Enteropathogenic Clostridia Flashcards
What species of Clostridium are enteropathogenic and enterotoxemia producing?
C. perfringens, C. difficile, C. colinum, C. spiroforme, C. piliforme
What are some general characteristics of C. perfringens?
gram positive pleomorphic rods, obligate anaerobes, non-motile, spores of boxcar shaped appearance
What is unique about the structure of C. perfringens?
only clostridium that possesses a capsule
What is the habitat of C. perfringens?
soil, feces, GI tract - invades dead tissue post-mortem
What type of C. perfringens is part of the normal intestinal flora and causes both enterotoxigenic/enteropathogenic and histotoxic infections?
type A
What are some predisposing factors of C. perfringens?
inappropriate husbandry, sudden dietary changes, environmental influences
What are the four major toxins of C. perfringens?
alpha toxin (all strains), beta toxin (B and C strains), epsilon toxin (B and D strains), iota toxin (E strain)
What does alpha toxin of C. perfringens cause?
hemolysis and cell necrosis
What does the beta toxin of C. perfringens cause?
enteritis and contraction of intestinal smooth muscle
What are the epsilon and iota toxins of C. perfringens produced as?
pro-toxins
What are some other virulence factors of C. perfringens?
8 other exotoxins, minor toxins/enzymes, capsule
What is the causative agent of necrotic enteritis (rot gut) in chickens?
C. perfringens type A
How is necrotic enteritis (rot gut) transmitted?
fecal-oral route
What are some predisposing factors of necrotic enteritis (rot gut)?
dietary, mucosal damage, coccidia occurring concurrently
What are some clinical signs of necrotic enteritis (rot gut)?
sudden death, depression, ruffled feathers, diarrhea
How do you diagnose necrotic enteritis (rot gut)?
clinical signs and post-mortem findings, smear and gram-stain of intestinal mucosa, histological findings, isolation of C. perfringens from intestinal contents
How do you treat and control necrotic enteritis (rot gut)?
antibiotics in water, prevent coccidiosis, good diet, isolation of sick animals
What is the causative agent of lamb dysentery?
C. perfringens type B
What are some clinical signs of lamb dysentery?
sudden death with no premonitory signs, abdominal distension, pain, bloody feces
What are some predisposing factors of lamb dysentery?
low proteolytic activity in neonatal intestines, incomplete establishment of normal intestinal flora in neonates, dietary influences in older animals
How do you diagnose lamb dysentery?
clinical signs and post-mortem findings, demonstration of gram-positive rods from intestinal mucosa, anaerobic culture to isolate C. perfringens, ELISA
What are some post-mortem findings of lamb dysentery?
hemorrhagic enteritis with ulceration of small intestine, fluid accumulation in peritoneal cavity and pericardial sac NOTE: no visible external lesions
What is the causative agent of “struck” in sheep?
C. perfringens type C
What is the major toxin of “struck” in sheep?
beta toxin NOTE: causes intestinal inflammation and necrosis
What is the minor toxin of “struck” in sheep?
alpha toxin NOTE: causes hemolysis
What are some clinical signs of “struck” in sheep?
sudden death, acute enterotoxemia in adult sheep, possible terminal convulsions
What are some post-mortem findings of “struck” in sheep?
jejunal ulceration, patchy hyperemia in small intestines, peritonitis
What is the causative agent of hemorrhagic enteritis in pigs?
C. perfringens type C
What is the pathogenesis of hemorrhagic enteritis in pigs?
beta toxin -> binds vascular endothelial cells -> vascular necrosis and necrosis of villi
What are some clinical signs of hemorrhagic enteritis in pigs?
sudden death in newborn piglets, dullness, anorexia, blood-stained feces, perianal hyperemia
What are some post-mortem findings of hemorrhagic enteritis in pigs?
hallmark lesion, necrosis of intestinal mucosa with blood stained contents in small intestines, cecum, and colon, serosanguineous fluid in the pleural and peritoneal cavity
What is the hallmark lesion of hemorrhagic enteritis in pigs?
segmental mucosal necrosis with marked hemorrhage in the small intestine
What is the causative agent of pulpy kidney (over-eating disease)?
C. perfringens type D
What species are mostly affected by pulpy kidney (over-eating disease)?
thriving lambs 3-10 weeks old
What is the predisposition of pulpy kidney (over-eating disease)?
excessive consumption of high grain and low roughage diet, immunocompromised animals, GI parasites, decreased intestinal motility
What is the pathogenesis of pulpy kidney (over-eating disease)?
high starch content -> rapid proliferation of clostridial organisms -> partially digested food from rumen to intestine -> production of epsilon (major) toxin and beta (minor) toxin
What are some of the clinical signs of pulpy kidney (over-eating disease)?
lambs found dead, dullness, opisthotonos, convulsions, coma, blindness, head pressing, bloating in later stages, hyperglycemia and glycosuria
How do you diagnose pulpy kidney (over-eating disease)?
clinical signs and post-mortem findings, toxin neutralization in mice, PCR, ELISA
What are some of the post-mortem findings of pulpy kidney (over-eating disease)?
endocardial hemorrhage and excess pericardial fluid in acute cases, rapid kidney autolysis, focal symmetrical encephalomalacia
How do you diagnose C. perfringens enterotoxemia?
history, direct smears from mucosa or intestines, toxin neutralization tests, ELISA, isolation of C. perfrigens types B and C
T/F: antibiotic therapy is generally effective in the treatment of C. perfringens enterotoxemia
FALSE
How do you treat and control C. perfringens enterotoxemia?
hyperimmune serum, vaccination, avoid sudden dietary changes
What are some diseases associated with C. difficile?
diseases associated with antibiotic use, pseudomembranous colitis, chronic diarrhea in dogs, hemorrhagic enterocolitis in horses, neonatal diarrhea in pigs, nosocomial infection in humans
What is the habitat of C. difficile?
normal flora of the gut
What are some virulence factors of C. difficile?
toxin A (stimulates fluid secretion and diarrhea). toxin B (damages enterocytes in gut causing hemorrhage)
What is the pathogenesis of C. difficile?
antimicrobials cause disruption in normal intestinal flora -> overgrowth of C. difficile from spores -> toxin production and diarrhea
What are some clinical signs of C. difficile?
colic, profuse diarrhea, weakness, dehydration, death can occur in young animals within 24 hours
How do you diagnose C. difficile?
clinical signs and history of antibiotic use, demonstration of toxin in feces using cytotoxicity assays/ELISA, PCR
How do you treat and prevent C. difficile?
metronidazole and amoxicillin in dogs, good antimicrobial prescribing practices, alleviation of stress, cleaning and disinfection
What disease is assoicated with C. colinum?
enteritis in quails, chickens, turkeys, pheasant, and grouse
How is C. colinum transmitted?
via feces of sick and recovered birds
What are some post-mortem findings of C. colinum?
intestinal ulceration and hepatic necrosis
How do you treat and control C. colinum?
antibiotics in drinking water or feed, remove contaminated litter regularly
What disease is associated with C. spiroforme?
spontaneous antibiotic-induced enteritis in rabbits
What are some predisposing factors to C. spiroforme?
oral administration of antibiotics, low-fiber diets
How do you diagnose C. spiroforme?
PCR
How do you treat and control C. spiroforme?
antitoxin
What species is characterized as the atypical clostridium?
C. piliforme
What are some general characteristics of C. piliforme?
gram-variable
What diseases are associated with C. piliforme?
hepatic necrosis (Tyzzer’s disease) in lab animals, sporadic infection leading to coma and death in foals less than 6 weeks old
What are some predisposing factors of C. piliforme?
stress, immunosuppression
What are some clinical signs of C. piliforme?
depression, anorexia, fever, jaundice, diarrhea
What are some post-mortem findings of C. piliforme?
hepatomegaly and hepatic necrosis
How do you diagnose C. piliforme?
histological demonstration in hepatocytes using Warthin-Starry stain, PCR
T/F: C. piliforme is difficult to treat since it presents as acute disease
TRUE
What is the etiological agent involved in causing segmental mucosal necrosis with marked hemorrhage of the small intestine in piglets? a) C. perfringens type A b) C. perfringens type B c) C. perfringens type C d) Salmonella cholerasuis e) E coli
c) C. perfringens type C
What is the etiological agent of pulpy kidney in lambs? a) C. perfringens type B b) C. perfringens type C c) C. perfringens type D d) Salmonella cholerasuis e) E coli
c) C. perfringens type D
What species of Clostridium are histotoxic?
C. chauvoei, C. septicum, C. novyi type A and type B, C. perfringens type A, C. sordelli, C. hemolyticum
What are some general characteristics of histotoxic clostridia?
causes variety of lesions in domestic animals, endospores widely distributed in the environment, bacteria may be produced in wounds and produce exotoxins
How are histotoxic clostridia spores transmitted?
may enter through intestines, latent spores present in tissues can germinate
What disease is C. chauvoei associated with?
blackleg in cattle and sheep
What HISTOTOXIC disease is C. perfringens type A associated with?
gas gangrene
What disease is C. septicum associated with?
braxy (abomasitis) in sheep
When and where is braxy most likely to occur?
winter when heavy frost or snow occurs in Northern Europe
What is the pathogenesis of braxy?
ingestion of frozen herbage -> localized devitalization of abomasal tissue as point of contact with rumen
What are some clinical signs of braxy?
death without premonitory signs. anorexia, depression, and fever shortly before death
How do you diagnose braxy?
fluorescent antibody technique on abomasal lesions
What disease is C. novyi type A associated with?
big head in young rams
What disease is C. novyi type B associated with?
infectious necrotic hepatitis (black disease) in sheep and cattle
What is the pathogenesis of black disease?
migrating parasites damage liver tissue -> spore germinate -> toxins produced -> flukes carry bacteria and/or spores to liver
What are some clinical signs of black disease?
rapid death with no premonitory signs
What is the differential diagnosis of black disease?
acute fasciolosis
What are some post-mortem findings of black disease?
dark discoloration of skin caused by marked venous congestion of SQ tissue
How do you diagnose black disease?
fluorescent antibody technique from liver lesions
What disease is C. hemolyticum (C. novyi type D) associated with?
bacillary hemoglobinuria in cattle and sheep
What is the pathogenesis of bacillary hemoglobinuria?
endospores present in liver -> fluke migration occurs -> beta toxin causes intravascular hemolysis and hepatic necrosis
How do you diagnose bacillary hemoglobinuria?
fluorescent antibody techniqe
What is the protocol for culture of Clostridium spp?
incubate anaerobically with 10% CO at 37ºC for 2-4 days
What are some techniques for laboratory diagnosis of C. perfringens?
samples of pus, necrotic tissue, food, or feces. culture anaerobically at 37º for 24-48 hours. fluorescent antibody technique. nagler reaction. litmus test. reverse CAMP test
What types of media can be used for the laboratory diagnosis of C. perfringens?
blood, chocolate, phenyl ethyl acohol agar, robertson cooked meat (RCM) broth or thioglycolate broth
What is the nagler reaction?
plate neutralization test used to identify lecithinase activity of alpha toxin of C. perfringens
What is the protocol for the nagler reaction?
culture on egg yolk medium and add alpha antitoxin to 1/2
What does the litmus test indicate?
lactose fermentation, litmus reduction, gas and clot production
What is the protocol for the reverse CAMP test?
streak S. agalactiae across BAP, streak suspected C. perfringens at right angle of S. agalactiae without touching, incubate, observe for bow tie zone of hemolysis toward S. agalactiae
