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Hold your water: Faucet study spurs controversy
APIC, engineering group challenge findings
Researchers at Johns Hopkins University School of Medicine have determined that electronic-eye faucets, which presumably lower bacterial hand contamination via hands-free usemay actually endanger high-risk patients with Legionella infection.
Presented recently in Dallas at the annual meeting of the Society for Healthcare Epidemiology of America (SHEA), the findings were subsequently challenged by infection control and engineering groups that advised caution in interpreting them.
Electronic-eye, non-touch faucets have been increasingly utilized in healthcare settings to lower water consumption and in an attempt to reduce recontamination of the hands of healthcare personnel. But do they carry a hidden risk of their own?
Emily Sydnor, MD, an infectious disease fellow at Hopkins, and colleagues examined bacterial growth from faucets of two clinical wards within the hospital from December 2008 through January 2009. The study included 20 manual faucets and 20 electronic faucets, each receiving water from the same source.
Cultures obtained from the faucets showed that 50% of water cultures from electronic faucets grew Legionella species, compared to 15% of water cultures from manual faucets. Overall, 54 (50%) of 108 water cultures from electronic faucets grew Legionella spp. compared to 11 (15%) of 75 water cultures from manual faucets.1 Sydnor also found that 26% of water cultures from electronic faucets had significant growth on heterotrophic plate count (HPC) culturesan estimate of the number of bacteria in the watercompared to 13% of water cultures from manual faucets. Overall, 15 (26%) of 58 electronic faucet HPC cultures grew with greater than 500 colony forming units per ml as compared to 6 (13%) of 45 manual faucet cultures
While the HPC rates were not statistically different, Sydnor said the differences were worth noting. Additionally, following a flush of the water system using chlorine dioxide the disparity between electronic and manual faucets persisted. After the cleaning, 29% of electronic faucet cultures were still contaminated with bacteria compared with 7% of manual faucet cultures. Overall, after chlorine dioxide remediation, 4 (14%) of 28 electronic faucet and 1(3%) of 30 manual faucet water cultures grew Legionella. Eight (29%) electronic faucets and two (7%) manual faucets cultures had HPC growth.
Sydnor speculated that the increased bacterial growth in electronic faucets may be due to contamination of the numerous parts and valves that make up the faucet. During the course of collecting water samples, researchers discovered that all of the electronic faucet parts grew Legionella. However, the study's findings should not create cause for concern over the use of electronic faucets by the general public, Sydnor emphasized. The levels of both Legionella and bacterial burden on HPC were still within the range that is well tolerated by healthy individuals, she noted.
"The levels of bacterial growth in the electronic faucetsparticularly the Legionella specieswere of concern because they were beyond the tolerable thresholds determined by the hospital," Sydnor said. "Exposure to Legionella is dangerous for chronically ill or immune compromised patients because it may cause pneumonia in these vulnerable patients."
In light of the findings, Johns Hopkins Hospital is replacing electronic faucets in clinical areas with manual faucets, and has decided not to install electronic faucets in clinical areas of its new hospital building now under construction.
APIC, AHSE response
After the SHEA meeting, the American Society for Healthcare Engineering (ASHE) and the Association for Professionals in Infection Control and Epidemiology (APIC) urged healthcare facilities to review additional literature before making policy changes regarding hands-free faucets.
"This has been presented as an oral session at a scientific meeting," said ASHE and APIC in a statement posted on the organizations' websites. "It has not been published in a peer-reviewed, scientific journal. As such it is an interesting study, but any major changes in policy or actions by others should await publication as more details will be revealed, and peer-review always improves the context and significance of findings. This study also needs to be considered in the context of other published studies and evidence-based guidelines."
ASHE and APIC pointed out that there have been several studies which found that manual, handle-operated faucets were the source of bacterial infections in patients, as well as another study of electronic faucets which did not find these to be a source of bacteria. Previous investigations of electronic controlled faucets have raised the issue of infection control and prevention. ASHE and APIC responded to the study in part because of on-going revisions and updates that will be included in the 2014 edition of the "Facility Guidelines Institute's Guidelines for Design and Construction of Health Care Facilities."
Highlights from the joint statement include:
APIC and ASHE endorse and support the use of the Infection Control Risk Assessment (ICRA)a multidisciplinary, documented assessment process intended to proactively identify and mitigate risks from infection that could occur during design and construction activities. A key element of an ICRA is identifying the design and location of hand-washing stations. The 2010 ASHE guidelines permit electronic faucets. It is recommended that health care facilities implement an ICRA early in the planning phase of a construction or renovation project, when it serves as the forum for assessing risks and implementing design elements aimed at preventing of infection.
Several studies have found that manual, handle-operated faucets were the source of bacterial infections in patients, including Legionella.2-6 This demonstrates there is no single design feature that can mitigate all risk of cross transmission. Another study of electronic faucets did not find these fixtures to be a source of bacteria. In fact, a sample from a manual, handle-operated faucet was the only one that detected bacteria7 Electronic faucets do help with water conservation, which is important as hospitals are an industry noted for high use of water.8
Why do some studies find a higher likelihood of recovery of bacteria from electronic faucets? This is a complex question, but some feel this is due to the reduced water flow in electronic faucets which makes the flushing effect less pronounced than in a manual, handle-operated faucet. One strategy to minimize risk of contaminants inside the faucet is to ensure the length of the pipes connecting the valve and water outlet is as short as possible. Also, the frequency of use is important. Faucets, whether electronic or manual, that are not used on a regular basis will have stagnant water and low levels of bacteria will increase over time. There may also be some unique aspects to electronic faucets as they have more parts, including a magnetic valve made of rubber, plastic, and polyvinylchloride. These materials are more likely to develop a biofilm, which protects bacteria in the film from disinfectants that have been added to the water.