In vitro photodynamic antibacterial activity of cationic porphyrin derivative / 国际生物医学工程杂志

ABSTRACT

Objective To investigate susceptibility and antibacterial activity of cationic porphyfin derivative mediated photodynamic antimicrobial chemotherapy (CPD-PACT) against Pseudomonas aeruginosa,to provide experimental evidence for its high efficiency antibacterial activity.Methods The impacts of culture environments on minimum inhibitory concentration (MIC) were measured by double dilution method.The formation of inhibition zone was determined by diffusion plate method.The postantibiotic effect was analyzed by colony forming units.The viability and morphology of Pseudomonas aeruginosa were observed by confocal laser scanning microscopy (CLSM).Results The inoculum size of bacterial had a certain effect on the MIC.The MIC values increased as the pH of medium rose.When the calf serum content of culture medium increased,the MIC rose in light reaction and dropped in dark reaction.The diameter of inhibition zone mainly depended on the laser energy density,but not the concentration of photosensitizer.Though CPD possessed strong antimicrobial activity and persistent suppression on bacterial growth,the surviving Pseudomonas aeruginosa would soon continue to proliferate after PACT.The fluorescence images captured by CLSM showed that CPD-PACT could destroy the membrane integrity,leak the cytoplasmic component,decrease the bacterial activity and finally lead Pseudomonas aeruginosa to death.Conclusions CPD has strong inhibitory activity and obvious postantibiotic effect on Pseudomonas aeruginosa,which is suitable to be developed as an drug candidate for PACT.