Which bacterial enzyme of following ones is not associated with invasion?
A. Hyaluronidase;
B. beta-lactamases
C. IgA proteinase
D. staphylokinase
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The nature of bacterial capsules is to __________________.
A. cause widespread blood clotting;
B. allow phagocytes to engulf these bacteria;
C. affect the virulence of these bacteria;
D. have no effect on the virulence of bacteria
Which one of the following pathogens are most likely to cause severe infectious disease?
A. opportunistic pathogens in a weakened host;
B. pathogens lacking the enzyme kinase;
C. pathogens lacking the enzyme collagenase;
D. highly virulent microorganisms
Which is not the condition for the opportunist to cause diseases?
A. Phagocytes activated by Lipid A.
B. Immune cells are killed by chemotherapy against tumor;
C. long term and large doses antibiotics taken;
D. Change of inhabiting sites;
In which type of symbiosis does one member get benefit from itshost, causing harm to another member. ?
A. Mutualism
B. parasitism
C. commensalism
D. all above.
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