing fibrin and debris in uclers of colon mucosa)
C. difficile is harbored in dormant state in ______
large intestine
C. difficile and antibiotics
Spores resistant to antibiotics
Antibiotics kill other bacteria,
Now spores have more nutrients, vegetate, produce toxin
Does C. difficile invade the bowel wall?
no
C. difficile toxin A
Enterotoxin: fluid production, damage to mucosa
C. difficile toxin B
Cytotoxin: round of tissue culture cells
How do Toxins A and B act?
glycosylate GTP binding proteins in cytoplasm
C. perfringens is found
Intestinal tract of animals and
Every soil except Sahara desert sand
C. C. perfringens common mode of infection
wounds
Conditions for C. perfringens spore gemination (4)
Anaerobic
Compromised blood supply
Calcium ions
Availability of peptide and aminos
How many toxins does C. perfringens produce?
12
C. perfringens main toxin
Alpha-toxin (lecithinase)
Damages membranes, causes gangrene
Alpha-toxin
Types
What does it do
Phospholipase type C
Hydrolizes phosphatidylcholin and sphingomyelin
What is the only treatment for C. perfringens
Restoring arterial blood supply
C. perfringens food poisoning toxin type
enterotoxin
Clostridum botulinum spore and toxin
Heat resistant spores produce anaerobically
People then ingest the toxin (Neurotoxin)
Botulinum toxin most common in humans
A, B, E
900kDa BoNT composition
150 kDa Toxic component
750 kDa non-toxic component
BoNT mechanism
zinc metalloprotease prevents release of acetylcholine (cranial nerves affected first)
BoNT paralysis within ___ hours
12 to 36 hours
Types of botulism
Food borne
Wound
Infant
Infant botulism
infants younger than 1
Slow onset
Favorable outcome
