LAB WORK​
  • Gram (-)
  • Urine antigen detects serogroup 1 only (16 serotypes of Legionella pneumophila in existence), which is most common serogroup associated with infections (serogroup 2 also possible)
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TREATMENT​ OPTIONS
  • ​Azithromycin OR Fluoroquinolone
  • ​Doxycycline may also be an option, but macrolides and fluoroquinolones preferred
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​CLINICAL NOTES​
  • Accounts for 1-5% of pneumonia cases
  • Risk factors for infection
    • ​Travel within the past 2 weeks, particularly cases involving a stay in hotels or cruise ships
    • Recent exposure to standing water like hot tubs, spas, or recent plumbing work
    • Immunosuppression
    • Age > 50
    • Smoking
    • Advanced renal or liver disease
    • Organ transplant
    • Alcohol abuse
    • Male sex
  • Transmitted via inhalation of aerosolized bacteria
  • Incubation period 2-14 days, with some patients experiencing a prodrome of muscle aches, headache, decreased appetite, fever, rigors, diarrhea, abdominal pain, or malaise
  • Has been associated with some lab abnormalities including hyponatremia