Applications of Photodynamic Therapy for the Eradication of ESKAPE Pathogens

Antimicrobial photodynamic therapy (aPDT) is one of the efficient and alternate therapeutic strategies to combat planktonic and biofilm cells of ESKAPE pathogens. This therapeutic method requires a photosensitizer, light, and oxygen. ESKAPE superbugs are responsible for most of the nosocomial infections and it needs urgent attention in healthcare system. aPDT is emerged as a safer and effective method against the elimination of resistant ESKPAE pathogens, as the therapy is not involved in the generation of antibiotic-resistant strains. Reactive oxygen species produced through type I and II photoreactions of aPDT has multiple cellular targets in the bacteria, i.e., protein, DNA, and lipids. ROS exerts oxidation of cellular targets where the photosensitizer is localized. There are several classes of photosensitizers tested and used against variety of pathogens, especially ESKAPE such as from the family of chlorins, porphyrins, phthalocyanines, and bacteriochlorins. Additionally, several photosensitizers of plant origin and nanoparticles are found to be efficient against ESKPAE pathogens. In comparison to Gram-negative pathogens, aPDT is more efficient against Gram-positive pathogens owing to their cell wall structure. Cationic and neutral photosensitizers are more efficient in the eradication of Gram-positive pathogens, while photosensitizers are modified for Gram-negative pathogens. Here, we discussed applications and effectiveness of different photosensitizers against pathogenic forms of ESKAPE group.