Photodynamic activity of the haematoporphyrin derivative with rutin and arginine substituents (HpD-Rut(2)-Arg(2)) against Staphylococcus aureus and Pseudomonas aeruginosa.

The impact of the new photosensitizer HpD-Rut(2)-Arg(2)on the growth of methicillin-resistant Staphylococcus aureus(MRSA), methicillin-susceptible Staphylococcus aureus (MSSA) and Pseudomonas aeruginosa clinical strains isolated from infected burn wounds was examined. The susceptibility of the isolates to the photodynamic action of the sensitizer was evaluated by the determination of minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) using the newly developed microdilution method. The results were compared with the previously investigated HpD-Arg(2). All clinical isolates examined proved to be susceptible to the photodynamic action of HpD-Rut(2)-Arg(2). The MIC of this newly synthetized photosensitizer ranged from 0.8 to 12.5 microg ml(-1) for MRSA, from 0.4 to 6.2 microg ml(-1) for MSSA and from 6.2 to 50 microg ml(-1) for P. aeruginosa. While MBC ranged from 1.6 to 12.5 microg ml(-1) for MRSA, 0.4 to 6.2 microg ml(-1) for MSSA and 6.2 to 100 microg ml(-1) for P. aeruginosa. This photosensitizer is more effective in its bactericidal photodynamic action than previously tested HpD-Arg(2). Copyright 2001 Academic Press.