C. perfringens: general Enteric Clostridia Formerly called C. welchii Thick rods, forming spores Non motile Grow fast Habitats: Soil and sewage and in the intestines of animals and humans Double zone hemolysis on BA Toxins More than 15 have been reported 4 toxins (α, β, ε, ι) are major their functions are described in Table 33-4 Five types (A to E) of C. perfringens based on production of 4 toxins (α, β, ε, ι) Double zone hemolysis C. perfringens: Types & toxins C. perfringens: Types & toxins Type Major toxins Diseases α β ε ι A X Myonecrosis and gas gangrene (humans and domestic animals) * Lamb enterotoxemia (yellow lamb disease) Necrotic enteritis (chickens) Necrotizing enterocolitis (pigs) Hemorrhagic diarrhea (dogs) B X X X Lamb dysentery Hemorrhagic diarrhea (calves and foals) C X X Hemorrhagic nectrotic enteritis and enterotoxemia (Neonatal pigs, calves, lambs, and goats) Enterotoxemia called struck (adult sheep) Necrotic enteritis (chickens) Enterotoxemia known as overeating disease or pulpy D X X kidney disease (sheep) Enterotoxemia (sucking claves) E X X Enterotoxemia (lambs, calves, and rabbits) *Type A is histotoxic & enteric 1
C. perfringens type A : Histotoxic & Enteric Toxin: α-toxin (produces large amounts of α-toxin, compared to other types) Histotoxic: Myonecrosis and gas gangrene in humans and animals (a frequent cause of human myonecrosis) Enteric Type A Lambs: Enterotoxemia (Yellow lamb disease) - Ingestion of contaminated colostrum High mortality in lambs during the first week of life - Affected animals exhibit anemia, icterus, Icterus and hemoglobinuria of the gums - Dying rapidly Neonatal piglets: Necrotizing enterocolitis Neonatal foals: Hemorrhagic diarrhea Icterus of the eyes Domestic poultry: Necrotic enteritis Dogs: Hemorrhagic gastroenteritis (watery to bloody diarrhea) C. perfringens type A: Gas gangrene (histotoxic) C. perfringens types B&C C. perfringens type C Type B (α, β, ε toxins) Lamb dysentery - Bacterial multiplication toxin production enterotoxemia - Severe abdominal pain, bloody diarrhea, sudden death - Very rare in Canada Calves, foals and goats: hemorrhagic enteritis Type C (α, β toxins) Newborn animals are typically susceptible due to the absence of normal intestinal flora - Neonatal pigs, calves, lambs, foals and goats: hemorrhagic necrotic enteritis and enterotoxemia Older animals: alteration of flora (e.g. by sudden dietary change) Adult sheep: enterotoxemia (called struck ), sudden death Chickens: Necrotic enteritis 2
C. perfringens types D&E Type D (α, ε toxins) Sheep: enterotoxemia known as overeating disease or pulpy kidney disease Excess dietary starch (by overeating) Rapid multiplication of type D Increases production of the ε toxin results in toxemia Suddenly die without obvious symptoms Suckling calves: enterotoxemia Rare in adult cattle, deer, and horses C. perfringens: Treatment Vaccination Toxoids are routinely used Type C or D toxoids: newborns of several species Type D: used routinely in lambs e.g. Toxoids of C. perfringens (type D) Pulpy kidney C. septicum Malignant edema, Braxy C. tetani Tetanus C. novyi (type B) Black disease C. chauvoei Blackleg Intervet Type E (α, ι toxins) Lambs, calves, and rabbits: enterotoxemia Toxin: ι-toxin is the major C. perfringens from jejunum In pulpy kidney Treatment: Dogs:tylosin or metronidazole Rapid course little benefit to treatment C. perfringens: Humans Gas gangrene (histotoxic) C. perfringens type A is the major cause of gas gangrene in humans Food poisoning C. perfringens type A causes a mild form of food poisoning Multiplication of bacteria to high numbers in foods toxin production Necrotizing enteritis C. perfringens type C is responsible for this disease The disease is similar to necrotizing enteritis seen in animals Occurs in adults as well as children More severe than food poisoning A large rod Spore-forming Habitats: soil, marine sediment, feces of humans and animals C. difficile: General The organism can multiply to large numbers and causes diarrhea primarily in: 1. Unfilled bowel (neonates, infants, gnotobiotic animals) e.g. Neonatal swine 2. Emptied bowel (by antibiotic-therapy) e.g. Antibiotic-treated humans and animals Toxins Toxin A (enterotoxin) causes fluid accumulation in the gut Toxin B (cytotoxin) induces inflammation and necrosis 3
C. difficile: Age & Diarrheal Disease in Pigs C. difficile: Lesion Distribution Bacterial Diseases Nursing Weaning Growing- Finishing or Breeding C. difficile +++ + + C. perfringens type C enteritis ++ - - E. coli +++ +++ - Intestinal spirochetosis (Brachyspira pilosicoli) Porcine proliferative enteritis (Lawsonia intracellularis) - ++ +++ - ++ +++ Salmonella enteritis + ++ +++ Swine dysentery (Brachyspira hyodysenteriae) + + +++ Keel M K, Songer J G Vet Pathol 2006;43:225-240 C. difficile: Pigs Associated with the diarrhea in neonatal pigs (1 to 7 days of age) Mesocolon Disease: a common cause of mesocolonic edema Clinical signs - difficult breathing - abdominal distention, - diarrhea (but, may not be present in all infected pigs) Diagnosis Demonstration of either toxin A or B (ELISA, PCR) Culture Treatment Based on MIC, erythromycin, tetracycline, tylosin may be useful for treatment of suckling piglets C. difficile: Pigs Release of neutrophils into the lumen: volcano lesion in colon; neonatal pig with C. difficile-associated disease. Keel M K, Songer J G Vet Pathol 2006;43:225-240 4
C. difficile: Horses Habitats Often found in the feces of young foals but infrequently in normal horses Soil Disease Associated with changes in diet and antimicrobial therapy Neonatal foals: hemorrhagic necrotizing enterocolitis Adult horses: diarrhea Diagnosis History of antibiotic treatment Detection of toxins A and/or B (PCR or ELISA) Vaccination: No vaccine is available Treatment: metronidazole C. difficile: Humans and other animals Humans A cause of diarrhea in association with antibiotic treatment - responsible for about 25% of all antibiotic-associated diarrhea Other animals There is some evidence that it may be a problem in hamsters, rabbits and Guinea pigs Colon distended by fluid Adult hamster with C. difficileassociated disease Congested and distended cecum C. colinum Ulcerative enteritis of quail & chickens Often occurring in quail Also seen in a variety of wild and domestic avian species Birds younger than 3 months are commonly infected Disease Oral transmission Cause duodenal hemorrhagic enteritis, cecal necrosis and ulceration Mortality: 10-30% in chickens and 100% in young quail C. spiroforme Loosely coiled, spiral morphology Cause enterotoxemia of rabbits and other laboratory rodents - not found normally in the rabbit intestine but acquired from the environment Weaning and antibiotic treatment destabilize cecal flora rapid diarrhea development death The cecum is immensely dilated with watery contents 5
C. piliforme Gram-negative: the only gram-negative Clostridium Obligate intracellular Enterohepatic disease (Tyzzer's disease) A wide range of animals (such as rabbits, mice, rats, foals, guinea pigs, etc) often in young and stressed animals Necrotic and hemorrhagic enteritis Hepatitis, multifocal hepatic necrosis Severe diarrhea, depression, fever, anorexia High mortality Diagnosis Obligate intracellular parasite Hard to classify it due to the problems in growth Histopathology PCR Treatment: The disease is too acute to administer specific therapy 6