Which microorganism is commonly associated with water and poses a risk in healthcare settings?

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

Answer: (B)

Legionella is a bacterium that thrives in water systems, especially in warm, stagnant parts of buildings such as expansive plumbing, cooling towers, showers, and humidifiers. In healthcare settings, aerosolized water droplets can carry Legionella, making patients—particularly older or immunocompromised individuals—susceptible to Legionnaires’ disease, a serious form of pneumonia. Because its transmission hinges on exposure to contaminated water systems, it stands out as a primary water-associated risk and drives the need for hospital water-management programs that control temperature, flushing protocols, and disinfection. While other organisms can be present in water, Legionella is the classic, well-known waterborne threat in healthcare environments, which is why it’s considered the best answer in this context.