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.
Highlights
These cases are predominantly associated with Legionella pneumophila serogroup 1 strains present in the hospital hot water systems.[2,3,4]
A few outbreaks and isolated cases have been related to L. pneumophila (Lp) serogroup 5.5–7
Several factors can contribute to Legionella growth and persistence within hospital water systems: temperature, stagnation, biofilm, material, disinfectant, and water quality.[8,9,10,11,12]
Summary
These cases are predominantly associated with Legionella pneumophila serogroup 1 (sg1) strains present in the hospital hot water systems.[2,3,4] A few outbreaks and isolated cases have been related to L. pneumophila (Lp) serogroup 5 (sg5).[5,6,7]. We report a nosocomial outbreak of Lp sg[5] in the year following the installation of 2 heat exchangers in 2 distinct hospital wings as part of an energy conservation upgrade.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
