Microorganisms and Disease
Pseudomembraneous colitis is

caused by a spore-forming bacterium
caused by a gram-positive bacterium
precipitated by the use of certain antibiotics
All of these

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Microorganisms and Disease
Cholera toxin is an A-B type toxin in which the B portions bind to a receptor on a host cell and the A portion enters the cell to cause

ADP ribosylation of a G protein that locks it into an active form that stimulates adenylate cyclase to make cAMP
ADP ribosylation of guanylate cyclase that stimulates production of cGMP
cleavage of rRNA that results in disruption of ribosome function
ADP ribosylation of adenylate cyclase that stops production of cAMP

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Microorganisms and Disease
Prontosil is

an effective antibacterial when used in in-vitro cultures
an effective antibacterial when used in animals
an effective antibacterial both in animals as well as in in-vitro cultures
not used as an antibacterial agent

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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
What is common in catheters and ventilators?

They predispose patients to viral rather than bacterial infections
They are used primarily in neonatal intensive care units
They bypass important defenses of the body
Bacteria responsible for associated infections are usually susceptible to antibiotics

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