Antimicrobial effect of photodynamic therapy using a highly pure chlorin e6

Abstract

The aim of the present study is to evaluate the antimicrobial effect of photodynamic therapy (PDT) using a highly pure chlorin e(6) (Ce(6)), against various pathogenic bacteria. To examine the antimicrobial effect of Ce(6)-mediated PDT against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Salmonella enterica serovar Typhimurium, inhibition zone formation, CFU quantification, and bacterial viability were evaluated. Inhibition zone analysis showed that Ce(6)-mediated PDT is very effective to inhibit the growth of S. aureus and P. aeruginosa, but has only minor effect to E. coli and S. Typhimurium, which was dependent on the energy density of laser and dose of Ce(6). Ce(6)-mediated PDT also nearly inhibited the colony formation of S. aureus and P. aeruginosa, and partially inhibited that of E. coli and S. Typhimurium. In addition, the number of viable bacteria decreased greatly after PDT application with LS-chlorin e6 of 10 microM and laser and energy density of 20 J/cm(2). These results show that Ce(6)-mediated PDT can be an effective alternative for antimicrobial treatment.

Photobiological characteristics of chlorophyll a derivatives as microbial PDT agents

“…In previous studies with porphyrinoid photosensitizers, Gram-positive bacteria were inhibited after irradiation, but the activity against Gram-negative bacteria was limited. [29][30][31] In this study, we have obtained a low activity of chl-e6 and chl-e6H against a Gram-negative microorganism, and higher activity in a Gram-positive microorganism. Previous studies show that it is easier to inactivate Grampositive than Gram-negative bacteria, which can be explained by the electronic charges of the cell walls.…”

Antimicrobial, Antimycobacterial and Antibiofi lm Properties of Couroupita guianensis Aubl. Fruit Extract

“…e group examined the effect of Ce6-mediated PDT on in vivo bacterial growth in a mouse model of skin infection with S. aureus, and the reduction in the intensity of bioluminescence was observed immediately aer PDT. Moreover, on the 5th day aer infection, the signal was almost undetectable in mice treated with Ce6-mediated PDT [61]. Dai et al reported that a new MBmediated APDT effectively treated C. albicans skin abrasion infections in mice [67].…”

“…e most efficient was the BF2 derivative [60]. Park et al demonstrated that chlorin Ce6-mediated PDT signi�cantly reduced the colony formation of S. aureus in a dose-dependent manner [61]. Based on these data, it is clear that APDT can effectively kill various microbial species growing in planktonic culture.…”

“…Park et al performed experiments on bio�lms in an in vivo mouse model [61]. ey demonstrated that Ce6-PDT treatment signi�cantly reduced bio�lm formation by S. aureus when treated with 10 M Ce6 and 10 J/cm 2 of laser light.…”

Bacterial keratitis: Photodynamic inactivation reduced experimental inflammation

“…PDI functions on the principle that the accumulation of a specific photosensitizer in the relevant tissue induces the generation of reactive oxygen species (ROS) when exposed to light of a specific wavelength. These ROS may kill bacteria and be the initial step in healing bacterial keratitis (13)(14)(15)(16)(17). The histopathology of bacterial infected mice indicates focal cellular infiltrates within the corneal stroma.…”