Antimicrobial photodynamic inactivation of planktonic and biofilm cells by covalently immobilized porphyrin on polyethylene terephthalate surface.

The appearance of resistant strains and the persistence of biofilms on different surfaces in a wide range of settings represent serious public health threats. Antimicrobial photodynamic inactivation (aPDI) is a promising alternative technology to overcome these challenges. The current study assessed the antimicrobial effect of polyethylene terephthalate (PET) discs covalently functionalized with a cationic porphyrin, against E. coli ATCC 25922 and Pseudomonas aeruginosa (Schroeter) Migula (ATCC® 10145™) growth. Irradiation with white LED light for 6 h resulted in 1.51 ± 0.03 and 3.26 ± 0.24 log reduction of planktonic P. aeruginosa and E. coli , respectively. The study also assessed the effect of the functionalized discs on biofilm formation by E. coli , P. aeruginosa, and Staphylococcus aureus subsp. aureus (ATCC® 6538P™). The biovolumes of S. aureus , P. aeruginosa, and E. coli biofilms were decreased by 0.6 ± 0.1, 0.56 ± 0.13 and 0.74 ± 0.06 log reduction, respectively. These results emphasize the ability of porphyrin-functionalized photoactive surfaces to kill bacterial cells and consequently prevent biofilm formation. • Porphyrin tethered photoactive discs were assessed for their antimicrobial effect. • Irradiation of the discs reduced the counts of the tested strains. • Photodynamic inactivation of the tested strains also inhibited their biofilms. • The data demonstrates a potential approach to mitigate the threats of biofilms. [ABSTRACT FROM AUTHOR]