Susceptibility of Enterococcus faecalis and Propionibacterium acnes to antimicrobial photodynamic therapy

Author(s)

de Annunzio, Sarah Raquel ^[1] ; de Freitas, Laura Marise ^[1] ; Blanco, Ana Ligia ^[1] ; da Costa, Mardoqueu Martins ^[2] ; Carmona-Vargas, Christian C. ^[3] ; de Oliveira, Kleber Thiago ^[3] ; Fontana, Carla Raquel ^[1]

Affiliation

^[1] Univ Estadual Paulista Unesp, Fac Ciencias Farmaceut, Rodovia Araraquara Jau, Km 1, Campus Ville, BR-14800903 Araraquara, SP - Brazil

^[2] Univ Brasil UniBrasil, Dept Engn Biomed, Rua Carolina Fonseca 235, , BR-08230030 Sao Paulo, SP - Brazil

^[3] Univ Fed Scio Carlos UFSCar, Dept Quim, Lab Quim Bioorgan, Rodovia Washington Luis, Km 235 SP-310, BR-13565905 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY; v. 178, p. 545-550, JAN 2018.
• Web of Science Citations: 10

Abstract

Bacterial resistance to available antibiotics nowadays is a global threat leading researchers around the world to study new treatment modalities for infections. Antimicrobial photodynamic therapy (aPDT) has been considered an effective and promising therapeutic alternative in this scenario. Briefly, this therapy is based on the activation of a non-toxic photosensitizing agent, known as photosensitizer (PS), by light at a specific wavelength generating cytotoxic singlet oxygen and free radicals. Virtually all studies related to aPDT involve a huge screening to identify ideal PS concentration and light dose combinations, a laborious and time-consuming process that is hardly disclosed in the literature. Herein, we describe an antimicrobial Photodynamic Therapy (aPDT) study against Enterococcus faecalis and Propionibacterium acnes employing methylene blue, chlorin-e6 or curcumin as PS. Similarities and discrepancies between the two bacterial species were pointed out in an attempt to speed up and facilitate futures studies against those clinical relevant strains. Susceptibility tests were performed by the broth microdilution method. Our results demonstrate that aPDT mediated by the three above-mentioned PS was effective in eliminating both gram-positive bacteria, although P. acnes showed remarkably higher susceptibility to aPDT when compared to E. faecalis. PS uptake assays revealed that P. acnes is 80 times more efficient than E. faecalis in internalizing all three PS molecules. Our results evidence that the cell wall structure is not a limiting feature when predicting bacterial susceptibility to aPDT treatment. (AU)

• FAPESP's process: 16/05345-4 - Improving antimicrobial photodynamic therapy for infectious disease associating peptide aurein 1.2
• Grantee: Carla Raquel Fontana
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/24581-5 - Evaluation of the role of photodynamic therapy combined with antimicrobial peptides against bacterial resistance
• Grantee: Laura Marise de Freitas
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 15/21110-4 - Exploiting Photocatalyzed Reactions Under Continuous Flow Conditions by using Porphyrinoid Systems: (C-FlowPhotoChem)
• Grantee: Kleber Thiago de Oliveira
• Support Opportunities: Regular Research Grants