氢氧化钙与二甲亚砜对粪肠球菌联合抗菌作用的实验观察

Susceptibility testing of the combination of calcium hydroxide and dimethyl sulfoxide against E.faecalis in vitro

目的:研究氢氧化钙和二甲亚砜对粪肠球菌体外联合药敏实验中的相互作用及联合后化学性质的变化。方法:参照美国国家临床试验标准化委员会(NCCLS)提出的标准,采用棋盘试管稀释法对粪肠球菌进行了氢氧化钙与二甲亚砜体外联合药敏实验并检测了其pH值变化。结果:氢氧化钙与二甲亚砜联合时对粪肠球菌的抑菌浓度分数指数(FIC I)=0.8,从羟基离子的角度考虑时,对粪肠球菌的FIC I=0.35。氢氧化钙对粪肠球菌的最低抑菌浓度(M IC)=3.5 mg/mL,相应pH=10.03,最低杀菌浓度(MBC)=4.5 mg/mL,相应pH=11.05,二甲亚砜对粪肠球菌的M IC=20%,相应pH=7.50,MBC=40%,相应pH=8.20。结论:氢氧化钙与二甲亚砜体外联合对粪肠球菌的联合抗菌作用表现为协同相加作用,无拮抗作用。

AIM：To evaluate the antibacterial effect of calcium hydroxide combined with dimethyl sulfoxide against E.faecalis in vitro and the chemical effect after the combination. METHODS：The checkerboard macrodilution method recommended by the Nation Committee for Clinical Laboratory Standards（ NCCLS, USA）was applied to evaluate the antibacterial effect. MICs of calcium hydroxide combined with dimethyl sulfoxide were determined by macrodilution method ,The FIC index was calculated according to MIC results. RESULTS：The MIC of calcium hydroxide was reduced when combined with dimethyl sulfoxide. The FICI is 0.8 after the combination. FICI = 0.35, when hydroxyl ions are taken into account, The MIC of calcium hydroxide against E. faecalis was 3.5 mg/mL, （ pH = 10. 03 ）, MBC = 4.5 mg/mL, （pH = 11.05 ）, MIC of dimethyl sulfoxide against E. faeealis was 20% （pH = 7.50） , MBC =40% （pH = 8.20）. CONCLUSION ：Synergitie and additional interactions was existed between calcium hydroxide and dimethyl sulfoxide against E.faecalis in vitro without antagonism.