# Elimination of Legionella colonization in a hospital water system: evidence from 23 years of chlorine dioxide use

## TL;DR

A hospital successfully reduced Legionella bacteria in its water system over 23 years by using chlorine dioxide and replacing pipes.

## Contribution

The study demonstrates the long-term effectiveness of chlorine dioxide and pipe replacements in eliminating Legionella colonization.

## Key findings

- Chlorine dioxide application reduced Legionella positivity to less than 1% in hospital water systems.
- Iterative treatment of cold and hot water systems followed by pipe replacements was effective.
- Over 6,800 samples were analyzed to track Legionella levels over 23 years.

## Abstract

A hospital water system colonized with Legionella bacteria (three of four buildings, with > 50% of positive samples) was able to reduce detections to <1% positivity in the long term only after ClO2 was iteratively added first to the cold-water and then hot-water systems followed by pipe replacements (n = 6835 total samples).