What is the treatment for hospital-acquired pneumonia (HAP)?

Treatment of Hospital-Acquired Pneumonia

The most effective treatment for hospital-acquired pneumonia (HAP) requires prompt initiation of empiric broad-spectrum antibiotics based on risk factors for multidrug-resistant pathogens, followed by de-escalation based on culture results and clinical response. 1, 2

Diagnosis

HAP is defined by:

• New or progressive lung infiltrate on chest imaging
• Plus at least two of three clinical features:
  • Fever >38°C
  • Leukocytosis or leukopenia
  • Purulent secretions 1

Empiric Antibiotic Selection Algorithm

Step 1: Risk Stratification

Low Risk of Mortality and No MRSA Risk Factors:

• Monotherapy with one of the following:
  • Piperacillin-tazobactam 4.5g IV q6h
  • Cefepime 2g IV q8h
  • Levofloxacin 750mg IV daily
  • Imipenem 500mg IV q6h
  • Meropenem 1g IV q8h 1

Low Risk of Mortality but with MRSA Risk Factors:

• Base regimen (one of the following):
  • Piperacillin-tazobactam 4.5g IV q6h
  • Cefepime 2g IV q8h
  • Levofloxacin 750mg IV daily
  • Imipenem 500mg IV q6h
  • Meropenem 1g IV q8h
• Plus MRSA coverage (one of the following):
  • Vancomycin 15-20mg/kg IV q8-12h (target trough 15-20 μg/mL)
  • Linezolid 600mg IV q12h 1, 2

High Risk of Mortality or Recent IV Antibiotics (within 90 days):

• Two antipseudomonal agents (from different classes):
  • Piperacillin-tazobactam 4.5g IV q6h OR
  • Cefepime 2g IV q8h OR
  • Imipenem 500mg IV q6h OR
  • Meropenem 1g IV q8h
  • PLUS either:
    • Levofloxacin 750mg IV daily OR
    • Ciprofloxacin 400mg IV q8h OR
    • Amikacin 15-20mg/kg IV daily OR
    • Gentamicin 5-7mg/kg IV daily OR
    • Tobramycin 5-7mg/kg IV daily
• Plus MRSA coverage (if risk factors present):
  • Vancomycin 15-20mg/kg IV q8-12h OR
  • Linezolid 600mg IV q12h 1, 2

Step 2: Obtain Cultures Before Starting Antibiotics

• Respiratory samples (endotracheal aspirates with non-quantitative cultures are acceptable)
• Blood cultures 2

Step 3: Reassess at 48-72 Hours

• Review culture results
• Assess clinical response (temperature, WBC, chest X-ray, oxygenation, purulent sputum, hemodynamic changes)
• De-escalate therapy based on culture results and clinical response 1, 2

Duration of Therapy

• Standard duration: 7-8 days for patients with good clinical response
• Longer durations may be considered for:
  • Slow clinical response
  • Highly resistant pathogens
  • Structural lung disease
  • Complications 2

Special Considerations

Pseudomonas aeruginosa Infection

For confirmed Pseudomonas pneumonia, combination therapy with an antipseudomonal β-lactam plus either an aminoglycoside or a fluoroquinolone is recommended to prevent resistance development 3, 4.

MRSA Treatment

If MRSA is confirmed, targeted therapy with:

• Vancomycin 15-20mg/kg IV q8-12h (target trough 15-20 μg/mL) OR
• Linezolid 600mg IV q12h 1, 2

MSSA Treatment

For confirmed MSSA infection, narrow therapy to:

• Oxacillin, nafcillin, or cefazolin (preferred over broader agents) 1

Common Pitfalls to Avoid

1. Delaying empiric therapy - associated with increased mortality 1, 2
2. Using inadequate empiric coverage - especially in high-risk patients 2
3. Failing to de-escalate therapy - contributes to antibiotic resistance 2
4. Treating for longer than necessary - standard duration is 7-8 days for most patients 2
5. Ignoring local antibiograms - local resistance patterns should guide therapy 2
6. Using aminoglycosides as monotherapy - inadequate for HAP 2, 4
7. Not adjusting doses in renal impairment - especially important for aminoglycosides and vancomycin 2, 5

Risk Factors for Multidrug-Resistant Pathogens

• Prior IV antibiotic use within 90 days
• Late-onset HAP (≥5 days after admission)
• Septic shock
• Hospitalization in units with high rates of MDR pathogens
• Acute renal replacement therapy
• Structural lung disease
• Previous colonization with MDR pathogens 2

By following this algorithmic approach to HAP treatment, clinicians can ensure appropriate empiric coverage while minimizing unnecessary broad-spectrum antibiotic use, ultimately improving patient outcomes and reducing antibiotic resistance.