M- Nosocomial Pneumonia Flashcards Preview

Respiratory/Musculoskeletal > M- Nosocomial Pneumonia > Flashcards

Flashcards in M- Nosocomial Pneumonia Deck (46):
1

What are the laboratory features of P. aeruginosa?

-Gram negative rod
- aerobic, non-fermentor
- oxidase +
-pyocyanin, pyoverdin, pyorubin (blue, green, red pigment production)

2

What is the normal environment of pseudomonas aeruginosa?

Moist environments like:
soil, water, plant surfaces (artificial or natural)

3

What is the prevalence of P. aeruginosa infections in US hospitals?
How does it rank in terms of nosocomial pathogens?

It infects 4/1000 (0.4%) and is the fourth most common nosocomial pathogen isolated

4

What 3 manifestations can P. aeruginosa have in immunocompetent hosts?

1. Folliculitis
2. otitis externa
3. puncture wound osteomyelitis

5

What are the 5 manifestations of P. aeruginosa in immunocompromised hosts?

1. malignant external otitis (diabetics)
2. bacteremia (neutropenics)
3. ecthyma gangrenosum (neturopenics)
4. nosocomial/ventilator associated pneumonia
5. tracheobronchial infection (CF)

6

Who is most at risk for developing external otitis (not the malignant form)?
What is the mechanism by which it occurs?
What are the symptoms?
How is it treated?

Swimmers, divers are most at risk

1. Maceration of the canal epithelium from moisture
2. microbial invasion through the breach

Symptoms: ear pain and discharge
Treatment: topical antibiotics (if they wait too long- oral)

7

Who is most at risk for developing folliculitis from P. aeruginosa?
What is the progression of the folliculitis? What is the incubation period?
What gland does it have a predilection for?

How do you treat?

Hot tub or swimming pool exposure increases the risk for p. aeruginosa folliculitis especially if there is
- inadequate chlorine
- high pH
- crowding (too much nitrogenous waste inactivates chlorine)

The incubation of the bacteria is 72 hours and then the person will get pruritic papules (itchy dots) to pustules (pus filled bump).

Predilection for apocrine sweat glands

DO NOT USE STEROIDS-- it will resolve spontaneously. Steroids wipe out normal flora allowing for overgrowth of p. aeruginosa.

8

What drug should you not use to treat folliculitis caused by P. aeruginosa? Why?

Steroids because that will wipe out the normal flora and the p. aeruginosa can overgrow

9

What causes puncture wound osteomyelitis?
What is the incubation period?
What is the main site of infection?
What is treatment?

Stepping on a nail/rusty object in old shoes can cause puncture wound osteomyelitis.
The infection occurs 1-4 weeks after the puncture and infects the small bones of the foot and the cartilage (chrondritis, osteomyelitis)

Treatment is IV antibiotics (cefepime/ceftazidime, ciprofloxacin) for 3-6 months

A large worry for diabetics because of diabetic neuropathy, they may not even know if they have stepped on a nail!

10

Who is at the highest risk of developing malignant external otitis?
Describe how invasion of P. aeruginosa occurs.

What are the major symptoms?
What is treatment?

Diabetics and adults >60 are at greatest risk.
P. aeruginosa invades through fissures of Santorini.

Symptoms:
1. SEVERE pain and discharge
2. CN palsies (esp 7)
3. fever/leukocytosis (rare)

Treatment: oral/IV antibiotics + topical

11

What are the 4 clinical manifestations of p. aeruginosa most commonly associated with neutropenic patients?

1. bacteremia
2. ectheyma gangrenosum
3. pneumonia
4. septic shock

12

How does p. aeruginosa cause bacteremia in neutropenic patients?

What is the result?
How is it treated?

1. GI colonization after exposure (salads, flowers, moisture)
2. penetrates across denuded (eroded) mucosa

Causes:
bacteremia, ecthyma gangrenosum, pneumonia, septic shock.

It is treated with IV antibiotics, sometimes GMCSF to replenish neutrophils, but if you wait too long, it may require surgical debridement

13

What is the pathology of ecthyma gangrenosum?
What areas of the body are most affected?
What is the characteristic progression?

It is when bacteria invade the vasculature and replace the walls of veins with bacteria.
It occurs frequently in:
Glutes
genitalia
abdomen
due to being bed bound/moist areas

Progression:
edema->erythema-> hemorrhagic bulla-> necrosis

14

_______________ is the most common multidrug resistant gram negative bacterium that causes nosocomial pneumonias/ health care associated pneumonias.

P. aeruginosa

15

What is considered "early onset" pneumonia in a hospital setting?
What are the typical pathogens associated with early onset?

It is pneumonia less than 3 days after hospitalization.

Community-acquired pathogens are usually to blame. They are antibiotic susceptible though usually/
1. S. pneumoniae and H influenza
2. MRSA or susceptible S. aureus
3. anaerobes

16

What is considered "late onset" pneumonia in a hospital setting?
What are the typical organisms to blame?

Over 4 days after hospitalization- the organisms are usually "hospital-acquired" and drug resistant.

Ventilator-acquired:
1. gram negative bacilli (p. aeruginosa, actinobacter, strenophomonas)
2. S. aureus (usually MRSA)

17

What is the attributable mortality of a HAP?
How long does it prolong treatment by?
How much does ventilator increase the risk?

30-50% mortality for HAP.
It prolongs treatment by 7-9 days (excess 2 bil/year)
Ventilator increases risk by 6-20 fold

18

What are patient related reasons for nosocomial pneumonia?

1. Age >70
2. malnutrition
3. underlying illness
4. CNS dysfunction
5. Cig smoke, alcoholism
6. Pulmonary disease
7. DM, kidney injury
8, Trauma
9. burns
10. witnessed aspirations

18

What are patient related reasons for nosocomial pneumonia?

1. Age >70
2. malnutrition
3. underlying illness
4. CNS dysfunction
5. Cig smoke, alcoholism
6. Pulmonary disease
7. DM, kidney injury
8, Trauma
9. burns
10. witnessed aspirations

19

What are intervention-related causes of nosocomial pneumonia?

1. mechanical ventilation
2. paralytic agents
3. surgery (thoracic/abdominal)
4. antimicrobial exposure- resistant organisms
5. NG or ET tubes (biofilms)
6. pooled secretions
7. head of bed <30 degrees

19

What are intervention-related causes of nosocomial pneumonia?

1. mechanical ventilation
2. paralytic agents
3. surgery (thoracic/abdominal)
4. antimicrobial exposure- resistant organisms
5. NG or ET tubes (biofilms)
6. pooled secretions
7. head of bed <30 degrees

20

What are infection-control related causes of nosocomial pneumonia?

1. lack of hand hygiene
2. failure to use gloves
3. contaminated respiratory equipment

20

What are infection-control related causes of nosocomial pneumonia?

1. lack of hand hygiene
2. failure to use gloves
3. contaminated respiratory equipment

21

What are mechanisms by which a non-intubated patient would aspirate oropharyngeal secretions?

1. abnormal swallowing (stroke)
2. depressed consciousness
3. GI tract instrumentation
4. Recent surgery
5. supine position

21

What are mechanisms by which a non-intubated patient would aspirate oropharyngeal secretions?

1. abnormal swallowing (stroke)
2. depressed consciousness
3. GI tract instrumentation
4. Recent surgery
5. supine position

22

When does gram negative bacterial colonization of oropharyngeal secretions occur?
What are the factors that contribute to this?

A few days after admission to ICU
1. increased adherence to oropharyngeal epithelium
2. gastric reservoir, indwelling on gastric tubes
3. bronchoscopy
4. contaminated nebulizer

22

When does gram negative bacterial colonization of oropharyngeal secretions occur?
What are the factors that contribute to this?

A few days after admission to ICU
1. increased adherence to oropharyngeal epithelium
2. gastric reservoir, indwelling on gastric tubes
3. bronchoscopy
4. contaminated nebulizer

23

What is treatment of G- rods that cause hospital-acquired pneumonia?
How many should you give when it is suspected?
What is the only oral agent?

1. Anti-pseudomonal cephalosporin, carbepenem, b-lactam/b-lactamase inhibitor
2. antipseudomonal fluoroquinolones (ciprofloxacin, levofloxacin)
3. aminoglycosides (tobramyacin)

Fluoroquinolones are the only oral agents!
Give 2 because it takes days to get back sensitivities

23

What is treatment of G- rods that cause hospital-acquired pneumonia?
How many should you give when it is suspected?
What is the only oral agent?

1. Anti-pseudomonal cephalosporin, carbepenem, b-lactam/b-lactamase inhibitor
2. antipseudomonal fluoroquinolones (ciprofloxacin, levofloxacin)
3. aminoglycosides (tobramyacin)

Fluoroquinolones are the only oral agents!
Give 2 because it takes days to get back sensitivities

24

What is the treatment of MRSA causing hospital-acquired pneumonia?

VANCO or linezolid

24

What is the treatment of MRSA causing hospital-acquired pneumonia?

VANCO or linezolid

25

What are simple ways nosocomial pneumonia can be prevented?

1. hand washing
2. prevent aspiration - semi-recumbent, avoid large gastric volumes, subglottic suctioning
3. minimize time for NG/OG tubes
4. routine maintenance of ventilators

25

What are simple ways nosocomial pneumonia can be prevented?

1. hand washing
2. prevent aspiration - semi-recumbent, avoid large gastric volumes, subglottic suctioning
3. minimize time for NG/OG tubes
4. routine maintenance of ventilators

26

What is the leading cause of morbidity and mortality in burn victims?
What are 5 ways this can be prevented?

infection is the leading cause of morbidity and mortality and can be prevented by:
1. aseptic technique
2. sterile gloves/dressing material
3. wearing mask when changing dressing
4. spacial separation for patients (private rooms)
5. NO flowers/plants in units bc they harbor G- bacteria

27

What are the 5 respiratory manifestations of CF?

1. abnormal mucociliary clearance
2. chronic cough, sputum production
3. obstructed airway
4. frequent infection
5. bronchiectasis

28

What are the 2 major modes of pseudomonas infection?
Which is more invasive/ causes more bacteremia?

Motile - most common mode :
1. invasion with local spread (otitis externa, ecthyma gangrenosum)
2. invasion with systemic spread (bacteremia, pneumonia, burn wound infection)

Stationary mode - pulmonary infection in CF

29

What are the P. aeruginosa virulence factors in the motile mode?

1. flagella - motility
2. pili- adherence to epithelial cells
3. LPS- endotoxin
4. Secreted proteins:
- exo A, exo S
- elastase/protease
- phospholipase C

30

What are the 4 structural components that serve as virulence factors for P. aeruginosa?

1. flagella and pili - motility and adherence to epithelia
2. pyocyanin- impairs ciliary function
3. LPS- endotoxin
4. Capsule- prevent phagoctosis, inhibit antibiotics

31

What causes the switch of p. aeruginosa to the stationary mode?
Where does it grow?

It switches to stationary by losing the flagella

It grows in airways, surrounded by ECM, protected from antibodies, phagocytosis and antibiotics (biofilm)

There is minimal invasion, minimal bacteremia

32

What causes CF?
When are most patients colonized in the airways with p. aeruginosa? How are they able to live here?

It is an autosomal recessive mutation in the CFTR chloride channel on apical surfaces of epithelial cells.
Airways are colonized by 18 and the pseudomonas is protected from antibodies, antibiotics, and host defenses by biofilm formation

33

How does CF disrupt mucocilliary clearance?

It has excess mucus production, with decreased airway surface liquid. This impairs the mucociliary clearance and pathogens get "trapped" in the viscous mucous.

34

What are the main clinical features of CF?

1. chronic sinusitis
2. bronchiectasis
3. pancreatic insufficiency- steatorhea
4. male infertility
Plenty of others - lower respiratory infections, abnormal sweat secretions, diabetes, liver disease, kidney diseas, osteoporosis

35

What are the 5 respiratory manifestations of CF?

1. abnormal mucociliary clearance
2. chronic cough, sputum production
3. obstructed airway
4. frequent infection
5. bronchiectasis

36

For someone with CF, what is the most likely cause of infection from :
1. birth to 18
2. 18- 45+

1. oxacillin sensitive S. aureus

2. pseudomonas aeruginosa (slightly less staph, but still up there)

37

What most contributes to P. aeruginosa resistance over time?

P. aeruginosa undergoes a phenotypic switch from non-mucoid to mucoid type.
This means it overproduces ALGINATE (negatively charged polymer) which contributes to BIOFILM formation

38

What is treatment of pseudomonas in CF?

1. airway clearing therapy (bronchodilator, inhaled Antibiotics)
2. Anti-pseudomonal antibiotics:
Oral: fluoroquinolones
IV: aminoglycosides + b-lactam

3. Chronic maintenance requires nebulized antibiotics