Australian Guidelines for Antibiotic Choice in Mild and Moderate Hospital-Acquired Pneumonia
For mild to moderate hospital-acquired pneumonia (HAP) in Australia, piperacillin-tazobactam is the recommended first-line empiric therapy, with consideration for risk stratification based on timing of onset and risk factors for multidrug-resistant (MDR) pathogens. 1
Risk Stratification Approach
Low-Risk Patients (Early-onset HAP, no MDR risk factors)
- First choice: Amoxicillin-clavulanic acid OR
- Alternative: Second/third generation cephalosporin
Higher-Risk Patients (Late-onset HAP or MDR risk factors)
- First choice: Piperacillin-tazobactam 4.5g IV every 6 hours 1
- Alternative: Cefepime 1-2g IV every 8-12 hours
Risk Factors for MDR Pathogens
- Hospitalization for ≥5 days
- Recent antibiotic therapy (within past 90 days)
- High local prevalence of antibiotic resistance
- Immunosuppressed state
- Healthcare-associated pneumonia (HCAP) 1
Treatment Duration
- Standard course: 7-8 days for most patients with HAP 1
- Longer courses may be needed for non-responding infections or those caused by non-fermenting Gram-negative bacilli 1
Therapy Modification
- Reassess at 48-72 hours based on clinical response and microbiological data
- De-escalate therapy when possible based on culture results 1
- Consider discontinuation of therapy if an alternative diagnosis is established
Special Considerations
MRSA Coverage
- Add vancomycin (15 mg/kg IV every 12 hours, target trough 15-20 μg/ml) if MRSA is suspected 1
- Linezolid (600 mg IV/PO every 12 hours) is an alternative if vancomycin cannot be used 1, 2
Pseudomonas Risk
For patients with risk factors for Pseudomonas:
- Use piperacillin-tazobactam as first-line therapy 1, 3
- Consider adding an aminoglycoside (e.g., amikacin 20 mg/kg/day) for severe illness or suspected resistance 1
Clinical Pearls and Pitfalls
Common Pitfalls
- Overuse of broad-spectrum antibiotics: Not all HAP patients require antipseudomonal coverage 4
- Delayed appropriate therapy: Increases mortality; initiate empiric therapy promptly 1
- Prolonged therapy: Increases risk of resistant organism colonization without improving outcomes 1
Important Considerations
- Monotherapy is appropriate for most mild-moderate HAP cases without risk factors for MDR pathogens 1
- Combination therapy should be reserved for patients with severe illness or high risk of MDR pathogens 1
- Short-course therapy (7-8 days) is as effective as longer courses for most patients and reduces antibiotic resistance 1
By following these guidelines and adjusting therapy based on local resistance patterns, clinicians can provide appropriate coverage for HAP while minimizing unnecessary broad-spectrum antibiotic use.