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Chapter 12: Aerobic Non–Spore-Forming Gram-Positive Bacilli: Corynebacterium, Listeria, Erysipelothrix, Nocardia, and Related Pathogens

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Three months ago, a 53-year-old woman had surgery and chemotherapy for breast cancer. Four weeks ago, she developed a cough occasionally productive of purulent sputum. About 2 weeks ago, she noted a slight but progressive weakness of her left arm and leg. On chest examination, rales were heard over the left upper back when the patient breathed deeply. Neurologic examination confirmed weakness of the left arm and leg. Chest radiography showed a left upper lobe infiltrate. Contrast-enhanced computed tomography showed two lesions in the right hemisphere. Gram stain of a purulent sputum specimen showed branching gram-positive rods that were partially acid fast. Which of the following organisms is the cause of this patient’s current illness?

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(A) Actinomyces israelii

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(B) Corynebacterium pseudodiphtheriticum

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(C) Aspergillus fumigatus

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(D) Nocardia farcinica

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(E) Erysipelothrix rhusiopathiae

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Three months ago, a 53-year-old woman had surgery and chemotherapy for breast cancer. Four weeks ago, she developed a cough occasionally productive of purulent sputum. About 2 weeks ago, she noted a slight but progressive weakness of her left arm and leg. On chest examination, rales were heard over the left upper back when the patient breathed deeply. Neurologic examination confirmed weakness of the left arm and leg. Chest radiography showed a left upper lobe infiltrate. Contrast-enhanced computed tomography showed two lesions in the right hemisphere. Gram stain of a purulent sputum specimen showed branching gram-positive rods that were partially acid fast.

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The drug of choice to treat this patient’s infection is

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(A) Penicillin G

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(B) Trimethoprim–sulfamethoxazole

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(C) Gentamicin

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(D) Amphotericin B

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(E) A third-generation cephalosporin

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It is particularly difficult to differentiate Erysipelothrix rhusiopathiae from

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(A) Corynebacterium diphtheriae

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(B) Bacillus cereus

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(C) Actinomyces israelii

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(D) Nocardia asteroides

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(E) Lactobacillus species

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Movement of Listeria monocytogenes inside of host cells is caused by

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(A) Inducing host cell actin polymerization

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(B) The formation of pili (fimbriae) on the listeriae surface

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(C) Pseudopod formation

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(D) The motion of ...

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