What is the Legionella-positive test result for the public water supply in the last three sampling rounds?

The choice indicating that 2 of the 3 sampling rounds returned a positive result for Legionella in the public water supply is valid because it suggests that Legionella was detected in two separate instances out of three tests conducted. This scenario indicates a concerning trend, as the presence of Legionella bacteria in water systems can pose a significant health risk, particularly for vulnerable populations.

This result highlights the importance of continuous monitoring and testing of water supplies to identify potential sources of Legionella growth, which thrive in warm water environments. While detecting Legionella in two out of three samples suggests some level of contamination, it also implies that there may have been instances where conditions allowed for bacterial growth, warranting further investigation and management.

In the context of Legionella management, having a positive detection in a majority of samples (as in this case) necessitates a response to assess water system temperatures, biofilm buildup, disinfection protocols, and other environmental factors that can influence the presence and proliferation of the bacteria. Such actions are crucial to safeguard public health by minimizing the risk of Legionnaires' disease associated with water sources.