Reduction of surface contamination and biofilms of Enterococcus sp. and Staphylococcus aureus using a citrus-based vapour

SummaryBackgroundAntibiotic-resistant organisms such as meticillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus sp. (VRE) are an ongoing problem in hospitals. Essential oil vapours (EOs) have been shown to reduce environmental bacterial contamination.AimsTo assess the efficacy of Citri-V™, a vaporized blend of citrus EOs (orange: bergamot, 1:1 v/v) (Belmay, Northampton, UK), at removing Enterococcus sp. and S. aureus from stainless steel surfaces; and to investigate its effect on the formation of bacterial biofilms.MethodsA microplate assay was used to assess the effect of the citrus vapour on the formation of biofilms and their metabolic activity. Biofilm removal from stainless steel surfaces was measured by a colorimetric assay and by digital microscopy.FindingsThe citrus vapour reduced VRE and MRSA on stainless steel surfaces by 1.5–3 log10 after 24 h exposure. Staphylococcal biofilms were reduced both during and after formation, whereas enterococcal biofilms were significantly reduced (P ≤ 0.05) only after formation. Metabolic activity decreased by up to 72% in strains tested. Two-dimensional digital microscopy showed reductions in biofilm coverage of the stainless steel disc by as much as 99.5%.ConclusionCitrus vapour has potential for application in the clinical environment, for instance as a secondary disinfectant to reduce surface contamination by VRE and MRSA.