Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

GI Week 1 > Microbiology of the Upper GI Tract > Flashcards

Microbiology of the Upper GI Tract Flashcards

1
Q

What are the general GI system defenses against infection?

A 
epithelium barrier
mucus barrier
peristalsis to clear things
saliva with lysozyme, IgA, etc
normal flora 
acidity
peyer's patches in intestine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

True or false: normal flora begins to develop in our mouths during our first week of life?

A

false - babies have clean mouths until teeth erupt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

True or false: the upper GI tract contains a huge amount of normal flora compared to elsewhere in the gut?

A

false - actually relatively few compared to the mouth and large intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the four phyla that can be found in the normal biota of the stomach

A

proteobacteria
firmicutes
actinobacteria
bacteroidetes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the general classes of bacteria seen in microbiome of the large intestine?

A

anaerobes
gram negative rods
enterococcus
spirochetes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What do we call an infectious disease that causes tooth decay?

A

a dental cary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the risk factors for dental caries?

A

high-sugar diet, poor oral hygriene, reduced amount of saliva, smoking, periodontal disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What percentage of adults have had at least 1 tooth filled?

A

80%

highest incidence in AI/AN children

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What’s the mechanism for how the bacteria cause tooth decay? It;s not that the bacteria are “eating” the teeth….

A

When you eat fermentable sugars, acid-producing bacteria use them for energy and release acid as a byproduct

this decreases the pH of the mouth and leads to demineralization of teeth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What’s the treatment for dental caries and why do we take this so seriously?

A

you drill out the decayed area and put in a filling. We do this because if you don’t, the enamel can completely wear away and then you give the bacterial access to the blood supply underneath

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is periodontal disease?

A

an infectious disease destroying the supporting structures of the teeth.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What’s the mild form of periodontal disease?

A

gingivitis - only affects the gums with irritation, redness and swelling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What’s the more severe form of periodontal disease?

A

periodontitis, which is infection of underlying tissues and bones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are some conditions that periodontitis may be associated with?

A 
heart attack
stroke
lung disease
premature birth
DIABETES
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How is the damage in peridontal disease mostly mediated?

A

via the host immune response to the infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

While gingivitis is just swelling and redness of the gums, what will you see grossly in periodontitis?

A

the gums recede and you have localized loss of attachment of the teeth to the gums

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What virulence factor is essential for virtually all dental infectious diseases?

A

biofilm prroduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are biofilms composed of?

A

two or more bacterial microcolonies that are enclosed in glycocalyx (composed of polysaccharides)

also some proteins and DNA

note - there can be hundreds of species in a biofilm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe the process for formaiton of a biofilm.

A
  1. bacterial weakly adhere to the surface cells
  2. stronger adhereance over time - likely co-adhesion mediated
  3. multiplation of bacteria
  4. bacterial make polysaccharide
  5. polysaccharide builds up and the microbial composition changes over time as it makes it mroe suitable for organisms that otherwise wouldn’t survive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are some of the reasons why bacteria would want to live in a biofilm?

A 
easier to adhere
protects them from the immun system
protects them from ABx
allows for symbiotic relationships
local conditions of pH are more hospitable than the actual environment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Is plaque always bad? It’s basically a biofilm….

A

Plaque can be stable with no infectious microorgnisms, but it’s easy for perturbations to change the microbial balance toward more virulent orgnaisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What general type of organisms predominate in the oral cavity (we each cary about 100-200!)

A

anerobic organisms predominate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are some species of streptococci that play important roles in protecting against dental caries and periodontiis? How?

A

the “mitis” group = S sanguinis, S oralis, S gordonii and S. mitis

they produce hydrogen peroxide which inhibits the growth of other oral bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Where are the microbes that cause caries usually located?

A

plaques on tooth surfaces especially in crevices and between teeth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Are the species that cause caries usually gram negative or positive?

A

gram positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Microbes that cause periodontal disease are located where?

A

below the gumline int he subgingival space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Are microbes that cause periodontal disease usually gram negative or positive?

A

gram negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Why is it hard to identify specifically which “bad” oral microorgnisms are th ekey players in someone’s disease?

A

because they’re almost all streptococci and will look the same on growth and 16s rRNA analysis

also all strep viridans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What group is particularly associated with tooth decay?

A

mutans group -

strep mutans and strep sobrinus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What virulence factor for the mutans group make it likely to cause caries?

A

adhesin-like surface-associated proteins like the AgI and AgII family that are capable of binding to receptors in the pellicle

also extracellular glucosyltransferases Gtfs that are capable of synthesizing glucans - a type of polysaccharide from istu to make more S mutans binding sites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is a keystone pathogen?

A

It’s an organism that can be present without causing disease until it reaches a certain ratio, after which is can orchestrate destructive inflammation and remodling of the normally symbiotic microbiota into a dysbiotic state

mess with complement basically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are three examples of keystone pathogens involved in dental caries?

A

treponema denticola
tannerella forsythia
porphyromonas gingivalis (most studied bc it can be cultured)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what orgnaism is particularly related to the SEVERITY of periodontal disease?

A

aggregatibacter actinomycetemcomitans

34
Q

What are some ways to prevent dental caries and periodontal disease?

A

less sugar in diet
brush and floss regularly
fluoride
increase saliva flow

35
Q

How does fluoride work?

A

it promotes remineralizaiton to counterract the effects of demineralization under low pH conditions

Inhibits bacterial glycolysis and pH maintenance enzymes

36
Q

Which level of periodontal disease is reversible?

A

gingivitis is generally reversible with good oral care

37
Q

What are some of the treatment options for mild cases of periodonititis?

A

scaling to remove tartar and bacteria
root planing to discourage further growth
antibiotics - topiccal is typical but use oral if persistent

38
Q

What antibiotics are usually used for periodontitis?

A

amoxicillin and metronidazole

39
Q

What are some treatments for severe cases of periodontitis?

A

surgical treatments to fix permanent damage: flap surgery, soft tissue grafts, bone grafts

40
Q

Oral thrush is most common in what groups?

A

babies
elderly
immunocompromised

41
Q

What people get hairy leukoplaki?

A

HIV positive individuals with EBV infection

42
Q

What serious skin infection can occur from untreated dental infections spreading into the nearby tissue?

A

Ludwig’s angina

43
Q

What are the symptoms of ludwig’s angina?

A 
breathing difficulty
confusion or other mental changes
fever
neck pain
neck welling
erythema
weakness, fatigue
44
Q

Where can candidiasis occur?

A

usually on the tongue or inner cheeks

sometimes spreads to roof of mouth, bums, tonsils or pharynx

can reach esophagus, which is dangerous

45
Q

You can diagnose thrush entirely on signs and symptom, but scrapings would show what?

A

hyphae with spores at the edn

46
Q

How do you treat thrush?

A
  1. usually topical treament with clotrimazole or nystatin
  2. unresponsive cases with systemic antifugal such as fluconazole
  3. worse case scenario with IV amphotericin B
47
Q

How is H pylori transmitted?

A

fecal oral transmission

48
Q

How many adults are infected with H pylori?

A

50% in the US

virtually everyone in the third world

49
Q

H pylor gram positive or negative?

A

gram negative

50
Q

H pylori morphology?

A

flagellated helix-shaped rod (spirilli)

51
Q

H pylori relation to O2 use?

A

microaerophilic - can only survive in a little O2

makes it hard to culture

52
Q

H pylor urease positive or negative

A

urease positive

53
Q

What is the lifetime risk for ulcer disease in those with H pylor infections? Gastric cancer?

A

only 10-20% for peptic ulcer disease

1-2% for distal gastric cancer

54
Q

Why is there is range in presentations?

A

there are lots of different strains that can be more or less virulent

individual host responses differ

gastric microbiome differs and plays a role

55
Q

What are essentially the two non-cancer issues h pylori can cause?

A

symptoamtic gastritis

ulcers

56
Q

what are the two general cancers H pylori an trigger?

A

carcinoma

lymphoma

57
Q

What is gastritis?

A

inflammation fo the gastric mucosa - can be transient or chronic

58
Q

What are the symptoms of gastritis?

A

gnawing or burning ache in upper abdomen (may be worse or better with eating
nausea
vomiting
feeling of fullness in upper abdomen after eating

59
Q

What are the symptoms of gastric ulcers?

A

burning abdominal pain almost anywhere, worse when stomach empty - flares at night - temporarily relieved by eating foods and can disappear and then return for a few days or weeks

can also vomit blood, bloody stools, nausea, vomiting, weight loss, appetite changes

60
Q

What are some of the ways that H pylori survives in the stomach?

A

inhibits phagocytosis

inhibits the adaptive immune response

evades killing by ROS and NO

evades recognition by PAMPs

Urease activity raises local pH so it doesn’t have to live at pH 2 (since it can’t)

61
Q

How does urease increase local pH?

A

It breaks down urea into CO2 and ammonia, which is basic

62
Q

Where in the stomach does the H pylori like to live and why?

A

along the epithelium because the pH is about 6 there, which is can withstand

it just has to make it there through the more acidic lumen using the urease buffering

63
Q

How does it manage to get thorugh the pH = 2 layer so quickly?

A

It has an excellent flagella-based motility system

64
Q

How does it know where to go?

A

It has a chemotaxis system based on pH gradient - helps them know which direction to go to get to the epithelium and pH of 6

65
Q

What will the H pylori do once they reach the epithelium?

A

they adhere to the epithelium toa void mechanical clearance

this promotes invasion and persistence

the adhesins contribute to the inflammation

66
Q

What are the two best characterized specific virulence factors of H pylori?

A

VacA and CagA

67
Q

What is VacA?

A

It’ a pore-forming cytotoxin that allows leakage of Ca+ from epithelial cells

68
Q

What is CagA?

A

it travels through a type 4 secreiton system into the host cytosol and affects the proliferative activities, adhesion and cytoskeletal organization of epithelial cells

whole system is highly proinflammatory

69
Q

How does H pylori cause ulcers?

A

basically, we cause the ulcer

  1. they attach to the epithelium and trigger inflammation
  2. our inflammatory cells are indescriminant and kill our own epithelium, forming an ulcer
70
Q

What are the 4 types of diagnostic tests for htis?

A

encoscopy with culture
breath test
stool test
blood test

71
Q

A week of “triple therapy” is currently used. What does this entail?

A

2 antiibotics (clarithromycin and amoxicillin) and a PPi to aid in the healing of the ulcer

72
Q

What are the consideratios for endoscopy and culture for diagnosis?

A

it’s a gold standard test because you can actually see the uclers, but it’s hugely invasive and way expensive

73
Q

What’s a test we can do on culture after endoscopy to check for H pylori?

A

the rapid urease test, which detects the actual enzyme urease

74
Q

How does the breath test work for H pylori?

A

it detects radioactive CO2 that’s formed thorugh the urease reaction

75
Q

Can the breath test diagnose? check for cure? What’s the issue?

A

It’s good for both diagnosis and confirming cure, but it require sa skilled technician - easy to screw up

76
Q

What is being detected by the blood test for H pylori? What does this mean for utility?

A

it detects antibodies against H pylori

means it’s useful for initial diagnosis only and can’t confirm a cure

77
Q

What’s being detected by the stool test for H pylori? What does this mean for it’s utility?

A

looks for H pylori antigen

this means it’s good for both diagnosis and confirming cure

78
Q

If you had to pick wuich cancer to get from H pylori, which would you pick?

A

gastric MALT over carcinoma

79
Q

Describe gastric MALT

A

it’s mucosa-associated lymphoid tissue lymphoma in the stomach due to long term inflammation

basically a tumor of B cells - get indigestion, heartburn and abdominal pain

80
Q

H pylori is a risk factor in what percentage of gastric carcinoma?

A

65-80%

GI Week 1 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions