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Post Conference Questions and Answers:
Legionella Case/Outbreak Response and Long-term Mitigation A Facilities Management Perspective- Kevin Merritt, MSE
Question: Our facilities manager is saying POU filters are unnecessary in critical care areas- Do you have literature supporting the use of filters? What about dialysis- he said reverse osmosis filtrations covers everything- is this true? What happens if the filter system fails in the osmosis filtration system? He said if it’s “not a drinking water source there is no need for POU filters. How do I present danger lurks in the sink, faucets, and showerhead?
Answer: First I would state that installation of POU filters is a clinical decision that falls under the jurisdiction of a facility’s Infection Control team. If there is a case/outbreak then water restrictions will be implemented to reduce further risk. As most health care professionals know, water restrictions place a significant impact on quality of care and that impact can be reduced by installing POU filters in critical care areas (ICU’s oncology and rad therapy units, cardiac care etc.)
He is incorrect that drinking water is the only concern. The disease is contracted when a susceptible host aspirates aerosolized water droplets that contain Legionella. This can happen at a sink or shower (cooling towers routinely provide the source for community outbreaks) and has been indicated as a transmission source in cases/outbreaks (see CDC material regarding Legionella and sources of transmission). You could drink water with high concentrations of Legionella without contracting the disease if there is no aspiration as the bacteria requires entrance into the lungs.
Facilities are now moving toward installing POU filters on ice machines and bottle filling stations to further reduce the future impact of water restrictions should a case or outbreak occur (ice and drinking water would not be impacted, nor would hand washing with filters installed on sinks).
With regard to dialysis operations, he is correct. Dialysis units have dedicated water treatment systems utilizing reverse osmosis that are designed to further treat the water. Dialysis water treatment units are NOT designed to treat raw source water (there are RO units designed for use in natural disasters that are capable of doing so). However, Dialysis units reliably remove contaminants, including bacteria, when treating previously treated potable water from a municipal plant, therefore are not impacted by water restrictions.
There are several manufacturers of exclusionary filters, but two have obtained FDA 501(k) clearance to market their filter products as medical devices. They are extremely effective when installed properly and replaced at the manufacturer’s recommended intervals. These filters have been validated to be an effective barrier against bacteria, to include Legionella. I have used them personally in our medical center and at facilities that experienced an outbreak when I was a consultant (we received no monetary gain as we did not recommend a particular manufacturer) with no failures.
The bottom line is they are an effective tool to limit the impact of water restrictions by preventing exposure to the bacteria causing the disease. Their use is situation-dependent, but if water restrictions are implemented then their use can significantly reduce or eliminate the impact of water restrictions that may be in place for sometimes weeks until the health department declares an outbreak is over.