Evaluation of Hydrogen Peroxide Vapour Biodecontamination Against Clinically Relevant Presentations of Multi-drug Resistant Biofilms

Abstract

<h3>Background</h3> It has become acknowledged and accepted that microbiological contamination of surfaces within the healthcare environment can influence the rate of hospital acquired infection. Exploration of the presentation of microbiological organisms on healthcare surfaces has identified biofilms. Due to mechanisms such as the production of extracellular polymeric substances, enhanced protein and gene expression and co-ordinated support through quorum sensing, biofilms are more resistant to antimicrobial agents compared to planktonic phenotypes. Clinically relevant biofilms continue to exist on healthcare surfaces post high level terminal cleaning and research efforts are currently underway to investigate the link between the presence of biofilms within the patient environment and infection. <h3>Methods</h3> One high level disinfection technology used within the healthcare environment is hydrogen peroxide vapour (VH2O2). The presentation will introduce data from a 2-year government sponsored pilot evaluation to generate biofilms of clinically relevant microorganisms to be used in disinfectant evaluation and specifically to test the efficacy of a hydrogen peroxide vapour biodecontamination system. <h3>Results</h3> Biofilms of multi-drug resistant K.pneumoniae, S.aureus, A. baumannii, E.faecalis and P.aeruginosa with a microorganism density representative of the high loadings documented on clinical surfaces (averaging 7.15 Log10 CFU/cm2), were located in a 27m3 room, representative of a typical hospital side room. Biofilms were exposed to a standardised VH2O2 cycle, with timed removal of samples to determine the disinfection kinetics. The study included a desiccation stage to ensure biofilm formation experienced environmental stresses related to hospital surfaces. <h3>Conclusions</h3> Full elimination of all multi-drug resistant biofilms was achieved over triplicate repeats. Epifluorescence microscopy demonstrated massive disruption to biofilm colony formation and matrix structure as a result of oxidative damage. The presentation will discuss the applicability and implications of current mono-specie, planktonic-based standard disinfectant test methods and the need for standardised tests that better represent the challenge posed by biofilms.