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Chapter 11: Spore-Forming Gram-Positive Bacilli: Bacillus and Clostridium Species

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A housewife who lives on a small farm is brought to the emergency department complaining of double vision and difficulty talking. Within the past 2 hours, she noted a dry mouth and generalized weakness. Last night she served home-canned green beans as part of the meal. She tasted the beans before they were boiled. None of the other family members are ill. On examination, there is symmetrical descending paralysis of the cranial nerves, upper extremities, and trunk. The correct diagnosis is which one of the following?

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(A) Tetanus

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(B) Strychnine poisoning

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(C) Botulism

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(D) Morphine overdose

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(E) Ricin intoxication

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Which one of the following is an important virulence factor of Bacillus anthracis?

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(A) Protective antigen

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(B) Lipopolysaccharide

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(C) Pili

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(D) A toxin that inhibits peptide chain elongation factor EF-2

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(E) Lecithinase

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A young man sustains major soft tissue injury and open fractures of his right leg after a motorcycle accident. One day later, he has a temperature of 38°C, increased heart rate, sweating, and restlessness. On examination, the leg is swollen and tense, with thin, dark serous fluid draining from the wounds. The skin of the leg is cool, pale, white, and shining. Crepitus can be felt in the leg. His hematocrit is 20% (~50% of normal), and his circulating hemoglobin is normal. His serum shows free hemoglobin. Which of the following microorganisms is the most likely cause of this infection?

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(A) Clostridium tetani

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(B) Staphylococcus aureus

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(C) Escherichia coli

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(D) Bacillus anthracis

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(E) Clostridium perfringens

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A young man sustains major soft tissue injury and open fractures of his right leg after a motorcycle accident. One day later, he has a temperature of 38°C, increased heart rate, sweating, and restlessness. On examination, the leg is swollen and tense, with thin, dark serous fluid draining from the wounds. The skin of the leg is cool, pale, white, and shining. Crepitus can be felt in the leg. His hematocrit is 20% (~50% of normal), and his circulating hemoglobin is normal. His serum shows free hemoglobin.

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For this patient, which of the following is likely to be responsible for the hemolysis?

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