Avaliação da inativação fotodinâmica em s. aureus, e. coli e p. aeruginosa utilizando os fotossensibilizadores eosina azul de metileno e metalo-clorofilina

Abstract

The present study evaluated the potential use of sodium copper chlorophyllin salt (CuChlNa) and eosin methylene-blue according to Giemsa (EMB) as antimicrobial photosensitizers (aPS) for photoinactivation (PDI) of Staphylococcus aureus (Gram-positive) P. aeruginosa and Escherichia coli (Gram-negative) bacteria. The results revealed that both EMB and CuChlNa can be used as aPS for the photoinactivation of S. aureus while only EMB was able to photoinactivate E. coli. Nevertheless, a more complex experimental setup was needed for obtaining the photoinactivation against E. coli. On contrary, none of the photosensitizers was effective for P. aeruginosa under several tested experimental conditions. The data showed that EMB and CuChlNa presented similar photoinactivation effect on S. aureus in which the bacterial growth was completely inhibited at PS concentrations over 5 μM, previously incubated during 30 min, when irradiated by a light dose of 30/J cm2 at 625nm. In the case of E. coli, the bacterial growth was completely inhibited only when combining a PS incubation period of 120 min with concentrations over 20 μM.