title: Energy Conservation and the Promotion of Legionella pneumophila Growth: The Probable Role of Heat Exchangers in a Nosocomial Outbreak.
abstract: OBJECTIVE To determine the source of a Legionella pneumophila serogroup 5 nosocomial outbreak and the role of the heat exchanger installed on the hot water system within the previous year. SETTING A 400-bed tertiary care university hospital in Sherbrooke, Canada. METHODS Hot water samples were collected and cultured for L. pneumophila from 25 taps (baths and sinks) within wing A and 9 taps in wing B. Biofilm (5) and 2 L water samples (3) were collected within the heat exchangers for L. pneumophila culture and detection of protists. Sequence-based typing was performed on strain DNA extracts and pulsed-field gel electrophoresis patterns were analyzed. RESULTS Following 2 cases of hospital-acquired legionellosis, the hot water system investigation revealed a large proportion of L. pneumophila serogroup 5 positive taps (22/25 in wing A and 5/9 in wing B). High positivity was also detected in the heat exchanger of wing A in water samples (3/3) and swabs from the heat exchanger (4/5). The outbreak genotyping investigation identified the hot water system as the source of infections. Genotyping results revealed that all isolated environmental strains harbored the same related pulsed-field gel electrophoresis pattern and sequence-based type. CONCLUSIONS Two cases of hospital-acquired legionellosis occurred in the year following the installation of a heat exchanger to preheat hospital hot water. No cases were reported previously, although the same L. pneumophila strain was isolated from the hot water system in 1995. The heat exchanger promoted L. pneumophila growth and may have contributed to confirmed clinical cases. Infect. Control Hosp. Epidemiol. 2016;1475-1480.
authors.affiliation: 1Department of Civil Engineering,Polytechnique Montréal,Montréal,Canada.
authors.forename: Emilie
authors.initials: E
authors.lastname: Bédard
authors.affiliation: 2Laboratoire de Santé Publique du Québec/ Institut National de Santé Publique du Québec,Sainte-Anne-de-Bellevue,Canada.
authors.forename: Simon
authors.initials: S
authors.lastname: Lévesque
authors.affiliation: 3Department of Microbiology and Infectious diseases, Faculty of Medicine and Health Sciences,Université de Sherbrooke,Sherbrooke,Canada.
authors.forename: Philippe
authors.initials: P
authors.lastname: Martin
authors.affiliation: 4Department of Community Health Sciences, Faculty of Medicine and Health Sciences,Université de Sherbrooke,Sherbrooke,Canada.
authors.forename: Linda
authors.initials: L
authors.lastname: Pinsonneault
authors.affiliation: 5Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences,McGill University,Sainte-Anne-de-Bellevue,Canada.
authors.forename: Kiran
authors.initials: K
authors.lastname: Paranjape
authors.affiliation: 2Laboratoire de Santé Publique du Québec/ Institut National de Santé Publique du Québec,Sainte-Anne-de-Bellevue,Canada.
authors.forename: Cindy
authors.initials: C
authors.lastname: Lalancette
authors.affiliation: 1Department of Civil Engineering,Polytechnique Montréal,Montréal,Canada.
authors.forename: Charles-Éric
authors.initials: CÉ
authors.lastname: Dolcé
authors.affiliation: 6Centre d'expertise en analyse environnementale du Québec,Québec,Canada.
authors.forename: Manuela
authors.initials: M
authors.lastname: Villion
authors.affiliation: 3Department of Microbiology and Infectious diseases, Faculty of Medicine and Health Sciences,Université de Sherbrooke,Sherbrooke,Canada.
authors.forename: Louis
authors.initials: L
authors.lastname: Valiquette
authors.affiliation: 5Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences,McGill University,Sainte-Anne-de-Bellevue,Canada.
authors.forename: Sébastien P
authors.initials: SP
authors.lastname: Faucher
authors.affiliation: 1Department of Civil Engineering,Polytechnique Montréal,Montréal,Canada.
authors.forename: Michèle
authors.initials: M
authors.lastname: Prévost
mesh_terms: D002170:Canada; D003246:Conservation of Energy Resources / Q000379:methods; D003428:Cross Infection / Q000382:microbiology* / Q000635:transmission*; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D004780:Environment, Controlled; D005260:Female; D005838:Genotype; D006785:Hospitals, University; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D016952:Legionella pneumophila / Q000235:genetics / Q000302:isolation & purification*; D007877:Legionnaires' Disease / Q000635:transmission*; D008297:Male; D014871:Water Microbiology; D014881:Water Supply