Histiotoxic/ Enteropathogenic Clostridia Flashcards
What do the endotoxins of histiotoxic clostridia produce? What is the effects of this? Where are they typically present in the body/ where can they be found in the environment?
- Exotoxins induce local tissue necrosis and systemic effects LETHAL.
- They are present in tissue as latent spores (muscle and liver).
- Endospores are widely distributed in the environment and persist for
long periods in soil.
How does histotoxic clostridia cause endogenous infections? What is the steps? What about exogenous infections?
- Endogenous:
Spores in intestinal lumen -> tissue (phagocytes) ->Tissue injury (reduced oxygen) -> Spore germination -> vegetative bacteria -> exotoxins production -> Necrosis and Toxaemia - Exogenous infections Infected wounds
What is egg yolk agar? What characteristics does it support? What can be seen if the bacteria plated is specific for this characteristic?
Egg Yolk Agar is a differential and enriched medium used in the isolation and presumptive differentiation of different species based on their lecithinase activity. Lecithin is a normal component of the egg yolk
Such an opaque halo, surrounding the colony when grown on the egg yolk agar medium indicates positive lecithinase activity of the test organism.
What is seen in this image? What bacteria likely causes these lesions?
- Necropsy: Necrosis of muscles/ dark discoloration, emphysema usually in larger muscles of the body. Clostridium produces gas. You can also see edematous fluid that’s hemorrhagic.
This is C. chauvoei, causing black leg in cattle.
What are the 4 clostridia that can cause malignant edema?
Malignant edema can be caused by 4 clostridium:
◦ Clostridium perfringens Type A
◦ Clostridium novyi
◦ Clostridium chauvoei
◦ Clostridium sordellii
- Also CL Septicum
A farmer accidentally punctured the skin with a fork trying to get the cow up. What is likely causing the pathology in these images? What is another name for this condition?
Cause is likely one of the 5 clostridia that causes malignant edema. These are signs of malignant edema
What can you see in this image? What is the likely cause?
Braxy, Clostridium septicemia-> hemorrhagic, abomasum -> ulcerated
What can be seen in the stomach and liver of cattle with C. Novyi? What is the name of the disease? What is it associated with? What animals is it a
How does fasicola hepatica enhance the experience of C. Novyi?
◦ When the liver parasites are there it creates and anaerobic environment -> this allows the spores of clostridium to start to reproduce since the environment is now favorable.
What is occurring in these images? What is a way to remember these lesions? What can be seen in both the liver and stomach?
A.) Full stomach and gas bubbles in the liver.
B.) The liver uniformly infiltrated with gas bubbles, presenting a spongy appearance on the cut surface, probably the most distinguishing feature of sudden death in sows caused by clostridium Novyi
What is a key findings in patients with Clostridium Haemolyticum?
- Jaundice/ icteric (yellow color or pale of gum and sclera)
- Pinpoint red blood spots ( petechia)
Dark purple/ red port wine colored urine (hemoglobinuria) and dark colored feces ( melena)
What is seen in this images? What is likely the cause?
Left: Jaundice/ icterus
Right: Open urinary bladder showing dark red urine in lumen.
Clostridium haemolyticum
Bacillary haemoglobinuria
What is the cause of jaundice and hemaglobinuria in cases infected with C. Haemolyticum?
Clostridium haemolyticum- Bacillary haemoglobinuria
* High numbers of RBC are being destroyed in body. The hemoglobin cannot be metabolized/ eliminated, if kidney starts excreting hemoglobin, it will cause dark, hematuria. You can see yellow discoloration of MM/ pinpoint red blood spots ( petechia)
* Melena
* Port wine urine.
What are the immunological aspects of histotoxic clostridia?
- Circulating antibody to toxins and cellular components determines resistance
What are the types of Laboratory diagnostics that can be preformed for Histotoxic clostridia? What are the requisites?
Laboratory Diagnosis
- Immunofluorescence of infected tissue smears
* Sporulated gram positive rods - Isolation requisites:
* Strict anaerobic conditions
* Culture medium rich in cysteine and water-soluble vitamins - Detection in tissue or identification in culture can be done by molecular methods (PCR)
* Flagellin and other genes 16S-23S DNA spacer regions
What are the treatment options available for Histotoxic Clostridia? Is treatment usually effective?
- Treatment is often disappointing
- Intravenous penicillin (but it is hard to catch infection early)
What are control measures/ preventative measures in place for farms exposed to histotoxic clostridia?
- Cattle are vaccinated at 3-6 months (usually combined vaccine)
* Vaccination should precede exposure by at least 2 weeks
* Pregnant ewes are vaccinated 3 weeks prior to parturition
* Lambs may require vaccination during their first year
* Change of pasture is advisable when cases are first observed
What are the enteropathogenic / enterotoxaemia producing clostridia? Where do they live? What effects does the toxins produce?
- Clostridium present and replicate in GI tract
- Clostridium produce toxins
- Toxins can produce local and generalized effects/damage
- Produce disease only in defined circumstances
- Clostridium perfringens type A, B, C, D, and E.
What are the factors that predispose animals to the development of enterotoxemias associated with C. Perfringens in sheep
What kind of tissue destruction is caused by enterotoxemia A? What Diseases are caused by this bacteria?
- Tissue destruction
- Membrane active toxins and connective tissue toxins Diseases
- Outbreaks of gastritis and hemolytic diseases of ruminants
- Yellow lamb diseases
- Hemorrhagic enteritis in cattle, horses and infant alpacas
- Necrotic enteritis in poultry
- Canine hemorrhagic gastroenteritis
- Food poisoning in humans
- Antibiotic-associated diarrheas
What is important toxins for Enterotoxemia Type A?
α-TOXIN, perfringlolysin O and enterotoxins are important!!!
What is seen in these images? In chickens, what can be seen as a coinfection of this bacteria?
What is seen in this image?
- Necrosis seen on the abomasum of this calf
What is seen in this image?
- Necrotic enteritis, ( hemorrhagic necrosis) in chickens.
- 20 sheep present -> presented with HGE and distended abdomens. They died pretty quickly. You can see hemorrhagic large and small intestine. ( Left)
- Right image: you can see pericardial sac -> dilated with fluid and fibrin
What is seen in these images?
What is seen in this image? What is the likely cause?
What signs can be seen in patients with enterotoxemia type D that has caused encephalomalecia?
- Clinical Signs:
◦ Opisthotonos, encephalomalacia, ulcerative fibronecrotic ileitis.
What can you see on blood agar when plating for C. perfringens? Is it proteolytic? Does it have an odor? Is it hemolytic? What do the colonies look like?
If you were to take the same blood agar plate with C.Perfringens, what would you see if it is examined with transmitted light?
When looking at sample isolations of c. perfringens, what would you see that is called stormy milk?
Clotting of milk followed by gaseous disruption
Proteins of milk are digested and produces gas.
Can see bubbles on surface.
What are the characteristics of C. dificile? What does it cause in humans? what can be seen in other animals?
Clostridium difficile
* Gram-positive, motile, encapsulated, spore-forming anaerobic rod
* Significant cause of diarrheal diseases in humans
* Antibiotic-associated diarrhea
* Pseudomembranous colitis
* Isolated from symptomatic and asymptomatic dogs, cats and horses
Typhilitis in hamsters. - inflammation of cecum
Colon main organ affected
What is the pathogenesis of C. Difficile?
- trigger event -> Normal flora disrupted (C.diff takes advantage)-> adheres to lg intestine, produces toxins, causes epithelial cell death -> intense inflammatory response. ( fluid + electrolyte secretion, diarrhea w/ or w/o blood.
What is seen in these images?
What is seen in these images? What is this presentation classic for? In the 2nd image, what is the black arrow indicating?
Image 1: position of fibrin and necrotic tissue is classic for c.diff.
Image 2: Characteristic plaque seen ( black arrow) overlying intact intestinal mucosa) H& E stain
