Hospital-acquired pneumonia (HAP) affects 0.5–1.0% of inpatients and is the commonest healthcare-associated infection contributing to death.

The mortality rate of HAP is between 30–70%. It increases hospital stay by 7–9 days.

In immunocompetent patients, HAP is typically caused by bacteria (e.g. Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus) and rarely by viral or fungal pathogens.

Risk factors for hospital-acquired pneumonia are:

• Age >70
• Chronic lung disease
• Diabetes
• Reduced level of consciousness
• Recent chest or abdominal surgery
• Mechanical ventilation
• Nasogastric feeding
• Immunosuppression (e.g. long-term corticosteroid use, chemotherapy)