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目的 探讨雌二醇对乳腺癌术后假体表面表皮葡萄球菌生长以及生物膜形成能力及其结构的影响.方法 取表皮葡萄球菌标准株ATCC35984,调整浓度至1×107CFU/mL或1×108 CFU/mL,与硅胶片和终浓度为125 pmol/L的雌二醇混合培养,制备硅胶材料表面细菌生物膜体外模型.于培养后4、6、12、24、48、72 h,采用结晶紫染色半定量检测硅胶材料表面细菌生物膜形成能力,XTT法检测硅胶材料表面细菌生长动力;根据以上检测结果,选择细菌悬液实验浓度.取实验浓度表皮葡萄球菌ATCC35984悬液以及终浓度为50、125、250、500 pmol/L的雌二醇悬液,分别与硅胶片混合培养制备生物膜体外模型,以未添加雌二醇悬液(0 pmol/L)作为对照;另取实验浓度表皮葡萄球菌ATCC12228悬液,同法制备模型,作为阴性对照.于培养后4、6、12、24、48、72 h同上法检测硅胶材料表面细菌生长动力及生物膜形成能力,扫描电镜观察硅胶材料表面细菌生物膜超微结构;培养6、12、24 h激光共聚焦显微镜观察硅胶材料表面细菌生物膜厚度.结果 根据XTT法及结晶紫染色半定量检测结果,选择浓度为1×107 CFU/mL细菌悬液进行实验.XTT法检测示,ATCC12228和ATCC35984菌株分别在4、6、12、24、72 h和4、6、24、72 h时,其125、250、500 pmol/L组细菌生长速度快于0、50 pmol/L组(P＜0.05),4、6、72 h时500 pmol/L组快于125、250 pmol/L组(P＜0.05),72 h时250 pmol/L组快于125 pmol/L组(P＜0.05),其余组间比较差异无统计学意义(P＞0.05);同一时间点两种菌株相同雌二醇浓度组比较,差异均无统计学意义(P＞0.05).结晶紫染色半定量检测:各时间点ATCC12228菌株各雌二醇浓度组生物膜形成均为阴性.而ATCC35984菌株培养4h即有生物膜形成,随时间延长逐渐增厚,24 h时达峰值;培养4、6h,0 pmol/L组生物膜厚度大于125、250、500 pmol/L组(P＜0.05);12 h开始125 pmol/L组生物膜最厚,与其他组比较差异均有统计学意义(P＜0.05).激光共聚焦显微镜观察示,ATCC35984菌株在培养6h时125、250、500 pmol/L组的生物膜厚度小于0、50 pmol/L组(P＜0.05),其余组间比较差异无统计学意义(P＞0.05);之后各组生物膜厚度逐渐增加,12、24 h时125 pmol/L组生物膜厚度明显大于其他浓度组(P＜0.05).扫描电镜观察示,各时间点与其他浓度组相比,125 pmol/L组形成的生物膜结构范围最广,结构最致密、最丰富、层次最多.结论 高浓度雌二醇可促进表皮葡萄球菌生长、生物膜形成和生物膜的成熟.“,”Objective To investigate the effect of the estradiol hormones on biofilm formati on and structure of Staphylococcus epidermidis after breast implant surgery.Methods The concentration of Staphylococcus epidermidis strains ATCC35984 was adjusted to 1×107 CFU/mL or 1×108 CFU/mL,and the type strains were incubated on the surface of silica gel in 125 pmol/L estradiol suspensions to prepare bacterial biofilms model in vitro.After cultured in vitro for 4,6,12,24,48,and 72 hours,bacteria growth and biofilm formation ability were assessed by means of the XTT and crystal violet staining respectively.According to the above results,the bacterial suspension concentration was selected for experiments.The experimental concentration of Staphylococcus epidermidis ATCC35984 suspension and the concentrations of 50,125,250,500 pmol/L estradiol suspensions were mixed with silica gel respectively to prepare biofilm model in vitro,no estradiol suspension served as control group.The experimental concentration of Staphylococcus epidermidis ATCC12228 suspension was used to prepare the same model in the negative control.After cultured in vitro for 4,6,12,24,48,and 72 hours,the same methods were used to assess the bacteria growth dynamics and biofilm forming ability,and the scanning electron microscope (SEM) was used to observe bacterial biofilm structure cultured on the surface of silica gel;the laser scanning confocal microscope (CLSM) was used to measure bacterial biofilm thickness on the surface of silica gel after 6,12,and 24 hours.Results According to the results of semi quantitative detection of crystal violet stain and XTT methods,the bacterial suspension of 1×107 CFU/mL was selected for the experiment.XTT results indicated that the growth rates of ATCC12228 strain (at 4,6,12,24,and 72 hours) and ATCC35984 strain (at 4,6,24,and 72 hours) in 125,250,and 500 pmol/L estradiol were significantly faster than those in 0 and 50 pmol/L (P＜0.05).The growth rate of 500 pmol/L group was significantly faster than 125 and 250 pmol/L groups at 4,6,and 72 hours (P＜0.05),and the growth rate of 250 pmol/L group was significantly faster than that of 125 pmol/L group at 72 hours (P＜0.05),but there was no significant difference between 0 and 50 pmol/L groups (P＞0.05).At the same time point and same estradiol concentration,the growth rates showed no significant difference between 2 strains (P＞0.05).Semi quantitative detection of crystal violet staining showed no biofilm formed in ATCC 12228 strain in all estradiol concentration groups at different time points.In ATCC35984 strain,the biofilm was found at 4 hours and gradually thickened with time,reached the peak at 24 hours.After cultured for 4 and 6 hours,the biofflm of 0 pmol/L groups were significantly thicker than that of 125,250,and 500 pmol/L groups (P＜0.05).At 12 hours,the 125 pmol/L group had the thickest biofilm,showing significant difference when compared with other groups (P＜0.05).The CLSM showed ATCC35984 biofilm thickness of 125,250,and 500 pmol/L was significantly less than that of 0 and 50 pmol/L groups at 6 hours (P＜0.05),but difference was not significant between other groups (P＞0.05).Then the thickness of the biofilm increased gradually,and the thickness of 125 pmol/L group was significantly larger than that of other concentration groups at 12 and 24 hours (P＜0.05).The SEM observation showed that the biofilm of 125 pmol/L group was denser and thicker than that of the other concentration groups at each time point.Conclusion High level estradiol can promote bacteria growth,biofilm formation,and biofilm maturity of Staphylococcus epidermidis.