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
What is the morphology of Clostridium perfringens?
thick rods, spores are oval and do not form in acid media - non-motile
What do colonies of Clostridium perfringens look like?
sharp hemolytic zones (double zone) especially in fresh isolates
What does Clostridium perfringens do to litmus milk?
stormy fermentation - a lot of gas is produced
How many types of Clostridium perfringens are there and what are they based on?
5 types based on the production of 4 toxins: alpha, beta, epsilon, and iota
What does Clostridium perfringens type A cause in lambs?
yellow lamb disease
What toxin is yellow lamb disease caused by and what lesions are associated with this infection?
alpha toxin which is absorbed by the small intestine causing massive intravascular hemolysis (jaundice) and capillary damage
What does Clostridium perfringes type A cause in piglets?
enteric disease that can mimic a mild E. coli infection and have an effect on the rate of growth of the piglets
What does Clostridium perfringes type A cause in dairy cattle?
hemorrhagic bowel syndrome (HBS)
What is hemorrhagic bowel syndrome?
a sporadic by highly fatal disease that affects adult cows
Alpha-toxin-producing strains of Types A, B, and C of Clostridium perfringens cause what in broiler chickens?
necrotic enteritis (necrosis of the small intestine)
What have Clostridium perfringins type A organisms been caused recently in sheep and foals?
severe fatal enteritis in sheep and clostridial enteritis in foals
What type of Clostridium perfringins do non-toxigenic strains belong in?
type A
What do non-toxigenic strains of Clostridium perfringens cause in humans?
wound infections and gas gangrene
some strains also produce an enterotoxin that is responsible for mild food poisoning in humans and dogs
Are there any preventative measures that can be taken against Type A Clostridium perfringens organisms?
yes there are bacterins but only in swine and cattle
What does Clostridium perfringens type B cause?
lamb dysentery and hemorrhagic enteritis
What does Clostridium perfringens type C cause in calves?
Enterotoxemia in calves and lambs - hemorrhagic and necrotic enteritis
What calves are usually affected by Clostridium perfringens?
the most healthy and vigorous
What does Clostridium perfringens type C cause in piglets (1-5 days old)?
enterotoxemia - acute hemorrhagic enteritis with high mortality
What Clostridium perfringens toxin is responsible for causing enterotoxemia in young piglets?
beta toxin
What is beta toxin easily inactivated by?
trypsin
What does Clostridium perfringens type D cause in sheep?
enterotoxemia in sheep - also known as overeating disease or pulpy kidney disease
What population of lambs are usually affected with Clostridium perfringens type D?
those that are the best off
What Clostridium perfringens toxin is in charge of causing Enterotoxemia in sheep and how is it activated?
Epsilon toxin - it needs to be activated by cleavage of the prototoxin by trypsin
What enhances the absorption of the epsilon toxin in cases of enterotoxemia?
the toxins permease activity
What is the pathogenesis of enterotoxemia in sheep?
Receptors in the vascular endothelium and the toxin forms a large complex in target cells that apparently forms a pore which results in loss of potassium from the cells. The brain is the most sensitive and the toxin produces liquefactive necrosis, edema, and hemorrhage.
How are Clostridium perfringens toxins detected?
via PCR
Toxoids for Clostridium perfringens toxoids are routinely used in calves, sows, and sheep. Types ___ and ____ cross-protect.
B and C
Which toxoids should be routinely used to protect lambs?
Clostridium perfringens type C and D and tetanus toxoids
How is Clostridium perfringens infection controlled in lambs?
restrict concentrate feeding in lambs and add tetracycline and sulfas in feed
What does Clostridium chauvoei cause?
blackleg in ruminants
What is the morphology of Clostridium chauvoei?
it is a typical large rod, usually found singly or in short chains from infection sights and is motile
What is the natural habitat for Clostridium chauvoei?
it exists in the soil as spores and is very resistant
What toxins are associated with Clostridium chauvoei?
alpha - delta; alpha toxin is lethal, necrotizing, and hemolytic. Gamma is a hyaluronidase, and delta is a hemolysin
What age of cattle are usually affected by Clostridium chauvoei?
6 months to 2 years of age but may affect older animals
What population of cattle are most likely affected by Clostridium chauvoei?
usually fat, rapidly growing animals are more likely to develop blackleg
What lesions are associated with black leg?
areas of black, necrotic muscle with gas and crepitation that is usually easily palpated
What are the two theories for the pathogenesis of Clostridium chauvoei infections?
its already in the muscle and proliferates when there is damage to the muscle or it may enter the body when the cow loses its deciduous teeth
How is a Clostridium chauvoei infections diagnosed?
via clinical signs and postmortem lesions
black leg can be diagnosed with culture
What is used for immunization against Clostridium chauvoei?
aluminum hydroxide-precipitated formalinized cultures are used - heat labile, soluble, protective antigen
What does Clostridium septicum cause?
malignant edema associated with wounds in humans and animals as well as necrotic or gangrenous dermatitis in fattening poultry and gastroenteritis in carnivores
What is the morphology of Clostridium septicum?
tends to grow in long chains in animal exudates
What is the pathogenesis of Clostridium septicum?
the organism enters via wounds or the umbilicus and produces malignant edema - there are gelatinous subcutaneous and intermuscular exudates
Necrotic or gangrenous dermatitis is caused by infection with _____________, _________________, and _____________ either alone or in combination.
Clostridium septicum, Clostridium perfringens type A, and Staphylococcus aureus
What specifically does Clostridium septicum cause in sheep?
Braxy
In order to cause braxy, how does Clostridium septicum enter sheep?
it enters via the abomasal lining thought to be due to consumption of coarse, often frozen roughage
What lesions are associated with braxy?
edema, hemorrhage, and sometimes necrosis of the abomasum and anterior small intestine
How do you diagnose a Clostridium septicum infection?
via culture or fluorescent antibody testing
What provides immunity against Clostridium septicum?
formalinized whole cultures can prooduce lifelong immunity
Protection against Clostridium septicum is primarily _______ rather than _________.
antibacterial; antitoxic
How do you treat Clostridium septicum infections?
with penicillin and tetracycline early
What does Clostridium sordellii cause?
gas gangrene, enterotoxermia, and other clostridial infections
What is considered one of the largest Clostridia?
Clostridium novyi
Clostridium novyi is more ______ sensitive than the other clostridia.
oxygen
How many toxins does Clostridium novyi produce?
4
What is the natural habitat of Clostridium novyi type A?
soil and the intestinal tract of herbivores
What does Clostridium novyi type A cause?
gas gangrene in humans and animals and produces ‘big head’ and rams that fight and get head wounds
What does Clostridium novyi type B cause?
black disease - infectious necrotic hepatitis
What species does black disease affect?
sheep, occasionally cattle and other animals
What is the pathogenesis of black disease?
Spores of the organism originate in the intestine, migrate to the liver and remain there in a dormant state in Kupffer cells. Fasciola hepatica migrates through the liver and creates a favorable environment for the germination of the spores already present. The organisms multiply and produce toxin where it is absorbed into blood
What lesions are associated with Black disease?
extensive blood-stained subcutaneous edema with straw colored fluid in the serous cavities
How do you diagnose a Clostridium novyi infection
?
need to demonstrate the alpha toxin is in the affected tissues
What is used to immunize against black disease?
alum-precipitated formalinized cultures
How do you treat black disease?
use hyperimmune serum during outbreaks - penicillin can be useful but the disease course is very rapid so it may not be effective``
What is Clostridium hemolyticum also known as?
Clostridium novyi type D
What does Clostridium hemolyticum cause?
bacillary hemoglobinuria or Redwater disease of cattle, deer, elk, and sometimes sheep
What is required for optimum growth and toxin production of Clostridium hemolyticum?
tryptophan
What parasite is Clostridium hemolyticum infection associated with?
Fascioloides magna
What allows for Clostridium hemolyticum infection?
the liver flukes cause initial damage allowing for subsequent colonization of the necrotic areas by Clostridium hemolyticum
What principle toxin is associated with Clostridium hemolyticum?
lecithinase C
What does lecithinase C cause?
intravascular hemolysis and capillary damage with lysis of the RBC
What lesions are associated with Clostridium hemolyticum infection?
severe hemorrhagic enteritis and extensive hemorrhages - characteristic liver lesion is a large infarct
How do you diagnose a Clostridium hemolyticum infection?
culture and toxin demonstration in the liver
How do you provide immunity against Clostridium hemolyticum?
formalinized whole cultures every 6-12 months
How do you treat for a Clostridium hemolyticum infection?
antiserum and large doses of intravenous penicillin
What does Clostridium piliformae cause and in what species?
Tyzzer’s disease - primarily in rodents but can be seen in horses, cats, and dogs
What population of animals does Clostridium piliformae typically manifest in?
in stressed animals
In younger animals, what is the characteristic lesion associated with a Clostridium piliformae infection?
enteritis
In older animals, what is the characteristic lesion associated with a Clostridium piliformae infection?
focal hepatic necrosis accompanied by jaundice and catarrhal enterocolitis
How do you diagnose a Clostridium piliformae infection?
histopathology
How do you treat a Clostridium piliformae infection?
penicillin, ampicillin, tetracycline, neomycin, and erythromycin
What does Clostridium colinum cause?
quail disease or ulcerative enteritis
How is Clostridium colinum transmitted?
orally
What lesions are associated with Clostridium colinum?
diffuse necrosis of the liver and ulcerations of the lower 1/3 of the intestine
What does Clostridioides difficile cause in pigs?
mesocolonic edema
What age of pigs does Clostridioides difficile affect?
1-7 days of age
What does Clostridioides difficile cause in foals?
watery diarrhea in foals 2-5 dyas of age
What does Clostridioides difficile cause in mature horses?
acute colitis
What does Clostridioides difficile cause in humans?
diarrhea in association with adminitration of antimicrobial agents and pseudomembraneous colitis
What other animals does Clostridioides difficile infection cause problems in in associated with antimicrobial therapy?
hamsters, rabbits, and guinea pigs
What are the two toxins that Clostridioides difficile produce?
A an enterotoxin and B a cytotoxin
How do you diagnose Clostridioides difficile infections?
special media, detection of toxins, and PCR (only in equine)
How is Clostridioides difficile infection treated?
supportive therapy, antimicrobials such as metronidazole
