Unit 3: Clostridium Flashcards
In regards to oxygen, what type of organisms are in the genus Clostridium?
obligate anaerobes
What do bacteria in the genus Clostridium look like on gram stain?
gram-positive, large, rods
What do the spores of Clostridium look like?
usually oval, often greater than the diameter of the rod
What is the best way to identify different Clostridium species?
MALDI-TOF-MS
What do many veterinary professionals rely on for Clostridium diagnosis?
clinical signs
What is the natural habitat of the genus Clostridium?
intestine, damaged tissue, decaying organic material
What are the two broad types of clostridia?
those that do not actively invade and multiply (rely on toxin production) and those that invade and multiply in the tissues
True or False: Clostridia produce diseases that are generally contagious from one animal to another.
False
How are Clostridia spores killed?
By boiling them for 15 minutes or autoclaving for 15-20 minutes
What is most of the disease associated with Clostridia caused by?
exotoxins
What does Clostridium tetani cause?
tetanus (lockjaw)
What does Clostridium tetani look like on gram stain?
gram positive, single, slender rod with terminal spores
What do colonies of Clostridium tetani look like?
they are beta hemolytic, swarming, and may have a very foul odor in broth
What is the natural habitat of Clostridium tetani?
soil as spores, fecal material, readily found in horse and human feces
What toxins does Clostridium tetani release?
Tetanospasmin, hemolysin, and non-spasmogenic toxin
What is tetanospasmin responsible for?
clinical disease due to Clostridium tetani
What does tetanospasmin do?
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 results in continuous spasms of opposing groups of muscles. The toxin binds to gangliosides almost irreversibly and antibody is not effective once it is bound
What is the role of the hemolysin toxin released by Clostridium tetani?
it produces local necrosis and thereby stimulates the growth of the organism
What is the role of the non-spasmogenic toxin released by Clostridium tetani?
it binds to the neuromuscular junction and is responsible for overstimulation of the peripheral nervous system
What is the pathogenesis of a Clostridium tetani infection?
The organism enters wounds or other tissue sites that have a low oxygen tension. These areas can include the umbilical stump and the uterus of post-parturient females. Deep wounds usually are inoculated with contaminating bacteria which cause necrosis in the surrounding tissues, reduce oxygen tension and thereby the Eh, and allow the germnination and growth of C. tetani
What are the two routes by which Clostridium tetani is spread?
Along peripheral nerves and hematogenous and through lymph
Describe Clostridium tetani’s spread along peripheral nerves.
This is termed ascending tetanus and first affects those nerves closest to the lesion - less common route
Describe Clostridium tetani’s hematogenous spread and spread through lymph.
This is termed as descending tetanus. The nerves affected first are those that are most sensitive to the effects of the toxin.
This is common in horses and humans.
What species are typically affected by Clostridium tetani?
horses, humans, lambs, calves, and others
How are horses infected with Clostridium tetani?
via nail punctures and wounds
How are humans infected with Clostridium tetani?
via nail punctures and wound
What humans are at a higher risk of infection of Clostridium tetani?
the elderly, diabeticss, and injection drug users
How are lambs typically infected with Clostridium tetani?
wounds, tail docking, and castration
How are calves typically infected with Clostridium tetani?
with elastrator band use
What ‘other’ animals typically get infected by Clostridium tetani?
dogs, cats, and swine
What is Antitoxin?
An antiserum prepared by hyper-immunizing horses with tetanus toxoid
Is treatment effective to cure Clostridium tetani infection?
no, not once clinical signs appear
What can help control the muscle spasms associated with Clostridium tetani?
muscle relaxants and sedatives
What is given to provide immediate passive immunity (to Clostridium tetani) following an injury?
antitoxin
If you stab someone with a pure culture of Clostridium tetani will they get tetanus?
no - Wound needs to be infected - you can stab someone with pure cultures of tetanus and they will be fine but if they get stabbed with pure cultures of tetanus and already have a staph aureus infection going on that sucked up all of the oxygen then the tetanus will thrive and they will die from tetanus
What is the toxoid for Clostridium tetani good for?
a preventative measure to protect against Clostridium tetani
What is classical botulism poisoning caused by?
intoxication of Clostridium botulinum
On gram stain, what does Clostridium botulinum look like?
gram positive, large rod, with spores
What do colonies of Clostridium botulinum look like?
large and semi-transparent
What is Clostridium botulinum classified by?
its toxins
What is the natural habitat of Clostridium botulinum toxin types A, B, E, F, G?
soil and are found in sea sediments
What is the natural habitat of Clostridium botulinum toxin types C and d?
they are obligate parasites of the intestinal tract of mammals and birds and found in soil and sediments only as contaminants
How is Clostridium botulinum transmitted?
ingestion of the toxin (in improperly preserved foods, improperly cured meats
What is infant botulism associated with the consumption of?
honey
What provides a better anaerobic environment for botulism toxin when stored on the ground and why is this bad?
large round bales or big square bales because they can be mechanically processed and distributed to a large quantity of feed (we are talking about horses here)
When do foals typically get infected with Clostridium botulinum and what does it result in?
3-8 weeks of age; shaker foal syndrome
What is aphosphorosis and how does it lead to botulism?
it is a nutritional deficiency of phosphorus causing cattle and sheep to begin chewing on bones to increase phosphorus intake. They can ingest enough toxin from the bones that will lead to botulism
What is a good preventative measure for botulism in sheep and cattle?
proper mineral supplementation
How can mink and foxes ingest botulism toxin?
if they are fed offal and fish
What is limberneck?
a term used to describe botulism in birds
What population of birds are most likely to get limberneck?
those that feed on the vegetation at the bottom of ponds and lakes
What lesion is associated with limberneck?
flaccid paralysis of the neck muscles
What is the pathogenesis of botulism?
The toxin is absorbed into the blood and lymph and carried to the peripheral nerve system where it binds to the neuromuscular junction and causes paralysis of the cholinergic nerve fibers by blocking release of acetlycholine.
What does botulism cause specifically?
flaccid paralysis
The ___ acute the onset of clinical disease, the higher is the _______ _____.
more; mortality rate
What is the most acute toxin type?
type E toxin - therefore it has the highest mortality rate
What are the common toxin types in US cases of botulism?
type A and B
What are the two types of toxoids for immunization against Clostridium botulinum?
a toxoid specific for the type of toxin that produces disease or a polyvalent toxoid to produce immunity against multiple toxins
How is a Clostridium botulinum infection diagnosed?
find the toxin in serum, intestinal contents, and feed - finding the organism alone isnt good enough
How are humans treated for Clostridium botulinum?
polyvalent antitoxin
Generally, what is Clostridium perfringens the cause of?
gas gangrene, fatal toxemias, and malignant edema-like infections in sheep