Exam 3 Lecture 22 Flashcards

1
Q

Describe the gram stain of Campylobacter and Helicobacter

A

gram-negative helical rods

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2
Q

Campylobacter and Helicobacter are part of which broad group?

A

Epsilonproteobacteria

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3
Q

True or false: though they were discovered in the last 50 years, Campylobacter and Helicobacter are common bacterial pathogens

A

True

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4
Q

Campylobacter and Helicobacter are _____ and ____

A

microaerophilic; fastidious

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5
Q

Campylobacter and Helicobacter infect the __ ___ of humans and other animals

A

GI tract

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6
Q

True or false: Campylobacter and Helicobacter do not have flagellar motility

A

False

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7
Q

C. jejuni has ____ flagella, which contributes to what kind of motility?

A

bipolar; darting motility

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8
Q

Lophotrichous flagella

A

Multiple flagella found at one end of the bacterium

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9
Q

H. pylori has ____ flagella, which allows for:

A

lophotrichous; penetration of mucus (which likely attributes to its ability to get into the tissue and cause infection)

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10
Q

How do Campylobacter and Helicobacter have molecular mimicry?

A

Their LPS/LOS structures mimic host glycosylation, which can induce autoantibodies (those that mistakenly target the host)

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11
Q

How many species of Campylobacter do we know of? How many subspecies?

A

32 species; 9 subspecies

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12
Q

True or false: Campylobacter is the major cause of foodborne bacterial infections in developed nations

A

True (more than Salmonella, E. coli, Shigella combined)

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13
Q

Does Campylobacter cause disease via low or high inoculum?

A

Low (400-500 sufficient to cause infection)

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14
Q

Most Campylobacter infections are caused by:

A

C. jejuni

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15
Q

C. coli attributes to -% of Campylobacter infections

A

1-25%

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16
Q

True or false: Campylobacter can commonly colonize domestic animals where it doesn’t cause much disease.

A

True

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17
Q

C. jejuni causes ____, which consists of what symptoms?

A

Enteritis; symptoms = diarrhea; sometimes bloody, fever, abdominal pain, inflammation

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18
Q

C. jejuni symptoms usually appear in __-__ hours. The range is - days.

A

24-48 hours; 1-7 days

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19
Q

True or false: C. jejuni enteritis usually is self-limiting and resolves within a week

A

True

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20
Q

Sometimes, C. jejuni infection can become _____, which can lead to other diseases, such as:

A

extraintestinal; biliary tract, bacteremia, meningitis, others

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21
Q

How is C. jejuni infection treated?

A

fluids and electrolytes, antibiotics for severe infections

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22
Q

True or false: antibiotic resistance is a problem when treating C. jejuni

A

True - presumably due to resistance having developed in livestock

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23
Q

Which antibiotics are used for treating C. jejuni?

A

Azithromycin, Ciprofloxacin

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24
Q

True or false: For diagnosing C. jejuni, culture via selective media is the gold standard

A

True

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25
Besides culture, what are some other ways to diagnose C. jejuni?
1. looking for darting motility in fresh stool samples | 2. serum serology and PCR
26
Most cases of C. jejuni are due to ____ ____
sporadic zoonosis
27
You can contract C. jejuni infection through: (2; hint - one is rare)
1. contaminated/undercooked poultry | 2. (rare) pets, contact with farm animals, person to person
28
True or false: raw milk or untreated water can cause outbreaks in C. jejuni
True
29
C. jejuni cases peak during ___ ___
warmer months
30
What are the four steps of C. jejuni pathogenesis?
1. adheres to intestinal epithelial cells 2. induced toxin-mediated cell damage 3. uses cytolethal distending toxin to induce cell cycle arrest 4. performs endocytosis and transcytosis (which is thought to be important for immune evasion)
31
True or false: C. jejuni flagella are required for infection
True (darting motility)
32
Regarding C. jejuni flagella, FlaA and FlaB expression can be turned on or off due to ___ ____, which is controlled by ___-___ ____
phase variation; slip-strand mispairing
33
Which flagellin monomers make up the C. jejuni flagella?
FlaA and FlaB
34
True or false: generally, bacterial flagella are normally glycosylated
False
35
C. jejuni flagellin glycosylation is important for _______ and _____ _____
autoagglutination; microcolony formation
36
Besides making up the flagellar structure, what else is the basal body in C. jejuni responsible for?
Exporting other proteins, such as FlaC, Cia proteins, and FspA
37
Generally, flagella are made via what type of secretion system?
(Modified) T3SS
38
Name the C. jejuni virulence factors (7)
1. motility 2. chemotaxis 3. adhesion and invasion 4. capsule 5. iron uptake 6. biofilm formation and antibiotic resistance 7. LPS/LOS
39
Describe the chemotaxis of C. jejuni
attracted to mucus, glycoproteins of mucus, nutrients | repelled by bile
40
C. jejuni adheres to host ____ via what proteins?
CadF and FlpA
41
Which protein of C. jejuni binds to host heat shock protein?
JlpA
42
True or false: C. jejuni flagella are thought to be important for adhesion to host cells.
True
43
True or false: in addition to FlaA/FlaB expression, C. jejuni turns capsule biosynthesis on/off via slip-strand mispairing
True
44
C. jejuni capsule is important for:
survival, adherence, immune evasion
45
How many serotypes exist in C. jejuni?
over 100
46
What serotypes are associated with GBS?
Serotypes O19 and O41
47
What type of toxin is CDT?
AB2
48
CdtB gene codes for? And what functions does this protein product have?
A subunit of the CDT toxin; has DNase and phospholipase activity
49
What do CdtA and CdtC genes code for?
binding subunits of the AB2 CDT toxin
50
CdtA and CdtC bind to ____-rich regions on the host cell membrane and drives internalization of the toxin via _____-____ __
cholesterol; clathrin-coated pits
51
True or false: the CDT toxin is unique solely in C. jejuni
False - found in many Gram negative organisms, such as E. coli, H. ducreyi, Helicobacter spp, S. Typhi, Shigella
52
How does C. jejuni CDT cause cell cycle arrest/apoptosis?
B subunit migrates into the nucleus, induces double strand breaks; also activates ATM, p53
53
What does GBS syndrome cause?
ascending paralysis
54
Approximately _/___ patients develop GBS after C. jejuni infection
1/1000
55
True or false: GBS correlates with presence of anti-GM1, anti-GD1a, IgG (antibodies against host proteins)
True - this attributes to paralysis
56
In GBS, antibodies that are produced attack the ___ and assemble complement, essentially destroying the ___
nerves
57
In addition to causing GBS, C. jejuni can also cause ____ ____
reactive arthritis
58
C. fetus major reservoir
animals such as cattle, sheep, reptiles
59
C. fetus grows optimally at __ºC
37ºC
60
C. fetus can cause ____ and ___ ___
diarrhea; fetus loss
61
True or false: C. fetus was the first Campylobacter characterized
True
62
____ grows more slowly than Campylobacter
Helicobacter
63
True or false: there is a correlation between H. pylori and peptic cancer
True
64
H. pylori infection occurs ___ in life and can ____ for life
early; persist
65
What is the H. pylori reservoir?
stomach
66
H. pylori is ____ transmitted within families. As such, there is a strong ____ ____ to the genetic variation of Helicobacter spp.
vertically; ethnogeographic signature
67
Most cases of H. pylori are ____ ____
asymptomatic gastritis
68
H. pylori can cause what type of ulcers?
gastric and duodenal ulcers
69
H. pylori can also cause ___ ___ ___ ___, which resolves upon eradication of infection.
Mucosa Associated Lymphoid Tissue
70
Asymptomatic gastritis is characterized by? (3)
1. neutrophil infiltration 2. proinflammatory cytokines (increases acid) 3. can progress to atrophic gastritis (loss of parietal cells, less acid)
71
Parietal cells
epithelial cells that line the stomach and secrete HCl
72
What does H. pylori gastritis look like?
bumpy lining, hyperplasia, loss of parietal cells, immune cells infiltrate, inflammation
73
How does H. pylori survive the acidic environment of the stomach?
secretes urease
74
True or false: patients with gastric cancer know early on that they have it
False - often is silent until tumor grows so large that it becomes hard to eat
75
True or false: MALT lymphoma is rare
True
76
H. pylori gastric cancer ___ doesn't match ___. Ex: China
incidence; prevalence
77
H. pylori diagnosis (4)
1. urea breath test (carbon isotope) 2. stool antigen test 3. serological test (anti-H. pylori IgG) 4. endoscopy and biopsy (for culture and histology purposes)
78
Do we treat H. pylori if there are no symptoms?
No
79
If there are symptoms or cancer risk, treat H. pylori with:
Combination therapy - 2 antibiotics - drug to reduce acid - bismuth to promote mucosal healing
80
True or false: H. pylori treatments rarely fail
False- it can happen so we are wary of it due to resistance, pH effect on drugs, non-compliance due to long course of treatment
81
Majority of H. pylori live in:
mucus layer overlying the gastric epithelium
82
Urease has two main functions, which are:
1. buffers stomach acid via cleaving urease to make NH3 | 2. changes rheological properties of mucin to make it easier to swim through
83
H. pylori uses ___ ___ and ____ __ __ to get to epithelium
flagellar motility; helical cell shape
84
H. pylori toxins (3)
VacA, Nap, CagA
85
VacA
vacuolating cytotoxin
86
Nap
recruit immune cells
87
CagA
subvert host cell signaling
88
H. pylori uses adhesins __ and __ to bind to? (respectively)
BabA and SabA; lewis antigens; sialyl-lewis antigens
89
True or false: there is molecular mimicry with H. pylori due to Lewis antigens on LPS
true
90
VacA has different ___ ___ ___ which can lead to higher/lower levels of its expression and binding ability
signal sequence polymorphisms
91
VacA induces cells to fill up with big ____, which is ____. It also increases the ____ of the epithelium
vacuoles; cytostatic; permeability
92
VacA can induce apoptosis via interaction with?
mitochondria
93
VacA can inhibit _-___
T- cells
94
Cag is coded within _____ ___
pathogenicity island
95
Cag is associated with ___ and ___
ulcer and cancer
96
Cag is displaced into a host cell via what secretion system?
T4SS
97
Cag induces _____ ___
proinflammatory cytokines
98
translocation of CagA into host does what two things?
1. activate growth receptor signaling pathways | 2. induce cell shape changes and motility
99
True or false: Cag pathogenicity island is found in all strains of H. pylori
False - only in some strains, but found in those associated with causing ulcers/cancer
100
CagA has ___ motifs. East Asians in particular have the _ motif which binds ___ much more tightly.
EPIYA; D; SHP-2
101
SHP-2 binds to what specifically?
Phosphorylated Y within EPIYA
102
True or false: Kids who have H. pylori are much more likely to have asthma and other allergic conditions
False: less likely
103
Regarding H. pylori, protection against allergies/chronic inflammatory disorders is mediated through ____ _ ___
regulatory T cells