Antimicrobial efficacy of <i>in-situ</i> plasma-generated ozone against <i>Pseudomonas aeruginosa</i> biofilms in drains and water-submerged surfaces

Abstract Aims To demonstrate a novel method of gaseous disinfection that can eradicate biofilms inhabiting elusive regions of plumbing systems. Methods &amp; Results Highly biocidal ozone is generated in-situ using the ambient air inside a model sink and drain, via portable plasma discharge, with the plasma device sealing the treated area, ensuring no ozone escape to the external environment. Subsequent bacterial recovery illustrates an approximate bioburden reduction of 5log 10 for biofilms suspended in the drain, and 6log 10 for biofilms placed in the sink. Conclusions Plasma-generated ozone is a safe and effective method for controlling bioburden in periodically wetted, otherwise inaccessible pipework and drains, both above and below the water line. Significance and Impact of Study The ozone generation system described has potential for controlling healthcare associated infections (HAIs) and infections linked to closed environments, such as cruise ships, from bacteria arising from waste water systems by aerosolization or splash-back. The method has additional benefits provided by an absence of toxic residues after application, reducing risks to users and the waste water system. Cost effectiveness is high, requiring minimal energy input from the electrical supply and only ambient air (no additional feedstock gas is necessary) to generate ozone.