Quiz 1

Question 1

Which of the following archaea are opportunistic pathogens of humans?

Answer 1

No archaea

Question 2

Which of the following act as barrier defenses against the entry of pathogens into the body?

Answer 2

skin, mucus, ciliated epithelial, and stomach acid

Question 3

Cholera toxin is an example of a cytotonic enterotoxin. What is a cytotonic enterotoxin?

Answer 3

an exotoxin that alters the function of the cells in the Gi tract but does not kill them

Question 4

Certain organisms, for example, Salmonella type, are able to establish a state of chronic carriage in some individuals. What does chronic carriage mean?

Answer 4

individuals are carriers of the pathogen. colonization or inapparent infection is permanent.

Question 5

Which of the following are is/are clinical signs of disease?

Answer 5

Clinical signs of disease are effects that a clinical can measure or observe during a physical exam such as temperature, blood pressure, etc. Not headache, myalgia, and nausea

Question 6

The Gram positive bacterium, Clostridium difficile, an obligate anaerobe, can give rise to endogenous infections that result in antibiotic associated gastrointestinal disease. Which of the following statements about C. diff is/are correct?

Answer 6

Endogenous infections caused by opportunistic pathogens. Must be able to colonize healthy humans. Not always associated with disease. Can only grow in the absence of oxygen.

Question 7

What kind of relationship does a commensal microbe have with its host

Answer 7

microbe benefits. host is neither helped nor harmed

Question 8

What happens when a pathogen infects a dead end host

Answer 8

disease may be caused and the pathogen cannot be transmitted

Question 9

Diphtheria toxin is an example of a cytolytic toxin. What is a cytolytic toxin?

Answer 9

one that kills the host cell

Question 10

What class of microbial pathogens causes the most endogenous infections of humans

Answer 10

fungi and bacteria

Question 11

Which of the following is/are characteristics of organisms that establish exogenous infections in humans?

Answer 11

come from outside the host. all obligate many opportunistic

Question 12

Which of the following are characteristics of a facultative intracellular pathogen?

Answer 12

disseminate inside infective host cells. use transcytosis as a mechanism for invasion. Can grow inside host cells if the opportunity presents itself, but they can grow outside host cells as well.

Question 13

excessive cytokine production causes which of the following immunopathologies?

Answer 13

chronic inflammation, delayed type hypersensitivity, and toxic shock syndrome

Question 14

The gram-negative bacterium, Campylobacter jejune is generally considered to have a low infective dose in humans. what odes it mean to have a low infective dose

Answer 14

only a few organisms required to cause disease

Question 15

Which of the following mechanisms for local invasion of tissues potentially could be employed by an obligate extracellular pathogen

Answer 15

secrete hyaluronidase to break down extracellular matrix, produce exotoxins to kill or disable the host.

Question 16

Which of the following types of clinical specimens would not normally contains microorganisms?

Answer 16

blood, CSF, joint fluid, chest fluid

Question 17

The gram-positive, spore-forming bacterium Bacillus anthracis is an obligate pathogen of humans. What is an obligate pathogen?

Answer 17

an organism that when found in humans always causes disease

Question 18

In the context of med micro, what does the term parasite refer to?

Answer 18

any non-fungal eukaryote that causes disease

Question 19

Which of the following may be consequences of a failure of the immune system to resolve an infection?

Answer 19

host may die, pathogen may establish persistent or latent infection, chronic carriage.

Question 20

Which of the following are routes by which pathogens can potentially disseminate within the body

Answer 20

blood, lymph, nerves.

Question 21

When present in a bacterium, which of the following could be virulence factors?

Answer 21

adhesins, cytolytic exotoxins, proteases, and phospholipases

Question 22

Which of the following are virulence factors commonly found among protozoans parasites?

Answer 22

adhesins, proteases, and phospholipases

Question 23

Among viruses that commonly cause human disease, which of the following virus-host interactions result in active replications and production of new virus particles

Answer 23

persistent infection and lytic infection

Question 24

Which of the following are possible outcomes or viral infection with a cell?

Answer 24

failed, latent infection, persistent infection without cell death, lytic infection leading to cell death.

Question 25

Which of the following are predisposing factors that would make an opportunistic pathogen more likely to cause disease?

Answer 25

virulence factors, large number of individual microbes enter the body, microbe gains access to NSS, and the host has a weakened immune system.