Outbreak of Pseudomonas aeruginosa producing VIM carbapenemase in an intensive care unit and its termination by implementation of waterless patient care
Gaud Catho,
R. Martischang,
F. Boroli,
M. N. Chraïti,
Y. Martin,
Z. Koyluk Tomsuk,
G. Renzi,
J. Schrenzel,
J. Pugin,
P. Nordmann,
D. S. Blanc,
S. Harbarth
Affiliations
Gaud Catho
Infection Control Program, WHO Collaborating Center for Patient Safety, Faculty of Medicine, Geneva University Hospitals
R. Martischang
Infection Control Program, WHO Collaborating Center for Patient Safety, Faculty of Medicine, Geneva University Hospitals
F. Boroli
Division of Critical Care, Faculty of Medicine, Geneva University Hospitals
M. N. Chraïti
Infection Control Program, WHO Collaborating Center for Patient Safety, Faculty of Medicine, Geneva University Hospitals
Y. Martin
Infection Control Program, WHO Collaborating Center for Patient Safety, Faculty of Medicine, Geneva University Hospitals
Z. Koyluk Tomsuk
Division of Critical Care, Faculty of Medicine, Geneva University Hospitals
G. Renzi
Bacteriology Laboratory, Faculty of Medicine, Geneva University Hospitals
J. Schrenzel
Bacteriology Laboratory, Faculty of Medicine, Geneva University Hospitals
J. Pugin
Division of Critical Care, Faculty of Medicine, Geneva University Hospitals
P. Nordmann
Emerging Antibiotic Resistance Unit, Medical and Molecular Microbiology, Department of Medicine, Faculty of Science and Medicine, University of Fribourg
D. S. Blanc
Swiss National Reference Center for Emerging Antibiotic Resistance
S. Harbarth
Infection Control Program, WHO Collaborating Center for Patient Safety, Faculty of Medicine, Geneva University Hospitals
Abstract Background Long-term outbreaks of multidrug-resistant Gram-negative bacilli related to hospital-building water systems have been described. However, successful mitigation strategies have rarely been reported. In particular, environmental disinfection or replacement of contaminated equipment usually failed to eradicate environmental sources of Pseudomonas aeruginosa. Methods We report the investigation and termination of an outbreak of P. aeruginosa producing VIM carbapenemase (PA-VIM) in the adult intensive care unit (ICU) of a Swiss tertiary care hospital with active case finding, environmental sampling and whole genome sequencing (WGS) of patient and environmental strains. We also describe the implemented control strategies and their effectiveness on eradication of the environmental reservoir. Results Between April 2018 and September 2020, 21 patients became either infected or colonized with a PA-VIM strain. For 16 of them, an acquisition in the ICU was suspected. Among 131 environmental samples collected in the ICU, 13 grew PA-VIM in sink traps and drains. WGS confirmed the epidemiological link between clinical and environmental strains and the monoclonal pattern of the outbreak. After removing sinks from patient rooms and implementation of waterless patient care, no new acquisition was detected in the ICU within 8 months after the intervention. Discussion Implementation of waterless patient care with removal of the sinks in patient rooms was successful for termination of a PA-VIM ICU outbreak linked to multiple environmental water sources. WGS provides highly discriminatory accuracy to investigate environment-related outbreaks.
