Deck 21: Virulence Factors and Pathogenic Mechanisms of Bacterial Infections

Question 1

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

Answer 1

C

Question 2

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

Answer 2

C

Question 3

Lipoteichoic acids are associated with which of these bacteria?

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

Answer 3

A

Question 4

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

Question 5

Enteropathogenic E.coli may increase nutrient absorption exposure by:

A)Projection into the intestinal lumen when host-encoded Tir protein binds bacterially encoded intimin protein,resulting in a pedestal formation due to actin rearrangement
B)Projection into the intestinal lumen when host-encoded intimin protein binds bacterially encoded Tir protein,resulting in a pedestal formation due to actin rearrangement
C)Projection into the intestinal lumen when bacterially-encoded Tir protein binds bacterially encoded intimin protein,resulting in a pedestal formation due to actin rearrangement
D)Projection into the intestinal lumen when host-encoded Tir protein binds host encoded intimin protein,resulting in a pedestal formation due to actin rearrangement
E)None is a correct description

Question 6

An attachment structure which aids in overcoming the charge repulsion between host/microbe cells is:

A)Capsule
B)Fimbriae
C)Flagella
D)Congugation pili
E)Peptidoglycan

Question 7

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 8

Which of these bacteria displays most capsular antigenic shift?

A)Streptococcus pneumoniae
B)Escherichia coli
C)Haemophilus influenzae
D)Streptococcus pyogenes
E)Neisseria gonorrhoeae.

Question 9

Verotoxins are associated with which of these bacteria?

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

Question 10

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.

Question 11

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 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

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

Question 14

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 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

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 17

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 18

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 19

Bacteria can steal iron from host cells through their production of:

A)lactoferrin
B)transferrin
C)cytochromes
D)siderophores
E)leghemoglobin

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

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 22

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 23

The primary pathogenic effect of increased cAMP levels within cells is:

A)Loss of cellular energy
B)Increased ADP synthesis
C)Disruptions of ion and water balance
D)Overactivity of ATP synthase
E)Protein synthesis inhibition

Question 24

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 25

ADP ribosylation of elongation factor -2 (EF-2)causes:

A)Inhibition of protein synthesis by cleaving the small ribosomal subunit
B)Inhibition of protein synthesis by cleaving the large ribosomal subunit
C)Preventing ribosomal movement down the mRNA
D)Blocking the initial AUG codon
E)Preventing recognition of stop codons

Question 26

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 27

What BEST explains recurrent cycling between latent and reactivation tuberculosis conditions in a patient?

A)Living in overcrowded conditions
B)HIV infection with HAART therapy available
C)Changes in the strength of humoral immune defenses
D)Changes in the strength of cellular immune defenses
E)Antibiotic resistance of Mycobacterium tuberculosis

Question 28

What is the genus of the organism that causes pertussis?

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

Question 29

Which cells are destroyed by hemolysins?

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

Question 30

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 31

Which of these bacteria causes gangrene?

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

Question 32

The primary pathogenic effect of increased Shiga toxins within cells is:

A)Loss of cellular energy
B)Increased ADP synthesis
C)Disruptions of ion and water balance
D)Overactivity of ATP synthase
E)Protein synthesis inhibition

Question 33

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 34

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 35

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 36

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 37

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 38

Of those infected with Mycobacterium tuberculosis,what percentage will be disease free?

A)10%
B)25%
C)60%
D)90%
E)99%

Question 39

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 40

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 41

Which of these cytokines would be present in high levels in a person with latent tuberculosis? (Select all that apply)

A)IFNɤ
B)IL-4
C)IL-10
D)IL-6
E)TNFα

Question 42

The paralysis observed in tetanus victims is a result of: (Select all that apply)

A)Cleaving SNAP-25 protein
B)Stimulating synaptobrevin activity
C)Phosphorylation of syntaxin
D)Inhibiting acetylcholine release at the neuromuscular junction
E)Preventing GABA release by inhibitory neurons

Question 43

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 44

Syntaxin can bind to: (Select all that apply)

A)SNAP-25
B)Synaptobrevin
C)Botulotoxin A
D)Tetanotoxin
E)Botulotoxin C

Question 45

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 46

Which of these bacteria produce toxins that increase cAMP levels? (Select all that apply)

A)Corynebacterium diphtheriae
B)Clostridium botulinum
C)Clostridium difficile
D)Bordetella pertussis
E)Enterotoxigenic E.coli

Question 47

SNAP-25 can bind to: (Select all that apply)

A)Synaptobrevin
B)Syntaxin
C)Botulotoxin A
D)Tetanotoxin
E)Botulotoxin C

Question 48

Synaptobrevin can bind to: (Select all that apply)

A)SNAP-25
B)Syntaxin
C)Botulotoxin A
D)Tetanotoxin
E)Botulotoxin C

Question 49

Type III secretion systems are associated with which of these bacteria? (Select all that apply)

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

Question 50

Fimbrial attachments to host cells are associated with which of these bacteria? (Select all that apply)

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

Question 51

Tuberculosis can be caused by: (Select all that apply)

A)Mycobacterium leprae
B)Mycobacterium bovis
C)Mycobacterium tuberculosis
D)Mycobacterium caninum
E)All choices are incorrect

Question 52

Clostridium botulinum toxin(s)act by: (Select all that apply)

A)Cleaving SNAP25
B)Cleaving synaptobrevin
C)Cleaving syntaxin
D)Inhibiting acetylcholine release at the neuromuscular junction
E)Preventing acetylcholine release by inhibitory neurons

Question 53

Corynebacterium phage β promotes its host's (and own)survival:

A)Increasing transcription of human genes
B)Increasing available iron for bacterial use by killing human cells
C)Increasing available iron for human use by killing bacterial cells
D)Inhibiting transcription of bacterial genes
E)Possessing genes encoding siderophores

Question 54

Clostridium tetani toxin acts by: (Select all that apply)

A)Cleaving SNAP25
B)Cleaving synaptobrevin
C)Cleaving syntaxin
D)Inhibiting acetylcholine release at the neuromuscular junction
E)Preventing acetylcholine release by inhibitory neurons

Question 55

Fibronectin-binding proteins are associated with which of these bacteria? (Select all that apply)

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

Question 56

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

Question 57

Evidence that the human disease arising from Shiga toxin production may be co-incidental comes from the observation that:

A)Shiga toxin production stimulates iron uptake by host cells
B)Shiga toxin production increases the survival of E.coli which would be consumed by Tetrahymena protozoa
C)Shiga toxin is not expressed in bovine animals
D)Shiga toxin only affects amaoeboid organisms found in air conditioning units
E)Shiga toxin is bacteriophage-encoded.

Question 58

Which of these cytokines would be present in high levels in a person with active tuberculosis? (Select all that apply)

A)IFNɤ
B)IL-4
C)IL-10
D)IL-6
E)TNFα

Question 59

The paralysis observed in botulism sufferers is a result of: (Select all that apply)

A)Cleaving SNAP-25 protein
B)Stimulating synaptobrevin activity
C)Phosphorylation of syntaxin
D)Inhibiting acetylcholine release at the neuromuscular junction
E)Preventing GABA release by inhibitory neurons

Question 60

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 61

Enterotoxins produced by Staphylococcus aureus are weak superantigens.

Question 62

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

Question 63

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

Question 64

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

Question 65

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

Question 66

Exotoxins that act specifically on the intestine are called __________________.