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
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.
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.
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.