Bacterial Photodynamic Inactivation Mediated by Methylene Blue and Red Light Is Enhanced by Synergistic Effect of Potassium Iodide

• DOI: 10.1128/aac.00019-15
• Publication Date: 2015-06-16T03:01:14Z
• Authors: Daniela Vecchio; Asheesh Gupta; Liyi Huang; Giacomo Landi; Pinar Avci; Andrea Rodas; Michael R. Hamblin
• Keywords: Methylene blue; Phototoxicity; Rose bengal; Mechanism of Action

ABSTRACT The inexorable increase of antibiotic resistance occurring in different bacterial species is increasing the interest developing new antimicrobial treatments that will be equally effective against multidrug-resistant strains and not themselves induce resistance. One these alternatives may photodynamic inactivation (PDI), which uses a combination nontoxic dyes, called photosensitizers (PS), excited by harmless visible light to generate reactive oxygen (ROS) type 1 (radical) 2 (singlet oxygen) pathways. In this study, we asked whether it was possible improve efficacy PDI vitro vivo addition inert salt potassium iodide (KI) commonly investigated PS, phenothiazinium dye methylene blue (MB). By adding KI, observed consistent red light-mediated killing Gram-positive Gram-negative vivo. , also less recurrence wounds days posttreatment. mechanism action probably due formation iodine are produced quickly with short lifetime. This finding have relevant clinical impact reducing risk amputation and, some cases, death, leading improvement care patients affected localized infections.