A patient with community-acquired pneumonia and recent hotel or cruise ship travel is most likely infected with which pathogen?

A patient with community-acquired pneumonia and recent hotel or cruise ship travel is most likely infected with which pathogen?

• A. Streptococcus pneumoniae
• B. Haemophilus influenzae
• C. Legionella
• D. Mycoplasma pneumoniae

Answer: (C)

Exposure to hotel or cruise ship environments points to Legionella because this pathogen spreads through inhalation of aerosolized water from building water systems such as cooling towers, showers, and hot tubs found in large hotels and ships. Legionella pneumophila can cause Legionnaires’ disease, a form of severe pneumonia that often accompanies systemic features like high fever, GI symptoms, and sometimes confusion or hyponatremia. This epidemiologic clue—recent travel in a hotel or cruise-ship setting—makes Legionella the most likely culprit. In contrast, Streptococcus pneumoniae is the most common cause of community-acquired pneumonia overall but lacks a specific link to hotel or cruise-ship water systems; Haemophilus influenzae is more common in patients with COPD or smoker history; Mycoplasma pneumoniae typically causes milder, “walking” pneumonia in younger adults and has a different epidemiology not tied to hotel outbreaks.

Exposure to hotel or cruise ship environments points to Legionella because this pathogen spreads through inhalation of aerosolized water from building water systems such as cooling towers, showers, and hot tubs found in large hotels and ships. Legionella pneumophila can cause Legionnaires’ disease, a form of severe pneumonia that often accompanies systemic features like high fever, GI symptoms, and sometimes confusion or hyponatremia. This epidemiologic clue—recent travel in a hotel or cruise-ship setting—makes Legionella the most likely culprit.

In contrast, Streptococcus pneumoniae is the most common cause of community-acquired pneumonia overall but lacks a specific link to hotel or cruise-ship water systems; Haemophilus influenzae is more common in patients with COPD or smoker history; Mycoplasma pneumoniae typically causes milder, “walking” pneumonia in younger adults and has a different epidemiology not tied to hotel outbreaks.