title: Efficacy of two hydrogen peroxide vapour aerial decontamination systems for enhanced disinfection of meticillin-resistant Staphylococcus aureus, Klebsiella pneumoniae and Clostridium difficile in single isolation rooms.
abstract: BACKGROUND
  Hydrogen peroxide vapour (HPV) disinfection systems are being used to reduce patients' exposure to hospital pathogens in the environment. HPV whole-room aerial disinfection systems may vary in terms of operating concentration and mode of delivery.
  
  
  OBJECTIVE
  To assess the efficacy of two HPV systems (HPS1 and HPS2) for whole-room aerial disinfection of single isolation rooms (SIRs).
  
  
  METHODS
  Ten SIRs were selected for manual terminal disinfection after patient discharge. Test coupons seeded with biological indicator (BI) organisms [∼10(6) colony-forming units (cfu) of meticillin-resistant Staphylococcus aureus (MRSA) or Klebsiella pneumoniae, or ∼10(5)cfu Clostridium difficile 027 spores] prepared in a soil challenge were placed at five locations per room. For each cycle, 22 high-frequency-touch surfaces in SIRs were sampled with contact plates (∼25cm(2)) before and after HPV decontamination, and BIs were assayed for the persistence of pathogens.
  
  
  RESULTS
  Approximately 95% of 214 sites were contaminated with bacteria after manual terminal disinfection, with high numbers present on the SIR floor (238.0-352.5cfu), bed control panel (24.0-33.5cfu), and nurse call button (21.5-7.0cfu). Enhanced disinfection using HPV reduced surface contamination to low levels: HPS1 [0.25cfu, interquartile range (IQR) 0-1.13] and HPS2 (0.5cfu, IQR 0-2.0). Both systems demonstrated similar turnaround times (∼2-2.5h), and no differences were observed in the efficacy of the two systems against BIs (C. difficile ∼5.1log10 reduction; MRSA/K. pneumoniae ∼6.3log10 reduction). Despite different operating concentrations of hydrogen peroxide, MRSA persisted on 27% of coupons after HPV decontamination.
  
  
  CONCLUSIONS
  Enhanced disinfection with HPV reduces surface contamination left by manual terminal cleaning, minimizing the risks of cross-contamination. The starting concentration and mode of delivery of hydrogen peroxide may not improve the efficacy of decontamination in practice, and therefore the choice of HPV system may be based upon other considerations such as cost, convenience and logistics.
authors.affiliation: Clinical Microbiology and Virology, University College London Hospitals NHS Foundation Trust, London, UK. Electronic address: shanom.ali@uclh.nhs.uk.
authors.forename: S
authors.initials: S
authors.lastname: Ali
authors.affiliation: Clinical Microbiology and Virology, University College London Hospitals NHS Foundation Trust, London, UK.
authors.forename: M
authors.initials: M
authors.lastname: Muzslay
authors.affiliation: University College London Hospitals NHS Foundation Trust, London, UK.
authors.forename: M
authors.initials: M
authors.lastname: Bruce
authors.affiliation: University College London Hospitals NHS Foundation Trust, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Jeanes
authors.affiliation: Biosafety Group, Public Health England, Porton Down, Salisbury, UK.
authors.forename: G
authors.initials: G
authors.lastname: Moore
authors.affiliation: Clinical Microbiology and Virology, University College London Hospitals NHS Foundation Trust, London, UK.
authors.forename: A P R
authors.initials: AP
authors.lastname: Wilson
mesh_terms: D000336:Aerosols; D016360:Clostridioides difficile / Q000187:drug effects*; D004202:Disinfectants / Q000494:pharmacology*; D004203:Disinfection / Q000379:methods*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007711:Klebsiella pneumoniae / Q000187:drug effects*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*
chemical_list: D000336:Aerosols; D004202:Disinfectants; D006861:Hydrogen Peroxide
keywords: Clostridium difficile; Hydrogen peroxide; Infection control; Klebsiella pneumoniae; MRSA; Whole-room aerial decontamination