Bacterial Pneumonia 2 (6) Flashcards

1
Q

What is the bacteriology or Legionella?

A

Poorly staining gram (-) rods

Facultative intracellular parasite

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2
Q

What are the two “phases” of Legionella bacteria?

A

Infectious phase: free- lining motile with flagella

Replicative phase: intracellular nonmotile

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3
Q

What is the natural lifestyle of legionella?

A

Form biofilms in stagnant freshwater–> parasitize protozoa–> complete full life cycle

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4
Q

What is the unnatural lifestyle of legionella?

A

Form biofilms in HVAC systems–> enters human lungs–> parasitize alveolar macrophages–> dead end

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5
Q

What occurs when humans breath in/ aspirate water contaminated with legionella?

A

1- asymptomatic seroconversion

2- Pontiac fever

3- Legionnaires Disease

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6
Q

What are the steps in the pathogenesis of legionella?

A

1- Taken up by macrophages

2- Contained in an altered phagosome

3- T4SS fusion with lysosome and replicates within the phagosome

4- Becomes motile and escapes phagosome

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7
Q

Virulence factors/gene loci of legionella?

A

1- mip: invade monocytes

2- Dot/ Icm locus: T4SS

3- PilE and PilD: pilus formation (attachment)

4- Mac/ pmi/ Mil: unknown function

5- Pep/ Pro: Zinc metalloprotease (escape from phagosome)

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8
Q

Describe Pontiac fever?

A

Present hours- 2 days after exposure

Flu like symptoms

Patient previously healthy

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9
Q

What generates the symptoms in pontiac fever?

A

Symptoms are immunogenic…as the immune system kills live and or clears dead bacteria

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10
Q

What are the risk factors for developing legionnaires disease?

A

Patient is previously ill, elderly, immunosuppressed, diabetic, has heart/ lung disease, smokes, has kidney disease, has alcohol at time of exposure

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11
Q

What are the symptoms of Legionnaires disease?

A

Pneumonia w/ kidney involvement and diarrhea

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12
Q

What are key factors in the history to look for when diagnosing Legionnaires disease?

A

Male, elderly, pre-existing malfunction or swallowing, immunity or respiratory systems

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13
Q

What are the lab tests to Dx Legionella infections?

A

Urine antigen tests–> quicly detects LP1 strain (90% of US infections)

Culture–> requires special nutrients, slow, needed to trace outbreaks

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14
Q

What is the treatment for pontiac fever?

A

Usually resolves without treatment

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15
Q

What is the treatment for legionnaires disease?

A

Admit to the hospital

Fluoroquinolones, doxy, azithromycin, or macrolides

Supportive care for recovery

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16
Q

What is the bacteriology of C. burnetii?

A

Proteobacteria (related to legionella)…related to legionella

Extremely infectious!!

17
Q

Virulence factors of C. burnetii?

A

Acid phophatase and superoxide dismutase–> help bacteria survive in FUSED lysosome-endosome

18
Q

Where is C. burnetii common?

A

Netherlands, France, Spain and Iraq

19
Q

What organs does C. burnetii infect though “trojan horse” macrophages?

A

Liver, spleen, bone marrow

20
Q

What are the symptoms of a C. burnetti infection?

A

Pneumonia and Hepatitis!

also: fever, HA, chills, sweats, dry cough

21
Q

Treatment for C. burnetti infection?

A

Doxycyclines or fluoroquinolones

Can be prevented with vaccine

22
Q

What is the bacteriology of mycoplasma pneumoniae?

A

Smallest free living organism

Strictly aerobic

No cell wall

Cell membrane contains cholesterol

23
Q

How many serotypes are there of mycoplasma pneumoniae?

A

only 1…but immunity is incomplete

24
Q

What is the pathogenesis of Mycoplasma pneumoniae?

A

Pathogenic only to humans and transmitted by respiratory droplets

In lungs it assumes a rod shape…P1 adhesion binds to respiraoty epithelium

25
What diseases are caused by Mycoplasma pneumoniae?
Tracheobronchitis, bronchiolitis, Atypical pneumonia (walking pneumonia)
26
Why can Mycoplasma pneumonia cause anemia?
Cold agglutinins that attack and destroy RBCs
27
What are the virulence factors of Mycoplasma pneumoniae?
P1 adhesion CARDS endotoxin Bacterial metabolism produces hydrogen peroxide (which damages tissue)
28
Symptoms of Mycoplasma pneuominiae?
Nonproductuve cough, sore throat, earache, small amounts of whitish sputum, fever, HA, myalgia, malaise
29
What will a CXR for Mycoplasma pneumoniae show?
Prominent infiltrates
30
What are the lab tests used to Dx Mycoplasma pneumoniae?
Not usually required Culture is possible but requires special media Serology for cold agglutinings Complement fixation shows increased in specific antibodies
31
Treatment for Mycoplasma pneumoniae?
Macrolides or tetracyclines or fluoroqunolones Extended course of treatment (10-14 days) because it is slow growing