改良光活化消毒对浮游和生物膜培养中的粪肠球菌和混合菌斑细菌的体外杀灭作用。

Ex vivo killing of Enterococcus faecalis and mixed plaque bacteria in planktonic and biofilm culture by modified photoactivated disinfection.

机构信息

Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, BC, Canada.

出版信息

Int Endod J. 2013 Jul;46(7):649-59. doi: 10.1111/iej.12041. Epub 2013 Jan 4.

DOI:10.1111/iej.12041

PMID:23289964

Abstract

AIM

To compare the efficacy of conventional and modified photoactivated disinfection (PAD) against Enterococcus faecalis and mixed plaque bacteria in suspension and biofilms.

METHODOLOGY

Enterococcus faecalis (four strains) and mixed plaque bacteria from three adult volunteers were suspended in water, added to methylene blue (MB, 15 μmol L⁻¹), MB mixed with 0.5% hydrogen peroxide and 0.05% chlorhexidine (CHX), MB mixed with 0.5% hydrogen peroxide and 0.05% EDTA or MB mixed with 0.05% EDTA and 0.05% CHX and exposed to laser irradiation from 10 s to 5 min. After exposure, samples were taken, serially diluted and grown aerobically and anaerobically on Tryptic Soy Agar plates or on blood agar plates for 24 and 72 h, respectively. For biofilm experiments, E. faecalis and mixed plaque biofilms were grown on sterile hydroxyapatite (HA) discs coated overnight with bovine dermal collagen type I for 3 weeks. After exposure to MB or MB and low concentration of EDTA with either hydrogen peroxide or CHX, the percentage of killed bacteria by PAD was evaluated using viability staining and confocal laser scanning microscope. For statistical analysis, one-way analysis of variance was performed.

RESULTS

Conventional PAD killed from 90.76% to 100% E. faecalis for 3 min, but failed to kill all plaque bacteria even after 5 min of laser irradiation. In modified PAD, up to 100% of suspended E. faecalis and mixed plaque bacteria were killed after 1 min and 30 s of irradiation. Up to twenty times more biofilm bacteria were killed by modified PAD than by conventional PAD with 15 μmol L⁻¹ MB (P < 0.001) and up to eight times more than 2% CHX (P < 0.001) and 1% sodium hypochlorite (P < 0.001).

CONCLUSION

Modified PAD was superior to conventional PAD against planktonic and biofilm bacteria.

摘要

目的

比较常规和改良光动力消毒（PAD）对悬浮和生物膜中粪肠球菌和混合菌斑细菌的杀菌效果。

方法

将粪肠球菌（4 株）和来自 3 位成年志愿者的混合菌斑细菌悬浮于水中，加入亚甲基蓝（MB，15 μmol L⁻¹），MB 与 0.5%过氧化氢和 0.05%洗必泰（CHX）混合，MB 与 0.5%过氧化氢和 0.05%乙二胺四乙酸（EDTA）混合或 MB 与 0.05% EDTA 和 0.05% CHX 混合，并接受激光照射 10 秒至 5 分钟。照射后，取样本，连续稀释，在胰蛋白酶大豆琼脂平板或血琼脂平板上于需氧和厌氧条件下分别培养 24 和 72 小时。对于生物膜实验，将粪肠球菌和混合菌斑生物膜在无菌羟磷灰石（HA）载玻片上生长，这些载玻片经过一整夜涂覆牛真皮Ⅰ型胶原，生长 3 周。将 MB 或 MB 和低浓度 EDTA 与过氧化氢或 CHX 暴露后，通过活菌染色和共聚焦激光扫描显微镜评估 PAD 杀灭的细菌百分比。采用单因素方差分析进行统计学分析。

结果

常规 PAD 在 3 分钟内杀灭了 90.76%至 100%的粪肠球菌，但即使激光照射 5 分钟也无法杀灭所有菌斑细菌。在改良 PAD 中，照射 1 分钟和 30 秒后，悬浮的粪肠球菌和混合菌斑细菌的杀灭率达到 100%。改良 PAD 杀灭生物膜细菌的效果比常规 PAD 加 15 μmol L⁻¹ MB 高 20 倍（P < 0.001），比 2% CHX（P < 0.001）和 1%次氯酸钠（P < 0.001）高 8 倍。