In vitro antimicrobial activity of several concentrations of sodium hypochlorite and chlorhexidine gluconate in the elimination of Enterococcus faecalis
In vitro antimicrobial activity of several concentrations of sodium hypochlorite and chlorhexidine gluconate in the elimination of Enterococcus faecalis
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DOI：
10.1046/j.1365-2591.2001.00410.x
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发表时间：
2001-09-01
影响因子：
5
通讯作者：
Souza, FJ
中科院分区：
文献类型：
--
作者：
Gomes, BPFA;Ferraz, CCR;Souza, FJ
目的：研究不同浓度（0.5%、1%、2.5%、4%和5.25%）的NaOCl和三种浓度（0.2%、1%和2%）的葡萄糖酸氯己定（凝胶和液体）对粪肠球菌的体外清除效果。方法采用24孔细胞培养板进行肉汤稀释试验，记录冲洗液杀灭细菌细胞所需时间。将10%羊血加BHI琼脂培养皿培养的粪肠球菌纯培养24 h的分离菌落悬浮于0.85% NaCl无菌溶液中。用分光光度法调整细胞悬浮液，使其符合麦克法兰0.5标度的浊度。将每种被测物质的一个nif放置在24孔细胞培养板（Corning， NY）的孔底，包括对照组（无菌生理盐水）。每个时间段和灌溉浓度使用6口井。将2 mL菌悬液与冲洗液超声混合10 s，与冲洗液接触10、30、45 s；1、3、5。10、20、30分钟；每段时间后，将每孔中的1ml转移到含有2ml新配制的BHI +中和剂的管中，以防止冲洗剂的残留作用。所有试管37℃孵育7 d。那些在孵育期间呈现中等浊度的试管被认为是正生长的。数据采用Kruskal-Wallis检验进行统计学分析。显著性水平为P < 0.05。结果所有灌洗剂均能有效杀灭粪肠杆菌，但时间不同。液体氯己定（0.2%、1%和2%）和NaOCl（5.25%）的冲洗效果最好。而0.2%氯己定液和2%氯己定凝胶促进阴性培养所需时间分别为30 s和1 min。结论尽管所有的冲洗液都具有抗菌活性。清除粪芽孢杆菌所需的时间取决于所使用的冲洗剂的浓度和类型。
Aim The aim of this study was to assess, in vitro, the effectiveness of several concentrations of NaOCl (0.5%, 1%, 2.5%, 4% and 5.25%) and two forms of chlorhexidine gluconate (gel and liquid) in three concentrations (0.2%, 1% and 2%) in the elimination of E. faecalis.Methodology A broth dilution test using 24-well cell culture plates was performed and the time taken for the irrigants to kill bacterial cells was recorded. Isolated 24 h colonies of pure cultures of E. faecalis grown on 10% sheep blood plus Brain Heart Infusion (BHI) agar plates were suspended in sterile 0.85% NaCl solution. The cell suspension was adjusted spectrophotometrically to match the turbidity of a McFarland 0.5 scale. One nif, of each tested substance was placed on the bottom of wells of 24-well cell culture plates (Corning, NY), including the control group (sterile saline). Six wells were used for each time period and irrigant concentration. Two mL of the bacterial suspension were ultrasonically mixed for 10 s with the irrigants and placed in contact with them for 10, 30, and 45 s; 1, 3, 5. 10, 20, and 30 min; and 1 and 2 h. After each period of time, 1 ml, from each well was transferred to tubes containing 2 mL of freshly prepared BHI + neutralizers in order to prevent a residual action of the irrigants. All tubes were incubated at 37 degreesC for 7 days. The tubes considered to have positive growth were those which presented medium turbidity during the incubation period. Data were analysed statistically by the Kruskal-Wallis test. with the level of significance set at P < 0.05.Results All irrigants were effective in killing E. faecalis, but at different times. Chlorhexidine in the liquid form at all concentrations tested (0.2%, 1% and 2%) and NaOCl (5.25%) were the most effective irrigants. However, the time required by 0.2% chlorhexidine liquid and 2% chlorhexidine gel to promote negative cultures was only 30 s and I min. respectively.Conclusions Even though all tested irrigants possessed antibacterial activity. the time required to eliminate E. faecalis depended on the concentration and type of irrigant used.