Affiliation: 1. Infection Control Program and WHO Collaborating Center on Patient Safety, University of Geneva Hospitals and Faculty of Medicine, Geneva, Switzerland. Received December 6, 2011; accepted December 6, 2011; electronically published January 19, 2012. 2012 by The Society for Healthcare Epidemiology of America. All rights reserved. 0899-823X/2012/3303-0006$15.00. DOI: 10.1086/664494 Hands-free, electronic-eye, automatic faucets are installed in healthcare settings for convenience and reduction of water consumption, and thus they contribute to cost control. As it has been shown that faucet handles may be sources of microorganism cross-transmission, automatic faucets are also thought to reduce pathogen transmission because no surface needs to be touched for hand washing. Despite this widespread belief, electronic faucets have been repeatedly reported as a source for potentially harmful bacteria, such as Pseudomonas aeruginosa, other nonfermentative gram-negative organisms, and Legionella species. In this issue of the journal, Sydnor et al report that electronic-eye faucets in use at Johns Hopkins Hospital were more likely to be contaminated with Legionella species, a pathogen that causes severe pneumonia in immunocompromised patients, than manual faucets. Following disruption of the city water supply, almost all electronic-eye faucets grew Legionella species from at least 1 water sample. Standard hospital water-treatment practices were not effective at disinfecting the faucets. Even remediation with 5-ppm chlorine dioxide was not able to remove all bacteria, although there was a reduction in the frequency of pathogen detection in the samples, and no significant difference could be detected any longer between electronic and manual faucets. Of note, significantly more Legionella species were found on various parts of the electronic-eye faucets before remediation with high-dose chlorine dioxide. It is not clear why electronic rather than mechanical faucets are more readily contaminated with bacteria. Previously hypothesized reasons include low water flow, retrograde contamination from the faucet outlet, tepid water temperature, and bacterial colonization of the internal magnetic valves. The more complex structure of the faucet may also offer niches for bacterial growth, and the design and materials may facilitate biofilm formation. However, more information is needed because the study cannot explain the detailed pathogenesis of faucet colonization. The double interruption of the city water supply most likely produced a fresh influx of Legionella species and other bacteria. Without this unfortunate incident, the authors might not have detected significant differences in colonization and water contamination between the 2 faucet types. In particular, the authors found that complete restoration of the integrity of the water supply following its rupture was not possible. This is an important finding because it shows the importance of baseline contamination of the water supply and highlights the problem of stagnant water. Importantly, misuse or underutilization was not evidenced, as the scheduled hygiene flush was never triggered on any electronic faucet during the evaluation period because of frequent use. The study does not report the clinical significance of the findings, as no pneumonia due to Legionella pneumophila was detected during the study period, and no information is provided as to whether the hospital had a significant problem with this pathogen in the past—assuming that the electroniceye faucets have been in place for a few years. Because more Legionella anisa than L. pneumophila was isolated from electronic faucets, the clinical significance of the results is even more difficult to interpret. Unlike common practice for tap water quality control, the authors collected 500 mL of first-draw water for microbiological testing. Although at first glance the technique may seem inadequate, the procedure makes sense because water flow from electronic-eye faucets is activated by positioning the hands below the outlet, and it is the first-draw water that hits the hands and potentially generates aerosols. As a consequence of the study findings, all electronic-eye faucets were replaced with manual faucets in the authors’ institution. Although the study confirms previous reports of electronic faucet contamination with nonfermentative gramnegative bacteria and unequivocally provides information about the extent of Legionella species colonization, there is insufficient evidence to recommend the removal of electroniceye faucets from all healthcare institutions. Nevertheless, the