Enterotoxigenic clostridium Flashcards
(66 cards)
1
Q
What is C. perfringens?
A
- Gram +
- Spore formin- subterminal
- Rod shaped
- With double zone hemolysis
2
Q
Where is C. perfringes found?
A
3
Q
What are the types of C. perfringens and what toxins do they produce?
A
- A* - alpha toxins
- B - Alpha, Beta, Epsilon toxins
- C* - Alpha, Beta toxins
- D* - Alpha, Epsilon toxins
- E - Alpha, Iota toxins
- F - Alpha, CP Enterotoxin
- G* - Alpha, Necrotic enteritis beta-like toxin (NetB)
4
Q
What is the activity and effects of Alpha toxin in C. perfringens?
A
- A zinc metallophospholipase
- Hemolytic and cytotoxic
5
Q
What is the activity and effects of Beta toxin ot C. perfringens?
A
- A pore-forming toxin
- Induces inflammation and necrosis in the intestine
6
Q
What is the activity and effects of Epsilon toxin of C. perfringens?
A
- Secreted as a prototoxin and requires activation by pepsin and chymotrpsin in the gut
- Third most potent clostridial toxin
- A pore-forming toxin, increases intestinal permeability
7
Q
What is the activity and effects of Iota toxin ot C. perfringens?
A
- A binary toxin because it has two polypeptides, named IA and IB
- IA: ADP-ribosylates of skeletal muscle and nonmuscle actins causing cell death
- IB: Mediates binding to cells
8
Q
What is the activity and effects of CPE toxin ot C. perfringens?
A
- A pore-foring cytotoxin
- Produced by all types, except B.
- Induces cell death of enterocytes and fluid secretion
9
Q
What is the activity and effects of NetB toxin of C. perfringens?
A
- A pore-forming cytotoxin.
- Lyses enterocytes
- Mostimportant toxin involved in avian necrotic enteritis
10
Q
What other toxins of C. perfringens are there?
A
- At least 8 other exotoxins
- Gamma, Delta, Eta, Theta, Kappa, Lambda, Mu, Nu
11
Q
What is Perfringolysin (PFO)?
A
- Also called Theta toxin
- A pore-forming hemolysin
- Acts synergistically with alpha hemolysin
- Involved in gas gangrene
12
Q
What is Enterotoxemia?
A
- Commonly used term to describe enteritis caused by C. perfringens
- Implies systemic spread of the toxin produced in the intestines
- In many instances the toxin effect is confined to the intestines alone
- Preferred term “Necrotic enteritis”
13
Q
What diseases do type A Infections of C. perfringens cause?
A
- Humans - Gas Gangrene in humans and animals
- Cattle, Goats, Swine, Horse, Dogs, Minks - Necrotic enteritis (Hemorrhagic enteritis or Enterotoxemia)
- Calves - Abomasal bloat and Ulcers
- Dairy cows - Hemorrhagic bowel syndrome
- Sheep - Yellow lamb disease
- Chicken - Gagrenous Dermatitis
14
Q
What diseases does a Type B infection of C. perfringes cause?
A
- Caused by Alpha, Beta, and Epsilon toxins
- Sheep - Lamb dysentery
- UK, Middle East, S. Africa
- Cattle, Goats - Necrotic enterits (Hemorrhagic enteritis or Enterotoxemia)
- Not common in the US
15
Q
What diseases are caused by Type C infections of C. perfringens?
A
- Caused by Alpha and Beta toxins
- Humans - Necrotic enteritis (Pig bel)
- Sheep, Goats - Struck (Enterotoxemia) in Britain Necrotic enteritis (Enterotoxemia) in lambs and kids
- Cattle - Necrotic enteritis (Enterotoxemia) in calves
- Horses - Necrotic enteritis (Enterotoxemia) in foals
- Swine - Necrotic enteritis (Endotoxemia) in piglets
- Most common type in the US
16
Q
What are Type C infections?
A
- Alpha Toxin: hemolytic
- Beta Toxin: Induces inflammation and necrosis in the intestines
- Most common in newborn (<1 week old)
- More common in piglets than other animals
- Acute disease
- High mortality
17
Q
What are the clinical signs of Type C infections?
A
- Depression
- Hemorrhagic diarrhea
- Death
- Lesions: Hemorrhagic inflammation of the jejunum and ileum
- Necrosis (with gas) of the mucosa and the submucosa
18
Q
What is the Pathogenesis of Type C infections?
A
- Generally seen in animals healthy and vigorous
- Increased feed intake
- Gut stasis
- Overgrowth of bacteria and production of toxins
- Toxin may or may not get absorbed
- Acute illness and death
19
Q
What diseases are caused by Type D infections of C. perfringens?
A
- Sheep - Enterotoxemia (Overeating disease or Pulpy Kidney disease)
- Cattle, Goats - Necrotic enteritis (Enterotoxemia)
20
Q
What diseases are caused by Type E infections of C. perfringens?
A
- Rabbits - Iotaenterotoxemia. Rarely in calves and lambs
21
Q
What is Epsilon Toxin?
A
- Third most potent clostridial toxin (Botulinum, Tetanospasmin)
- Requires activation by trypson or Chymotrypsin
- Enhances intestinal permeability
- Rapid absorption of toxin
- Affects of CNS and other organs
- Responsible for perivascular edema, foci of necrosis and hemorrhages in the meninges
22
Q
What diseases are caused by Type F infections of C. perfringens?
A
- Humans - Foodborne gastroenteritis
23
Q
What diseases are caused by Type G infections of C. perfringens?
A
- Chickens - Necrotic enteritis
24
Q
What is Yellow Lamb Disease?
A
- Occurs in the spring in CA and OR
- Nursing lambs
- Alpha toxin from the intestine enters blood and causes hemolysis
25
What are the clinical signs of Yellow Lamb Disease?
* Acute onset
* Anemia
* Dyspnea
* Hemoglobinuria
* icterus
* Lesion: Generalized icterus, red urine in the bladder, enlarged spleen
26
What is Abomasal Bloat and Ulcers?
* Neonatal calves, lambs, and goat kids
* Copper and/or selenium deficiencies may be predisposing factos
27
What are the clinical signs of Abomasal Bloat and Ulcers?
* Acute onset
* Anorectic
* Abdominal bloat
* discomfort
* Lesions: Gas, hemorrhage, ulceration
28
How are Abomasal Bloat and Ulcers treated?
* Oral Antibiotics: **Tetracyclines**, **monensin**
* 0.1% formalin in milk replacers
* Type A toxoid vaccine
29
What is *Sarcina ventriculi*?
* Anaerobic, Gram positive cocci
* Ferments carbohydrtes and exhibits vigorous gas production
* Can survive in acidic pH of abomasum
* Possible role in Abomasal Bloat?
30
What is Hemorrhagc Bowel Syndrome?
* Relatively new disorder affecting primarily dairy cows
* Intraluminal hemorrhage or submucosal hematoma in the jejunum
31
What is the Etiology of Hemorrhagic Bowel Syndrome?
* *Clostridium perfringens,* Type A
* *Aspergillus fumigatus*
32
What are the clinical signs of Hemorrhagic Bowel Syndrome?
* Abdominal pain
* Inappetance
* Weakness
* Drop in milk production
* Scat feces
* Abdominal distension
* Death
33
34
What is the Etiology of Gangrenous Dermatitis?
* *C. perfringens* Type A
* *C. septicum* with or without *S. aureus*
35
What are the clinical signs of Gangrenous Dermatitis?
* Depression
* Incoordination
* Weakness
* Inappetence
* Ataxia
* Lesions: Skin-edematous with or without gas, and necrotic
36
What is Overeating Disease or Pulpy Kidney Disease
* Occurs in Sheep and goats fed high grain diets
* Rarely in cattle
* Grain diets leads to overgrowth of *C. perfringens*
* Epsilon Toxin is the major virulence factor
37
What are the Clinical Signs of Overeating/Pulpy Kidney Disease?
* Sudden death
* Neurological signs often precede death
* Dullness
* Blindness
* Ataxia
* Convulsions
38
What lesions are seen in Overeating/Pulpy Kidney Disease?
* Hemorrhages and foci of necrosis on the meninges
* Hemorrhages present on serosal surfces of rumen, abomasum, duodenum, and in the diaphragm and abdominal muscles
* Kidneys: Hyperemia and degenerative changes
* Soft and friable (pulpy) because of rapid autolysis
39
What are Type F infections?
* Thrid most prevalent bacterial foodborne illness (~600,000 cases)
* Virulence factor: *C. perfringens* enterotoxin
* Toxin is produced during sporulation and released by lysis of vegetative cells
* Role of this toxinin animals is not known
40
What is the pathogenesis of Foodborne Enteritis?
1. *C. perfringens* grows in the food
2. Sporulates in the stomach
3. Produces enterotoxin in the SI
4. Signs 8-12 h after ingestion of food
* Diarrhea, abdominal cramps
* self-limiting infection
41
What are some Foodborne Pathogens?
* *Staphylococcus aureus*
* *Escherichia coli* O157:H7
* *Salmonella enteric*
* *Chronobacter sakazaki*
* *Yersinia enterocolitia*
* *Clostridium botulinum*
* *Clostridium perfringens*
42
What are Type G *C. perfringens* infections?
* Chickens and turkeys
* Most common clostridial disease in poultry
* Major virulence factor:
* Necrotic enteritis beta-like toxin (NetB)
* About 38% amino acid identity with beta toxin
43
What is Necrotic Enteritis?
* Chickens and turkeys
* 2 forms: Acute and subacute
* **Acute form:** Death in a few hours
* Depression, anorexia, ruffled feather, diarrhea
* **Subacute Form:** Diarrhea and poor growth rate
44
What lesions are seen with Nerotic Enteritis?
* Confined to the jejunum and ileum
* Coagulative necrosis. Yellow to green pseudomembrane
* Contents are dark brown or yellow-green
* In chronic form: thickened intestinal wall
45
How is Necrotic Enteritis Diagnosed?
* Clinical signs
* Demonstration of toxin in the contents: toxin neutralizaiton in mice; ELISA
* Isolation of *C. perfringens* and PCR confirmation of *netB* gene
46
How is Necrotic Enteritis Treated?
* Antibiotics in feed or water
* Lincomycin, bacitracin, oxyttracycline
* Treat the anorexia, ruffled feathers, diarrhea
* **No vaccine available**
47
What Vaccines are available for *C. perfringens*?
* Bacterins and/or toxoids
* Mostly Toxoids: Monovalent or multivalent vaccines
* Sows are vaccinatd during mid-gestation with type C toxoid
* Sheep in feedlos: Type D toxoid
48
What is Quail Disease?
* Ulcerative entritis of Wild and Domestic Birds
* Caused by *Clostridium colinum*
* Secondary to coccidiosis or infectious bursal disease
49
What is the Mode of infection of Quail Disease?
* Oral
* Infection ofthe GI tract
* Through the blood to the liver to cause diffuse necrosis
* Virulence factor unknown
50
How is Quail Disease treated?
* Tetracyclines in water
51
What is *Clostridium piliforme?*
* Causes "Tyzzer's disease" in rabbits, rodents and horses
* Gram -
* Long slender rods and heavily fimbriated
* Not cultivable in culture media
* Grows in tissue culture or chick embryos (obligate intracellular pathogen)
* Habitat: intestinal tract of rodents
52
What is the mode of infection of Tyzzer's Disease?
* Ingestion of spores
53
What is the Pathogenesis of Tyzzer's Disease?
* Invades intestinal epithelial cells - Enteritis, colitis
* Invades hepatic cells - hepatitis
54
What lesions are present in Tyzzer's Disease?
* Necrosis
55
How is Tyzzer's Disease prevented?
* Tetracycline
56
What is Tyzzer's Disease in Horses?
* Mainly in foals between 1 - 4 weeks
* Mode of infection: ingestion of spores
* Disease is profressive hepatitis
* Clinical signs: lethargy, fever, seizures, death
* Lesions: Heptomagaly with 1 - 5 mm necrotic foci Tetracycline
* Diagnosis: Demonstration of the bacteria in the parenchymatic cells. Also PCR
* Treatment: Penicillin, erythromycin, tetracycline
57
What is *C. spiroforme?*
* Spiral shaped, Gram + and spore forming
* Virulence factor: Iota toxin
* Causes Entertoxemia in weanling rabbits and laboratoy rodents
* Clinica Signs: spontaneous diarrhea and death
* Lesions: Cecum is dilated with watery contents. Necrosis of the lining
58
What is *Clostridium difficile?*
* First recognized as a human pathogen in 1977
* Causes **Pseudomembranous colitis**
* Part of the normal flora
* Disease results from overgrowth of the organism and production of toxins
* **Major nosocomial pathogen**
59
What Antibiotic treat *C. difficile?*
* Clindamycin, erythromycin, Ampicillin, Amoxicillin, Cephalosporins, and Fluoroquinolones
* 25% of all Antibiotic-associateed diarrhea
* Can be induced in lab animals - feeding antibiotics to guinea pigs and hamsters
* Hypervirulent strains: Rapid spread and higher mortality
60
What is Community-Associated CDI?
* No history of antibiotic use
* Food born? Zoonotic?
* Isolated from raw and ready-to-eat meat from grocery stores
* Foodborne illness not documented yet.
61
What are the Virulence Factors of *C. difficile?*
* Toxin A (TcdA): Enterotoxin
* Causes fluid accumulation
* Toxin B (TcdB): Cytotoxin
* Does not cause fluid accmulation
* Both act synergistically
* Not all strains produce toxins
62
What is Pseudomembranous Colitis?
* Severe hemorrhgic colitis or ileitis
* Watery and bloody diarrhea
* Ulceration of the colonic mucosa
* Formation of pseudomembrane
* Diagnosis: Demonstration of toxins in the feces
63
How do *C. difficile* infections (CDI) affect animals?
* Most common in horses and swine
* Rarely in cattle, dogs, and cats
* Healthy animals carry the organism (5 - 40% fecal prevalence)
* Mode of infection: Endogenou or exogenous
* Organism has been isolated from raw meat intended for pet consumption
64
How does CDI affect horses?
* Not age dependent. More common in foals than adults
* Adults: Hospital associated; antibiotic associated
* Foals: Hemorrhagic necrotizing entercolitis. 1st week of birth
* Clinical signs: Profuse diarrhea, colic, weak, and dehydration
* Death usually within 24h
* Treatment: Metronidazole or vancomycin
65
How does CDI affect pigs?
* Age dependent. Seen in piglets of **1-7 days of age**
* Infection of colon (colitis) and cecum (Cecitis); Typhlocolitis
* Profuce diarrhea. Some exhibit dyspnea, abdominal distension and scrotal edema
* Lesion: Necrotic lesions in the lamina propria of the colon and edema ofthe colon
* Diagnosis: TcdA and TcdB toxins in the blood
66
How is C. difficile a zoonotic pathogen?
* *C. difficile* spores are shed in the feces of healthy humansand animals
* High rates of carriage in healthy swine farmers and handlres
* Identical genetic types in swine and clinical human cases
