What are the Canadian guidelines for treating reinfection with community-acquired pneumonia (CAP) after 30 days?

Canadian Guidelines for Treating Reinfection with Community-Acquired Pneumonia After 30 Days

The Canadian guidelines recommend treating reinfection with community-acquired pneumonia (CAP) after 30 days with the same empiric antibiotic regimens as for initial CAP episodes, with a minimum treatment duration of 5 days. 1, 2

Initial Assessment and Treatment Selection

• For outpatient treatment of reinfection with CAP, the recommended options include:

  • Previously healthy patients: a macrolide (azithromycin) or doxycycline 3
  • Patients with comorbidities: a respiratory fluoroquinolone (levofloxacin or moxifloxacin) or combination therapy with a β-lactam plus a macrolide 2, 3

• For hospitalized patients with non-severe CAP reinfection:

  • Combination therapy with a β-lactam (ampicillin-sulbactam, ceftriaxone, or cefotaxime) plus either a macrolide (azithromycin or clarithromycin) or doxycycline 1, 3
  • Alternatively, monotherapy with a respiratory fluoroquinolone (levofloxacin or moxifloxacin) 1

• For hospitalized patients with severe CAP reinfection:

  • Combination therapy with a β-lactam plus either a macrolide or a respiratory fluoroquinolone 1, 3
  • For patients with risk factors for Pseudomonas: an antipseudomonal β-lactam plus either ciprofloxacin or levofloxacin 2
  • For patients with risk factors for MRSA: add vancomycin or linezolid to the standard regimen 2

Pathogen Considerations for Reinfection

• The likely bacterial pathogens in CAP reinfection remain the same as in initial episodes, including Streptococcus pneumoniae, Haemophilus influenzae, Chlamydia pneumoniae, and Staphylococcus aureus 1, 2

• The healthcare-associated pneumonia (HCAP) classification should be abandoned; clinicians should only cover empirically for MRSA or P. aeruginosa if locally validated risk factors for either pathogen are present 2, 3

• Testing for bacterial pathogens with sputum and blood cultures is most useful when there is concern for multidrug-resistant pathogens 1

Duration of Therapy

• Patients with CAP reinfection should be treated for a minimum of 5 days, even if clinical stability is achieved earlier 1, 2

• Most patients will achieve clinical stability within 48-72 hours, making a total duration of 5 days appropriate for most patients 1

• Criteria for clinical stability include resolution of vital sign abnormalities (heart rate, respiratory rate, blood pressure, oxygen saturation, and temperature), ability to eat, and normal mentation 1

• For CAP due to suspected or proven MRSA or P. aeruginosa, a longer duration of 7 days is recommended 1

Switching from IV to Oral Therapy

• Patients can be switched from IV to oral antibiotics when they demonstrate:

  • Improvement in cough and dyspnea
  • Afebrile status (temperature <37.8°C)
  • Decreasing white blood cell count
  • Functioning gastrointestinal tract with adequate oral intake 2, 3

• When switching from parenteral to oral antibiotics, either the same agent or the same drug class should be used 1

Management of Treatment Failure

• Failure to achieve clinical stability within 5 days should prompt assessment for:

  • Pathogens resistant to current therapy
  • Complications of pneumonia (e.g., empyema or lung abscess)
  • Alternative sources of infection 1

• Additional diagnostic testing, including repeat imaging and microbiological studies, should be considered in patients who fail to improve as expected 3

Prevention of Recurrent CAP

• Pneumococcal and influenza vaccines are recommended for prevention of CAP in appropriate at-risk populations 2, 4

• Smoking cessation should be promoted in all patients to eliminate an important risk factor for CAP 2