Lecture 15 Flashcards
What is the biocontainment level for Clostridium botulinum in lab?
3 & 2 in any other setting
Describe the appearance of Clostridium botulinum
Gram positive
Spore forming
Rods
Describe the metabolism of Clostridium
Anaerobic
Clostridium novyi is a strict anaerobe, can work with others fairly easy
What is the appearance of Clostridium perfringens?
Gram positive
Rods
Boxcar morphology
Describe the appearance of Clostridium perfringens on plate
2 zones of hemolysis
Can be enhanced by placing in fridge & then incubate
Describe the appearance of Clostridium tetani
Terminal spores
Drumstick morphology
Where is clostridium found?
Wide distribution
Envr - water & soil
Many spp of normal microbiota (found in feces)
What tests are used to dx clostridium? & What does a positive result look like for each?
Lecithinase - positive = precipitation around streak
Lipase tests - positive = clear zone around streak
How do animals acquire Clostridium tetani? What are 3 exs of this situation?
Organisms enter body through beaches in the skin
Ex: step on rusty nail
Ex: fecal contamination of umbilicus
Ex: tail docking
Describe the pathogenesis of Clostridium tetani
Damage to skin barrier occurs
Organism enters
Organism multiples in necrotic tissue
Organism produces toxins
What toxins does Clostridium tetani produce? & What are the roles of the toxins?
Tetanolysin - enhances tissue invasion
Tetanospasmin - neurotoxin which causes muscle spasms
How do you tx Clostridium tetani? (2)
High dose of penicillin
Tetanus anti-toxin
What symptoms does Clostridium tetani cause in humans? (3)
Generalized tetanus
Muscle stiffness
Opisthotonos
What symptoms does Clostridium tetani cause in dogs?
Muscle spasm of the face - lockjaw
Characteristic risks sardonicus
Where is Clostridium botulinum found?
Soils & aquatic enviers
When does Clostridium botulinum produce toxins?
when spores germinate in anaerobic envrs
Describe how the spores of Clostridium botulinum do in the envr?
Extremely resistant
Survive boiling
Need to be careful when canning
How are animals exposed to Clostridium botulinum?
Ingestion
How does disease arise from Clostridium botulinum? & what is the main symptom?
Extremely potent botulism toxin which prevents release oc ACh at neuromuscular junction
Causes flaccid paralysis
Describe the exposure & pathogenesis of Clostridium botulinum in waterfowl
C. botulinum spores located on lake bottom
Birds eat inverts from lake bottom
Become intoxicated
Droopy necks = drown or rest failure
Carcasses eaten by maggots
Toxin laden maggots eaten by birds –> perpetuates disease
What are the 5 forms of botulism in humans?
- Food borne
- Wound botulism
- Infant botulism
- Adult intestinal toxaemia
- Latrogenic botulism (accidentally infect yourself)
What is the tx for Clostridium botulinum? (4)
A/bs - works for infection, not for toxin ingestion
Antitoxin
Supportive therapy
Vacc (in horses)
What disease does Clostridium chauvoei cause in cattle & sheep?
Blackleg
Where is Clostridium chauvoei found? (2)
Envr & feces
Describe the pathogenesis of Blackleg from Clostridium chauvoei
Ingest endospores which usually pass without prob
Occasionally, they become lodged in tissues (hindquarters & cardiac muscle)
Disease occurs when spores are stimulated to germinate
What are the clinical signs of blackleg from Clostridium chauvoei? (3)
Acute febrile disease - lameness & sudden death
May feel crepitation (bloated)
Muscle is dark red-black & spongy with rancid odour
What is the tx of blackleg? (3)
Not practical
Penicillin
Sx debridement
Can vaccinate
What disease does Clostridium septicum cause & in who?
Malignant edema in large animals of all ages
How do large animals get Clostridium septicum?
Infection usually occurs following deep puncture & trauma
Ex: vacc, sx or through umbilicus
Results in fatal toxaemia due to production of neurotoxins
Neurotoxins cause edema & gangrene
How is Clostridium septicium tx? (2)
High dose of penicillin systemically & inj around primary lesions
Antitoxin
How do you prevent Clostridium septicum infection from occurring?
Hygiene when performing invasive procedures
Vacc
Does Clostridium septicum pose a zoonotic risk?
No, they are infrequently isolated from infections which are often fatal
Assoc with malignancy
What disease does Clostridium novyi type B cause in sheep, cattle, horses & rarely pigs?
Black disease - Acute, necrotic hepatitis (animals are usually found dead)
How do animals get Clostridium novyi?
Via envr
Fecal contamination by carrier of pasture thought to be important
What pops of sheep get blackleg from Clostridium novyi?
Well nourished adult sheep
Describe the pathogenesis of black disease in sheep
Ingest spores from feed
Spores reach liver hematogenously
Germinate with necrotic insult
Release alpha toxin
What is black disease from Clostridium novyi in sheep normally assoc with? (3)
Liver flukes
Cysticercus tenuicollis
Liver trauma
What is the tx for black disease form Clostridium novyi in sheep?
No effective tx
Vacc available
Prevent liver fluke infestation
Where is Clostridium perfringens normally found?
Intestinal microbiota
What toxins does Clostridium perfringens use to cause disease? (5)
Enterotoxin - released reign sporulation, responsible for food poisoning in people
Alpha toxin - lecithinase (type of phospholipase), attacks cell PMs resulting in necrosis
Beta toxin - pore forming toxin which is lethal & necrotizing. Binds to endothelial cells & causes necrosis
E-toxin - pro-toxin activated by proteolytic enzymes. Pore forming & damages endothelium
I-toxin - pro-toxin, activated by proteolytic enzymes, cytotoxic
What disease does Clostridium perfringens cause in sheep? (2)
Lamb dysentery
Pulpy kidney disease
How do lambs get lamb dysentry from Clostridium perfringens?
Predisposed by abrupt change in diet
Allows overgrowth of C. perfringens leading to production of the toxin at high levels
May have sudden death
What disease does Clostridium perfringens cause in pigs?
Hemorrhagic enteritis in piglets
What disease does Clostridium perfringens cause in chickens?
Necrotic enteritis
How do lambs acquire pulpy kidney disease?
Assoc with gorging on grain or lush pasture
Describe the pathogenesis of pulpy kidney disease in lambs
Gorge on lush pasture or grain
High starch content stimulates overgrowth of C. perfringens
Excess E-toxin production leads to toxaemia
Acute - often found dead
How do you tx pulpy kidney disease?
Control diet
What happens when people get Clostridium perfringens?
Cause necrotizing intestinal disease
Assoc with fooods containing trypsin inhibitors
What disease does Clostridium difficile cause in pigs?
Early onset of scours in young pigs leading to sudden death
What enterotoxins does Clostridium difficile produce? & what do they do?
A & B
Colonic dysregulation & cell death
How do you tx Clostridium difficile in people?
Vanomycin & metronidazole
Fecal transplants
How do you dx C. tetani in the lab?
gram stain displaying drumstick organisms
How do you dx C. botulinum in the lab?
Toxicity studies where you inj mice with serum or filtrate of rumen contents
How do you dx C. chauvoei, C. septicum & C. novyi in the lab? (3)
Culture - collect large chunks of tissue (maintain anaerobic envr)
Fixed tissues for histo
Fourescent antibody test
How do you dx C. perfringens in the lab?
Culture feces when there is diarrhea & renal tissue when there is pulpy kidney disease
Gram stian - box car cells
Identify toxin via PCR
Histo
How do you dx C. difficile in the lab?
Culture feces
Identify toxin via PCR
Does C. perfringens pose a zoonotic risk?
Yes, causes food borne illness
Assoc with contained meats
