An Investigation of the Use of Antimicrobial Blue Light for the Effective Surface Disinfection of Multidrug-resistant Organisms in a Hospital Environment

Description

Healthcare-associated infections (HAIs) are a serious global public health issue. The threat associated with the high occurrence of multidrug-resistant organisms (MDRO) has high rates of morbidity and mortality. In the United States, 1.7 million HAIs develop each year, resulting in over 98,000 deaths. A study in China showed that HAIs increased hospital stays by 8.2 to 12.6 days. There is solid evidence showing that a contaminated hospital environment contributes to HAIs. Although chemical disinfectants are commonly used, increasing evidence suggests the ineffectiveness of cleaning and decontaminating surfaces in hospitals. Furthermore, the recurrence of contamination on surfaces after disinfection poses a significant challenge, particularly for high-touch surfaces. Photodynamic inactivation has been demonstrated to be highly effective against a wide range of microorganisms. Antimicrobial blue light (aBL) as a non-touch disinfection approach has the benefit of minimal cytotoxicity to mammalian cells, being much safer than ultraviolet C for human cell lines as demonstrated by the existing literature. aBL has the potential to be used in the presence of people and be operated continuously, which is a huge operational advantage. In addition, aBL penetrates deeper into surfaces and thus might give higher surface disinfection than UVC for porous materials like fabrics. Nonetheless, in the literature, almost all aBL studies have focused on water or food processing.  In the proposed project, we will investigate the surface disinfection efficacy of 405-nm aBL using light-emitting diodes as the light source. Different MDRO will be selected from the threat list of the Centers for Disease Control and Prevention. MDRO in the forms of adhered cells and biofilms will be tested. We will conduct experiments to pursue multiple goals. The first goal will be to enhance the disinfection efficacy of aBL. To this end, the efficacy of pulsed operation and the exogenous photosensitizers will be examined. The second goal will be to study the aBL effectiveness for decontaminating fabrics and non-porous surfaces commonly found in hospital wards. The final goal will be to test aBL in a full-scale chamber to evaluate the disinfection performance in practical scenarios. No study has systematically investigated methods using aBL for enhancing surface disinfection on various surfaces in hospital environments, which is very relevant to mitigate the HAIs. The successful completion of this project will have a number of profound impacts on public health and contribute to a multifaceted approach that combines aBL with conventional healthcare hygiene protocols to further reduce HAIs.