L21: Clostridia Flashcards
what shape spores does clostridia have ?
oval bulging spores
which clostridia spp. has a drum stick appearance ?
C. tetni
what is the habitat of C.tetni ?
soil
what is the usual portal of entry for C.tetni?
would site
what is the tetonus toxin and how does it function ?
exotoxin that is carried to the CNS , bind to ganglioside receptors and blocks release of inhibitory mediators at spinal synapses
C. tetni neurotoxin causing contraction of muscle :
tetanospasmin
tetanus usually begins with :
lock-jaw / trismus
neonatal tetanus stems from :
mother never being immunized +infection of unhealed umbilical stump ( cutting of umbilical cord with unsanitary instruments )
which treatment of tetanus can neutralize the bacterias toxin ?
hyper immune human globulin
how often should the tetanus toxoid booster be given?
every 10 years
C. perfringens spore:
subterminal spores
what disease can be caused by C. perfringens ?
gas gangrene
food poisoning
what is the habitat of C. perfringens ?
soil , vegetative cells are normal flora of colon and vagina
gas gangrene is associated with
war wounds / automobile accidents
septic abortions
what is gas gangrene ?
germination of spores under anaerobic conditions
anaerobic metabolism causes degenerative enzymes to produce gas in tissues
what toxin of C. perfringens is responsible for gas gangrene ?
alphatoxin (lecithinase)
food poisoning caused by C. perfringens is due to :
enterotoxin similar to that of S. aureus
what agar can detect alphatoxin lecithinase of C. perfingens ?>
egg yolk agar (naglers test )
what is the habitat of C. botulinum ?
soil , contaminated vegetables and meats
what are some high risk food concerning C. botulinum ?
alkaline vegetables likes green peas , peppers , mushrooms , and smoked fish
how is C.botulinum toxin absorbed ? how does it affect the body ?
absorbed from gut and carried via blood to peripheral nerve supply where protease cleaves proteins involved in acetylcholine release causing flacid paralysis
heat liable toxin
what are the 2 clinical forms of C. botulinum infection ?
wound botulinum : spores contaminate a wound , germinate and produce toxin at site
infact botulism : organism grows in gut and produces toxin there
swollen cans should be discarded because they may contain which organism ?
C,botulinum : clostridial proteolytic enzyme can form gasses which then swells the cans
which clostridium spp. is found in the colon ?
C. difficlle
which infection causes pseudomembranous colitis ? on the sigmoid colon
C. difficile , also causes antibiotic associated diarrhea and antibiotic associated colitis
route of transmission for C. difficile :
feco-oral route
exotoxins of C.difficile :
exotoxin A and B
B: causes death of enteroytes
