BACKGROUND: Two proven nosocomial cases of Legionella pneumonia occurred at the Wesley Hospital (Brisbane, Australia) in May 2013. To trace the epidemiology of these cases, whole genome sequence analysis was performed on Legionella pneumophila isolates from the infected patients, prospective isolates collected from the hospital water distribution system (WDS), and retrospective patient isolates available from the Wesley Hospital and other local hospitals. METHODS: Legionella pneumophila serogroup 1 isolates were cultured from patient sputum (n = 3), endobronchial washings (n = 3), pleural fluid (n = 1), and the Wesley Hospital WDS (n = 39). Whole genome sequencing and de novo assembly allowed comparison with the L. pneumophila Paris reference strain to infer phylogenetic and epidemiological relationships. Rapid disinfection of the hospital WDS with a chlorinated, alkaline detergent and subsequent superchlorination followed by maintenance of residual free chlorine, combined with removal of redundant plumbing, was instituted. RESULTS: The 2011 and 2013 L. pneumophila patient isolates were serogroup 1 and closely related to all 2013 hospital water isolates based on single nucleotide polymorphisms and mobile genetic element profiles, suggesting a single L. pneumophila population as the source of nosocomial infection. The L. pneumophila population has evolved to comprise 3 clonal variants, each associated with different parts of the hospital WDS. CONCLUSIONS: This study provides an exemplar for the use of clinical and genomic epidemiological methods together with a program of rapid, effective remedial biofilm, plumbing and water treatment to characterize and eliminate a L. pneumophila population responsible for nosocomial infections.
BACKGROUND: Two proven nosocomial cases of Legionella pneumonia occurred at the Wesley Hospital (Brisbane, Australia) in May 2013. To trace the epidemiology of these cases, whole genome sequence analysis was performed on Legionella pneumophila isolates from the infectedpatients, prospective isolates collected from the hospital water distribution system (WDS), and retrospective patient isolates available from the Wesley Hospital and other local hospitals. METHODS:Legionella pneumophila serogroup 1 isolates were cultured from patient sputum (n = 3), endobronchial washings (n = 3), pleural fluid (n = 1), and the Wesley Hospital WDS (n = 39). Whole genome sequencing and de novo assembly allowed comparison with the L. pneumophila Paris reference strain to infer phylogenetic and epidemiological relationships. Rapid disinfection of the hospital WDS with a chlorinated, alkaline detergent and subsequent superchlorination followed by maintenance of residual free chlorine, combined with removal of redundant plumbing, was instituted. RESULTS: The 2011 and 2013 L. pneumophilapatient isolates were serogroup 1 and closely related to all 2013 hospital water isolates based on single nucleotide polymorphisms and mobile genetic element profiles, suggesting a single L. pneumophila population as the source of nosocomial infection. The L. pneumophila population has evolved to comprise 3 clonal variants, each associated with different parts of the hospital WDS. CONCLUSIONS: This study provides an exemplar for the use of clinical and genomic epidemiological methods together with a program of rapid, effective remedial biofilm, plumbing and water treatment to characterize and eliminate a L. pneumophila population responsible for nosocomial infections.
Authors: Andrew H Buultjens; Kyra Y L Chua; Sarah L Baines; Jason Kwong; Wei Gao; Zoe Cutcher; Stuart Adcock; Susan Ballard; Mark B Schultz; Takehiro Tomita; Nela Subasinghe; Glen P Carter; Sacha J Pidot; Lucinda Franklin; Torsten Seemann; Anders Gonçalves Da Silva; Benjamin P Howden; Timothy P Stinear Journal: Appl Environ Microbiol Date: 2017-10-17 Impact factor: 4.792
Authors: Jingrang Lu; Helen Buse; Ian Struewing; Amy Zhao; Darren Lytle; Nicholas Ashbolt Journal: Environ Sci Pollut Res Int Date: 2016-11-04 Impact factor: 4.223
Authors: Jeffrey W Mercante; Shatavia S Morrison; Heta P Desai; Brian H Raphael; Jonas M Winchell Journal: PLoS One Date: 2016-09-29 Impact factor: 3.240