Preventing Healthcare-Associated Legionellosis with Rapid Reduction of High Concentrations of Legionella Using Mechanical Removal of Blind Ends and Intensive Hot Water Flushing

Background: The aim of this paper was to present the effectiveness of the mechanical removal of blind ends and flushing of hot water systems at outlets as the only possible emergency measures to reduce the concentration of Legionella spp in hot water. Methods: Two measures have been undertaken: mechanical removal of blind ends and intensive hot water flushing when the water has not been used for more than 7 days. Results: We detected Legionella pneumophila serogroup 1 in concentration of 1.000- 55.000 CFU/L at all samples sites. In the control sampling, after three weeks, we found seven sampling sites negative for Legionella and only two sampling sites positive. All nine sampling sites were negative after ten weeks. Conclusion: Establishing good water flow throughout the hospital seems to be the most important measure, in order to make the multiplication of Legionella in the hot water distribution systems unlikely.