Deck 21: Survival in the Host

Question 1

What is the primary effect of lipopolysaccharide (LPS)on the host?

A) Attacks cells of the immune system.
B) Triggers an intense inflammatory response.
C) Acts as a neurotoxin.
D) Causes diarrhea.
E) Lyses epithelial cells.

Answer 1

B

Question 2

Which component of lipopolysaccharide is responsible for inducing a strong inflammatory response?

A) phospholipid
B) lipid A
C) core polysaccharide
D) O-antigen
E) teichoic acid

Answer 2

B

Question 3

Select the example of a virulence factor that does not directly cause damage to host cells but elicits a strong,damaging inflammatory host response.

A) immunoglobulin protease
B) endotoxin
C) cytotoxin
D) fimbriae
E) urease

Answer 3

B

Question 4

Perfringolysin is produced by Clostridium perfringens.What is its mechanism to cause lysis?

A) Through pore formation within the host cell membrane.
B) By disruption of protein synthesis.
C) By disruption of membrane synthesis.
D) Through the breakdown of membrane phospholipids.
E) By destroying host cell membrane proteins.

Question 5

Which of these bacteria causes gangrene?

A) Pseudomonas aeruginosa
B) Corynebacterium diphtheriae
C) Staphylococcus aureus
D) Clostridium perfringens
E) Bacillus subtilis

Question 6

Lipoteichoic acids are associated with which of these bacteria?

A) Staphylococcus aureus
B) Escherichia coli
C) Shigella sonnei
D) Klebsiella pneumoniae
E) Neisseria gonorrhoeae.

Question 7

Listeriolysin is a cytolysin produced under acidic conditions by Listeria monocytogenes.What does this exotoxin allows the pathogen to do?

A) lyse lymphocytes
B) invade epithelial cells
C) escape the endosome to avoid digestion
D) lyse macrophages
E) lyse neurons

Question 8

Which of these virulence factors is NOT possessed by the pathogen Neisseria gonorrhoeae?

A) Fimbriae for attachment.
B) Secretory IgA protease.
C) Production of urease.
D) Endotoxin.
E) The ability to change surface pilin antigens.

Question 9

Cattle may serve as a reservoir for E.coli strain O157:H7 because this strain does not cause any disease in cattle.This strain of E.coli can cause a potentially lethal Shiga toxin-mediated hemolytic uremic syndrome (HUS)in humans.Why don't cattle develop HUS?

A) The shiga toxin is not expressed in cattle.
B) E. coli is unable to effectively colonize the bovine intestine.
C) A protease in the cattle destroys the toxin.
D) Bovine kidney cells do not have a shiga toxin receptor.
E) They produce antibody against the shiga toxin.

Question 10

Tetanus toxin acts on inhibitory neurons by preventing the release of _________ from the neurons.

A) acetylcholine
B) glutamate and glutamine
C) glycine and GABA
D) acetylcholine and glutamate
E) glycine and glutamate

Question 11

Botulinum toxin belongs to a group of toxins called A-B toxins.What does the term "A-B" refer to?

A) Their antigen-binding properties.
B) Their antibody-binding toxins.
C) Their enzymatically active subunit and cell binding subunit.
D) Their action on the brain.
E) Their activation of B-cells.

Question 12

Neisseria meningitidis is the causative agent of meningitis.Which of these accounts for the damage caused by this bacterial infection?

A) A potent exotoxin that lyses epithelial cells.
B) A potent neurotoxin that targets brain cells.
C) A cytolytic toxin that destroys B-cells.
D) An endotoxin-induced inflammatory response.
E) An exotoxin that destroys macrophages.

Question 13

Which of these symptoms is caused by a toxin produced by Clostridium botulinum?

A) uncontrolled twitching
B) flaccid paralysis
C) spastic paralysis
D) meningitis
E) encephalitis

Question 14

Enteropathogenic and enterohemorrhagic strains of Escherichia coli attach to host cells in the intestinal lumen via this mechanism.

A) fimbriae and capsule
B) capsule and the surface protein intimin
C) fimbriae and the surface protein intimin
D) fimbriae and LPS
E) LPS and capsule

Question 15

For most pathogenic bacteria,what is the first step it takes to facilitate entry into its host?

A) attachment
B) toxin production
C) protease production
D) sequestering iron
E) lysis of the host cell

Question 16

Staphylococcus aureus produces a potent exotoxin which causes cell damage that induces a very strong inflammatory response in the host.What is this toxin?

A) pneumolysin
B) α-toxin
C) enterotoxin
D) streptolysin O
E) Protein A

Question 17

Which cells are destroyed by hemolysins?

A) lymphocytes
B) macrophages
C) epithelial cells
D) red blood cells
E) heart cells

Question 18

Staphylococcus aureus produces a fibronectin-binding protein as a virulence factor to aid in which activity?

A) host cell lysis
B) sequestering iron
C) attachment
D) toxin mediated cell inactivation
E) avoiding antibodies

Question 19

All of the following are examples of how virulence factors facilitate establishment of disease by a pathogen EXCEPT:

A) gaining entry into the host.
B) evade or overcome host defenses.
C) obtain nutrients from the host.
D) antibiotic resistance.
E) lyse host cells for nutrients.

Question 20

The DTaP vaccine is designed to protect against which diseases?

A) diarrhea, tetanus, and polio
B) diphtheria, tetanus, and pertussis
C) diarrhea, tetanus, and pertussis
D) diphtheria, tetanus, and polio
E) diarrhea, measles, and polio

Question 21

Which of these are associated with Type III secretion systems?

A) Gram positive bacteria
B) Gram negative bacteria
C) Staphylococcus aureus
D) Streptococcus pyogenes
E) pathogenic fungi

Question 22

What directly causes the damage during an active Mycobacterium tuberculosis infection?

A) A potent cytolysin that targets alveolar macrophages.
B) A cell-mediated inflammatory response.
C) A cytolysin that destroys lung tissue.
D) Growth of the bacterium in macrophages.
E) An exotoxin that enters into the bloodstream and targets heart muscle.

Question 23

A person who has strep throat should always be treated with antibiotics to reduce the risk of sequelae.What are the two most common sequelae?

A) Toxic shock syndrome and scarlet fever.
B) Glomerulonephritis and scarlet fever.
C) Toxic shock syndrome and pneumonia.
D) Glomerulonephritis and rheumatic fever.
E) Scarlet fever and rheumatic fever.

Question 24

What is the genus of the organism that causes pertussis?

A) Corynebacterium
B) Mycoplasma
C) Streptococcus
D) Mycobacterium
E) Bordetella

Question 25

Which of these is NOT a mechanism of horizontal gene transfer?

A) transduction
B) transformation
C) conjugation
D) mother cell to daughter cell
E) transposable elements

Question 26

Siderophores are a virulence factor because they allow the pathogen to perform what action?

A) Lyse lymphocytes.
B) Bind the Fc region of the antibody molecule.
C) Scavenge for free iron.
D) Compete with the host cells for glucose.
E) Invade host cells.

Question 27

Hemolytic uremic syndrome is caused by Staphylococcus aureus.

Question 28

How does the bacterial capsule act as a virulence factor?

A) It prevents both phagocytosis and complement activation.
B) It prevents complement activation.
C) It prevents phagocytosis only.
D) It acts as an enterotoxin.
E) It allows the bacterium to bind to the cell surface and lyse the host cell.

Question 29

Toxic shock syndrome caused by Staphylococcus aureus is mediated by an exotoxin that acts as a _____ .

A) cytotoxin
B) neurotoxin
C) hemolysin
D) superantigen
E) superantibody

Question 30

Streptococcus pyogenes is not efficiently opsonized for phagocytosis because of this component of its capsule.

A) hyaluronic acid
B) lipid A
C) lipopolysaccharides
D) teichoic acid
E) Protein A

Question 31

Many pathogenic bacteria adhere to host cells via fimbriae.

Question 32

Where is the diphtheria toxin gene located?

A) A pathogenicity island.
B) A conjugative plasmid.
C) A transposon.
D) A prophage.
E) A cryptic plasmid.

Question 33

A person may develop strep throat several times because of the antigenic variations of this.

A) teichoic acids
B) capsule proteins
C) M-protein
D) lipopolysaccharide
E) streptolysin-O

Question 34

A toxin that is part of the cell structure and usually found in the surface elements of the cell is called an endotoxin.

Question 35

Pathogenicity islands are blocks of genes on the bacterial chromosome that most likely arose from this process.

A) spontaneous mutation
B) horizontal gene transfer
C) vertical gene transfer
D) chemically induced mutagenesis
E) mutation via gamma radiation

Question 36

What is the most common cause of pharyngitis and tonsillitis in children?

A) Staphylococcus aureus
B) Corynebacterium tuberculosis
C) Mycoplasma pneumoniae
D) Streptococcus pyogenes
E) Streptococcus pneumoniae

Question 37

Type III secretion systems of Gram negative bacteria allow for the direct secretion of toxin into the target cell.

Question 38

Enterotoxins produced by Staphylococcus aureus are weak superantigens.

Question 39

Impetigo can be caused by Streptococcus pyogenes.Impetigo is a type of __________ .

A) pneumonia
B) sequelae
C) toxic shock syndrome
D) ear infection
E) skin infection

Question 40

By what mechanism does the enzyme streptokinase allow Streptococcus pyogenes to spread through tissue?

A) By lysing smooth muscle cells.
B) By lysing skin epithelial cells.
C) By breaking down fibrin clots.
D) By lysing red blood cells.
E) By lysing white blood cells.

Question 41

A substance produced by a pathogenic agent that enables it to gain entry into the host,avoid host defenses,or obtain nutrients is called a(n)__________ factor.

Question 42

Describe the mechanism of tetanus toxin in causing spastic paralysis.

Question 43

Exotoxins that act specifically on the intestine are called __________________.

Question 44

Cellulitis is inflammation of the connective tissue and may be caused by Streptococcus pyogenes.

Question 45

A bacterial toxin that is secreted by the cell is called a(n)_________.

Question 46

The scientific name of a causative agent of bacterial meningitis is ____________ meningitidis.

Question 47

The capsule is considered a virulence factor for many pathogens.Explain how the capsule aids the pathogen in establishing the disease process.

Question 48

Explain how superantigens are able to cause toxic shock syndrome.

Question 49

Horizontal gene transfer by bacteriophage is thought to be a very rare mechanism.

Question 50

A primary pathological feature of a Mycobacterium tuberculosis infection is the appearance of ___________ in the lungs.

Question 51

Cytolysins are cytotoxins that act on the ________ membrane to lyse the cell.