Antimicrobial mechanisms behind photodynamic effect in the presence of hydrogen peroxide


Autoria(s): GARCEZ, Aguinaldo Silva; NUNEZ, Silvia Cristina; BAPTISTA, Mauricio S.; DAGHASTANLI, Nasser Ali; ITRI, Rosangela; HAMBLIN, Michael R.; RIBEIRO, Martha Simoes
Contribuinte(s)

UNIVERSIDADE DE SÃO PAULO

Data(s)

19/04/2012

19/04/2012

2011

Resumo

This study describes the use of methylene blue (MB) plus light (photodynamic inactivation, PDI) in the presence of hydrogen peroxide (H(2)O(2)) to kill Staphylococcus aureus, Escherichia coli, and Candida albicans. When H(2)O(2) was added to MB plus light there was an increased antimicrobial effect, which could be due to a change in the type of ROS generated or increased microbial uptake of MB. To clarify the mechanism, the production of ROS was investigated in the presence and absence of H(2)O(2). It was observed that ROS production was almost inhibited by the presence of H(2)O(2) when cells were not present. In addition, experiments using different sequence combinations of MB and H(2)O(2) were performed and MB optical properties inside the cell were analyzed. Spectroscopy experiments suggested that the amount of MB was higher inside the cells when H(2)O(2) was used before or simultaneously with PDI, and ROS formation inside C. albicans cells confirmed that ROS production is higher in the presence of H(2)O(2). Moreover enzymatic reduction of MB by E. coli during photosensitizer uptake to the photochemically inactive leucoMB could be reversed by the oxidative effects of hydrogen peroxide, increasing ROS formation inside the microorganism. Therefore, the combination of a photosensitizer such as MB and H(2)O(2) is an interesting approach to improve PDI efficiency.

FAPESP[05/51598-7]

FAPESP[05/00253-0]

CNPq

US NIH[R01AI050875]

AFOSR US Air Force[FA9550-04-1-0079]

Identificador

PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES, v.10, n.4, p.483-490, 2011

1474-905X

http://producao.usp.br/handle/BDPI/16727

10.1039/c0pp00082e

http://dx.doi.org/10.1039/c0pp00082e

Idioma(s)

eng

Publicador

ROYAL SOC CHEMISTRY

Relação

Photochemical & Photobiological Sciences

Direitos

closedAccess

Copyright ROYAL SOC CHEMISTRY

Palavras-Chave #VISIBLE-LIGHT IRRADIATION #METHYLENE-BLUE #SINGLET OXYGEN #CHEMOTHERAPY PACT #ESCHERICHIA-COLI #BACTERIA #DESTRUCTION #RESISTANCE #REDUCTION #THERAPY #Biochemistry & Molecular Biology #Biophysics #Chemistry, Physical
Tipo

article

original article

publishedVersion