The Johns Hopkins University School of Medicine is replacing its new high-tech, electric-eye faucets with the old-fashioned kind after discovering that the new hands-free designs actually allowed more contamination from Legionella and other bacteria than the old style.
Although the high-tech faucets cut daily water consumption by well over half, Johns Hopkins researchers identified Legionella growing in 50 percent of cultured water samples from 20 electronic-eye faucets in or near patient rooms on three different inpatient units, but in only 15 percent of water cultures from 20 traditional, manual faucets in the same patient care areas. Weekly water culture results also showed half the amount of bacterial growth of any kind in the manual faucets than in the electronic models.
While the precise reasons for the higher bacterial growth in the electronic faucets still need clarification, the researchers say it appears that standard hospital water disinfection methods, which complement treatments by public utilities, did not work well on the complex valve components of the newer faucets. They suspect that the valves simply offer additional surfaces for bacteria to become trapped and grow.
This episode isn't an argument against innovation, just a reminder that it needs to be field tested--reality still is much more complex than we can imagine. In time it's likely that a new generation of hands-free valve mechanisms will at least equal the hygienic record of traditional designs. Meanwhile Johns Hopkins deserves credit for careful investigation and for prompt announcement of its findings.
(Thanks to Scott Harrup!)