What are the best antibiotics for hospital-acquired pneumonia (HAP)?

Best Antibiotics for Hospital-Acquired Pneumonia (HAP)

For hospital-acquired pneumonia, empiric antibiotic therapy should be stratified based on risk factors for mortality and multidrug-resistant pathogens, with piperacillin-tazobactam as the backbone for most regimens. 1

Risk Stratification for Empiric Therapy

Low Risk Patients (not at high risk of mortality, no MRSA risk factors)

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

Moderate Risk Patients (not at high risk of mortality but with MRSA risk factors)

• Use monotherapy with one of the following options 1:
  • Piperacillin-tazobactam 4.5 g IV q6h
  • Cefepime or ceftazidime 2 g IV q8h
  • Levofloxacin 750 mg IV daily
  • Ciprofloxacin 400 mg IV q8h
  • Imipenem 500 mg IV q6h
  • Meropenem 1 g IV q8h
  • Aztreonam 2 g IV q8h (if severe penicillin allergy)
• Plus MRSA coverage with one of the following 1:
  • Vancomycin 15 mg/kg IV q8-12h (target trough 15-20 mg/mL)
  • Linezolid 600 mg IV q12h

High Risk Patients (high mortality risk or recent IV antibiotics)

• Use dual antipseudomonal coverage with two of the following (avoid using two β-lactams) 1:
  • Piperacillin-tazobactam 4.5 g IV q6h
  • Cefepime or ceftazidime 2 g IV q8h
  • Levofloxacin 750 mg IV daily
  • Ciprofloxacin 400 mg IV q8h
  • Imipenem 500 mg IV q6h
  • Meropenem 1 g IV q8h
  • Amikacin 15-20 mg/kg IV daily
  • Gentamicin 5-7 mg/kg IV daily
  • Tobramycin 5-7 mg/kg IV daily
  • Aztreonam 2 g IV q8h (if severe penicillin allergy)
• Plus MRSA coverage with one of the following 1:
  • Vancomycin 15 mg/kg IV q8-12h (target trough 15-20 mg/mL)
  • Linezolid 600 mg IV q12h

Risk Factors to Consider

Risk Factors for Mortality

• Need for ventilatory support due to pneumonia 1
• Septic shock 1

Risk Factors for MRSA

• Intravenous antibiotic treatment during the prior 90 days 1
• Treatment in a unit where MRSA prevalence among S. aureus isolates is >20% or unknown 1
• Prior detection of MRSA by culture or screening 1

Special Considerations

• For confirmed methicillin-sensitive S. aureus (MSSA), narrow to oxacillin, nafcillin, or cefazolin (preferred over broader agents) 1
• For severe penicillin allergy, use aztreonam but ensure MSSA coverage is maintained 1
• Carbapenems may result in better clinical cure rates than other antibiotics for HAP 2
• Piperacillin-tazobactam is FDA-approved for nosocomial pneumonia with a recommended dosage of 4.5 grams every six hours 3
• Levofloxacin is FDA-approved for nosocomial pneumonia due to susceptible pathogens 4

Common Pitfalls to Avoid

• Failing to obtain appropriate cultures before initiating antibiotics 5
• Not considering local antimicrobial resistance patterns when selecting empiric therapy 5
• Using inappropriate monotherapy in high-risk patients who require combination therapy 1
• Unnecessary use of broad-spectrum antibiotics in low-risk patients, which contributes to antimicrobial resistance 1
• Delayed administration of appropriate antibiotics, which is associated with increased mortality 5
• Not adjusting therapy based on culture results and clinical response 1

Emerging Options for Multidrug-Resistant Pathogens

• For carbapenem-resistant Enterobacterales: ceftazidime-avibactam, imipenem-relebactam, or meropenem-vaborbactam 6
• For multidrug-resistant Pseudomonas aeruginosa: ceftazidime-avibactam, ceftolozane-tazobactam, imipenem-relebactam, or cefiderocol 6
• For multidrug-resistant Acinetobacter baumannii: cefiderocol, plazomicin, or eravacycline 6

Remember that guideline-adherent initial antibiotic therapy is associated with better clinical outcomes, shorter hospital stays, and lower costs 5.