Cutaneous bacterial
wound infections typically involve gram-positive cocci such as Staphylococcus aureus (SA) and usually become biofilm
infections. Bacteria in biofilms may be 100-1000-fold more resistant to an
antibiotic than the clinical laboratory minimal inhibitory concentration (MIC) for that
antibiotic, contributing to antimicrobial resistance (AMR). AMR is a growing global threat to humanity. One pathogen-
antibiotic resistant combination, methicillin-resistant SA (MRSA) caused more deaths globally than any other such combination in a recent worldwide statistical review. Many
wound infections are accessible to light. Antimicrobial
phototherapy, and particularly antimicrobial
blue light therapy (aBL) is an innovative non-
antibiotic approach often overlooked as a possible alternative or adjunctive
therapy to reduce
antibiotic use. We therefore focused on aBL treatment of biofilm
infections, especially MRSA, focusing on in vitro and ex vivo porcine skin models of bacterial biofilm
infections. Since aBL is microbicidal through the generation of
reactive oxygen species (ROS), we hypothesized that
menadione (
Vitamin K3), a multifunctional ROS generator, might enhance aBL. Our studies suggest that
menadione can synergize with aBL to increase both ROS and microbicidal effects, acting as a
photosensitizer as well as an ROS recycler in the treatment of biofilm
infections.
Vitamin K3/
menadione has been given orally and intravenously worldwide to thousands of patients. We conclude that
menadione/
Vitamin K3 can be used as an adjunct to antimicrobial
blue light therapy, increasing the effectiveness of this modality in the treatment of biofilm
infections, thereby presenting a potential alternative to
antibiotic therapy, to which biofilm
infections are so resistant.