2018 Volume 33 Issue 2 Pages 56-61
Our hospital regularly performs an environmental investigation for Legionella, four times a year for the feed-water system, as part of our countermeasures to prevent hospital infection. Since Legionella pneumophila serogroup 5 (SG 5) was detected in the water feed on the first floor, where the emergency center is located, we took countermeasures to deal with the accumulated water, but repeatedly detected the bacteria. Suspecting systematic contamination by colonization of Legionella bacteria, we investigated all sites of the feed-water system in the area where the emergency center is located, to clarify the cause of the contamination and take appropriate countermeasures.
L. pneumophila SG 5 was detected at 12 sites. The water temperature, which was measured in the investigation, was 30°C or higher at seven sites. This was considered to be caused by the piping route, which was through the mechanical and boiler rooms in the basement. As countermeasures, we repaired the piping route and successfully controlled the systematic contamination by Legionella by lowering the water temperature. Rust was found to have accumulated in the lumen of dismantled feed-water pipes and was considered to form a hotbed for the increase of Legionella.
We successfully controlled the systematic contamination of the feed-water system by Legionella, which was detected during a regular environmental investigation for the bacteria, by immediately taking appropriate countermeasures. Although there has been no development of hospital infection by Legionella in our hospital, such a development would not only cause detriment to patients but also have a large impact on hospital management. Hospital administrators should monitor the detection of Legionella bacteria in the feed-water system on a daily basis as a part of risk management and make efforts to reduce the risk of legionellosis by taking countermeasures to reduce the detection of the bacteria to below the detection limits in the early phase.
