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Photodynamic Inactivation of Bacterial and Yeast Biofilms With a Cationic Porphyrin
Author(s) -
Beirão Sandra,
Fernandes Sara,
Coelho Joel,
Faustino Maria A. F.,
Tomé João P. C.,
Neves Maria G. P. M. S.,
Tomé Augusto C.,
Almeida Adelaide,
Cunha Angela
Publication year - 2014
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.12331
Subject(s) - biofilm , candida albicans , pseudomonas aeruginosa , staphylococcus aureus , porphyrin , microbiology and biotechnology , chemistry , yeast , polysaccharide , bacteria , biology , biochemistry , genetics
The efficiency of 5,10,15,20‐tetrakis(1‐methylpyridinium‐4‐yl)porphyrin tetra‐iodide (Tetra‐Py + ‐Me) in the photodynamic inactivation of single‐species biofilms of Staphylococcus aureus , Pseudomonas aeruginosa and Candida albicans and mixed biofilms of S. aureus and C. albicans was evaluated. The effect on the extracellular matrix of P. aeruginosa was also assessed. Irradiation with white light up to an energy dose of 64.8 J cm −2 in the presence of 20 μ m of Tetra‐Py + ‐Me caused significant inactivation in all single‐species biofilms (3–6 log reductions), although the susceptibility was attenuated in relation to planktonic cells. In mixed biofilms, the inactivation of S. aureus was as efficient as in single‐species biofilms but the susceptibility of C. albicans decreased. In P. aeruginosa biofilms, a reduction of 81% in the polysaccharide content of the matrix was observed after treatment with a 20 μ m PS concentration and a total light dose of 64.8 J cm −2 . The results show that the Tetra‐Py + ‐Me causes significant inactivation of the microorganisms, either in biofilms or in the planktonic form, and demonstrate that polysaccharides of the biofilm matrix may be a primary target of photodynamic damage.