Basic studies in antimicrobial PDT

Abstract

Microorganisms (MO) multiply rapidly and mutations that guarantee its survival forward to antimicrobials become prevalent in new populations. The inexorable rise of multidrug-resistant MO leads to an effort to search for alternative approaches that, hypothetically, MO could not easily develop resistance. Antimicrobial photodynamic therapy (PDT) is an effective alternative treatment for infected lesions in animals. The goal of the technique is to destroy a sufficient number of pathogenic MO to prevent recolonization and avoid unacceptable destruction of the host tissue. An important observation concerns the selectivity of the photosensitizer by microbial cells when compared to the host. This is because the photosensitizer (PS) uptake by host cells is slower than by MO. If the site of infection is irradiated after a short interval from the PS application (minutes), the damage to host tissue is minimized. Currently, antimicrobial PDT has proven its effectiveness against bacteria, virus, fungi, and parasites. This chapter reviews the literature regarding antimicrobial PDT especially for veterinary medicine.