Bacterial Gastroenteritis (Exam #3) Flashcards

1
Q

What type of agar is used to diagnose Enterobacteriaceae (Bacterial Gastroenteritis)?

A

MacConkey agar

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2
Q

What results are seen on MacConkey agar for Salmonella?

A

Lac-

H2S+

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3
Q

What results are seen on MacConkey agar for E. coli?

A

Lac+

H2S-

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4
Q

What results are seen on MacConkey agar for Shigella?

A

Lac-

H2S-

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5
Q

What three VF are seen with almost all Enterobacteriaceae (Bacterial Gastroenteritis)?

A
  • Flagella (H antigen)
  • Capsule (K and Vi antigens)
  • LPS (O antigen)
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6
Q

Are Enterobacteriaceae (Bacterial Gastroenteritis) G- or G+?

A

G-

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7
Q

What VF allows for the transfer of bacterial proteins to the host cells?

A

T3SS

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8
Q

What is the general transmission for the three Enterobacteriaceae (Bacterial Gastroenteritis)?

A

Fecal-oral transmission via contaminated food/water

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9
Q

Of the three Enterobacteriaceae (Bacterial Gastroenteritis), which is NOT transmitted via person-to-person contact? Which need LOW vs HIGH infectious doses?

A

HIGH infectious dose = Salmonella enterica
- NOT spread person-to-person because of this

LOW infectious dose = E. coli and Shigella = spread person-to-person

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10
Q

What is the recommended treatment for Enterobacteriaceae (Bacterial Gastroenteritis)? What treatment is NOT recommended, and what would be the exception to this?

A

Supportive care

  • NO abx unless immunocompromised
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11
Q

What can be a complication of abx use with Enterobacteriaceae (Bacterial Gastroenteritis)?

A

DHUS = diarrhetic hemolytic uremic syndrome

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12
Q

By what two VF is Salmonella enterica serotyped by?

A
  • Flagella (H antigen)

- LPS (O antigen)

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13
Q

Based on serovars of Salmonella enterica, which two do NOT cause Bacterial Gastroenteritis?

A

No Typhi or Paratyphi = cause Bacterial Gastroenteritis

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14
Q

What organism involves the VF of SPI1 T3SS?

A

Salmonella enterica

- Bacterial Gastroenteritis

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15
Q

Which Enterobacteriaceae (Bacterial Gastroenteritis) can present systemically as bacteremia?

A

Salmonella enterica

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16
Q

What are the three types of E. coli that cause Bacterial Gastroenteritis?

A
  • Enterotoxic E. coli (ETEC)
  • Enterohemorrhagic E. coli (EHEC)
  • Enteroinvasive E. coli (EIEC)
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17
Q

Which of the three types of E. coli (Bacterial Gastroenteritis) is common in developing countries and travelers?

A

Enterotoxic E. coli (ETEC)

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18
Q

Which organism involves VF of LT1 and STb? What are these two VF, and what is an important characteristic of each?

A

Enterotoxic E. coli (ETEC)

  • LT1 = heat labile toxin
  • STb = heat stable toxin
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19
Q

With LT1 and STb of Enterotoxic E. coli (ETEC), what substance does each cause an increase in?

A
  • LT1 = increased cAMP

- STb = increased cGMP

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20
Q

With LT1 of Enterotoxic E. coli (ETEC), what toxin is it similar to?

A

LT1 is similar to Cholera AB toxin

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21
Q

What is another name for Enterohemorrhagic E. coli (EHEC)?

A

STEC = Shiga Toxin-producing E. Coli

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22
Q

What is the most common serotype of Enterohemorrhagic E. coli (EHEC)?

A

O157:H7

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23
Q

What four VF are associated with Enterohemorrhagic E. coli (EHEC)? What is a characteristics/important note for each?

A
  • Shiga-like toxin (binds human receptor)
  • AB toxin (stops protein synthesis)
  • Intimin (allows for adhesion
  • Tir T3SS (acts as Intimin receptor)
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24
Q

What organism is associated with Shiga-LIKE toxin?

A

Enterohemorrhagic E. coli (EHEC)

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25
Q

What organism is associated with Intimin and Tir T3SS?

A

Enterohemorrhagic E. coli (EHEC)

26
Q

What organism is essentially like Shigella, and what are three important characteristics about this organism?

A

Enteroinvasive E. coli (EIEC)

  • Obligate intracellular
  • NO flagella
  • No adhesions
27
Q

Which two Enterobacteriaceae (Bacterial Gastroenteritis) present with bloody diarrhea/dysentery?

A
  • Enteroinvasive E. coli (EIEC)

- Shigella

28
Q

What is the primary symptom associated with Shigella?

A

Bloody diarrhea/dysentery

29
Q

What three VF are associated with Shigella?

A
  • Shiga toxin 1
  • Shiga toxin 2
  • ShET1
  • ShET2
30
Q

Shiga toxin 1 is associated with what organism? What is it similar to, and how potent is it?

A

Shigella

  • Similar to O157:H7 Shiga-like toxin
  • VERY POTENT
31
Q

What is the most virulent form of Shigella?

A

Shigella dysenteriae

32
Q

What is an important VF associated with Cholera? What does this VF result in?

A
Cholera toxin (AB toxin)
- Causes increased cAMP → Cl secretion → other ions and water follow = osmotic diarrhea
33
Q

What two signs/symptoms present with Cholera?

A
  • Watery diarrhea

- Dehydration

34
Q

Is Vibrio Cholerae G- or G+? What is its shape?

A

G- curved rod

35
Q

What population is C. diff most common in?

A

Hospitalized patients on abx

36
Q

Is C. diff G- or G+? What is an important characteristic of this organism?

A

G+

- Obligate anaerobe

37
Q

What two VF are associated with C. diff?

A
  • Endospores (infectious)

- Toxins (A and B)

38
Q

If life-threatening case of C. diff, what two conditions may present?

A
  • Colitis

- Pseudomembranous colitis

39
Q

What two treatments MUST be performed with C. diff patients? What other treatment may be considered?

A
  • STOP ABX
  • ISOLATE PATIENT

Consider fecal transplant

40
Q

Why must C. diff patients be isolated, and what are you at risk of if you do not isolate?

A

Endospores only killed by autoclave (and you can’t autoclave an entire room…)
- At risk for recurrence due to endospores

41
Q

Is Campylobacter G- or G+? What is its shape?

A

G- spiral rod

42
Q

What is the most common cause of Bacterial Gastroenteritis in the U.S.?

A

Campylobacter

43
Q

What organism requires gas concentrations to grow?

A

Campylobacter

- Bacterial Gastroenteritis

44
Q

What organism is associated with Guillain-Barre Syndrome?

A

Campylobacter jejuni

- Bacterial Gastroenteritis

45
Q

Which two diagnostic tests are used to diagnose Campylobacter?

A
  • S-shaped organisms in stool sample

- Antigen detection (Campy)

46
Q

Does Campylobacter require a high or low infectious dose?

A

LOW

47
Q

What organism is similar to Campylobacter?

A

Haemophilus pylori

- Bacterial Gastroenteritis

48
Q

What organism produces urease, oxidase+ and catalase+?

A

Haemophilus pylori

- Bacterial Gastroenteritis

49
Q

What organism produces urease, and how does this benefit the organism?

A

Haemophilus pylori
- Bacterial Gastroenteritis

Alkalizes environment and allows for survival in acidic stomach

50
Q

What two VF are associated with Haemophilus pylori?

A
  • VacA

- CagA

51
Q

What two conditions are associated with Haemophilus pylori? Which of its VF can increase risk for one of these conditions?

A
  • Gastric ulcers

- Gastric CA = CagA+ increases risk for Gastric CA

52
Q

What organism is associated with VF of VacA and CagA, and what condition is a patient at increased risk for if CagA is +?

A

Haemophilus pylori
- Bacterial Gastroenteritis

CagA+ increases risk for Gastric CA, especially in E. Asia

53
Q

What diagnostic test is used for Haemophilus pylori?

A

Antigen detection (H. pylori antigens)

54
Q

What organism is associated with foodborne intoxication if food gets below 60 degrees?

A

Clostridium perfringens

- Bacterial Gastroenteritis

55
Q

Are Bacillus spp. G+ or G-? How might this appear on stain?

A

G+ in CHAINS

56
Q

What organism is associated with emetic AND diarrheal disease?

A

Bacillus cereus

57
Q

With Bacillus cereus, what type of toxin causes emetic disease and which causes diarrheal disease? What is a possible food source for each?

A
  • Emetic = heat stable toxin = eating rice

- Diarrheal = heat labile toxin = eating meat/veggies

58
Q

What is an important VF associated with Bacillus spp. (Bacterial Gastroenteritis)?

A

Form spores

59
Q

What test can be used to differentiate Staphylococcus spp. from other G+ cocci?

A

Catalase

- Staphylococcus = catalase+

60
Q

What VF is associated with Staphylococcus spp. (Bacterial Gastroenteritis)?

A

Superantigens = enterotoxins (heat labile)