A 17-Month Evaluation of a Chlorine Dioxide Water Treatment System to Control Legionella Species in a Hospital Water Supply

Abstract

Objective:To assess the safety and efficacy of a chlorine dioxide water treatment system in controlling Legionella in a hospital water supply.Design:For 17 months following installation of the system, we performed regular water cultures throughout the building, assessed chlorine dioxide and chlorite levels, and monitored metal corrosion.Results:Sites that grew Legionella species decreased from 41% at baseline to 4% (P = .001). L. anisa was the only species recovered and it was found in samples of both hot and cold water. Levels of chlorine dioxide and chlorite were below Environmental Protection Agency (EPA) limits for these chemicals in potable water. Further, enhanced carbon filtration effectively removed the chemicals, even at chlorine dioxide levels of more than twice what was used to treat the water. After 9 months, corrosion of copper test strips exposed to the chlorine dioxide was not higher than that of control strips. During the evaluation period, there were no cases of nosocomial Legionella in the building with the system, whereas there was one case in another building.Conclusions:Our results indicate that operation of a chlorine dioxide system effectively removed Legionella species from a hospital water supply. Furthermore, we found that the system was safe, as levels of chlorine dioxide and chlorite were below EPA limits. The system did not appear to cause increased corrosion of copper pipes. Our results indicate that chlorine dioxide may hold promise as a solution to the problem of Legionella contamination of hospital water supplies.

Progress in the Battle Against Nosocomial Legionnaires' Disease: Shedding Light on Shades of Gray

“…11 This is the first report of the safety and efficacy of this disinfection method in the United States, and the data confirm earlier reports from Europe. After disinfection was initiated, sites growing Legionella decreased from 41% to 4% (P = .001), and only Legionella anisa was cultured.…”

Control of Legionella Contamination and Risk of Corrosion in Hospital Water Networks following Various Disinfection Procedures

“…We also studied hydrogen peroxide, which has not yet been used extensively to control Legionella in hospital water distribution systems (36,37). A comparison was carried out between these new procedures and two popular methods, chlorine dioxide and hyperthermia, which have widely been reported to be effective (38)(39)(40)(41)(42).…”

Point-of-care controls for nosocomial legionellosis combined with chlorine dioxide potable water decontamination: a two-year survey at a Welsh teaching hospital

“…In this hospital, the maximum permissible level in the UK of 0.5 ppm of chlorine dioxide was used, but successful control of legionella was only achieved with a chlorine dioxide level of 0.8 ppm in a report from the USA in a far less complex system than at our institution. 15 The three cases of nosocomial Legionnaires' disease reported in this study are notable for several facts. There were no epidemiological data to suggest aerosol inhalation as the possible route of infection, and no other cases were detected in patients in proximity to each of the cases.…”