S B Jørgensen1, M S Bojer2, E J Boll3, Y Martin4, K Helmersen5, M Skogstad5, C Struve6. 1. Akershus University Hospital, Department of Clinical Microbiology and Infection Control, Lørenskog, Norway; Vestre Viken Hospital Trust, Department of Clinical Microbiology, Bærum, Norway. Electronic address: silje.bakken.jorgensen@ahus.no. 2. Faculty of Health and Medical Sciences, Department of Veterinary Disease Biology, University of Copenhagen, Denmark. 3. Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark. 4. Akershus University Hospital, Department of Anaesthesiology, Lørenskog, Norway. 5. Akershus University Hospital, Department of Clinical Microbiology and Infection Control, Lørenskog, Norway. 6. Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark; WHO Collaborating Centre for Reference and Research on Escherichia and Klebsiella, Statens Serum Institut, Copenhagen, Denmark.
Abstract
BACKGROUND: We describe an outbreak with an extended-spectrum β-lactamase-producing Klebsiella pneumoniae strain in an intensive care unit in a secondary care hospital in Norway. The outbreak source was a fibreoptic intubation endoscope in which the outbreak strain survived despite chemothermal disinfection in a decontaminator designated for such use. The genetic marker clpK, which increases microbial heat resistance, has previously been described in K. pneumoniae outbreak strains. AIM: To investigate the role of clpK in biofilm formation and heat-shock stability in the outbreak strain. METHODS: The outbreak investigation was done by review of clinical records, screening of patients and culture from intubation endoscopes and bronchoscopes. Amplified fragment length polymorphism was used to identify the outbreak strain. clpK detection was performed by polymerase chain reaction, followed by mutant construction and heat-shock assays. FINDINGS: Five patients and one intubation endoscope contained K. pneumoniae with the same amplified fragment length polymorphism pattern. The outbreak strain contained the clpK genetic marker, which rendered the strain its increased heat resistance. The survival rate of the strain grown as biofilm following heat treatment was also strongly dependent on clpK. CONCLUSION: Although clpK has been associated with clinical isolates of K. pneumoniae in earlier outbreaks, this is the first time that a ClpK-producing strain has been isolated from an environmental outbreak source. Heat resistance of certain K. pneumoniae strains may facilitate survival in biofilms on medical equipment and hence increase the potential of those strains to persist and disperse in the hospital environment.
BACKGROUND: We describe an outbreak with an extended-spectrum β-lactamase-producing Klebsiella pneumoniae strain in an intensive care unit in a secondary care hospital in Norway. The outbreak source was a fibreoptic intubation endoscope in which the outbreak strain survived despite chemothermal disinfection in a decontaminator designated for such use. The genetic marker clpK, which increases microbial heat resistance, has previously been described in K. pneumoniae outbreak strains. AIM: To investigate the role of clpK in biofilm formation and heat-shock stability in the outbreak strain. METHODS: The outbreak investigation was done by review of clinical records, screening of patients and culture from intubation endoscopes and bronchoscopes. Amplified fragment length polymorphism was used to identify the outbreak strain. clpK detection was performed by polymerase chain reaction, followed by mutant construction and heat-shock assays. FINDINGS: Five patients and one intubation endoscope contained K. pneumoniae with the same amplified fragment length polymorphism pattern. The outbreak strain contained the clpK genetic marker, which rendered the strain its increased heat resistance. The survival rate of the strain grown as biofilm following heat treatment was also strongly dependent on clpK. CONCLUSION: Although clpK has been associated with clinical isolates of K. pneumoniae in earlier outbreaks, this is the first time that a ClpK-producing strain has been isolated from an environmental outbreak source. Heat resistance of certain K. pneumoniae strains may facilitate survival in biofilms on medical equipment and hence increase the potential of those strains to persist and disperse in the hospital environment.
Authors: Erik J Boll; Roger Marti; Henrik Hasman; Søren Overballe-Petersen; Marc Stegger; Kim Ng; Susanne Knøchel; Karen A Krogfelt; Joerg Hummerjohann; Carsten Struve Journal: Front Microbiol Date: 2017-04-07 Impact factor: 5.640