Pseudomonas aeruginosa: Overview
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Pseudomonas aeruginosa overview
- Characteristics
- Gram negative rod
- Have a motile appearance on microscopy
- Oxidase +
- Encapsulated
- Higher risk of severe infection in asplenic patients (prior surgery, sickle cell)
- Catalase +
- Non-lactose fermenting
- Has a grape-like odor
- Aerobic
- Biofilm formation may contribute to pneumonia in cystic fibrosis
- Gram negative rod
- Virulence Factors
- Exotoxin A
- inactivates EF-2 (elongation factor) via ADP ribosylation
- inhibits protein synthesis at the ribosome, since EF-2 is needed to translocate tRNA to allow peptide elongation
- Similar mechanism to diphtheria toxin (Corynebacterium diphtheriae)
- Pyoverdine and pyocyanin
- blue-green pigment often seen on microscopy
- Generates reactive oxygen species
- Phospholipase C
- Breaks down phospholipids to degrade cell membranes
- Endotoxin
- Causes fever, shock, and DIC in patients
- Seen in all gram-negative bacteria due to LPS in the bacterial membrane
- Elastase
- Breaks down elastin
- Important for blood vessel and connective tissue destruction (e.g. ecthyma gangrenosum)
- Exotoxin A