Amphiphilic tetracationic porphyrins are exceptionally active antimicrobial photosensitizers: In vitro and in vivo studies with the free‐base and Pd‐chelate

• Published in: Journal of biophotonics Vol. 12; no. 8; pp. e201800318 - n/a
• Main Authors: Xuan, Weijun, Huang, Liyi, Wang, Yuguang, Hu, Xiaoqing, Szewczyk, Grzegorz, Huang, Ying‐Ying, El‐Hussein, Ahmed, Bommer, Jerry C., Nelson, Mark L., Sarna, Tadeusz, Hamblin, Michael R.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY‐VCH Verlag GmbH & Co. KGaA 01.08.2019; Wiley Subscription Services, Inc
• Subjects: Abrasion; amphiphilic tetracationic porphyrins; Antiinfectives and antibacterials; Antimicrobial agents; antimicrobial photodynamic inactivation; bioluminescence imaging; broad‐spectrum activity; Chelates; Deactivation; E coli; In vivo methods and tests; Inactivation; Infections; Methicillin; Microorganisms; palladium‐porphyrin; Photosensitization; Porphyrins; Singlet oxygen; Skin; uropathogenic Escherichia coli infection; Yeast; Yeasts; bioluminescence imaging; amphiphilic tetracationic porphyrins; antimicrobial photodynamic inactivation; uropathogenic Escherichia coli infection; broad-spectrum activity; palladium-porphyrin
• ISSN: 1864-063X; 1864-0648
• DOI: 10.1002/jbio.201800318

Antimicrobial photodynamic inactivation (aPDI) employs the combination of nontoxic photosensitizing dyes and visible light to kill pathogenic microorganisms regardless of drug‐resistance, and can be used to treat localized infections. A meso‐substituted tetra‐methylpyridinium porphyrin with one methyl group replaced by a C12 alkyl chain (FS111) and its Pd‐derivative (FS111‐Pd) were synthesized and tested as broad‐spectrum antimicrobial photosensitizers when excited by blue light (5 or 10 J/cm2). Both compounds showed unprecedented activity, with the superior FS111‐Pd giving 3 logs of killing at 1 nM, and eradication at 10 nM for Gram‐positive methicillin‐resistant Staphylococcus aureus. For the Gram‐negative Escherichia coli, both compounds produced eradication at 100 nM, while against the fungal yeast Candida albicans, both compounds produced eradication at 500 nM. Both compounds could be categorized as generators of singlet oxygen (ΦΔ = 0.62 for FS111 and 0.71 for FS111‐Pd). An in vivo study was carried out using a mouse model of localized infection in a partial thickness skin abrasion caused by bioluminescent Gram‐negative uropathogenic E. coli. Both compounds were effective in reducing bioluminescent signal in a dose‐dependent manner when excited by blue light (405 nm), but aPDI with FS111‐Pd was somewhat superior both during light and in preventing recurrence during the 6 days following PDT. Two new porphyrins were synthesized and tested for antimicrobial photodynamic inactivation against methicillin‐resistent Staphylococcus aureus and uropathogenic Escherichia coli in vitro, and in a mouse model of a localized skin infection.