Lecture 15 Flashcards

1
Q

L. monocytogenesis stain

A

GramPos

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2
Q

L. monocytogenesis on a plate

A

Thin, tannish rods

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3
Q

L. monocytogenesis environment

A

Produces acid but no gas from fermentation
Psycrophile (cold temps-deli meat)
Motile at room temp but not 37° (diphtheriods are)
Facultative intracellular anaerobe

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4
Q

L. monocytogenesis transmission

A

Is a native flora in animals

Infection usually from food

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5
Q

L. monocytogenesis clinical manifestation

A

Diarrhea and dysentary
Followed by meningitis or bacteremia (occassionaly myocarditis) in IC patients and infants
Also two perinatal versions from infected placenta (can cross during 3rd trimester)

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6
Q

What are two outcomes of fetal infection from L. monocytogenesis

A

Early onset-fetal sepsis and still birth (granulomatosis infantiseptica)
Late onset-Infant bacterial meningitis

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7
Q

L. monocytogenesis pathogenesis

A

Iron binding protein (found in meat)
Intracellular growth (hijacks the actin-internalin)
Low pH of phagolysosome produces listeriolysin O (phospholipase)
Break out of phagolysosome via listeriolysin O
ActA protein causes actin to polymerize (shigella does this too)
Spread cell to cell (avoid Ab response and Abx Tx)

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8
Q

L. monocytogenesis control

A
No vaccines
Amp preferred (also e-mycin)
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9
Q

Pseudomonas aeruginosa stain

A

GramNeg

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10
Q

Pseudomonas aeruginosa appearance

A

Rods with single flagellum

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11
Q

Pseudomonas aeruginosa oxygen?

A

Generally called obligate aerobe (can grow with nitrate as a final electron acceptor)

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12
Q

Pseudomonas aeruginosa found where?

A

Soil and aquatic habitat
Can use many carbon sources
Lives in moist areas of skin

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13
Q

What are two easy ways to identify Pseudomonas aeruginosa?

A

Fruit aroma

Green appearance

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14
Q

How does Pseudomonas aeruginosa colonize?

A

Quorum sensing for biofilm production (pseudomonas quinolone system-maybe quinolones Abx make this harder to treat?)

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15
Q

How does Pseudomonas aeruginosa often attack?

A

Almost always opportunistic
Nosocomial infection
Especially in burn PTs and diabetics (ecthyma gangrenosum)
CF PTs with biofilms in lungs (carry as URT flora)
Otitis externa (swimmer’s ear)
Eye infection (after trauma or surgery)
UTI from catheter or irrigation
Bacteremia in leukemia PTs, burn PTs, diabetics
Folliculitis (hot tub folliculitis) and acne

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16
Q

Pseudomonas aeruginosa pathogenesis

A

Adhesion pili for biofilm
Persister strains
Location in biofilms and alginate capsule inhibit phagocytosis
LPS
Exotoxin A (Dtx homolog-ADP ribosylates EF-2)
Exotoxin S (Signals apoptosis via inhibiting signal pathways)
Elastase (Destroys elastin in lungs)

17
Q

Pseudomonas aeruginosa control?

A
Sterile precautions for burn PTs
Topical Abx for wounds
Prevent BF formations
Very resistant to many Abx (cipro is good)
Avoid monotherapy
18
Q

Besides Pseudomonas aeruginosa what is another opportunistic in CF PTs?

A
Burkholderia cepacia (this is another pseudomonas)
Also on cathetars (UTI)
19
Q

What can cause ventilator-associated pneumonia?

A

Actinobacter baumanii (this is another pseudomonas)
Can cause septicemia
Very resistant

20
Q

What is characteristic of almost all anaerobe infections?

A

They are mixed

Need facultative anaerobes (have enzymes to detoxify ROS) and to keep a reduced environment

21
Q

When we talk about anaerobes, were are most infections?

A

Colon and mouth

22
Q

Bacteroides fragilis is found where? Oxygen requirement? Stain

A

Colon
Anaerobe
GramNeg rod

23
Q

Bacteroides fragilis virulence factors?

A

Has some enzymes for O2 detox
Antiphagocytic capsule
Neuraminidase and heparinase
LPS is not as toxic here

24
Q

Bacteroides fragilis clinical manifestation? Tx?

A

Can cause abdominal abscesses

Aminoglycoside Tx

25
Q

Prevotella melaninogenica location and stain?

A

Mouth, anaerobe

GramNeg coccobacillus

26
Q

Prevotella melaninogenica virulence factor

A

Collagenase

Can be found in brain and lung abscesses

27
Q

Porphyromonas gingivalis location and stain

A

Mouth

GramNeg rod

28
Q

Porphyromonas gingivalis manifestation

A

Gingivitis and oral abscesses

Also infections in warm, moist areas

29
Q

Peptostreptococcus location and stain

A

Colon

GramPos coccus

30
Q

Peptostreptococcus infections

A

Mixed infections (bacteremia) and pleura/lungs

31
Q

Propionibacterium acnes location and stain

A

Epidermal

GramPos pleomorphic rods

32
Q

Propionibacterium acnes infections

A

Acne

Brain abscess

33
Q

Anaerobe pathogenesis

A

Normal flora that enter via trauma
Produce tissue destructive enzymes
Can occur in abdomen, salpingitis, lungs, URT, brain

34
Q

Anaerobe control

A

Drainage of accumulated fluid
PenG if not bacteroides or prevotella
Metronidazole and clinda for bacteroides and prevotella