The Use of Blue Light as an Antimicrobial Treatment Against Staphylococcus aureus : A Systematic Review

BACKGROUND: Staphylococcus aureus (S. aureus) is a major cause of skin, wound, and device-related infections. Blue light (405-470 nm), shows promise for treating this organism. However, the translatability, dosing parameters, safety, and effectiveness remain unclear, and no systematic review currently exists. OBJECTIVES: To evaluate the antimicrobial efficacy and safety of blue light therapy against S. aureus across experimental models. METHODS: All relevant in vitro, in vivo, and clinical studies were identified through systematic searches of PubMed, Embase, Web of Science, Cochrane Library, Scopus, and ClinicalTrials. gov. Studies evaluating blue light without exogenous photosensitizers reporting bacterial or clinical outcomes were included. Risk of bias was assessed using SYRCLE. This study was registered with PROSPERO (ID: CRD420251089518). RESULTS: A total of 33 articles met inclusion criteria: 20 planktonic models, 6 biofilm models, and 17 methicillin-resistant S. aureus (MRSA) specific outcomes. The predominant wavelength tested was 405 nm (87.9%). Blue light reduced bacterial burden across models, though results varied by dose and experimental conditions. Additionally, 57.6% of studies did not report statistical significance. CONCLUSIONS: Blue light demonstrates antimicrobial activity against S. aureus, including MRSA, but heterogeneity in study design and limited in vivo data restrict clinical translation. We propose a standardized set of 8 reported parameters for future blue light studies.