I recently had the opportunity to attend the “Managing Legionella in Building Water Systems” conference, which was held from May 9th – 11th in Baltimore, MD. The conference was organized by NSF International and the National Science Foundation, with the goal being “to raise awareness and encourage positive, coordinated actions to combat legionellosis”. The conference was filled to capacity with stakeholders from all aspects of water treatment and water safety. There were numerous presentations from the U.S. Environmental Protection Agency (EPA), the Centers for Disease Control (CDC), as well as numerous academic institutions, state health agencies, and engineering firms.
The program included sessions on biofilm, microbial contamination, Legionella prevention and mitigation, plumbing system design, risk factors and risk management, and implementation of guidances/standards/regulations. Being a microbiologist, obviously my favorite session was “Root of the Problem – Biofilm”. It is well understood that the ability of Legionella, and other pathogenic microorganisms, to reside within the biofilm of a water system is the basis of the problem. The biofilm in water systems provides a place for Legionella to live, replicate and be protected from outside environmental factors, including biocides. As long as the water system is functioning normally, everything remains in steady state and all appears well. However, when a significant perturbation occurs, such as source water change (Michigan), water main break (NY), or lack of biocide, the reservoir of Legionella are poised to populate the entire water system.
Overall, there were four primary take away messages from the conference:
- Biofilm is the root of the problem of Legionella in water systems.
- The rate of reported Legionnaire’s disease is rapidly increasing in the U.S.
- Facilities should establish, and adhere to, Water Safety Plans.
- Using ASHRAE 188 as a blueprint, states are being encouraged to develop and codify regulations such as have been established in New York.
