clostridium Flashcards
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morphology
spore forming rods.
species
C.botulinum ,C.tetani,C.difficile,C.perfringens,C.sordellii.
C.botulinum
produces a botulinum toxin in food and wounds.Causes botulinism.-Food poisoning. botox -used on cosmetic industrt
C. difficile
causes intestinal colitis . It flourishes when other gut flora bacteria are killed durimg antibiotic therapy leading to superinfection.
c.perfringens
causes;gas gangrene,cellulitis,fasciitis and food poisoning.
c.perfringens
causes;gas gangrene,cellulitis,fasciitis and food poisoning.
C.tetani
tetanus
c.sordellii
causes infections after medical abortions.
C.tetani
causes tetanus by a neurotoxin.It is a gram positive,spore forming rod .non vapsulated and motile by peritrichous flagella.
has two toxins
hemolysin-aids in tissue destruction. Neurotoxin-is responsie for clinical manifestations of tetanus.
neurotoxin has 2 polypeptide chains
heavy chain-binds specifically to neuron receptors. light chain-it is a protease responsible for proteolysis.
Transmission
through broken skin.endospores enter and when the oxygen tension is low because it grows in low oxygen they germinate ,profilate nd produce neurotoin.
pathogenesis
The endospores germinate,proliferate and produce neurotoxin. It spreads from the site of infection via bloodstream and binds to the ganglioside receptors in the CNS and block the release of inhibitory neurotransmitters. This causes convulsive contraction of voluntary muscles. Onset of signs starts with stifness and pain in or near the wound. Initial stiffnes of the jaw.boardlike rigidity from contraction of trunk muscles.death results from contraction of the diaphragm and intercostal respiratory muscles.
diagnosis
Isolation of C.tetani.Grows on horse blood agar plate with 4% agar.
