Enterotoxigenic clostridium Flashcards
What is C. perfringens?
- Gram +
- Spore formin- subterminal
- Rod shaped
- With double zone hemolysis
Where is C. perfringes found?
What are the types of C. perfringens and what toxins do they produce?
- 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)
What is the activity and effects of Alpha toxin in C. perfringens?
- A zinc metallophospholipase
- Hemolytic and cytotoxic
What is the activity and effects of Beta toxin ot C. perfringens?
- A pore-forming toxin
- Induces inflammation and necrosis in the intestine
What is the activity and effects of Epsilon toxin of C. perfringens?
- 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
What is the activity and effects of Iota toxin ot C. perfringens?
- 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
What is the activity and effects of CPE toxin ot C. perfringens?
- A pore-foring cytotoxin
- Produced by all types, except B.
- Induces cell death of enterocytes and fluid secretion
What is the activity and effects of NetB toxin of C. perfringens?
- A pore-forming cytotoxin.
- Lyses enterocytes
- Mostimportant toxin involved in avian necrotic enteritis
What other toxins of C. perfringens are there?
- At least 8 other exotoxins
- Gamma, Delta, Eta, Theta, Kappa, Lambda, Mu, Nu
What is Perfringolysin (PFO)?
- Also called Theta toxin
- A pore-forming hemolysin
- Acts synergistically with alpha hemolysin
- Involved in gas gangrene
What is Enterotoxemia?
- 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”
What diseases do type A Infections of C. perfringens cause?
- 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
What diseases does a Type B infection of C. perfringes cause?
- 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
What diseases are caused by Type C infections of C. perfringens?
- 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
What are Type C infections?
- 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
What are the clinical signs of Type C infections?
- Depression
- Hemorrhagic diarrhea
- Death
- Lesions: Hemorrhagic inflammation of the jejunum and ileum
- Necrosis (with gas) of the mucosa and the submucosa
What is the Pathogenesis of Type C infections?
- 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
What diseases are caused by Type D infections of C. perfringens?
- Sheep - Enterotoxemia (Overeating disease or Pulpy Kidney disease)
- Cattle, Goats - Necrotic enteritis (Enterotoxemia)
What diseases are caused by Type E infections of C. perfringens?
- Rabbits - Iotaenterotoxemia. Rarely in calves and lambs
What is Epsilon Toxin?
- 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
What diseases are caused by Type F infections of C. perfringens?
- Humans - Foodborne gastroenteritis
What diseases are caused by Type G infections of C. perfringens?
- Chickens - Necrotic enteritis
What is Yellow Lamb Disease?
- Occurs in the spring in CA and OR
- Nursing lambs
- Alpha toxin from the intestine enters blood and causes hemolysis
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
What is Abomasal Bloat and Ulcers?
- Neonatal calves, lambs, and goat kids
- Copper and/or selenium deficiencies may be predisposing factos
What are the clinical signs of Abomasal Bloat and Ulcers?
- Acute onset
- Anorectic
- Abdominal bloat
- discomfort
- Lesions: Gas, hemorrhage, ulceration
How are Abomasal Bloat and Ulcers treated?
- Oral Antibiotics: Tetracyclines, monensin
- 0.1% formalin in milk replacers
- Type A toxoid vaccine
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?
What is Hemorrhagc Bowel Syndrome?
- Relatively new disorder affecting primarily dairy cows
- Intraluminal hemorrhage or submucosal hematoma in the jejunum
What is the Etiology of Hemorrhagic Bowel Syndrome?
- Clostridium perfringens, Type A
- Aspergillus fumigatus
What are the clinical signs of Hemorrhagic Bowel Syndrome?
- Abdominal pain
- Inappetance
- Weakness
- Drop in milk production
- Scat feces
- Abdominal distension
- Death
What is the Etiology of Gangrenous Dermatitis?
- C. perfringens Type A
- C. septicum with or without S. aureus
What are the clinical signs of Gangrenous Dermatitis?
- Depression
- Incoordination
- Weakness
- Inappetence
- Ataxia
- Lesions: Skin-edematous with or without gas, and necrotic
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
What are the Clinical Signs of Overeating/Pulpy Kidney Disease?
- Sudden death
- Neurological signs often precede death
- Dullness
- Blindness
- Ataxia
- Convulsions
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
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
What is the pathogenesis of Foodborne Enteritis?
- C. perfringens grows in the food
- Sporulates in the stomach
- Produces enterotoxin in the SI
- Signs 8-12 h after ingestion of food
- Diarrhea, abdominal cramps
- self-limiting infection
What are some Foodborne Pathogens?
- Staphylococcus aureus
- Escherichia coli O157:H7
- Salmonella enteric
- Chronobacter sakazaki
- Yersinia enterocolitia
- Clostridium botulinum
- Clostridium perfringens
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
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
-
Acute form: Death in a few hours
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
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
How is Necrotic Enteritis Treated?
- Antibiotics in feed or water
- Lincomycin, bacitracin, oxyttracycline
- Treat the anorexia, ruffled feathers, diarrhea
- No vaccine available
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
What is Quail Disease?
- Ulcerative entritis of Wild and Domestic Birds
- Caused by Clostridium colinum
- Secondary to coccidiosis or infectious bursal disease
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
How is Quail Disease treated?
- Tetracyclines in water
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
What is the mode of infection of Tyzzer’s Disease?
- Ingestion of spores
What is the Pathogenesis of Tyzzer’s Disease?
- Invades intestinal epithelial cells - Enteritis, colitis
- Invades hepatic cells - hepatitis
What lesions are present in Tyzzer’s Disease?
- Necrosis
How is Tyzzer’s Disease prevented?
- Tetracycline
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
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
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
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
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.
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
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
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
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
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
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
