Antimicrobial properties of a new type of photosensitizer derived from phthalocyanine against planktonic and biofilm forms of Staphylococcus aureus

Publication date: Available online 4 January 2018
Source:Photodiagnosis and Photodynamic Therapy
Author(s): Yiru Gao, Bingjie Mai, Ao Wang, Min Li, Xiaobing Wang, Kun Zhang, Quanhong Liu, Shaohua Wei, Pan Wang
BackgroundBacterial infection is a common clinical problem. Community-associated Staphylococcus aureus (S. aureus) infections can cause extensive tissue damage and necrosis. Photodynamic antimicrobial chemotherapy (PACT) has recently attracted attention as a feasible alternative to bacterial therapy. Octa-cationic zinc phthalocyanines are newly identified photosensitizers derived from phthalocyanines bearing 1, 2-ethanediamine groups and quaternized derivatives with different numbers of positive charges (ZnPcⁿ⁺, n = 4 or 8). Here we report the antimicrobial effects of ZnPcⁿ⁺-mediated PACT on planktonic and biofilm cultures of S. aureus.MethodsZnPcⁿ⁺ uptake was detected by photometry after alkaline lysis. Dark-toxicity and light-mediated antimicrobial effects of the drug was determined by the plate count method. The production of intracellular reactive oxygen species (ROS) was detected by flow cytometry. SYTO 9 and propidium iodide (PI) were used to detect the bacterial cell membrane permeability. DNA damage after ZnPcⁿ⁺-PACT was analyzed by flow cytometry and PI staining. The destruction of biofilm was evaluated by scanning electron microscope (SEM).ResultsThe study of uptake showed that the relative fluorescence intensity of ZnPcⁿ⁺ in S. aureus peaked at 15 min. Generation of reactive oxygen species (ROS) by ZnPcⁿ⁺ was enhanced in PACT treatment groups. SYTO 9 and PI staining indicated that cell membrane was damaged. Flow cytometry and PI staining revealed DNA damage. Biofilms were damaged in PACT treatment groups.ConclusionsOur results suggest that light-activated ZnPcⁿ⁺ can efficiently inhibit planktonic and biofilm cultures of S. aureus.



http://ift.tt/2lTJu5v