Hospital-Acquired Pneumonia Antibiotic Treatment Guidelines

Introduction to Antibiotic Selection

The Infectious Diseases Society of America (IDSA) and American Thoracic Society (ATS) recommend monotherapy with piperacillin-tazobactam, cefepime, levofloxacin, imipenem, or meropenem for HAP without high mortality risk or MRSA risk factors 1
The IDSA/ATS guidelines provide a clear algorithmic approach based on mortality risk and MRSA risk factors 1

For low mortality risk without MRSA risk factors, single agent therapy is sufficient, with options including piperacillin-tazobactam, cefepime, levofloxacin, imipenem, or meropenem 1, 2
For low mortality risk with MRSA risk factors, add MRSA coverage to gram-negative coverage, with options including vancomycin or linezolid 1
For high mortality risk or recent IV antibiotics, use dual gram-negative coverage plus MRSA coverage, selecting two agents from different classes 1, 2

High mortality risk includes need for ventilatory support due to pneumonia and septic shock 1, 2
MRSA risk factors include prior IV antibiotic use within 90 days, treatment in a unit with high MRSA prevalence, unknown MRSA prevalence, and prior MRSA detection by culture or screening 1, 2

Never use aminoglycosides as sole antipseudomonal coverage, and avoid using two β-lactams together 1, 2
If using aztreonam for severe penicillin allergy, add MSSA coverage with vancomycin or linezolid 1, 2
Local antibiogram data should modify these recommendations, with empiric MRSA coverage becoming mandatory if the institution has high MRSA prevalence 1, 3

The American Thoracic Society recommends a treatment duration of 7-8 days for uncomplicated HAP cases with good clinical response 3
Obtain respiratory cultures before starting antibiotics, and de-escalate based on culture results and clinical response 3