Electronic-Eye Faucets: Legionella Species Contamination in Healthcare Settings

Objective. To compare heterotrophic plate counts (HPCs) and Legionella species growth from electronic and manual faucet water samples. Design. Proportions of water samples with growth and colony-forming units were compared using Fisher’s exact test and the Wilcoxon rank-sum test, respectively. Setting. Two psychiatric units and 1 medical unit in a 1,000-bed university hospital. Methods. Water samples were collected from 20 newly installed electronic faucets and 20 existing manual faucets in 3 hospital units. Manual faucets were located in rooms adjacent to the electronic faucets and received water from the same source. Water samples were collected between December 15, 2008, and January 29, 2009. Four electronic faucets were dismantled, and faucet components were cultured. Legionella species and HPC cultures were performed using standard methods. Results. Nearly all electronic faucets (19/20 [95%]) grew Legionella species from at least 1 water sample, compared with less than half (9/20 [45%]) of manual faucets ( ). Fifty-four (50%) of 108 electronic faucet water cultures grew Legionella species, compared with 11 (15%) of 75 manual faucet water cultures ( ). After chlorine dioxide remediation, 4 (14%) of 28 electronic faucet and 1 (3%) of 30 manual faucet water cultures grew Legionella species ( ), and 8 (29%) electronic faucet and 2 (7%) manual faucet cultures had significant HPC growth ( ). All 12 (100%) of the internal faucet components from 2 electronic faucets grew Legionella species. Conclusions. Electronic faucets were more commonly contaminated with Legionella species and other bacteria and were less likely to be disinfected after chlorine dioxide remediation. Electronic faucet components may provide points of concentrated bacterial growth.