What are the recent guidelines for Community-Acquired Pneumonia (CAP) and Hospital-Acquired Pneumonia (HAP) treatment?

Recent Guidelines for Community-Acquired Pneumonia (CAP) and Hospital-Acquired Pneumonia (HAP)

Community-Acquired Pneumonia (CAP) Guidelines

Diagnosis and Assessment

• Severity assessment should guide the decision for outpatient versus inpatient treatment, using tools like CURB-65 to identify patients who can be safely treated as outpatients 1
• Diagnostic testing recommendations have expanded to include more routine collection of respiratory tract samples for microbiological studies, particularly to avoid overuse of anti-MRSA and antipseudomonal therapy 2
• For patients admitted through the emergency department, the first antibiotic dose should be administered while still in the ED to minimize time to treatment 1

Outpatient Treatment

• For previously healthy patients with no risk factors for drug-resistant S. pneumoniae (DRSP):

  • A macrolide (azithromycin, clarithromycin, or erythromycin) OR
  • Doxycycline 2

• For patients with comorbidities (chronic heart, lung, liver, or renal disease; diabetes; alcoholism; malignancies; immunosuppression) or recent antibiotic use:

  • A respiratory fluoroquinolone (moxifloxacin, gemifloxacin, or levofloxacin [750 mg]) OR
  • A β-lactam plus a macrolide 2
  • High-dose amoxicillin (1g three times daily) is the preferred β-lactam 2

Non-Severe Inpatient Treatment

• Most patients can be adequately treated with oral antibiotics 2, 1
• Recommended regimens:
  • A respiratory fluoroquinolone alone OR
  • A β-lactam plus a macrolide 2, 1
  • Preferred β-lactams include cefotaxime, ceftriaxone, and ampicillin 2

Severe CAP (ICU) Treatment

• Standard regimen:

  • A β-lactam (cefotaxime, ceftriaxone, or ampicillin-sulbactam) plus either azithromycin or a respiratory fluoroquinolone 2, 1

• For suspected Pseudomonas infection:

  • An antipneumococcal, antipseudomonal β-lactam (piperacillin-tazobactam, cefepime, imipenem, or meropenem) plus either ciprofloxacin or levofloxacin (750 mg) 2, 1

• For suspected community-acquired MRSA:

  • Add vancomycin or linezolid to the standard regimen 2, 1

Duration of Therapy for CAP

• Patients with CAP should be treated for a minimum of 5 days 2, 1
• Patients should be afebrile for 48-72 hours and have no more than 1 CAP-associated sign of clinical instability before discontinuing therapy 2
• Longer duration may be needed if initial therapy was not active against the identified pathogen or if complicated by extrapulmonary infection 2

Hospital-Acquired Pneumonia (HAP) Guidelines

Key Changes in Approach

• The 2019 ATS/IDSA guidelines recommend abandoning the healthcare-associated pneumonia (HCAP) category that was previously used to guide extended antibiotic coverage 2
• Instead, clinicians should only cover empirically for MRSA or P. aeruginosa in adults with pneumonia if locally validated risk factors for either pathogen are present 2

Empiric Treatment for HAP

• For suspected MRSA:

  • Vancomycin (15 mg/kg every 12h, adjusted based on levels) OR
  • Linezolid (600 mg every 12h) 2

• For suspected P. aeruginosa:

  • Piperacillin-tazobactam (4.5g every 6h) OR
  • Cefepime (2g every 8h) OR
  • Ceftazidime (2g every 8h) OR
  • Aztreonam (2g every 8h) OR
  • Meropenem (1g every 8h) OR
  • Imipenem (500 mg every 6h) 2

Risk Factors for Resistant Pathogens

• The most consistently strong risk factors for MRSA or P. aeruginosa are:
  • Prior isolation of these organisms (especially from respiratory tract)
  • Recent hospitalization
  • Recent exposure to parenteral antibiotics 2

Clinical Management Strategies

Diagnostic Approach

• For HAP/VAP, two diagnostic strategies are recognized:
  1. Clinical strategy: Emphasizes prompt empiric therapy based on risk factors, with modification based on clinical response and semiquantitative cultures 2
  2. Bacteriologic strategy: Uses quantitative cultures from lower respiratory tract samples to guide therapy 2

Treatment Modifications

• De-escalation of therapy should be based on microbiologic cultures and clinical response 2
• Assess clinical stability within 5 days, as failure to achieve stability is associated with higher mortality 2
• Follow-up chest imaging is not routinely recommended for patients whose symptoms have resolved within 5-7 days 2

Special Considerations

• For patients with hypoxemia or respiratory distress, consider a trial of noninvasive ventilation unless immediate intubation is required 1
• Low-tidal-volume ventilation should be used for patients with diffuse bilateral pneumonia or ARDS 1

Common Pitfalls and Caveats

• Overuse of broad-spectrum antibiotics: The abandonment of the HCAP classification aims to reduce unnecessary use of anti-MRSA and antipseudomonal therapy 2, 3
• Delayed treatment: Delay in appropriate antibiotic therapy for HAP is associated with increased mortality; therefore, prompt empiric therapy is essential 2
• Inadequate duration: While shorter courses are now recommended (minimum 5 days for CAP), therapy should continue until clinical stability is achieved 2
• Failure to recognize treatment failure: Patients not improving within 5 days should be reassessed for resistant pathogens, complications, or alternative diagnoses 2