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
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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.
Which of the following is false concerning microbial contaminants?
A. Contaminants may become opportunistic pathogens.
B. Most microbial contaminants will eventually cause harm.
Contaminants may be a part of the transient microbiota.
D. Contaminants may be introduced by a mosquito bite.
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