In vitro antimicrobial photodynamic therapy using tetra-cationic porphyrins against multidrug-resistant bacteria isolated from canine otitis

Natural Photosensitizers in Antimicrobial Photodynamic Therapy

“…According to some studies, cationic porphyrins are particularly effective at photoinactivating bacterial species on tissues and surfaces, and thus porphyrin-based APDT provides efficient bacterial removal without inducing antimicrobial resistance and without affecting the microflora of the body [ 108 ]. Porphyrins are preferred organic PSs due their strong 1 O 2 generation efficiency and excellent fluorescence properties [ 109 ].…”

“…For instance, phthalocyanine derivatives in the presence of metal atoms, such as Zn, Al, and Si, yield a long T1 lifetime and a high 1 O 2 generation quantum yield, and these PSs have sufficient photophysical and photochemical properties [ 109 ]. In addition, Seeger et al [ 108 ] evaluated the APDT activities of two different tetracationic porphyrins (H 2 TMeP (free-base porphyrin) and ZnTMeP (zinc(II) derivative porphyrin)) against Gram-positive and Gram-negative bacteria that are commonly observed in canine otitis. Photoinactivation of both Gram-positive and Gram-negative bacteria was achieved.…”

“…Photoinactivation of both Gram-positive and Gram-negative bacteria was achieved. The best results were obtained against P. aeruginosa and Proteus mirabilis using H 2 TMeP, which achieved complete bacterial inactivation after 60 min of exposure, while ZnTMeP reached the maximum bacterial inactivation at 90 min [ 108 ]. Semisynthetic bacteriochlorins are produced by changing the centrally coordinated metal ion in the bacteriochlorophyll macrocycle: Mg 2+ is replaced with Zn 2+ , Ni 2+ , Cu 2+ , Pt 2+ , and Pd 2+ [ 107 ].…”

Latest trends on photodynamic disinfection of Gram-negative bacteria: photosensitizer’s structure and delivery systems

“…5), from which several applications are found in literature. In one of the most recent examples using 6, and compared with its zinc(II) derivative 7, Seeger et al demonstrated efficient photo-inactivation against model Proteus mirabilis and P. aeruginosa, but also against their respective clinical isolates from canine otitis, as a result of light-driven production of singlet oxygen [38] . Although normally the non-metalated TMPyP or its zinc(II)-metalated derivative are analyzed, Skwor et al have devoted to the analysis on the influence of the metalation (Cu 2+ , Fe 2+ , Pd 2+ , and Zn 2+ ) in the antibacterial activity, finding that 8, TMPyP derivative metalated with palladium(II), was the most efficient at eradicating E. coli [39] , evidencing the upmost importance of the metal used, and consequences on the photo physics of the PS.…”

Photoinactivation of S. Aureus by Сationic meso-Arylporphyrin and Its Zn(II) Complex

“…[13,14] Previously, the effectiveness of natural and synthetic porphyrins as PSs in APDT against a wide range of pathogenic microorganisms, such as viruses, bacteria, yeast, and protozoa, was shown. [15][16][17][18][19] Cationic derivatives of porphyrins are of particular interest due to the active interaction with the bacterial cell wall. [20] It was found that the presence of a zinc(II) ion in the macrocycle promotes intersystem crossing of excited molecules to the triplet state through heavy atom effect, thus enhancing the formation of singlet oxygen.…”