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GI Week 4 > Lower GI Micro- Zimmer > Flashcards

Lower GI Micro- Zimmer Flashcards

1
Q

Are we born with normal flora in our gut?

A

Nope! Human GI tract is sterile at birth, but RAPIDLY becomes colonized

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2
Q

What is one of the first colonizer’s in breast fed infants?

A

Bifidobacteria

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3
Q

What are some benefits of normal flora in our gut?

A
  • Generate vitamins
  • Help in digestion
  • Stimulate development of immunological tissue
  • PREVENT establishment and infection of alien microbes
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4
Q

How do you distinguish a bacterial GI infection from a parasite/viral infection?

A

Onset of symptoms!

Bacterial symptoms will hit more suddenly than viral/parasitic

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5
Q

What is “food poisoning”?

A

Occurs after consumption of food containing toxins

Toxin is PRE FORMED

Symptoms begin 30 mins- 6 hours after ingestion

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6
Q

What is a food-associated infection?

A

Longer incubation period

Organisms produce toxin in the GI tract or invade mucosal epithelium

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7
Q

Bacteria
Gram + Cocci
Catalase +
Coagulase +

A

Staph Aureus

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8
Q

Does staph aureus normally cause food poisoning or a “food-associated illness”

A

Food poisoning!

*Ingestion of toxin, not bacteria is what causes the illness

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9
Q

Which bacteria produces a toxin that would be found in food that sat out for a long time? Not even high salt ham will prevent colonization?

A

Staph Aureus

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10
Q

When do symptoms appear after ingestion of the Staph Aureus toxin?

A

1-7 hours

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11
Q

Which bacteria produces spores that can survive the rice cooking process?

A

Bacillus cereus

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12
Q

What does bacillus cereus look like on gram stain?

A

Purple box cars!!!! vroom vroom!

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13
Q 
Bacteria
Gram +
Large bacilli (rod)
Forms endospores
Facultative anaerobe
Mostly motile
B-hemolytic
A

Bacillus cereus

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14
Q

What is the pre from enterotoxin produced by bacillus cereus? how does it work?

A

Cereulide

Forms holes in membranes

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15
Q

What spores are commonly found in the soil or plant food grown close to the ground? (legumes, cereals, spices)

A

Bacillus cereus

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16
Q

Cereulide is associated with which form of infection of bacillus cereus?

A

Emetic (vomiting)/ food poising form

Symptoms 1-6 hours after ingestion

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17
Q

What are the two infection forms of bacillus cereus?

A

Emetic/vomiting = food poisoning

Diarrheal = food-associated (ingested bacteria)

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18
Q

What is the roll of the enterotoxin produced by bacillus cereus that causes the diarrheal infection?

A

causes intestinal fluid secretion

physically larger toxin than cereulide

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19
Q

What kind of toxin does clostridium botulinum produce? what is its MOA?

A

Neurotoxin

Irreversibly blocks the release of ACh from neurons

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20
Q 
Bacteria
Gram + bacilli
Spore-forming
Obligate anaerobe
Motile
A

Clostridium Botulinum

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21
Q 
Double/blurred vision
Drooping eyelids
Slurred speech
Difficulty swallowing
Dry mouth
Muscle weakness

What do you think it is?

A

Botulinum Toxin!

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22
Q

What organism is likely to grow in canned goods that weren’t heated to high enough temp? (and is now sealed, making the perfect ANAEROBE environment)

A

Clostridium Botulinum

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23
Q

How would you distinguish between clostridium botulinum and clostridium perfringens?

A

Botulinum is MOTILE

Perfringens = NON-MOTILE

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24
Q

What organism is normally found in GI tract, but if too much is ingested the amount of toxin produce will generate symptoms?

A

Clostridium perfringens

25
Q

Diarrhea and abdominal cramps

NO FEVER
NO VOMITING

Symptoms last less the 24 hours

What bug is it?

A

Clostridium Perfringens

26
Q

Cafeteria is associated with which bug? (food made in large quantities and kept warm for a long time before serving)

A

Clostridium perfringens

27
Q

Zoonosis infection associated with poultry that cannot usually multiply in food?

A

Campylobacter jejuni

28
Q

What agar is used to grow camplyobacter jejuni?

A

Karmali agar

  • charcoal based
  • contains vancomycin, cefoperazone, and cycloheximide to prevent growth of other organisms

**also cold sensitive

29
Q 
Diarrhea
Cramping
Abdominal pain
FEVER
Possibly BLOODY diarrhea
(2-5 day incubation, and symptoms can last up to a week)

Which bug?

A

Campylobacter jejuni

30
Q

Why is bloody diarrhea a possible symptom of camplyobacter jejuni?

A

Due to an inflammatory response to cell invasion by the organism

31
Q

What is a possible complication of campylobacter jejuni?

A

Guillain-Barre syndrome (autoimmunity against peripheral nervous system)

32
Q

What special things do Salmonella Shigella agar contain?

A

Bile salts- inhibits gram + organisms
Indicator - to detect lactose fermenting organisms (salmonella is not)
-Ferric citrate- indicates H2S production (why colonies appear black)

33
Q

Name 1 possible complication of salmonellosis…

A

Reactive arthritis

34
Q

What species is known as being “water loving”

Gram neg. rod with single flagellum

A

Vibrio Species

35
Q

What reagent would you use to distinguish E. coli and Vibrio cholerae?

A

Kovac’s oxidase reagent

E. coli = oxidase neg (would stay colorless)

Vibrio = oxidase pos (would turn pretty purple color)

36
Q

What things make Vibrio Parahaemolyticus pathogenic?

A 
Enterotoxins:
Hemolysin TDH (thermostable direct hemolysin) and/or TRH (zimmer never said what that was)
37
Q

Why should a pregnant woman not eat hot dogs?

A

She could get Listeria moncytogenes

38
Q

What is the invasive mechanism of Listeria monocytogenes?

A

Immune cells spread listeria to other organs (trojan horse) - you never know what could be inside! (Insert picture of Lester Drewes here)

Liver is major target

Once escaped from vacuole, cells in cytosol utilize actin polymerization to move and spread to new cell

39
Q

What population is more susceptible to Listeria infections?

A

Immunocompromised! It is an opportunistic pathogen

40
Q

How do you distinguish Shigella from the closely related E. coli?

A

Shigella have NO flagella, lactose negative, and non-motile

41
Q

What special symptom can some strains of shigella cause?

A

Dysentery = frequent, small bowel movements with blood and mucus

Accompanied by rectal pain and spasms

42
Q

How do shigella species gain access to our bodies? How do they get around

A

Through the M-cell!

They also have “actin rockets” to move around

43
Q

What changes “good” E. coli to “bad” E. coli?

A

They gain the ability to produce a toxin

44
Q

Possible complication of shigella if given antibiotics for infection?

A

HUS

45
Q

Which strain of shigella produces shiga toxin?

A

Shigella Dysenteriae

46
Q

What is the mechanism of the shiga toxin (AB5 toxin)?

A
  • bottom of 5 B subunits bind to Gb3 receptor
  • Subunit A gains access to cell
  • Subunit A inactivates ribosomes
47
Q

How can AB5 toxin be transmitted to other bacteria?

A

Lambda bacteriophage Vector

48
Q

Which E. coli produces Shiga toxin?

A

STEC (also called EHEC)

Shiga Toxin-producing E. Colig

49
Q

What E. coli produces travellers diarrhea and diarrhea in children?

A

ETEC

Enterotoxigenic E. Coli

50
Q 
Gram - bacteria
Bacillus
Facultative anaerobe
MOTILE
Non spore forming
LACTOSE POSITIVE

What bug?

A

E. Coli

51
Q

What is the main distinguishing symptom for E. Coli infection?

A

Diffuse Watery Diarreha

Also would have fever, chills, may progress to blood diarrhea, nausea

52
Q

2 Possible complications of STEC infection?

A

Hemorrhagic colitis
HUS

(Children more vulnerable)

53
Q

Is treatment usually recommended for E. coli infections?

A

Antibiotics generally NOT reccomended

54
Q

How does antibiotics lead to HUS?

A

Antibiotics at sub lethal doses causes increased production of toxin

Toxin causes vascular endothelial injury activating coag cascade

55
Q

What causes “rice water diarrhea”, loss of skin elasticity, and dry mucous membranes?

A

Vibrio Cholerae

56
Q

For which serotype of salmonella do we always do antibiotic treatment? why?

A

Salmonella Typhi (Typhoid fever)

Life-threatening illness, goes through GI tract to blood stream.

***After symptoms clear, person could still be a carrier

57
Q

What organism usually causes hospital associated diarrhea?

A

Clostridium difficile

Produce toxin

58
Q

Why is C. diff hard to culture?

A

Because it is an obligate anaerobe

GI Week 4 (8 decks)

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