Photodynamic therapy for the treatment of Pseudomonas aeruginosa infections: A scoping review

•Pseudomonas aeruginosa is a leading cause of superficial and deep infections.•P. aeruginosa is among the most relevant drug-resistant (MDR) bacteria.•PDT has been shown to help inactivate MDR-P. aeruginosa effectively.•The vast majority of studies test the effectiveness of PS only in vitro.•Future research efforts should focus on the safety and efficacy of these PS in vivo. Pseudomonas aeruginosa is a Gram-negative bacillus that causes superficial and deep infections, which can be minor to life-threatening. Recently, P. aeruginosa has gained significant relevance due to the increased incidence of multidrug-resistant (MDR) strains that complicate antibiotic treatment. Due to MDR strains, alternative therapies, such as antimicrobial photodynamic therapy (PDT), are presented as a good option to treat nonsystemic infections. PDT combines a photosensitizer agent (PS), light, and oxygen to generate free radicals that destroy bacterial structures such as the envelope, matrix, and genetic material. This work aimed to identify the development stage of the PDT applied to P. aeruginosa to conclude which research stage should be emphasized more. Systematic bibliographic search in various public databases was performed. Related articles were identified using keywords, and relevant ones were selected using inclusion and exclusion criteria according to the PRISMA protocol. We found 29 articles that meet the criteria, constituting a good body of evidence associated with using PDT against P. aeruginosa in vitro and less developed for in vivo research. We conclude that PDT could become an effective adjunct to antimicrobial therapy against P. aeruginosa. This effectiveness depends on the PS used and the location of the infection. Many PS already demonstrated efficacy in PDT, but the evidence is supported significantly by in vitro and very few in vivo studies. Therefore, we conclude that further research efforts should focus on demonstrating the safety and efficacy of these PSs in vivo in animal infection models.