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Infectious Disease Final > Lecture 11 - Legionella, Pseudomonas > Flashcards

Lecture 11 - Legionella, Pseudomonas Flashcards

1
Q

explain the structure of legionella pneumophilia
is it gram positive or negative?

A

slender, pleomorphic rods
gram NEGATIVE

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2
Q

what are the requirements for the growth of legionella pneumophila

A

OBLIGATE aerobe
also needs L-cysteine and ferric ions to grow

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3
Q

where is legionella pneumophila found?

A

ubiquitous (everywhere) in water and soil

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4
Q

legionella pneumophila has a strong tissue tropism for….

A

the LUNGS (specifically alveolar macrophages)

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5
Q

how does legionella pneumophila establish an infection

A

INTRACELLULAR macrophage infection

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6
Q

what is unique about legionella pneumophila

A

-LPS is less toxic than the LPS from other gram negative bacteria

-recruits ribosomes, mitochondria, and ER components into a phagosomal compartment

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7
Q

as mentioned, legionella pneumophila is unique in that it can recruit ribosomes, mitochondria, and ER components into a phagosomal compartment

what is the term for this compartment

A

LCV — legionella containing vacuole

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8
Q

how does legionella pneumophila produce this LCV (legionella containing vacuole)

A

it inhibits phagolysosome fusion and REMAINS in vacuoles where it replicates and produces proteolytic enzymes

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9
Q

does legionella pneumophila have a secretion system?

A

yes – type IV secretion system (nanosyringe) that delivers over 200 proteins, many of which are unknown

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10
Q

at later stages of infection, what does legionella pneumophila do?

A

produces pore-forming toxins to escape the LCV (vacuole) and the macrophage

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11
Q

what disease does legionella pneumophila cause?

A

causes destructive pneumonia
Legionnaires disease — severe form of pneumonia
-necrotizing multifocal pneumonia

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12
Q

does legionella pneumophila spread easily?

A

no – it rarely spreads outside of the lungs

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13
Q

what is very unique about pseudomonas aeruginosa

A

it produces colorful pigments

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14
Q

explain the structure of pseudomonas aeruginosa.
is it gram positive or negative?

A

gram negative
slightly curved, MOTILE rods. usually in PAIRS

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15
Q

explain the requirements needed for pseudomonas aeruginosa growth

A

aerobic
minimal requirements for its growth

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16
Q

what distinguishes psuedomonas aeruginosa from enterobacteriaceae?

A

it is cytochrome oxidase POSITIVE

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17
Q

what population does pseudomonas aeruginosa primarily infect? where is it found?

A

it is primarily opportunistic
infects burn victims

found in moist environments, UBIQUITOUS in nature and hospitals

18
Q

is pseudomonas aeruginosa encapsulated?

A

some produce a mucoid capsule – especially in cystic fibrosis

19
Q

pseudomonas aeruginosa primarily gets in through ______ but it can get in very slightly through _____

A

mainly through burns and wounds, but very slightly through lungs and eyes

20
Q

name the adhesins of pseudomonas aeruginosa

A

flagella, pili, LPS

21
Q

the mucoid capsule of pseudomonas aeruginosa is primarily composed of what?

A

alginate

22
Q

the expression of the mucoid capsule is under what kind of regulation?

A

gene regulation

23
Q

name 2 enzymes of pseudomonas aeruginosa and theur functions

A

elastases and phospholipases

elastases – degrade elastin, complement proteins, IgG and IgA. inhibits neutrophils

phospholipases – degradation of cell membranes

24
Q

what is the most important virulence factor of pseudomonas aeruginosa?
it has the same mechanism as what other toxin

A

Exotoxin A (exoA)
diphtheria toxin

25
Q

name a virulence factor (exclusive to pseudomonas aeruginosa) AND its function

A

Pyocyanin – induces the formation of toxic oxygen species and stimulates the release of CXCL8

26
Q

what bacteria has the virulence factor Exoenzyme S? what is itts function?

A

pseudomonas aeruginosa
acts on actin cytoskeleton and other signaling pathways. induces apoptosis of the host cell

delivered by a TYPE III SECRETION system

27
Q

explain how pseudomonas aeruginosa can evade the immune system

A

has elastases that degrade complement proteins, IgA, and IgG, inhibit neutrophils

28
Q

explain ExoA mechanism of pseudomonas aeruginosa

A

A subunit inhibits protein synthesis by binding to the ribosome

29
Q

true or false

most of the time, the immune system can handle a pseudomonas aeruginosa invasion

A

true

30
Q

does the actual pseudomonas aeruginosa bacteria get into the cell?

A

yes – the protective layer is gone in the case of burn victims. also, exoenzyme A and elastases degrade the cell so that the bacteria can then enter

31
Q

can pseudomonas aeruginosa cause bacteremia?

A

yes

32
Q

name another unusal thing about pseudomonas aeruginosa that makes it a clinical concern

A

it is inherently resistant to multiple antibiotics

33
Q

what antibiotics are pseudomonas aeruginosa resistant to?

A

beta lactams (penicillin), cephalosporins, and carbapenems

34
Q

explain how pseudomonas aeruginosa is resistant to beta lactams

A

prolific mutations increase their resistance (usually a PORIN PROTEIN mutation)

this mutant porin can block the antibiotic from entering the cell altogether

OR

it also contains beta lactamases that can inactivate beta lactams if they do get in

35
Q

pseudomonas aeruginosa are opportunistis. thus, when do they present themselves

A

-in burn victims
-following antibiotic treatment

36
Q

what kind of clinical diseases can P. aeruginosa cause (name 5 things)

A

LEADING COMPLICATION IN CYSTIC FIBROSIS
pulmonary infections
skin and soft tissue infections
bacteremia
endocarditis

37
Q

what does HAP stand for?
what bacteria is this an issue?

A

hospital acquired pneumonia
p. aeruginosa

commonly the source is respiratory equipment. patients with lung disease are highly susceptible

38
Q

the pulmonary infections caused by P. aeruginosa are primarily infecting the ____ respiratory tract and can range from ____ to _____

A

lower
asymptomatic to necrotizing bronchopneumonia

39
Q

name 3 skin and soft tissue infections caused by p. aeruginosa

A

wounds (burns)
ear and eye infections (contacts)
UTIs – catheters

40
Q

explain in detail how P. aeruginosa complicates things in cystic fibrosis patients

A

the bacteria adsorbs to the substratum of the lungs. some come off but most stay bound there. through quorum sensing, they begin alginate and exopolymer production to form MUCUS. this coats the lungs and O2 cannot get through.

the bacteria continue replicating in this mucus. the patient coughs up very thick amounts of this mucus

41
Q
A

Infectious Disease Final (13 decks)

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