Which of the following best describes the mechanism of actionof diphtheria toxin?
A. Forms pores in red blood cells causing hemolysis
B. Degrades lecithin in eukaryotic cell membranes
Causes release of tumor necrosis factor
D. Inhibits elongation factor 2
E. Causes increased adenylate cyclase activity
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Which of the following statements correctly describes enterotoxins?
A. They are not produced bySalmonella species
B. They are not produced byEscherichia coli
C. They stimulate adenyl cyclase
D. They are not antigenic
E. They contain lipid A
All of the following statements concerning endotoxins of gram-negative bacteria are true EXCEPT that ( )
A. they differ markedly in their toxicity according to their specific bacterial origins
B. they are found in the blood of patients suffering from endotoxic shock
C. they consist mainly of lipopolysaccharide complexes
D. they induce the release of endogenous pyrogens from leukocytes
E. they are found only in gram-negative bacteria
Which of the following statements is true?
A. Endotoxins produce varied effects such as neurotoxic or protein inhibition effects, but exotoxins produced generalized irritation and inflammation of epithelial surfaces
B. Endotoxins are found attached to the cell wall of certain bacteria, but exotoxins are secreted toxins that may exhibit their effect independently of the presence of the bacteria
C. Endotoxins include the neurotoxins of botulism and tetanus, while exotoxins include the enterotoxin of Staphylococcus aureus
D. More than one of the above statements is true
E. None of the above is true
The ability of a microbial species to cause disease is its ( )
A. pathogenicity
B. cuteness
C. mutation
D. infectious index
E. communicability
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