What should be done in a hospital where Legionella positivity is consistently greater than 70% after hyperchlorination?

In a hospital setting where testing reveals consistent Legionella positivity greater than 70% even after hyperchlorination, implementing a continuous supplemental disinfection system is a critical response. This approach is effective because hyperchlorination may not be sufficient on its own to eliminate Legionella bacteria, particularly in complex plumbing systems where biofilms and other factors can protect the bacteria from chlorine disinfection.

A continuous supplemental disinfection system, such as ultraviolet (UV) light, ozonation, or chloramination, can provide ongoing control of Legionella by maintaining lower, stable levels of disinfectants in the water supply. This method not only helps to reduce the concentration of Legionella bacteria but also aids in the prevention of re-establishment or regrowth, which can occur in water systems, especially in large facilities like hospitals.

In contrast, regular testing of the incoming water supply can certainly be beneficial for monitoring the quality of water, but it does not directly address the existing high levels of Legionella. Reducing the water temperature to below 50°C might minimize the growth conditions favorable for Legionella, but it could also create other issues, such as increased risk of other pathogens or inadequate performance of water heating systems. Increasing chlorine levels to 200 ppm could be harmful to the plumbing