Which statement regarding Legionella bacteria is incorrect?

The statement regarding the colonization of Legionella bacteria being favored by temperatures in the range of 5-15 degrees Celsius is incorrect. Legionella species proliferate most effectively at warmer temperatures, particularly between 20 to 50 degrees Celsius, with an optimal growth range around 35 to 40 degrees Celsius. This characteristic allows the bacteria to thrive in hot water systems, cooling towers, and other environments where water temperatures are sufficiently warm.

In contrast, the other statements are accurate. Legionella can indeed cause severe pneumonia in humans, commonly referred to as Legionnaires' disease. The bacteria are frequently found in water systems, making natural and artificial water sources a significant concern for public health. The ability of Legionella to thrive in temperatures above 20 degrees Celsius further emphasizes the need for monitoring and controlling water temperatures in systems where bacterial growth could pose health risks.