What is the treatment for Hospital-Acquired Pneumonia (HAP)?

Treatment of Hospital-Acquired Pneumonia (HAP)

All patients with HAP require empiric antibiotics with activity against Pseudomonas aeruginosa and other gram-negative bacilli, and the decision to add MRSA coverage depends on local resistance patterns (>20% MRSA prevalence among S. aureus isolates) or recent IV antibiotic use within 90 days. 1

Empiric Antibiotic Selection Algorithm

Step 1: Assess MRSA Risk Factors

Add MRSA coverage if ANY of the following are present: 1

• IV antibiotic use within the prior 90 days
• Treatment in a unit where MRSA prevalence among S. aureus isolates is unknown or >20%
• Prior MRSA detection by culture or screening

MRSA coverage options: 1

• Vancomycin OR
• Linezolid

Step 2: Determine Antipseudomonal Strategy

Use DUAL antipseudomonal therapy (two different antibiotic classes) if: 1

• Prior IV antibiotic use within 90 days
• Structural lung disease (bronchiectasis or cystic fibrosis)
• High mortality risk (need for ventilatory support due to HAP or septic shock)
• Gram stain showing numerous gram-negative bacilli

Use SINGLE antipseudomonal agent for all other HAP patients 1

Step 3: Select Specific Agents

Single antipseudomonal β-lactam options: 1

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

For dual therapy, add ONE of the following to the β-lactam: 1

• Levofloxacin 750mg IV daily OR
• Ciprofloxacin OR
• Amikacin (aminoglycoside)

Critical caveat: Do NOT use aminoglycosides as the sole antipseudomonal agent 1

Dosing Optimization

Use pharmacokinetic/pharmacodynamic (PK/PD)-optimized dosing rather than standard manufacturer recommendations, including extended infusions, continuous infusions, and weight-based dosing for certain antibiotics 1

Treatment Duration

Standard duration is 7-10 days for most HAP cases 1

For nosocomial pneumonia specifically, FDA-approved duration with piperacillin-tazobactam is 7-14 days 2

Renal Dose Adjustments

For piperacillin-tazobactam in patients with creatinine clearance ≤40 mL/min: 2

• CrCl 20-40 mL/min: 2.25g q6h (or 3.375g q6h for nosocomial pneumonia)
• CrCl <20 mL/min: 2.25g q8h (or 2.25g q6h for nosocomial pneumonia)
• Hemodialysis: 2.25g q12h plus 0.75g after each dialysis session

De-escalation Strategy

Obtain lower respiratory tract cultures BEFORE initiating antibiotics to guide narrowing of therapy at 48-72 hours 1

Once culture results are available: 1

• Narrow to pathogen-specific therapy
• For proven MSSA, switch to oxacillin, nafcillin, or cefazolin 1
• Discontinue unnecessary broad-spectrum coverage to reduce risk of C. difficile infection, antimicrobial resistance, and adverse effects 1

Common Pitfalls to Avoid

Do not use ceftriaxone plus metronidazole for HAP - this regimen lacks adequate Pseudomonas coverage and is only appropriate for community-acquired pneumonia 3

Do not assume all HAP requires the same treatment intensity - stratify patients by mortality risk and resistance factors rather than using a one-size-fits-all approach 1

Do not continue dual gram-negative coverage beyond culture results unless treating extensively drug-resistant (XDR) or pan-drug-resistant (PDR) organisms 1

Monitor for nephrotoxicity in critically ill patients, as piperacillin-tazobactam has been identified as an independent risk factor for renal failure in this population 2