What are the criteria and treatment guidelines for Hospital-Acquired Pneumonia (HAP)?

Hospital-Acquired Pneumonia (HAP) Criteria and Treatment Guidelines

Hospital-acquired pneumonia should be diagnosed using clinical criteria alone and treated with empiric antibiotics based on risk factors for multidrug-resistant pathogens, with therapy tailored according to respiratory culture results. 1

Diagnostic Criteria for HAP

HAP is defined as pneumonia that occurs 48 hours or more after hospital admission and was not incubating at the time of admission 1. Key diagnostic elements include:

• Clinical criteria: The primary method for diagnosis 1

  • New or progressive radiographic infiltrates
  • Plus at least two of the following:
    • Fever >38°C
    • Leukocytosis or leukopenia
    • Purulent secretions

• Respiratory samples: Should be obtained noninvasively before starting antibiotics 1

  • Spontaneous expectoration
  • Sputum induction
  • Nasotracheal suctioning
  • Endotracheal aspiration (if subsequently intubated)

• Biomarkers: Not recommended for routine use 1

  • Procalcitonin (PCT)
  • C-reactive protein (CRP)
  • Bronchoalveolar lavage fluid (BALF) sTREM-1
  • Clinical Pulmonary Infection Score (CPIS)

Risk Stratification for MDR Pathogens

Patients should be categorized based on risk for multidrug-resistant (MDR) pathogens:

High Risk for MDR Pathogens:

• Late-onset pneumonia (≥5 days of hospitalization) 1, 2
• Prior antibiotic use within 90 days 1, 2
• Septic shock at HAP diagnosis 1, 2
• ARDS
• Prior hospitalization for ≥5 days 2
• Prior colonization with MDR pathogens 2
• Admission from healthcare-related facility 1
• Treatment in units with high rates of resistant pathogens (>25% prevalence) 1

Low Risk for MDR Pathogens:

• Early-onset pneumonia (<5 days of hospitalization) without other risk factors 1
• No prior antibiotic use
• No septic shock
• Treatment in units with low rates of resistant pathogens

Empiric Antibiotic Treatment Recommendations

For Low-Risk Patients (early-onset, no MDR risk factors):

• Narrow-spectrum antibiotics 1:
  • Ertapenem 1g IV daily
  • Ceftriaxone 2g IV daily
  • Cefotaxime 2g IV q8h
  • Moxifloxacin 400mg IV daily
  • Levofloxacin 750mg IV daily

For High-Risk Patients (late-onset or MDR risk factors):

• Broad-spectrum coverage targeting Pseudomonas, ESBL-producing organisms, and Acinetobacter (if prevalent) 1:

  • Antipseudomonal β-lactam:

    • Piperacillin-tazobactam 4.5g IV q6h
    • Cefepime 2g IV q8h
    • Imipenem 500mg IV q6h
    • Meropenem 1g IV q8h

  • PLUS MRSA coverage if risk factors present:

    • Vancomycin 15mg/kg IV q8-12h (target trough 15-20 μg/mL) OR
    • Linezolid 600mg IV q12h

Duration of Therapy and De-escalation

• Standard duration: 7-8 days for patients with good clinical response 1

• Extended duration (10-14 days): Consider for:

  • Non-fermenting gram-negative bacilli (P. aeruginosa, Acinetobacter)
  • Inadequate initial clinical response
  • Immunocompromised patients

• De-escalation strategy: 1

  • Reassess at 48-72 hours based on clinical response and culture results
  • Narrow therapy to the most focused regimen based on culture data
  • Consider stopping antibiotics if cultures are negative and clinical improvement occurs

Common Pitfalls to Avoid

• Delayed therapy: Initiate antibiotics promptly as delays increase mortality 1
• Inadequate initial coverage: Consider local antibiograms when selecting empiric therapy 1
• Failure to obtain cultures: Always collect respiratory samples before starting antibiotics 1
• Prolonged antibiotic courses: Avoid unnecessarily long treatment durations to prevent resistance 1
• Failure to de-escalate: Narrow therapy once culture results are available 1
• Misdiagnosis: Up to 35% of clinically diagnosed HAP cases may not meet radiological criteria 3

Special Considerations

• For VAP (ventilator-associated pneumonia):

  • More likely to be caused by MDR pathogens
  • Requires broader empiric coverage
  • Consider quantitative cultures from endotracheal aspirates or bronchoalveolar lavage 1

• For HCAP (healthcare-associated pneumonia):

  • Treat similarly to HAP with MDR coverage 1
  • Often requires longer time to appropriate therapy 4

• For non-responding patients:

  • Evaluate for non-infectious mimics of pneumonia
  • Consider unsuspected or drug-resistant organisms
  • Assess for extrapulmonary sites of infection
  • Rule out complications of pneumonia and its therapy 1

By following these evidence-based guidelines for HAP diagnosis and treatment, clinicians can optimize patient outcomes while minimizing unnecessary antibiotic use and the development of resistance.