Non-tissue invading Clostridium Flashcards
List the general morphological features of bacteria which belong to the genus Clostridium
Obligate anaerobes
Gram-positive (old organisms decolorize readily)
Large, usually straight rods
Spore forming
- What biochemical tests are generally used in the identification of different Clostridium sp.
- Veterinary practitioners sometimes do not have enough time to do these tests. So what do they often rely on for their identification?
- The fermentation of different carbohydrates
- Clinical signs
What is the natural habitat of a Clostridium spp.?
Intestine (major reservoir)
Decaying organic material (soil)
Name the two general broad groups (or “types”) of Clostridia which produce Dz?
- Those that do not actively invade and multiply. These rely solely on toxin production at localized tissue sites (C. tetani) or in vitro (C. botulinum).
- Those that invade and multiply in the tissues: Gas gangrene group.
True or False
Clostridia sp. can be very contagious and one must treat surrounding animals of the same species for prophylactic treatment of all animals.
False
Clostridia produce diseases that are not generally contagious from one animal to another. Epizootics seldom occur.
What part of a Clostridial sp. generally causes the Dz presented?
The exotoxin released by the bacteria
The organisms are also most often listed according to the type of toxin or the combination of toxins that they produce.
List the two Clostridial sp. which do not actively invade and multiply within tissue
- Clostridium tetani*
- Clostridium perfringens*
What is the key morphological feature of C. tetani?
Spores are at the terminal end
What is the natural habitat of C. tetani species?
Soil
Fecal material
Horse and human feces
What do colonies of Clostridium tetani look like?
Beta hemolytic
Swarming
May have a very foul odor in broth
List the toxins produced by Clostridium tetani
- Tetanospasmin
- Hemolysin
- Non-spasmogenic toxin
- What is the importance of the tetanospasmin toxin in C. tetani?
- What is its function?
- Responsible for clinical disease.
- It blocks neurotransmitter release (specifically glycine and gamma-aminobutyric acid at the level of the spinal cord and brainstem) –> The inhibitory nerve network is affected and as a result –> continuous spasms of opposing groups of muscles. When the toxin binds to gangliosides it binds almost irreversibly and antibody is not effective.
What is the function of the hemolysin toxin in Clostridium tetani?
Produces local necrosis to stimulate the growth of the organism
What does the Non-spasmogenic toxin do in the species Clostridium tetani?
Binds to the neuromuscular junction but its function is unknown however
How is one infected with Clostridium tetani?
Organism enters wounds or other tissue sites that have a low oxygen tension. Deep wounds usually are inoculated with contaminating bacteria which cause necrosis in the surrounding tissues, reduce the oxygen tension and allow the germination and growth of C. tetani.