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Unit 6: Micro > Enteric Bacterial Infections 4: Campylobacter, Helicobacter, and Listeria > Flashcards

Enteric Bacterial Infections 4: Campylobacter, Helicobacter, and Listeria Flashcards

1
Q

What are the cellular characteristics of Campylobacter?

A
  • Comma/S-shaped
  • Gram (-) Rods
  • Motile
  • Oxidase (+)
  • Catalase (+)
  • Microaerophilic
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2
Q

What is microaerophilia?

A

Bacterial lifestyle in which bugs need a little bit of oxygen to grow

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3
Q

What is the reservoir of Campylobacter?

A

Domestic animals (100% of poultry)

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4
Q

What are protective mechanisms against Campylobacter?

A

Stomach acid

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5
Q

What is the relative infectious dose of Campylobacter?

A

High due to stomach acid

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6
Q

What is the pathogenesis of Campylobacter jejuni?

A
  • C. gets ingested and attaches to the brushborder
  • C. gets endocytosed
  • C. resists phagocytosis
  • Has T4SS which injects proteins into epithelium and Cytolethal toxin which causes necrosis of the cells
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7
Q

What are Syx of Campylobacter infection?

A

Initially watery foul-smelling diarrhea follwed by bloody stools with fever and abdominal pain

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8
Q

What is the culture procedure for Campylobacter?

A
  • Stool sample
  • Blood agar with ABs to inhibit normal flora
  • Two plates - 45C and 25C - Bugs should fail at low temperature
  • Microaerophilic - 5% oxygen, 10% CO2
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9
Q

What is the Tx strategy for Campylobacter infection?

A
  • Self-limited - rehydrate
  • AB - if child, high fever, blood diarrhea, >8 stools/day, worsening Syx, illness > 1wk, pregnancy, HIV
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10
Q

What is a big no-no for Campylobacter Tx?

A

DO NOT use antimotility agents

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11
Q

What is different b/w vibrio and campylobacter ubiology?

A
  • Reservoir
  • Growth at room T
  • Risk of reactive arthritis
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12
Q

What does Campylobacter strongly predispose a person to?

A

Guillain-Barre syndrome

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13
Q

What are the cellular characteristics of Heliobacter pylori?

A
  • Curved Gram (-) rod
  • STRONGLY urease (+)
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14
Q

What diseases are H. pylori associated with?

A
  • PUD
  • Mucosa-associatd lymphoid tissue (MALT) lymphomas, gastric lymphoma, adenocarcinoma of the stomach
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15
Q

What is the pathogenesis of H. pylori?

A
  1. Transmission unknown
  2. Bacteria attach to mucus-secreting cells of stomach w/ flagella
  3. Break down urea into ammonia w/ urease
  4. Ammonia neutralizes stomach pH, allowing bacterial growth and irritation of stomach lining
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16
Q

What other strategies does H. pylori utilize when infection its host?

A
  • Causes infiltration by proinflamm. cells
  • Upregulate caspases = apoptosis
  • Vac-A cytotoxin (some strains)
  • Cag-A chemotactic factor for neutrophils
17
Q

Typical Syx of those with H. pylori?

A

Generally asymptomatic, but can result in gastric bleeding ulcers

18
Q

What are the tests for H. pylori?

A

Radiolabeled Urea given to a patient. If H. pylori present, the patient will breathe off Radiolabeled CO2; PCR in the pipeline

19
Q

Tx of H. pylori?

A
  • Reduce irriation with bismuth salts
  • PPIs
  • Kill bacteria with triple AB therapies
20
Q

What are the cellular characteristics of Listeria monocytogenes?

A
  • Gram (+) rod
  • Facultatively anaerobic
  • Blue-green sheen on non-blood agar
  • Forms Ls and Vs on agar
  • Tumbling motility
  • Beta hemolytic
  • Grows well in cold
21
Q

What is the route of transmission of Listeria?

A

Infection from environmentally-contaminated food

22
Q

What are the serious complications of Liseria infection and the typical scenarios?

A

If immuncompromised, Listeria escapes GI tract, causing complications of pregnancy, meningitis, abscess, endocarditis, etc

23
Q

Describe the pathogenesis of Listeria in pregnancy

A

Bacteria escapes GI and proliferates in placenta (especially in the 3rd trimester) resulting in preterm labor, abortion, stillbirth, and intrauterine infection

24
Q

What does transmission of Listeria across the placenta cause? From the vaginia?

A
  • Transplacental - Early-onset sepsis and premature birth with abscesses/granulomas
  • Transvaginal - late-onset meningitis with sepsis
25
Q

What laboratory tests are used to Dx Listeria?

A
  • Blood culture
  • Spinal Tap

Look for motile bacteria with tumbling motility

26
Q

What area the Tx options for Listeria?

A

ABs are indicated if CNS manifestations or bacteremia; Ampicillin/Gentamicin combo

27
Q

How to prevent Listeria?

A
  • Cook food, wash hands, vegetables
  • Avoid unpasturized milk
  • IF PREGNANT - avoid leftover or read-to-eat mfoods until steaming (including deli meat); No soft cheeses

Unit 6: Micro (13 decks)

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