NT Clostridium Flashcards
General features
- spore forming
- gram +ve
- anaerobic
- toxin prod.
3 classifications of clostridium
- Histotoxic
- neurotoxic
- enterotoxic
Toxins
- can be pre-formed
- can be produces @ site of tissue damage or alteration of microenvironment
Name neurotoxic clostridia (2)
C. Botulinum
C. Tetani
C. Tetani characteristics
- gram +ve, rod/ drumstick shaped, obligate anaerobe
- high mortality rate
- etiologic agent of tetanus/lockjaw
Natural habitat of C. Tetani
Soil & GIT
Which spp are more susceptible to tetanus?
Horses(MAIN), ruminants, and swine
What is tetanus?
- neuroparalytic toxication caused by tetanospasmin
- causes tonic-clonic convulsions & spastic paralysis
- organism enters via wounds/abrasions, surgical incisions, dockings, castrations, injection sites, etc
Why are deep wounds and necrosis favorable environments for clostridium
Bc environment is reduced O2
Characteristics of C. Botulinum
- Obligate anaerobe, sub-terminal oval spores
- spores in soil & plants
- 1 mcg can kill person
C. Botulinum causes
Botulism (neuroparalytic intox. & flaccid paralysis
Toxicoinfection definition
Organism multiplies INSIDE HOST
Intoxication definition
Organism is pre-formed, then ingested
Toxicoinfectious botulism causes
- floppy baby syndrome
In which species is botulism seen in
Ruminants, waterfowl, horses
Examples of botulism intox.
- pica
- ingestion of contaminated animal carcasses
- poultry litter (given to ruminants as NPN source)
General MOA tetanus toxin
Inhibits NT release
General MOA botulinum toxin
Inhibits ACh fusion & release
Which clostridium causes limberneck
Botulinum (botulism)
Ascending pathogenesis of Tetanus
- toxin travels retrograde along motor n. To CNS
- acts on spinal inhibitory interneurons
Descending pathogenesis of clostridium
- toxing spread via circulation
- clinical effects @ distant sites
Pathogenesis of botulism
- toxin absorbed from stomach & small intestine
- distributed via blood
- receptor mediated endocytosis @ MNJ
- hydrolysis of locking proteins
CAUSING FLACCID PARALYSIS
Common names of botulism in horses, birds, and babies
- Horses: equine grass sickness or forage poisoning
- Birds: limberneck
- Babies: floppy baby syndrome
Dx & Tx Tetanus
- clin. Signs & history usually enough
- Gram stain (look for drumsticks)
- culture wound exudate in BA+ antitoxin
- PCR (look for TeNT gene)
- inj. Antitoxin
- toxoids for active immuniz. (TeNT & formaline/heat)
Dx & Tx Botulism (2 diagnoses; 2 Tx)
- clinical signs & history to confirm
- isolate organism from susp. Feeds/tissue & culture on BA
- supportive Tx
- can also Tx w/ inject. Antitoxin
