Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Micro 3010 > Unit 16 - GI Tract Infections > Flashcards

Unit 16 - GI Tract Infections Flashcards

(93 cards)

Start Studying
1
Q

What can diarrhea be caused by?

A 
E. coli
Salmonella
Campylobacter
Vibrio
Shigella
Listeria
Rotavirus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the difference between true food poisoning and food-associated infections?

A

True food poisoning:

  • Fast rxn
  • Ingestion of pre-formed toxin
  • Toxins survive cooking/heating

Food-associated infections:

  • Slow rxn
  • Food acts as a vehicle for the pathogen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Give two examples of food associated infection causes

A

campylobacter

salmonella

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

What are the 3 ways that GI infections can cause disease?

A

1) Fluid balance
- Change balance of water and electrolytes in small bowel - massive fluid secretion
2) Cell destruction & inflammation
- Invasion and/or cytotoxin production
3) Invasion
- Penetrate intestinal mucosa - spread and multiply outside the bowel

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

List some points about diarrhea

A
  • Increase in fluid and electrolyte loss in gut lumen (causes unformed or liquid feces)
  • Allows host to get rid of the pathogen
  • Allows pathogen to disseminate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does diarrhea affect people in resource-poor regions vs people in resource-rich regions?

A

Resource-poor regions:
-Major cause of mortality in children

Resource-rich regions:
-Usually mild and self-limiting, except very young, elderly and immunocompromised

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

Diarrhea:

Is the identity of the pathogen usually determined?

A

No

  • Generally identity of the pathogen not determined
  • Difficult to distinguish based on symptoms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Diarrhea:

What is very important to ask about when a patient has diarrhea?

A
  • Food intake

- Travel

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

Diarrhea:

Macroscopic and microscopic examination of feces for ___ and ___

A

blood and pus

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

Diarrhea:

Precise diagnosis important in ______

A

outbreaks

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

List the 6 different groups of E. coli with different pathogenic mechanism

A 
EPEC - Enteropathogenic E. coli
ETEC - Enterotoxigenic E. coli
EHEC - Entertohaemorrhagic E. coli
EIEC - Enteroinvasive E. coli
EAEC - Enteroaggregative E. coli
DAEC - Diffuse - aggregative E. coli
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Enteropathogenic E. coli (EPEC):

Affects who?

A

babies and young children

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

Enteropathogenic E. coli (EPEC):

What virulence factors does it have?

A

adhesions, bundle-forming pili and intimin

-allows for attachment to epithelial cells and microfilms

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

Enterotoxigenic E. coli (ETEC):

Affects who?

A

Children

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Enterotoxigenic E. coli (ETEC):

Where does it bind to?

A

Binds to receptors on cell membrane of small intestine

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

Enterotoxigenic E. coli (ETEC): List the 2 plasmid-encoded toxins

A

1) Heat labile (LT) toxin

2) Heat stabile (ST) toxin

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

Enterotoxigenic E. coli (ETEC):

Describe the Heat labile (LT) toxin

A

similar mode of action as cholera toxin

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

Enterotoxigenic E. coli (ETEC):

Describe the Heat stable (ST) toxin

A
  • increases guanylate cyclase activity
  • increases cGMP
  • increases fluid secretion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Enterohaemorrhagic E. coli (EHEC):

List the 2 key points about this type of E. coli

A

Invasive

Makes Toxin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Enterohaemorrhagic E. coli (EHEC):

Describe the two toxins

A

Verotoxin 1 and 2 (VTEC)
AKA Shiga Like Toxin

SLT-1 and SLT-2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Enterohaemorrhagic E. coli (EHEC):

What do the two toxins do and cause?

A
  • Toxins damage large intestine
  • Inhibit protein synthesis
  • Cause ulceration and bleeding
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Enterohaemorrhagic E. coli (EHEC):

Important serotype

A

Serotype O157:H7

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

Enterohaemorrhagic E. coli (EHEC):

What 2 things can EHEC cause?

A

HC - Hemorrhagic colitis

HUS - Hemolytic ureic syndrome

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

Enterohaemorrhagic E. coli (EHEC):

What is HC (hemorrhagic colitis)?

A

destruction of mucosa leads to hemorrhage and causes bloody diarrhea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Enterohaemorrhagic E. coli (EHEC): | What is HUS (hemolytic ureic syndrome)?
- toxin gets into bloodstream - verotoxin receptors found on renal epithelium - may account for kidney damage **KEY POINT THAT EHEC CAN CAUSE KIDNEY DAMAGE
26
Enterohaemorrhagic E. coli (EHEC): | Symptoms?
- Anemia (fatigue, weakness, light-headedness) due to destruction of RBC - Low platelet count and sudden kidney damage **AGAIN KEY POINT THAT A SYMPTOM OF EHEC IS KIDNEY DAMAGE
27
Enteroinvasive E. coli (EIEC): | Describe it's mechanism of action
- attaches to mucosa of large intestine - invade cells by endocytosis - multiply - spread to adjacent cells - tissue destruction - inflammation and ulceration - ulceration can result in blood and mucus in stool
28
Enteroaggregative E. coli (EAEC): | Has a _____ ____ appearance on tissue culture cells
stacked brick
29
Enteroaggregative E. coli (EAEC): | How does it aggregate?
plasmid-encoded fimbria
30
Enteroaggregative E. coli (EAEC): | Toxins produced but role in diarrheal disease _____
uncertain
31
Diffuse-aggregative E. coli (DAEC): | list one thing bout it
alpha-hemolysin and cytotoxic necrotizing factor 1
32
How do we diagnose E. coli?
There are specific tests to ID strains
33
What do we look for to determine that its EHEC?
shiga toxin genes
34
What do we look for to determine that its EIEC?
invasion of tissue culture cells or the presence of invasion associated genes
35
What is the treatment for E. coli diarrhea?
- Fluid replacement | - Antibacterial therapy not indicated
36
Why aren't antidiarrheal medications recommended?
They increase the contact time of pathogen with intestinal wall which increase the severity of disease.
37
____: Requires urgent treatment and may need dialysis
HUS (hemolytic uremic syndrome)
38
How do you prevent E. coli diarrhea?
- clean water, pasteurization, proper cooking - "boil it, peel it, cook it, or forget it!!" - da fuck, get dis preppiness outta ma E. coli notes
39
What can salmonella cause?
- Gastroenteritis and Food Poisoning | - Enteric Fever
40
Salmonella: | Sources?
meat, poultry, eggs, dairy products, farmed fishes
41
Salmonella: | When do symptoms of nausea, vomiting and diarrhea start to appear?
6-28 hours after ingestion
42
What causes typhoid fever?
Salmonella typhi
43
How is Salmonella typhi spread?
fecal-contamination of food or water
44
Initial symptoms of enteric fever?
- headache - fever (OBVS KUMAR) - general malaise - abdominal tenderness - constipation
45
Once S. typhi reaches gallbladder and Peyer patches, it reaches the ____ stage
diarrheal
46
Enteric fever: list 3 points about it
- gallbladder and biliary tree - persistent shedding - typhoid mary
47
What is the most common cause of bacterial gastroenteritis?
Campylobacter
48
Campylobacter: | High ___
ID50 | *High ID50 means it is not that virulent
49
Campylobacter: | ____ sensitive
heat
50
Campylobacter: | When do symptoms appear?
2-5 days
51
Campylobacter: | What symptoms appear?
- diarrhea with blood and pus (2-3 days) | - abdominal pain longer lasting
52
Campylobacter: | Causes a ____-______ disease
self-limited
53
Campylobacter: | Sources?
- poulty | - contaminated meat, water, unpasteurized milk
54
Campylobacter: | Therapy?
Fluoroquinolones | Macrolides
55
Vibrio Cholera is present where?
water environments, fish, shellfish
56
What does Vibrio Cholera cause?
- rapid dehydration | - rice water stools (many litres)
57
Describe the pathogenesis of Vibrio cholera
- Vibrio cholera ingested in large numbers - Sensitive to stomach acid so a large dose is needed to cause disease unless patient achlorhydria or taking antacids - Colonization of small intestine depends on motility (polar flagella) production of mucilage attachment to specific receptors - Toxin production - Massive loss of fluid and electrolytes - No damage to enterocytes, no blood or white blood cells in stool
58
List the 4 Shigella species
S. sonnei S. flexneri S. dysenteriae S. boydii
59
Shigella species have a low ___
ID50
60
_______ is easily transmitted, no animal reservoir
Shigellosis
61
What toxin does Shigella produce?
Shiga toxin - cytotoxic - enterotoxic - neurotoxic *Damages epithelial and kidney cells
62
What is the treatment for Shigellosis?
- Rehydration | - Antibiotics in severe cases
63
Clostridium difficile is _____-associated diarrhea
antibiotic *When given antibiotics, it kills some normal microflora. C. dif is not killed by antibiotics and therefore thrives when other normal microflora dies off when antibiotics have been administered.
64
What does Clostridium difficile cause?
- Mild-watery diarrhea to life-threatening toxic megacolon | - Can cause pseudomembranous colitis (neutrophils, fibrin, mucin, cellular debris)
65
What toxins does C. dif produce?
TcdA (Toxin A) | TcdB (Toxin B)
66
What is the emergent strain of C. dif?
C. difficile 027
67
Why does C. difficile 027 produce more TcdA and TcdB?
Because there is a deletion of the regulatory gene (TcdC)
68
Treatment for C. dif?
- Antibiotics for serious infections | - Fecal transplant
69
____ _____: consumption of preformed toxins in food
Food poisoning
70
What can food poisoning be caused by? (2)
- Staphylococcus aureus | - Clostridium botulinum
71
S. aureus produces?
enterotoxins
72
S. aureus is ____ stable
heat
73
S. aureus is resistant to ???
stomach/small intestine enzymes
74
Mechanism of S. aureus?
- Superantigen, bind to MHC class 2 molecules - T-cell stimulation - Effects CNS - causes severe vomiting within 3-6 hours after consumption
75
Does S. aureus food poisoning cause diarrhea?
no way jose
76
What causes Listeriosis?
Listeria monocytogenes
77
Listeria monocytogenes is ____-borne
food
78
Listeria monocytogenes can multiply at _____
4 degrees C
79
Listeria monocytogenes has an infectious dose of _____
<1000
80
Who is at enhanced risk of Listeriosis (caused by Listeria monocytogenes)?
- pregnant women | - immunocompromised individuals
81
Describe the life cycle of Listeria
- Endocytosis - Then the organism can escape the phagosome - Divide in host cell - Organism can polymerize the actin pili - Form actin tail - Actin tail pushes bacteria into a pseudopod that is endocytosized by the new host cell
82
______ are also a major causes of gastroenteritis
Viruses
83
_____ infants die from gastroenteritis each year
>3 million
84
2 viruses that cause gastroenteritis?
Rotavirus | Norovirus
85
Rotavirus: | _______ transmission?
oral-fecal
86
Rotavirus: | Symptoms
- vomiting - diarrhea - fever
87
Rotavirus: | Treatment?
fluid and salt replacement
88
Rotavirus: | Vaccine?
yes
89
Norovirus: | Part of ____ family
calcivirus
90
Norovirus: | causes ______
gastroenteritis
91
Norovirus: | Incubation period
24-48 hours
92
Norovirus: | Rate of infection ?
50%
93
Norovirus: | Is ______
unculturable *must use electron microscopy or RT-PCR

Micro 3010 (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions