Pigments influence the tolerance of Pseudomonas aeruginosa PAO1 to photodynamically induced oxidative stress
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Pigments influence the tolerance of Pseudomonas aeruginosa PAO1 to photodynamically induced oxidative stress. / Orlandi, Viviana T; Bolognese, Fabrizio; Chiodaroli, Luca; Tolker-Nielsen, Tim; Barbieri, Paola.
In: Microbiology, Vol. 161, No. 12, 12.2015, p. 2298-309.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Pigments influence the tolerance of Pseudomonas aeruginosa PAO1 to photodynamically induced oxidative stress
AU - Orlandi, Viviana T
AU - Bolognese, Fabrizio
AU - Chiodaroli, Luca
AU - Tolker-Nielsen, Tim
AU - Barbieri, Paola
PY - 2015/12
Y1 - 2015/12
N2 - Pseudomonas aeruginosa is an opportunistic pathogen known to be resistant to different classes of antibiotics and disinfectants. P. aeruginosa also displays a certain degree of tolerance to photodynamic therapy (PDT), an alternative antimicrobial approach exploiting a photo-oxidative stress induced by exogenous photosensitizers and visible light. To evaluate whether P. aeruginosa pigments can contribute to its relative tolerance to PDT, we analysed the response to this treatment of isogenic transposon mutants of P. aeruginosa PAO1 with altered pigmentation. In general, in the presence of pigments a higher tolerance to PDT-induced photo-oxidative stress was observed. Hyperproduction of pyomelanin makes the cells much more tolerant to stress caused by either radicals or singlet oxygen generated by different photosensitizers upon photoactivation. Phenazines, pyocyanin and phenazine-1-carboxylic acid, produced in different amounts depending on the cultural conditions, are able to counteract both types of PDT-elicited reactive oxygen species. Hyperproduction of pyoverdine, caused by a mutation in a quorum-sensing gene, rendered P. aeruginosa more tolerant to a photosensitizer that generates mainly singlet oxygen, although in this case the observed tolerance to photo-oxidative stress cannot be exclusively attributed to the presence of the pigment.
AB - Pseudomonas aeruginosa is an opportunistic pathogen known to be resistant to different classes of antibiotics and disinfectants. P. aeruginosa also displays a certain degree of tolerance to photodynamic therapy (PDT), an alternative antimicrobial approach exploiting a photo-oxidative stress induced by exogenous photosensitizers and visible light. To evaluate whether P. aeruginosa pigments can contribute to its relative tolerance to PDT, we analysed the response to this treatment of isogenic transposon mutants of P. aeruginosa PAO1 with altered pigmentation. In general, in the presence of pigments a higher tolerance to PDT-induced photo-oxidative stress was observed. Hyperproduction of pyomelanin makes the cells much more tolerant to stress caused by either radicals or singlet oxygen generated by different photosensitizers upon photoactivation. Phenazines, pyocyanin and phenazine-1-carboxylic acid, produced in different amounts depending on the cultural conditions, are able to counteract both types of PDT-elicited reactive oxygen species. Hyperproduction of pyoverdine, caused by a mutation in a quorum-sensing gene, rendered P. aeruginosa more tolerant to a photosensitizer that generates mainly singlet oxygen, although in this case the observed tolerance to photo-oxidative stress cannot be exclusively attributed to the presence of the pigment.
U2 - 10.1099/mic.0.000193
DO - 10.1099/mic.0.000193
M3 - Journal article
C2 - 26419906
VL - 161
SP - 2298
EP - 2309
JO - Microbiology
JF - Microbiology
SN - 1350-0872
IS - 12
ER -
ID: 152934324