Microorganisms and Disease
Type III secretion systems are used to inject "effector" proteins directly into a host cell. Salmonella uses a type III secretion system to help the pathogen to

survive the acid pH of the stomach
secrete LT (heat labile toxin) and ST (heat stable toxin) into the lumen of the intestine
activate T cells to proliferate and secrete cytokines
survive within macrophages

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Microorganisms and Disease
Which of the following is common in the disease caused by Coryne-bacterium diphtheriae and Bacillus anthracis?

Both organisms are gram-positive spore formers
The most serious disease symptoms are the direct result of toxin action
Both organisms cause skin and respiratory tract infections
Diphtheria toxin and edema toxin are ADP ribosylating toxins

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Microorganisms and Disease
A major difference between EHEC and EPEC is

EPEC passes through the placenta to infect the fetus and EHEC does not
EHEC possesses a type III secretion system and EPEC does not
EHEC secretes a Shiga-like toxin and EPEC does not
EPEC rearranges host cell actin and EHEC does not

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Microorganisms and Disease
The influenza vaccine is administered each year because

the vaccine is sufficiently toxic to make it necessary to administer only a small amount at any one time
None of these
it is a polysaccharide vaccine that does not confer long-term protection
mutations in the viral hemagglutinin may allow the virus to evade the immune response elicited by previous vaccines

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Microorganisms and Disease
Plastic implants can pose a serious nosocomial infection problem because

phagocytes have trouble moving on the plastic surface
infected implants usually have to be surgically removed
phagocytes have trouble engulfing bacteria embedded in a biofilm
All of these

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