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.
What are some examples of tissue sites that have a low oxygen tension which C. tetani can enter?
Umbilical stump and the uterus of post-parturient females (puerperal infection)
What are the two routes which C. tetani toxins can spread
Along peripheral nerves
Hematogenous and through lymph
- If the toxin of C**. tetani is spread along peripheral nerves where would the toxin effect first?
- What is the term for this type of C. tetani toxin?
- Affects those nerves closest to the lesion.
- Ascending tetanus
- If the toxin of C. tetani is spread hematogenously and lymph where would the toxin effect first?
- What is the term for this type of C. tetani toxin?
- Nervesare those that are most sensitive to the effects of the toxin. Horses and humans usually have this type.
- Descending tetanus
What species can be affected by Clostridium tetani?
Any species can be except BIRDS
- What is the common way humans and horses are infected with C. tetani infections?
- Name another way humans can become infected.
- Through nail punctures and wounds
- Diabetics through non-cleaning injection sites
- What is the common way that lambs are infected with C. tetani infections?
- What is the common way that calfs are infected with C. tetani infections?
- Tail docking and castration especially when elastrators bands are used
- Elastrator band use has led to increased reports of tetanus in calves
- Name two methods of treatment for C. tetani
Antitoxin injection
Penticillin: in lg doses + muscle relaxants and sedatives to help control pain
True or False
Preventive toxoid administration for C. tetani is routine in humans, horses, and lambs.
True
Antitoxin is given to provide immediate passive immunity following an injury. This is followed by or given simultaneously with the toxoid.
What is the common morphology of Clostridium botulism?
Large rod
Motile
Spores form readily
What is the natural habitat for Clostridium botulism?
- A, B, E, F, G are soil saprophytes and are found in sea sediments
- C,D 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 in nonhuman animals?
Ingestion of preformed toxin
What sources can a non-human animal C. botulinum infection come from?
- Decaying carcasses
- Forage poisonin in horses from poor quality feed or animals such as rabbits which are killed and baled in mowing process.
- Aphosphorosis in cattle and sheep causing them to bone chew on carcasses
- Vegetation at the bottom of ponds and lakes ingested by ducks and other aquatic birds
What are the two most common source of human C. botulinum infections?
Home canned vegetables
Infan botulism from the consumption of honey
- What is the Dz called in infectious botulism in foals 3 to 8 wks of age?
- What is the Dz name for botulism infection in birds
- Ashaker foal syndrome
- Limberneck
How does the toxin of botulism spread and what areas does it exert its effect on?
The toxin is absorbed into the blood and lymph –> brought to the peripheral nerve system –> Here it binds to the neuromuscular junction and causes paralysis of the cholinergic nerve fibers by blocking release of acetylcholine.
What are some clinical signs associated with a Clostridium botulinum toxin?
- Flaccid paralysis
- Vision disturbances
- Paralysis of muscles used in locomotion
- Unable to swallow and/or breath
Describe the Clostridium botulinum toxin
- Protein
- Complexed with a hemagglutinin
- Need to lyse the bacteria in order to release the toxin
- May need to be digested with proteolytic enzymes to become activated
- May need phage conversion (types C and D)
What Clostridium botulinum toxin acts the q?uickest and therefore has the highest mortality rate
Type E
- What immunizations are available to prevent Clostridium botulinum?
- What type of immunization needed to prevent clinical signs?
Toxoids for high risk populations
Need to produce immunity against multiple toxins with a polyvalent toxoid or have immunity with a toxoid specific for the type of toxin
How does one diagnose a Clostridium botulinum toxicosis or infection?
Demonstration of the toxin in: serum, intestinal contents, and feed
What treatments are available to the poor guy who got the Dz
Polyvalent antitoxin
