等离子体对基托树脂表面白色念珠菌生物膜的杀灭研究

Inactivation of Candida albicans biofilms on base resin surface by plasma

目的:评价氩气、30%H_2O_2和50%H_2O_2等离子体对基托树脂表面生物膜内白色念珠菌的杀灭效果。方法:将甲基丙烯酸甲酯材料制作成大小为9 mm×9 mm×2 mm试件68块,在试件表面培养48 h白色念珠菌生物膜。取64块试件随机分为对照组和15个处理组(n=4),对照组不做处理,氩气等离子体分别处理60、120、180、240、300 s,30%H_2O_2和50%H_2O_2等离子体分别处理20、40、60、80、100 s。处理后洗脱、系列稀释、涂板,采用菌落形成单位计数法评估杀菌效果。剩余4块试件:1块作为对照组,其余3块分别用氩气、30%H_2O_2和50%H_2O_2等离子体处理300 s,扫描电镜观察细胞表面损伤。结果:氩气等离子体处理300 s、30%H_2O_2等离子体处理100 s、50%H_2O_2等离子体处理80 s,杀灭率均超过99.99%。电镜下处理后的细胞膜表面粗糙,有孔洞。结论:氩气、30%H_2O_2和50%H_2O_2等离子体均能有效杀灭生物膜内的白色念珠菌。

Objective： To evaluate the fungicidal efficacy of argon, 30% H2O2 and 50% H2O2 on Candida albicans biofilms on acrylic resin. Methods： Candida albicans biofilms were cultivated for 48 h on 68 resin specimens with the size of 9 mm×9 mm×2mm. 64 specimens were randomly divided into 16 groups（ n = 4）. The control group did not receive any treatment and the other groups were exposed to 3 kinds of plasma for different time. The specimens were sonicated and serially diluted. Then aliquots of appropriate dilutions （200 μl） were inoculated on Sabouraud dextrose agar and incubated for 48 h before the colonies were counted. The anticandidal efficacy of plasma was evaluated by the reduction of colony forming units （CFU） in log10. Reduction of 4 log10 CFU was regarded as the threshold of clinical relevance in accordance with EN 1275 - 2005. One of the remaining 4 samples was not treated by plasma and the others were exposed to different plasma for 300 s. The morphological changes of Candida albicanss in biofilms were assessed by SEM. Results： The anticandidal efficacy of viable fungi in biofilms reached the threshold with 300 s for argon plasma, 100 s for 30% H2O2 plasma and 80 s for 50% H2O2 plasma treatment. The rouphness and perforation of the cell membrane of Candida albicans were observed after plasma exposure. Conclusion： Argon, 30% H2O2 and 50% H2O2 plasma are effective in inactivation of Candida albicans biofilms on resin.