Charge effect of water-soluble porphyrin derivatives as a prototype to fight infections caused by Acinetobacter baumannii by aPDT approaches

Abstract

In the last decade, Acinetobacter baumannii has emerged as a pathogen associated with infections in intensive care units worldwide, especially due to its ability to resist an extensive list of antibiotics. In this context, porphyrins have emerged as an important strategy in photodynamic therapy, since they are a group of tetrapyrrolic compounds with important photochemical and photobiological activities. In this study, the antimicrobial photodynamic activity of meso-tetra(4-N-methyl-pyridyl)porphyrin (H₂TMePyP⁺) and meso-tetra(4-sulfonatophenyl)porphyrin (H₂TPPS^‒) was evaluated against A. baumannii by minimum inhibitory concentration (MIC), anti-biofilm activity, and the interaction with antibiotics after exposure to white-light LED irradiation. The cationic derivative H₂TMePyP⁺ was more potent (MIC = 0.61 µM) than H₂TPPS^‒, with anti-biofilm activity and increased the antimicrobial activity of ciprofloxacin and amikacin. Given these findings, the tetra-cationic porphyrins can be assumed as prototypes to optimize and develop new agents by promoting oxidative stress and inducing free radical production.

Keywords:

• Porphyrin
• Antimicrobial Photoinactivation
• Adjuvants
• Biofilm
• Gram-negative

Acknowledgements

This project received financial support from CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico, 409150/2018-5, 428243/2018-5, 403210/2021-6, and 304711/2018-7), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Finance Code 001, and FAPERGS (Proc. no. 21/2551-0002114-4; B.A. Iglesias). Thank you also to Atlas Assessoria Linguística for language editing.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Coordination for the Improvement of Higher Education Personnel (CAPES), FAPERGS, and CNPq