Effectiveness of different methods to control legionella in the water supply: ten-year experience in an Italian university hospital.

Abstract

We report our ten-year experience of hyperchlorination, thermal shock, chlorine dioxide, monochloramine, boilers and point-of-use filters for controlling legionella contamination in a hospital hot water distribution system. Shock disinfections were associated with a return to pre-treatment contamination levels within one or two months. We found that chlorine dioxide successfully maintained levels at <100 cfu/L, whilst preliminary experiments gave satisfactory results with monochloramine. No contamination was observed applying point-of-use filters and electric boilers at temperatures of >58°C and no cases of nosocomial legionellosis were detected in the ten-year observation period. Our performance ranking in reducing legionella contamination was filter, boiler, chlorine dioxide, hyperchlorination and thermal shock. Chlorine dioxide was the least expensive procedure followed by thermal shock, hyperchlorination, boiler and filter. We suggest adopting chlorine dioxide and electric boilers in parallel.

• Authors: I Marchesi, P Marchegiano, A Bargellini, S Cencetti, G Frezza, M Miselli, P Borella
• Journal: The Journal of hospital infection (J Hosp Infect) Vol. 77 Issue 1 Pg. 47-51 (Jan 2011) ISSN: 1532-2939 [Electronic] England
• PMID: 21131100 (Publication Type: Evaluation Study, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2010 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.

Chemical References

• Disinfectants

Topics

• Bacterial Load
• Cross Infection (prevention & control)
• Disinfectants (pharmacology)
• Disinfection (methods)
• Filtration (methods)
• Hospitals, University
• Hot Temperature
• Humans
• Infection Control (methods)
• Italy
• Legionella (isolation & purification)
• Water Microbiology
• Water Supply