What is the recommended management approach for inpatient pneumonia, including suspected legionella cases?

From the Guidelines

For inpatient pneumonia management, including suspected legionella cases, the recommended laboratory tests include complete blood cell count and differential, serum creatinine, blood urea nitrogen, glucose, electrolytes, and liver function tests, as well as 2 pretreatment blood cultures, Gram staining and culture of expectorated sputum, and microbiological studies for tuberculosis and legionella infection, with the preferred tests for detection of Legionella species being the urinary antigen assay for Legionella pneumophila serogroup 1 and culture with selective media 1.

Key Laboratory Tests

• Complete blood cell count and differential
• Serum creatinine
• Blood urea nitrogen
• Glucose
• Electrolytes
• Liver function tests
• 2 pretreatment blood cultures
• Gram staining and culture of expectorated sputum
• Microbiological studies for tuberculosis and legionella infection

Legionella Detection

• Urinary antigen assay for Legionella pneumophila serogroup 1
• Culture with selective media

Additional Considerations

• HIV serology with informed consent should be considered, especially for persons aged 15–54 years 1
• Oxygen saturation should be assessed 1
• Patients with risk factors such as immunocompromise, recent travel, exposure to water systems, or pneumonia unresponsive to beta-lactam monotherapy should be suspected of having Legionella pneumonia and undergo diagnostic testing 1
• The preferred treatment for legionnaires’ disease is azithromycin or a fluoroquinolone, with treatment duration typically ranging from 10-14 days for suspected Legionella infections 1

From the FDA Drug Label

Azithromycin for Injection, USP is indicated for the treatment of patients with infections caused by susceptible strains of the designated microorganisms in the conditions listed below... Community-acquired pneumonia due to Chlamydia pneumoniae, Haemophilus influenzae, Legionella pneumophila, Moraxella catarrhalis, Mycoplasma pneumoniae, Staphylococcus aureus, or Streptococcus pneumoniae in patients who require initial intravenous therapy The recommended dose of Azithromycin for Injection for the treatment of adult patients with community-acquired pneumonia due to the indicated organisms is: 500 mg as a single daily dose by the intravenous route for at least two days

Typical pneumonia lab orders for inpatient including legionella:

• Azithromycin: 500 mg IV daily for at least 2 days, followed by oral azithromycin to complete a 7-10 day course of therapy 2
• Cefepime: 1-2 g IV every 8-12 hours for 10 days for moderate to severe pneumonia due to S. pneumoniae, P. aeruginosa, K. pneumoniae, or Enterobacter species 3 Key points:
• Azithromycin is effective against Legionella pneumophila
• Cefepime is not specifically indicated for Legionella pneumophila, but may be used for other causes of pneumonia
• Dosage and administration should be guided by the specific drug label and clinical judgment 2, 3

From the Research

Typical Pneumonia Lab Orders for Inpatient Including Legionella

• The following lab orders are typically recommended for inpatient pneumonia, including suspected legionella cases:
  • Complete Blood Count (CBC) with differential
  • Blood cultures (at least 2 sets)
  • Urine antigen test for Legionella pneumophila and Streptococcus pneumoniae 4
  • Sputum Gram stain and culture
  • Chest radiograph
  • Arterial Blood Gas (ABG) analysis
  • Liver function tests (LFTs)
  • Renal function tests (RFTs)

Recommended Management Approach

• The recommended management approach for inpatient pneumonia, including suspected legionella cases, involves:
  • Early initiation of antibiotic therapy, with coverage for Legionella pneumophila and other common pathogens 5, 6, 7
  • Use of urinary antigen tests to guide targeted therapy 4
  • Consideration of patient risk factors, such as age, comorbidities, and severity of illness, when selecting antibiotic therapy 5, 6
  • Monitoring of patient response to therapy and adjustment of antibiotic regimen as needed

Legionella-Specific Diagnostic Tests

• The following diagnostic tests are available for Legionella pneumonia:
  • Urinary antigen test 4, 8
  • Sputum culture and PCR 8
  • Serological assays 8
  • Mass spectrometry 8
  • Nucleic acid amplification technique 8

Antibiotic Therapy

• The following antibiotics are recommended for the treatment of Legionella pneumonia:
  • Levofloxacin 5
  • Macrolides (e.g. azithromycin, clarithromycin) 5, 6
  • Combination therapy with a beta-lactam and a macrolide or fluoroquinolone 7