Hospital-Acquired Pneumonia (HAP)

Definition

  • Pneumonia that develops 48 hours or more after hospital admission OR
  • Pneumonia in a patient that has been discharged from hospital within the last 7 to 10 days.
Residents of care homes or long-term care facilities who develop symptoms in their usual environment should be treated as community-acquired pneumonia (CAP).

Duration

  • Duration: The recommended treatment course is 5 days. Review the patient at day 5 and stop antibiotics if clinically stable (afebrile for 48 hours, stable blood pressure and heart rate).
  • Biomarkers: Consider measuring CRP 3 to 4 days after starting treatment if there is concern about treatment failure. Levels that do not decrease significantly are associated with treatment failure and require senior review.
Category Antimicrobial
Mild early onset HAP (>2 days <5days post admission) Doxycycline PO 200mg on day 1 then 100mg daily
Late onset (>5 days) or moderate-severe HAP without MDR risk factors 1st line: Co-trimoxazole IV or oral 960mg 12 hourly
AND
Gentamicin IV dosed as per NHS AA dosing guideline

 

2nd line or contraindications to co-trimoxazole or gentamicin:

Amoxicillin IV 1g 8-hourly
AND
Increased exposure dose Temocillin IV (adjusted for renal function)

 

3rd line or true penicillin / beta-lactam allergy: Levofloxacin PO 500mg 12-hourly
(Only use IV if oral route compromised.) 

Severe late onset HAP with MDR risk factors

If known colonization with P.aeruginosa or a multi-drug-resistant (MDR) organism use culture-based treatment.

If no previous positive cultures, but risk factors present (see below) discuss with an infection specialist.

Notes / Comments

Diagnosis & Investigations

  • Clinical Criteria: Diagnosis requires clinical signs of lower respiratory tract infection such as new-onset cough with purulent sputum plus new/worsening radiological changes.
    • Caution: Elderly or frail patients may present with non-specific signs (e.g., acute confusion/delirium, falls) in the absence of fever.
  • Imaging: Diagnosis usually requires new radiographic shadowing. Lung Ultrasound may be used as an alternative to Chest X-ray for diagnosis and to investigate complications (e.g., effusion).
  • Microbiology: Send a respiratory sample (sputum, tracheal aspirate) for bacterial culture from all patients with suspected HAP to guide de-escalation. Consider the need for respiratory viral PCR, particularly during “Flu season”.

Severity Assessment

  • Clinical Judgement: There is no single validated severity score for HAP. Assess severity based on clinical judgement regarding the risk of mortality and need for organ support.
  • Do not use CURB65. This score is validated only for Community-Acquired Pneumonia (CAP).
  • Severe HAP Indicators: Consider treating as Severe if the patient demonstrates physiological instability or signs of sepsis, such as:
    • Respiratory rate >30 breaths per minute
    • New onset hypoxia, e.g. PaO2 <8kPa or sO2 <93%
    • New onset hypotension or septic shock
    • Multi-lobar involvement on imaging

Risk Factors for Pseudomonas aeruginosa or Multi-Drug-Resistant (MDR) organisms

  • Known colonization with P. aeruginosa or MDR organisms (check previous respiratory isolates).
  • Recent invasive ventilation.
  • Structural lung disease (e.g., Bronchiectasis, Cystic Fibrosis).
  • Transfer from a healthcare facility abroad.

 

Guideline reviewed March 2026
Page updated July 2026



;