Lecture 5 Part 2: Pseudomonas & Other Opportunistic Gram-negative Bacilli Flashcards
What is the shape and motility of Pseudomonas aeruginosa?
Pseudomonas aeruginosa is a Gram-negative, slightly curved, motile rod, usually paired
Does Pseudomonas aeruginosa ferment glucose?
No, it oxidizes glucose (non-fermentative)
What are the oxygen requirements for Pseudomonas aeruginosa?
It is aerobic with minimal requirements
**
How does Pseudomonas aeruginosa distinguish itself from Enterobacteriaceae?
It is cytochrome oxidase positive, which helps distinguish it from Enterobacteriaceae
What type of pigments does Pseudomonas aeruginosa produce?
It produces colorful pigments
Does Pseudomonas aeruginosa produce a capsule?
Some strains produce a mucoid capsule
Where is Pseudomonas aeruginosa commonly found?
Found in moist environments, superficial colonizers
(ubiquitous in nature and hospitals)
What type of pathogen is Pseudomonas aeruginosa?
Primarily opportunistic
Is Pseudomonas aeruginosa usually part of the endogenous flora?
Not usually carried among endogenous flora
List the Virulence factors for Pseudomonas aeruginosa
1. Mucoid capsule
2. Type III Secretion System
3. Adhesins
4. Flagella
5. Pili
6. LPS
7. Alginate (mucoid capsule component; expression under genetic regulation)
8. Exotoxin A
9. Exoenzymes S & T
10. Pyocyanin (exclusive to P. aeruginosa)
11. Pyoverdin
12. Elastases
13. Alkaline protease
14. Phospholipase C
What is the most important virulence factor of Pseudomonas aeruginosa?
Exotoxin A (ExoA)
How does Exotoxin A (ExoA) contribute to virulence?
It blocks peptide chain elongation
Exotoxin A has the same mechanism of action as which bacterial toxin?
Diphtheria toxin
What are Exoenzymes S & T, and what do they do?
They are extracellular cytotoxins that act on the actin cytoskeleton and other signaling pathways
What is Pyocyanin, and why is it significant?
- Pyocyanin is exclusive to Pseudomonas aeruginosa
- induces the formation of toxic oxygen species
- stimulates release of IL-8 (CXCL8)
What is Pyoverdin, and what is its function?
- Pyoverdin is a siderophore that binds iron
- Pyoverdin regulates the secretion of Exotoxin A (ETA)
What is the function of elastases in Pseudomonas aeruginosa?
- Elastases degrade elastin and complement proteins
- Elastases inhibit neutrophil activity
What is the role of alkaline protease in Pseudomonas aeruginosa?
What does phospholipase C do in Pseudomonas aeruginosa?
(listed on the slide with no note so i just put a little sum so we know what is is)
Alkaline protease degrades host proteins
**Phospholipase C **degrades phospholipids in host cell membranes
Is Pseudomonas aeruginosa naturally resistant to antibiotics?
Yes, it is inherently resistant to many antibiotics
How does Pseudomonas aeruginosa develop increased antibiotic resistance, and what role do porin protein mutations play?
- Prolific mutations increase resistance
- Usually porin protein mutation
- Antibiotics usually pass outer membrane through porins
What are β-lactamases, and how do they contribute to resistance?
β-lactamases are enzymes that inactivate β-lactam
Which antibiotics are affected by β-lactamases produced by Pseudomonas aeruginosa?
Penicillins, cephalosporins, and carbapenems
TRUE OR FALSE
Penicillins, cephalosporins, and carbapenems are commonly inactivated by Pseudomonas aeruginosa’s β-lactamases
True
true or false
β-lactamases help antibiotics work more effectively against Pseudomonas aeruginosa.
False – β-lactamases break down β-lactam antibiotics, making them ineffective.
What type of pathogen is Pseudomonas aeruginosa?
It is an opportunistic pathogen
When are Pseudomonas aeruginosa infections commonly seen?
**They often occur after broad-spectrum antibiotic treatment
Does Pseudomonas aeruginosa lead to complication in Cystic Fibrosis**?
yes
**Pulmonary infections associated with Pseudomonas aeruginosa
- Respiratory equipment – major source
- Patients with lung disease highly susceptible
- Lower respiratory tract —> asymptomatic to necrotizing bronchopneumonia
TRUE OR FALSE
Burn wounds are particularly susceptible to Pseudomonas aeruginosa infections.
true
What type of wounds are particularly susceptible to Pseudomonas aeruginosa infections?
Burn wounds, suceptible to bacteremia
What other infections can Pseudomonas aeruginosa cause?
Ear infections and eye infections
UTIs (especially with indwelling catheters)
bacteremia, and endocarditis (in immunocompromised patients)
