Primary pneumonia due to Pseudomonas aeruginosa in healthy individuals is rare.
Infection normally develops in debilitated individuals with pre-existing lung disease, such as bronchiectasis, chronic bronchitis or cystic fibrosis, or following an aspiration pneumonia induced by sedation or endotracheal intubation.
It is a common hospital acquired pneumonia.
Secondary infection usually develops after the eradication of more sensitive flora with antibiotics and in patients with neutropaenia due to cytotoxic chemotherapy.
Pseudomonas pneumonia is of considerable clinical significance in patients with cystic fibrosis since it correlates with worsening clinical condition and increased mortality.