Photodynamic and Antibiotic Therapy in Combination to Fight Biofilms and Resistant Surface Bacterial Infections.
Although photodynamic therapy (PDT), a therapeutic approach that involves a photosensitizer, light and O₂, has been principally considered for the treatment of specific types of cancers, other applications exist, including the treatment of infections. Unfortunately, PDT does not always guarantee full success since it exerts lethal effects only in cells that have taken up a sufficient amount of photosensitizer and have been exposed to adequate light doses, conditions that are not always achieved. Based on our previous experience on the combination PDT/chemotherapy, we have explored the possibility of fighting bacteria that commonly crowd infected surfaces by combining PDT with an antibiotic, which normally does not harm the strain at low concentrations. To this purpose, we employed 5-aminolevulinic acid (5-ALA), a pro-drug that, once absorbed by proliferating bacteria, is converted into the natural photosensitizer Protoporphyrin IX (PpIX), followed by Gentamicin. Photoactivation generates reactive oxygen species (ROS) which damage or kill the cell, while Gentamicin, even at low doses, ends the work. Our experiments, in combination, have been highly successful against biofilms produced by several Gram positive bacteria (i.e., Staphylococcus aureus, Staphylococcus epidermidis, etc.). This original approach points to potentially new and wide applications in the therapy of infections of superficial wounds and sores.
Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples 80131, Italy. federica.barra@unina.it.
Federica
F
Barra
Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples 80131, Italy. emanuelaroscetto@gmail.com.
Emanuela
E
Roscetto
Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples 80131, Italy. amata.soriano@libero.it.
Amata A
AA
Soriano
Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples 80131, Italy. vollaroadriana@libero.it.
Adriana
A
Vollaro
Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples 80131, Italy. ilariapostiglione@gmail.com.
Ilaria
I
Postiglione
Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples 80131, Italy. giovannamaria.pierantoni@unina.it.|Institute of Experimental Endocrinology and Oncology (IEOS), National Research Council (CNR), Naples 80131, Italy. giovannamaria.pierantoni@unina.it.
Giovanna Maria
GM
Pierantoni
Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples 80131, Italy. palumbo@unina.it.
Giuseppe
G
Palumbo
Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples 80131, Italy. mariarosaria.catania@unina.it.
Maria Rosaria
MR
Catania
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D018441:Biofilms / Q000187:drug effects*; D024881:Drug Resistance, Bacterial; D005839:Gentamicins / Q000494:pharmacology; D008027:Light; D008826:Microbial Sensitivity Tests; D018613:Microscopy, Confocal; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D005839:Gentamicins; D017319:Photosensitizing Agents
5-aminolevulinic acid; Gentamicin; combination therapy; photodynamic therapy