基托树脂表面浮游态白色念珠菌的灭活研究

Study on inactivation of planktonic Candida albicans on the surface of denture base resin

目的:比较氩气、30%H_2O_2和50%H_2O_2等离子体对树脂表面浮游白色念珠菌的杀灭效果。方法:将甲基丙烯酸甲酯制作成9mm×9mm×2mm的试件56块,在浓度为1.0×10~8CFU/ml白色念珠菌菌悬液中培养2h后取出,PBS轻漂两次,分为14组(n=4)。对照组不做处理,氩气等离子体分别处理20s、40s、60s、80s、100s,30%H_2O_2和50%H_2O_2等离子体分别处理5s、10s、15s、20s。处理后洗脱、系列稀释、涂板。48h后计数菌落形成单位,计算杀灭对数值。参考欧洲标准EN 1275-2005,处理后真菌减少>4log_(10)CFU视为有效。结果:氩气等离子体处理100s、30%H_2O_2和50%H_2O_2等离子体处理15s后,白色念珠菌数量降低均>4 log_(10)CFU,均能达到有效杀灭。结论:氩气、30%H_2O_2和50%H_2O_2等离子体均能有效杀灭树脂表面浮游白色念珠菌。30%H_2O_2和50%H_2O_2等离子体杀菌效能优于氩气等离子体。

Objective：To investigate the fungicidal effects of different plasma（argon,30% H2O2 and 50% H2O2 plasma）on planktonic Candida albicans on the surface of acrylic resin.Methods：Candida albicans were inoculated on polymethyl methacrylate specimens with the size of 9mm×9mm×2mm.Fifty-six resin specimens were randomly divided into fourteen groups（n=4）.The specimens in control group did not receive any treatment and the other groups were exposed to argon,30% H2O2 and 50% H2O2 plasma for different time durations.Each specimen was immersed into phosphate bufffered saline（PBS）for 2h and sonicated for 5 min in an ultrasonic bath sonicater.PBS cell suspensions of corresponding specimens were serially diluted.Then aliquots of appropriate dilutions（200μl） were inoculated on Sabouraud dextrose agar and incubated at 37℃ for 48h before the colonies were counted.The anticandidal efficacy of plasma was evaluated by the reduction of colony forming units（CFU）in log（10）.Reduction of 4 log（10）CFU was regarded as the threshold of clinical relevance in accordance with EN 1275-2005.Results：The reduction of viable Candida albicans on the resin was 4.016 log（10）CFU with100s of argon plasma treatment.The inactivation efficacy of 4.220 log（10）CFU was observed after 15s for 30% H2O2 plasma treatment time.The reduction of viable fungi was 4.442 log（10）CFU with the prolonged exposure time of 20s.The anticandidal efficacy of 4.306 log（10） CFU was achieved after 15s 50% H2O2 plasma treatment.The reduction of Candida albicans cells was increased further up to 4.618 log（10）CFU when 50% H2O2 plasma treatment time extended to 20s.Conclusions：Argon,30% H2O2 and 50% H2O2 plasma are effective in inactivation of planktonic Candida albicans on the resin.The anticandidal effects of 30% H2O2 and 50% H2O2 plasma are superior to that of argon plasma.