| Objective : the emergence of multiply or extensively drug-resistant pathogens has brought great challenges for clinical infectious disease.The drug resistance situation of acinetobacter baumannii is very serious.Therefore,researchers put forward alternatives to antibiotics.The photodynamic antibacterial therapy is a promising new alternative strategy.Its three basic elements are photosensitizer,light and oxygen.Researches suggest that photodynamic antimicrobial therapy is significantly effective for pathogens,and the physical and chemical properties of photosensitizer have an important influence to photodynamic antibacterial effect.Preliminary researches suggest that cationic photosensitizer is effective in mediating antimicrobial photodynamic inactivation(a PDI)of Gram-negative bacteria.Therefore,the study evaluated the photodynamic activity of three cationic phthalocyanine for extensively drug-resistant acinetobacter baumannii.We analyzed the effect on photodynamic activity of illumination time,light power,and the concentration of photosensitizer,studied bacterial uptake of photosensitizer,and carried on comparative study on there photosensitizes.It is aim to select the most appropriate antimicrobial photosensitizer,and to provide reference for further study on the photodynamic antimicrobial treatment.Methods : 1 、 The bacteria and photosensitizer were incubated and then put the mixture in a dark room for irradiation.then the mixture were serially diluted 10-fold and each of the dilutions were streaked horizontally on Columbia sheep blood agar plates,the plates were incubated for 18–24 h and counted Colony-forming unit.2、Discussing the effect of illumination time,optical power density,concentration of photosensitizer on photodynamic activety by changing illumination time(10,20,30,40,50 min or 10,20,40min),optical power density(637,500,300mwcm-2),and the concentration of photosensitizer(5u M,2.5 u M).3、Studying the bacterial intake regularity of the photosensitizer by metering cell uptake rate of photosensitizer after different incubation time(12,24,36,48h)by UV-Vis spectrophotometer.Results: 1、 99.96% bacterial killing was achieved of MLZnPcI4(p < 0.05),99.64% bacterial killing was achieved of N1SiPc(p < 0.001),99.05% bacterial killing was achieved of N2SiPc(p=0.002).2、 To extend the irradiation time,to produce enhanced photodynamic antibacterial effect of MLZnPcI4,N1SiPc,N2SiPc for extensively drug-resistant acinetobacter baumannii with significant difference statistically(p < 0.05).Photodynamic antibacterial effect of MLZnPcI4,N1SiPc,N2SiPc at high concentration is better compared with low concentration with significant difference statistically(p < 0.001).Photodynamic antibacterial effect of MLZnPcI4,N1SiPc,N2SiPc at dfferent fluence rate are different,there are significant difference statistically(p < 0.05).3 、 Extensively drug-resistant acinetobacter baumannii were incubated with MLZnPcI4,N1SiPc after 24 h,reaching an intake peak.The uptake rate was 8.32% and 11.43%(p < 0.05).but the most uptake rate of N1SiPc was 6.17%,there were no statistical significance between groups(p > 0.05).4、 Compared with the blank group,bacteria survival rate of MLZnPcI4,N1SiPc,N2SiPc at 2.5u M were 94.04%,98.61%,97.77% respectively,there was no statistically significant difference(P = 0.511,P = 0.380,P = 0.064).Bacteria survival rate at 5u M were 91.75%,96.87% 97.49% with no statistically significant differences in statistics(P = 0393,P = 0.108,P = 0.142).Conclusions : Antimicrobial photodynamic inactivation of cationic water-soluble phthalocyanine for extensively drug-resistant acinetobacter baumannii are remarkably effective,the three cationic phthalocyanine on extensively drug-resistant acinetobacter baumannii are characterized by low toxicity,and MLZnPcI4-mediated photodynamic antimicrobial effect is better than of N1SiPc,N2SiPc.Photodynamic antimicrobial treatment is a new way with broad prospects. |
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