Criteria & Principles
- Community-acquired pneumonia (CAP) symptom onset occurs prior to or within the first 2 days of hospital admission.
- Pathogens to consider include: Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarhallis, respiratory viruses, and atypical pathogens (Legionella spp., Mycoplasma spp., Chlamydia pneumoniae). Staphylococcus aureus comprises <2% of CAP, but is more prevalent during influenza season.
- Respiratory and blood cultures are recommended for the following patients: severe CAP, those with a personal history of MRSA or Pseudomonas aeruginosa, or patients previously hospitalized and treated with IV antibiotics within the last 90 days.
- Additional diagnostic tests are appropriate for patients with severe CAP and/or risk factors: S. pneumoniae urine antigen, Legionella urine antigen, Legionella respiratory culture, respiratory viral panel.
- For patients started on empiric coverage for MRSA, a negative nasal MRSA PCR or respiratory culture without MRSA at 48 hours have high negative predictive values. De-escalation of anti-MRSA coverage is recommended.
- See separate pages for therapeutic management of viral pathogens (COVID-19, Influenza, RSV), which are all included in the Basic Respiratory Virus PCR Panel Test
- The Extended Respiratory Pathogen PCR Panel Test is restricted to the following:
- Inpatient (and ED) ) ≤3 days from admission
- Immunocompromised/Transplant
- Significant underlying lung disease
Treatment
Duration
5-7 days
- The majority of patients should be treated for 5 days, as most will achieve clinical stability within 48-72 hours.
- Patients with pneumonia due to MRSA or Pseudomonas aeruginosa should be treated for 7 days (See HAP/VAP guideline)
- High-dose (i.e. 500 mg) azithromycin achieves high concentrations in lung tissue that persist for several days. For most hospitalized patients, azithromycin can be stopped after three daily doses of 500 mg.
- Some pathogens require specific durations based on agent slection (See Pathogen-specific recommendations)
Severity
All Severity
Decisions regarding empiric therapy should be based on disease severity (Table 1) and risk factors (Table 2) for negative outcomes and specific pathogens including MRSA and Pseudomonas aeruginosa.
Mild-Moderate
NON-SEVERE
Outpatient community-acquired pneumonia (CAP):
Inpatient, non-severe, community-acquired pneumonia (CAP)
- Empiric MRSA or Pseudomonas aeruginosa coverage is not necessary in patients with non-severe CAP without risk factors (see Table 2).
- Patients with non-severe CAP and prior hospitalization or IV antibiotics in the last 90 days should have blood and respiratory cultures collected. Therapy may then be escalated to include MRSA or Pseudomonas if cultures return positive.
Severe
Inpatient, severe, community-acquired pneumonia (CAP)
*Recommend de-escalation of anti-MRSA and anti-pseudomonal agents at 48 hours if cultures are negative for these pathogens. Empiric anti-MRSA therapy can be discontinued based on a negative MRSA PCR in the appropriate clinical context (See MRSA nares PCR page)
†Recommend PO formulations if patient can tolerate enteral feeding and oral medication, and if gastrointestinal absorption is intact.
≠Linezolid-induced serotonin syndrome is rare. Use is generally safe in patients on only one serotonergic agent; however, risk may be increased with select agents, multiple concurrent serotonergic agents, and/or higher doses. See here for further information
Diagnosis-Specific Information
Pathogen-specific therapy and duration
Note: Agents and durations below are intended for adult immunocompetent patients. Consult ID service for patient-specific recommendations.
- Renal dosing adjustments are required for ampicillin/sulbactam, amoxicillin/clavulanate, piperacillin/tazobactam, cefuroxime, and vancomycin
- We recommend AGAINST beta-lactam class switching. For example, avoid a switch from cephalosporin to a penicillin class oral agent for discharge
- We recommend AGAINST a class switch to oral fluoroquinolone for discharge. For example, avoid a switch from an intravenous beta-lactam to oral fluoroquinolone for discharge
References
Metlay et al. Am J Respir Crit Care Med Vol 200, Iss 7, pp e45–e67, Oct 1, 2019