Fox J, Barthold S, Davisson M, Newcomer C, Quimby F, Smith A, eds. 2006. The Mouse in Biomedical Research, 2nd edition Elsevier Academic Press, San Diego, CA.

Volume 2 - Diseases Chapter 14 Clostridial Species pp. 349-363

QUESTIONS 1. Which of the following is false regarding the morphology of clostridia? a. Rod-shaped b. 8-12 µm long c. Shape, size & location of the endospore in a mother cell can be used to ID the species d. Very few are motile and have peritrichous flagella 2. Which of the following culture conditions is required for in vitro growth of most clostridia? a. anaerobic environment b. 42°C incubation c. nutrient-free media d. aerobic environment 3. T/F: Over 100 species of clostridia has been associated with disease in animals. 4. Match the following clostridial species with their type of disease: a. neurotoxic b. histotoxic c. enterotoxic d. sporadic disease 1. C. tetani 5. C. difficile 2. C. chauvoei 6. C. septicum 3. C. spiriforme 7. C. botulinum 4. C. perfringens 8. C. piliforme 5. Which of the following is known to cause naturally occurring disease in mice? a. C. botulinum b. C. tetani c. C. chauvoei d. C. piliforme 6. Give the scientific name of the Japanese waltzing mouse. 7. Which of the following is true regarding Clostridium piliforme? a. First described by Ernest Tyzzer in 1917 b. Previously named Bacillus piliformis c. Causes “Tyzzer’s disease” d. All of the above 8. T/F: CBA/N, nude, ICR, and DBA/2 have increased susceptibility to C. piliforme infection. 9. Clinical signs and pathologic changes associated with C. piliforme infection include a. Sudden death b. Watery to pasty diarrhea c. Grayish-white foci of necrosis in the liver d. Reddening of the ileum and large intestine e. All of the above 10. T/F: C. piliforme clusters are characteristically found within the cytoplasm of mucosal epithelial cells. 11. T/F: Only the vegetative forms of C. piliforme are found in the tissues. 12. T/F: Neutrophils are common in early but rare in late C. piliforme hepatic lesions. 13. Which child’s toy does C. piliforme resemble when seen histologically with the Warthin- Starry silver stain? a. Marbles b. Legos c. Pickup sticks d. Jax 14. Which of the following statements about C. piliforme pathogenesis is false? a. The mechanism of cell entry is by bacterially directed phagocytosis. b. Invasion of primary mouse hepatocyte cultures can be suppressed by cytochalasin D. c. Invasion of primary mouse hepatocyte cultures can be markedly suppressed by vinblastine. d. Depletion of neutrophils or natural killer cells increases the severity of experimentally induced disease. 15. T/F: C. piliforme is potentially zoonotic to immunocompromised individuals. 16. What is the stain of choice for demonstrating C. piliforme in tissue sections? 17. T/F: C. piliforme rapidly disappears from tissues following the death of the host. 18. Which C. perfringens type causes gangrene in humans and other animals? 19. T/F: Unlike other clostridia, C. perfringens is nonmotile. 20. T/F: C. perfringens enterotoxin is released with the bacterial spore after lysis and is primarily produced by C. perfringens type A. 21. Which of the following necropsy findings would be expected with C. perfringens infection? a. Enlarged, gas-filled small and large intestines b. Hyperemic intestinal mucosa c. Presence of pseudomembranes d. All of the above e. None of the above 22. T/F: C. perfringens can be a part of the normal microbiota in man and domestic animals. 23. Match the following C. perfringens toxin with the type that produces it. (There may be more than one type per toxin.) Toxin: α, , ,  Type: A, B, C, D, E 24. Three of the four major C. perfringens toxins act on the cell membrane to cause membrane disruption or pore formation. Which is the fourth that instead acts inside the cell to cause depolymerization of actin filaments? a. α b.  c.  d.  25. Match the following C. perfringens types (A-E) with the diseases they are known to cause: a. A b. B c. C d. D e. E 1. Hemorrhagic enteritis in calves 7. Enterotoxemia in calves and goats 2. Necrotic enteritis in chickens 8. Necrotizing enterocolitis in piglets 3. Canine hemorrhagic gastroenteritis 9. Sudden death in goats and feedlot cattle 4. “Struck” in adult sheep 10. Hemorrhagic enteritis in neonatal piglets 5. Pulpy kidney in sheep 11. Enteritis in rabbits 6. Lamb dysentery 26. T/F: Inability to detect C. perfringens toxins in fecal contents refutes a diagnosis of clostridial disease. 27. T/F: C. difficile has been implicated in antibiotic-associated colitis in humans, Syrian hamsters, guinea pigs, rabbits, prairie dogs, and ostriches. 28. Which of the following bacterial properties apply to C. difficile? a. Strict anaerobe b. Non-motile c. Gram negative d. All of the above e. None of the above 29. What are the major enterotoxins produced by C. difficile? 30. Describe the clinical signs and gross necropsy findings of C. difficile-associated disease in hamsters. 31. Histopathologic lesions found in hamsters with C. difficile-associated disease include a. Vascular congestion in the distal ileum, cecum, and colon b. Accumulation of acute inflammatory cells in the lamina propria of the mucosa c. Edema-distended villus tips d. Focal erosion of the mucosal surface e. All of the above 32. T/F: C. difficile is highly tissue invasive, but only non-toxigenic strains are associated with disease. 33. C. difficile Toxin A / Toxin B is believed to play the more critical role in disease pathogenesis. 34. Important practices in the prevention of clostridial infection in mouse colonies are a. Good sanitation and maintaining strict husbandry practices b. Avoidance of sudden dietary changes and other stressors c. Judicious use of antibiotics d. All of the above

ANSWERS 1. d. – A majority of clostridia have peritrichous flagella and are motile. 2. b. 3. F – less than 20 species 4. 1-a, 2-b, 3-d, 4-c, 5-d, 6-b, 7-a, 8-d 5. d. 6. Mus bactrianus 7. d. 8. T 9. e. 10. T 11. F – both vegetative and spore forms can be found in the tissues 12. T 13. c. 14. b. – invasion enhanced by the addition of cytochalasin D 15. T 16. silver stain (Warthin-Starry or Steiner’s) 17. T 18. type A 19. T 20. T 21. d. 22. T 23. α – A-E;  - B, C;  - B, D;  - E 24. d. 25. a – 2, 3, 8; b – 1, 6; c – 2, 4, 9, 10; d – 5, 7; e – 1, 11 26. F – because clostridial toxins tend to be labile 27. T 28. a. – C. difficile is anaerobic, motile, and Gram positive to Gram variable. 29. Toxin A and Toxin B 30. Clinical – anorexia, ruffled fur, dehydration, diarrhea, soiled perianal fur Gross – hemorrhagic ileocolitis 31. e. 32. F – C. difficile is not tissue invasive, and only toxigenic strains are associated with disease. 33. Toxin A 34. d.