Can Antimicrobial Photodynamic Therapy Complement Antimicrobial Chemotherapy?

Caetano P. Sabino, BSc, PhD Student, Clinical Analysis, School of Pharmaceutical Sciences, University of Sao Paulo, discusses how antimicrobial photodynamic therapy could be used to complement antimicrobial chemotherapy in order to manage drug-resistant infections.

Interview Transcript (slightly modified for readability)

“Since we don’t have any evidence, or any evolutionary principle that should bring any resistance to photodynamic therapy and such intense oxidative stress, it’s really questionable whether any bug can develop any resistance against it. In all cases that [antimicrobial] chemotherapy may fail in localized infections or in places that are avascular or poorly vascularized, or necrotic, we can treat them just as easy as it sounds.

You spray the photosensitive drug, and you shine the light over it, and it’s going to be treated. Another important feature of photodynamic therapy is that it has intrinsic synergy with chemotherapeutics, because it can target different structures with photodynamic therapy, and there won’t be so much damage for the chemotherapy to act.

We are not leaving behind the regular chemotherapy we’re using, but we are proposing a complementary method to manage those drug-resistant infections, especially for chronic wounds and wounds that could be easily reached. So, let’s see: diabetic feet, decubitus ulcers, burns—all types of chronic wounds can be easily treated by photodynamic therapy and not a chronic administration of chemotherapeutics. We are avoiding to use only chemotherapeutics to treat those infections in select drug-resistant bacteria. Photodynamic therapy kills all bacteria in the same way, in the same pattern; it doesn’t matter if they are resistant to chemotherapy or not, we are going to manage those infections.”