超星 - 球菌--章节练习

单选题

The exfoliative toxins, TSST-1, and the enterotoxins are all superantigens. The genes for these toxins are

A. Present in all strains of Staphylococcus aureus
B. Widely distributed on the staphylococcal chromosome
C. On both the staphylococcal chromosome (TSST-1 and exfoliative toxins) and on plasmids (enterotoxins)
D. On the staphylococcal chromosome in a pathogenicity island
E. On plasmids

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单选题

Which of the following statements regarding the role of protein A in the pathogenesis of infections caused by Staphylococcus aureus is correct?

A. It is responsible for the rash in toxic shock syndrome
B. It converts hydrogen peroxide into water and oxygen
C. It is a potent enterotoxin
D. It is directly responsible for lysis of neutrophils
E. It is a bacterial surface protein that binds to the Fc portion of IgG1

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单选题

S. pneumoniae can be part of the normal flora of 5–40% of people. At what anatomic site can it be found?

A. Conjunctiva
B. Nasopharynx
Colon
D. Urethra
E. Vagina

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单选题

Enterococci can be distinguished from nonenterococcal group D streptococci on the basis of which of the following characteristics?

A. γ-Hemolysis
B. Esculin hydrolysis
C. Growth in 6.5% NaCl
D. Growth in the presence of bile
E. Gram stain morphology

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