Question 1

Bacteria such as E. coli and Salmonella produce invasins that bind host cells, thus causing the cells to

Accepted Answer

A)   destroy the bacteria.
B)   release TNF.
C)   engulf the bacteria.
D)   produce iron-binding proteins.
E)   release cytokines.F) B) and C)
G) None of the above

Question 2

The M protein enhances the virulence of Streptococcus by preventing phagocytosis.

Accepted Answer

A) True 
 B)False

Question 3

All of the following are methods of avoiding host antibodies EXCEPT

Accepted Answer

A)   membrane-disrupting toxins.
B)   antigenic changes.
C)   inducing endocytosis.
D)   IgA proteases.
E)   invasins.F) C) and E)
G) All of the above

Question 4

Twenty-five people developed symptoms of nausea, vomiting, and diarrhea three to six hours after attending a church picnic where they ate a ham and green bean casserole with cream sauce. The most likely cause of this case of food intoxication is

Accepted Answer

A)   erythrogenic toxin.
B)   aflatoxin.
C)   cholera toxin.
D)   staphylococcal enterotoxin.
E)   botulinum toxin.F) C) and D)
G) None of the above A

Question 5

Which of the following cytopathic effects is cytocidal?

Accepted Answer

A)   inclusion bodies
B)   giant cells
C)   transformation
D)   release of enzymes from lysosomes
E)   antigenic changesF) D) and E)
G) C) and D)

Question 6

Endotoxins are

Accepted Answer

A)   A-B toxins.
B)   associated with gram-positive bacteria.
C)   part of the gram-negative cell wall.
D)   excreted from the cell.
E)   molecules that bind nerve cells.F) A) and E)
G) A) and D)

Question 7

Nonpathogenic Vibrio cholerae can acquire the cholera toxin gene by

Accepted Answer

A)   infecting a pathogenic Vibrio cholerae.
B)   transduction.
C)   transformation.
D)   conjugation.
E)   phagocytosis.F) B) and E)
G) D) and E)

Question 8

The Limulus amoebocyte assay is used to detect minute amounts of endotoxin in drugs and medical devices.

Accepted Answer

A) True 
 B)False

Question 9

Injectable drugs are tested for endotoxins by

Accepted Answer

A)   culturing bacteria.
B)   the Limulus amoebocyte lysate test.
C)   filtering out the cells.
D)   looking for turbidity.
E)   counting the viable bacteria.F) B) and E)
G) None of the above

Question 10

Polio is transmitted by ingestion of water contaminated with feces containing polio virus. What portal of entry does polio virus use?

Accepted Answer

A)   skin only
B)   parenteral only
C)   mucous membranes only
D)   skin and parenteral
E)   skin, parenteral, and mucous membranesF) A) and D)
G) B) and E)

Question 11

Which of the following does NOT contribute to the symptoms of a fungal disease?

Accepted Answer

A)   capsules
B)   metabolic products
C)   cell walls
D)   allergic response of the host
E)   toxinsF) A) and B)
G) A) and C)

Question 12

Symptoms of intense inflammation and shock occur in some gram -positive bacterial infections due to

Accepted Answer

A)   lipid A.
B)   superantigens.
C)   A-B toxins.
D)   membrane-disrupting toxins.
E)   erythrogenic toxin.F) B) and E)
G) C) and D)

Question 13

In general, the LD50 for exotoxins is much greater than the LD50 for endotoxins.

Accepted Answer

A) True 
 B)False

Question 14

Patients developed inflammation a few hours following eye surgery. Instruments and solutions were sterile, and the Limulus assay was positive. The patientsʹ inflammation was due to

Accepted Answer

A)   bacterial infection.
B)   exotoxin.
C)   endotoxin.
D)   viral infection.
E)   The answer cannot be determined based on the information provided.F) D) and E)
G) A) and D)

Question 15

Siderophores are bacterial proteins that compete with the hostʹs

Accepted Answer

A)   red blood cells.
B)   white blood cells.
C)   iron-transport proteins.
D)   antibodies.
E)   receptors.F) None of the above
G) A) and E) C

Question 16

Biofilms provide pathogens with an adhesion mechanism and aid in resistance to antimicrobial agents.

Accepted Answer

A) True 
 B)False

Question 17

Ergot and aflatoxin are toxins sometimes found in grains contaminated with fungi.

Accepted Answer

A) True 
 B)False  True

Question 18

Superantigens produce intense immune responses by stimulating lymphocytes to produce

Accepted Answer

A)   leukocidins.
B)   cytokines.
C)   endotoxins.
D)   interferons.
E)   exotoxins.F) A) and C)
G) B) and D)

Question 19

In A-B exotoxins, the A component binds to the host cell receptor so that the B component can enter the cell.

Accepted Answer

A) True 
 B)False

Question 20

All of the following bacteria release endotoxin EXCEPT

Accepted Answer

A)   Proteus vulgaris.
B)   Clostridium botulinum.
C)   Salmonella typhi.
D)   Neisseria meningitidis.
E)   Haemophilus influenzae.F) A) and E)
G) D) and E)

Exam 15: Microbial Mechanisms of Pathogenicity

Bacteria such as E. coli and Salmonella produce invasins that bind host cells, thus causing the cells to

Correct AnswerverifiedShow Answer

The M protein enhances the virulence of Streptococcus by preventing phagocytosis.

Correct AnswerverifiedShow Answer

All of the following are methods of avoiding host antibodies EXCEPT

Correct AnswerverifiedShow Answer

Twenty-five people developed symptoms of nausea, vomiting, and diarrhea three to six hours after attending a church picnic where they ate a ham and green bean casserole with cream sauce. The most likely cause of this case of food intoxication is

Correct AnswerverifiedA

Which of the following cytopathic effects is cytocidal?

Correct AnswerverifiedShow Answer

Endotoxins are

Correct AnswerverifiedShow Answer

Nonpathogenic Vibrio cholerae can acquire the cholera toxin gene by

Correct AnswerverifiedShow Answer

The Limulus amoebocyte assay is used to detect minute amounts of endotoxin in drugs and medical devices.

Correct AnswerverifiedShow Answer

Injectable drugs are tested for endotoxins by

Correct AnswerverifiedShow Answer

Polio is transmitted by ingestion of water contaminated with feces containing polio virus. What portal of entry does polio virus use?

Correct AnswerverifiedShow Answer

Which of the following does NOT contribute to the symptoms of a fungal disease?

Correct AnswerverifiedShow Answer

Symptoms of intense inflammation and shock occur in some gram -positive bacterial infections due to

Correct AnswerverifiedShow Answer

In general, the LD50 for exotoxins is much greater than the LD50 for endotoxins.

Correct AnswerverifiedShow Answer

Patients developed inflammation a few hours following eye surgery. Instruments and solutions were sterile, and the Limulus assay was positive. The patientsʹ inflammation was due to

Correct AnswerverifiedShow Answer

Siderophores are bacterial proteins that compete with the hostʹs

Correct AnswerverifiedC

Biofilms provide pathogens with an adhesion mechanism and aid in resistance to antimicrobial agents.

Correct AnswerverifiedShow Answer

Ergot and aflatoxin are toxins sometimes found in grains contaminated with fungi.

Correct AnswerverifiedTrue

Superantigens produce intense immune responses by stimulating lymphocytes to produce

Correct AnswerverifiedShow Answer

In A-B exotoxins, the A component binds to the host cell receptor so that the B component can enter the cell.

Correct AnswerverifiedShow Answer

All of the following bacteria release endotoxin EXCEPT

Correct AnswerverifiedShow Answer

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C

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True

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