The healthcare facility has installed an open water wall in the main lobby. Which organism should the IP ask the laboratory to monitor for?

• A. Escherichia coli
• B. Legionella pneumophila
• C. Pseudomonas aeruginosa
• D. Staphylococcus aureus

Answer: (B)

Open water features can release aerosols that carry Legionella pneumophila, the bacterium linked to Legionnaires’ disease. In a hospital-like setting, a decorative water wall provides warmth and moisture that support Legionella growth, and the aerosolized particles can be inhaled by people nearby. Because of this specific risk, monitoring for Legionella pneumophila is the most appropriate action to detect and prevent potential outbreaks stemming from the water system.

E. coli would indicate fecal contamination, which isn’t the primary concern with decorative water features. Pseudomonas can inhabit water and cause infections, but Legionella is the more relevant threat when aerosols are involved. Staphylococcus aureus relates more to skin or environmental contamination and isn’t the specific hazard in this context. Testing for Legionella pneumophila targets the real risk presented by the open water wall.