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Photodynamic and Antibiotic Therapy in Combination to Fight Biofilms and Resistant Surface Bacterial Infections.

Barra F, Roscetto E, Soriano AA, Vollaro A, Postiglione I, Pierantoni GM, Palumbo G, Catania MR - Int J Mol Sci (2015)

Bottom Line: 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.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.).

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples 80131, Italy. federica.barra@unina.it.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus

(A) Confocal laser scanner microscopy (CLSM) micrographs: three dimensional (left panels) and orthogonal reconstructions (right panels) of the biofilm formed by S. aureus. The pictures refer to the various experimental conditions as indicated on the left. Light fluence was set at 250 J·cm−2, Gentamicin concentration at 2 μg/mL. The fluorescence is associated with live (green) and dead (red) cells, respectively; (B) CLSM micrographs: three dimensional (left panel) and orthogonal reconstructions (right panel) of the biofilm formed by S. epidermidis. The pictures refer to the various experimental conditions as indicated on the left. Light fluence was set at 250 J·cm−2, Gentamicin concentration at 2 μg/mL. The fluorescence is associated with live (green) and dead (red) cells, respectively; (C) CLSM micrographs: three dimensional (left panels) and orthogonal reconstructions (right panels) of biofilm formed by S. haemolyticus. The pictures refer to the various experimental conditions as indicated on the left. Light fluence was set at 250 J·cm−2, Gentamicin concentration at 2 μg/mL. The fluorescence is associated with live (green) and dead (red) cells, respectively. Scale bars represent 100 μm as indicated in micrographs.
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ijms-16-20417-f003: (A) Confocal laser scanner microscopy (CLSM) micrographs: three dimensional (left panels) and orthogonal reconstructions (right panels) of the biofilm formed by S. aureus. The pictures refer to the various experimental conditions as indicated on the left. Light fluence was set at 250 J·cm−2, Gentamicin concentration at 2 μg/mL. The fluorescence is associated with live (green) and dead (red) cells, respectively; (B) CLSM micrographs: three dimensional (left panel) and orthogonal reconstructions (right panel) of the biofilm formed by S. epidermidis. The pictures refer to the various experimental conditions as indicated on the left. Light fluence was set at 250 J·cm−2, Gentamicin concentration at 2 μg/mL. The fluorescence is associated with live (green) and dead (red) cells, respectively; (C) CLSM micrographs: three dimensional (left panels) and orthogonal reconstructions (right panels) of biofilm formed by S. haemolyticus. The pictures refer to the various experimental conditions as indicated on the left. Light fluence was set at 250 J·cm−2, Gentamicin concentration at 2 μg/mL. The fluorescence is associated with live (green) and dead (red) cells, respectively. Scale bars represent 100 μm as indicated in micrographs.

Mentions: Figure 3A–C depict micrographs of biofilm formed by S. aureus (A), S. epidermidis (B), and S. haemolyticus (C), the effects caused by mono and combined therapy (5-ALA/PDT and 5-ALA/PDT followed by Gentamicin) and other controls. In particular:


Photodynamic and Antibiotic Therapy in Combination to Fight Biofilms and Resistant Surface Bacterial Infections.

Barra F, Roscetto E, Soriano AA, Vollaro A, Postiglione I, Pierantoni GM, Palumbo G, Catania MR - Int J Mol Sci (2015)

(A) Confocal laser scanner microscopy (CLSM) micrographs: three dimensional (left panels) and orthogonal reconstructions (right panels) of the biofilm formed by S. aureus. The pictures refer to the various experimental conditions as indicated on the left. Light fluence was set at 250 J·cm−2, Gentamicin concentration at 2 μg/mL. The fluorescence is associated with live (green) and dead (red) cells, respectively; (B) CLSM micrographs: three dimensional (left panel) and orthogonal reconstructions (right panel) of the biofilm formed by S. epidermidis. The pictures refer to the various experimental conditions as indicated on the left. Light fluence was set at 250 J·cm−2, Gentamicin concentration at 2 μg/mL. The fluorescence is associated with live (green) and dead (red) cells, respectively; (C) CLSM micrographs: three dimensional (left panels) and orthogonal reconstructions (right panels) of biofilm formed by S. haemolyticus. The pictures refer to the various experimental conditions as indicated on the left. Light fluence was set at 250 J·cm−2, Gentamicin concentration at 2 μg/mL. The fluorescence is associated with live (green) and dead (red) cells, respectively. Scale bars represent 100 μm as indicated in micrographs.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4613211&req=5

ijms-16-20417-f003: (A) Confocal laser scanner microscopy (CLSM) micrographs: three dimensional (left panels) and orthogonal reconstructions (right panels) of the biofilm formed by S. aureus. The pictures refer to the various experimental conditions as indicated on the left. Light fluence was set at 250 J·cm−2, Gentamicin concentration at 2 μg/mL. The fluorescence is associated with live (green) and dead (red) cells, respectively; (B) CLSM micrographs: three dimensional (left panel) and orthogonal reconstructions (right panel) of the biofilm formed by S. epidermidis. The pictures refer to the various experimental conditions as indicated on the left. Light fluence was set at 250 J·cm−2, Gentamicin concentration at 2 μg/mL. The fluorescence is associated with live (green) and dead (red) cells, respectively; (C) CLSM micrographs: three dimensional (left panels) and orthogonal reconstructions (right panels) of biofilm formed by S. haemolyticus. The pictures refer to the various experimental conditions as indicated on the left. Light fluence was set at 250 J·cm−2, Gentamicin concentration at 2 μg/mL. The fluorescence is associated with live (green) and dead (red) cells, respectively. Scale bars represent 100 μm as indicated in micrographs.
Mentions: Figure 3A–C depict micrographs of biofilm formed by S. aureus (A), S. epidermidis (B), and S. haemolyticus (C), the effects caused by mono and combined therapy (5-ALA/PDT and 5-ALA/PDT followed by Gentamicin) and other controls. In particular:

Bottom Line: 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.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.).

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples 80131, Italy. federica.barra@unina.it.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus