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
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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.
The process by which microorganisms attach themselves to hostcells is _____________.
A. Infection
B. contamination
C. disease
D. adhesion
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