What is the recommended management of Hospital-Acquired Pneumonia (HAP)?

Management of Hospital-Acquired Pneumonia (HAP)

For HAP management, stratify patients by risk factors for multidrug-resistant (MDR) pathogens and septic shock, then initiate empiric antibiotics accordingly: narrow-spectrum monotherapy (ertapenem, ceftriaxone, cefotaxime, moxifloxacin, or levofloxacin) for low-risk patients, or broad-spectrum combination therapy covering Pseudomonas aeruginosa, ESBL-producing organisms, and MRSA for high-risk patients. 1

Risk Stratification

Low-risk patients include those without septic shock, no prior antibiotic use within 90 days, hospitalization ≤5 days, no previous MDR colonization, and local ICU resistance rates <25%. 1

High-risk patients present with septic shock and/or: prior antibiotic use within 90 days, prolonged hospitalization (>5 days), previous MDR colonization, or local ICU resistance rates >25% for MDR pathogens. 1

Empiric Antibiotic Selection

Low-Risk HAP

• Use narrow-spectrum monotherapy with ertapenem, ceftriaxone, cefotaxime, moxifloxacin, or levofloxacin 750 mg IV/PO daily. 1, 2, 3
• Third-generation cephalosporins carry higher risk of Clostridioides difficile infection compared to penicillins or quinolones. 1

High-Risk HAP

• Initiate combination therapy with an antipseudomonal beta-lactam (piperacillin-tazobactam 4.5g IV q6h, cefepime 2g IV q8h, meropenem 1g IV q8h, or imipenem 500mg IV q6h) PLUS coverage for MRSA if risk factors present. 1, 2
• For MRSA coverage, use vancomycin 15 mg/kg IV q8-12h or linezolid 600 mg IV/PO q12h. 1, 2, 3, 4
• In settings with high Acinetobacter prevalence, ensure empiric coverage includes carbapenem therapy. 1
• For structural lung disease, use two antipseudomonal agents to prevent resistance development. 2, 5

Microbiological Sampling

• Obtain lower respiratory tract samples (distal quantitative, proximal quantitative, or qualitative culture) before initiating antibiotics to guide de-escalation. 1
• Distal quantitative samples in stable patients reduce antibiotic exposure and improve diagnostic accuracy. 1

Reassessment and De-escalation

• Reassess at 48-72 hours using temperature trends, white blood cell count, chest radiography, oxygenation parameters, and hemodynamic stability. 6
• Tailor therapy to culture susceptibilities by day 3—this represents good practice. 1
• De-escalate from combination to monotherapy once cultures identify susceptible organisms, unless treating XDR/PDR nonfermenting gram-negatives or carbapenem-resistant Enterobacteriaceae. 1
• Consider procalcitonin (PCT) levels plus clinical criteria to guide antibiotic discontinuation, though benefits are uncertain when standard therapy is already ≤7 days. 1

Duration of Therapy

• Treat for 7-8 days in patients with good clinical response, no immunodeficiency, and no complications (lung abscess, empyema, cavitation, necrotizing pneumonia). 1, 6
• Longer courses may be necessary for immunocompromised patients, those with complications, or inadequate initial empiric therapy. 6

Common Pitfalls

• Failure to obtain respiratory cultures before antibiotics limits ability to narrow therapy and contributes to antimicrobial resistance. 1, 6
• Continuing broad-spectrum antibiotics despite clinical improvement and negative cultures drives resistance—de-escalate when appropriate. 6
• The 25% resistance threshold recommended in guidelines has 100% sensitivity but only 0.03% specificity for MRSA, leading to overtreatment in 94.81% of cases. 7
• In practice, 35% of clinical HAP diagnoses lack radiological confirmation when objective criteria are applied. 8

Special Considerations

• For patients with negative cultures but persistent symptoms, evaluate non-infectious causes including heart failure or pulmonary embolism. 6
• Negative culture results are most reliable when obtained before antibiotics or within 72 hours of antibiotic changes. 6
• Local antibiograms should guide empiric therapy—the ICU-specific resistance rate (not hospital-wide) is the relevant factor. 1
• Pressor requirement and recent IV antibiotics within 90 days are associated with MRSA; mechanical ventilation is associated with resistant gram-negative rods. 7
• Radiologically confirmed HAP represents a distinct phenotype with higher inflammatory markers and sputum culture positivity. 8