Potentiated antimicrobial blue light killing of methicillin resistant Staphylococcus aureus by pyocyanin

• Main Authors: Dai, T. (Author), Leanse, L.G (Author), Zeng, X. (Author)
• Format: Article
• Language: English
• Published: Elsevier B.V. 2021
• Subjects: abrasion; animal; Animals; antimicrobial activity; Antimicrobial blue light; Antimicrobial resistance; Article; bacterial colonization; bacterial infection; bacterial load; biofilm; Biofilms; blue light; concentration (parameter); connective tissue; controlled study; dose response; Dose-Response Relationship, Drug; drug effect; drug exposure; hydrogen peroxide; in vitro study; light; Light; methicillin resistant Staphylococcus aureus; Methicillin-Resistant Staphylococcus aureus; Mice; microbial viability; Microbial Viability; microbiology; mouse; MRSA; nonhuman; physiology; plankton; priority journal; proof of concept; Pseudomonas aeruginosa; Pyocyanin; pyocyanine; Pyocyanine; radiation response; singlet oxygen; skin; Skin; staphyloxanthin; unclassified drug; Wound infection; xanthine
• Online Access: View Fulltext in Publisher

 As antimicrobial resistance continues to threaten the efficacy of conventional antibiotic therapy, it is paramount that we investigate innovative approaches to treat infectious diseases. In this study, we investigated the antimicrobial capabilities of the innovative combination of antimicrobial blue light (aBL; 405 nm wavelength) with the Pseudomonas aeruginosa pigment pyocyanin against methicillin resistant Staphylococcus aureus (MSRA. We explored the effects of different radiant exposures of aBL and increasing concentrations of pyocyanin against planktonic cells and those within biofilms. In addition, we investigated the effect of the aBL/pyocyanin on the endogenous staphyloxanthin pigment, as well as the role of hydrogen peroxide and singlet oxygen scavenging in the efficacy of this combination. Lastly, we investigated the potential for the aBL/pyocyanin to reduce the MRSA burden within a proof-of-principle mouse abrasion infection model. We found pyocyanin to be a powerful potentiator of aBL activity under all in vitro conditions tested. In addition, we serendipitously discovered the capability of the aBL/pyocyanin combination to bleach staphyloxanthin within colonies of MRSA. Furthermore, we established that singlet oxygen is an important mediator during combined aBL/pyocyanin exposure. Moreover, we found that the combination of aBL and pyocyanin could significantly reduce the viability of MRSA within a proof-of-principle early onset MRSA skin abrasion infection. Exposure to the treatment did not have deleterious effects on skin tissue. In conclusion, the combination of aBL and pyocyanin represents a potentially powerful therapeutic modality for the treatment of infections caused by MRSA. © 2020 Elsevier B.V.