不同浓度葡萄糖对多药耐药鲍氏不动杆菌生物膜形成能力的影响

Impact of different glucose concentrations on the biofilm formation ability of multidrug-resistant Acinetobacter baumannii

目的探索多药耐药鲍氏不动杆菌在不同浓度葡萄糖环境中其生物膜形成能力的变化,为糖尿病患者预防与治疗感染提供理论依据。方法用测定MIC方法筛选2012年4月-2013年10月临床分离的多药耐药鲍氏不动杆菌,用含有不同葡萄糖浓度的胰蛋白胨大豆肉汤培养,分别测定其570nm处吸光度值,采用激光共聚焦显微镜（CLSM）观察和测定生物膜在不同浓度、不同时间形成的形态及厚度,不同浓度下膜生成能力采用Kruskal-Wallis H检验及t检验法进行统计。结果 30株多药耐药鲍氏不动杆菌对头孢他啶、哌拉西林、阿米卡星的耐药率均为96.7%;葡萄糖浓度为11.1~30.0mmol/L时膜形成能力与无糖培养比较吸光度值差异有统计学意义（P〈0.05）,但≥11.1mmol/L的各浓度吸光度值比较差异无统计学意义;CLSM观察显示,多药耐药鲍氏不动杆菌葡萄糖浓度在11.1~30.0mmol/L时菌株荧光强度均在大约24h基本达到最强,48h有一个强度维持,比无糖环境提前24h;生物膜厚度数据统计显示,加糖培养12~36h膜厚度达到最大,加糖培养膜厚度最大值与无糖培养膜厚度最大值相比差异均有统计学意义（P〈0.05）。结论多药耐药鲍氏不动杆菌在环境中葡萄糖浓度≥11.1mmol/L时,形成生物膜的能力明显增强,形成生物膜的厚度增加,形成生物膜的周期明显缩短。

OBJECTIVE To explore the biofilm-forming ability of multidrug-resistant Acinetobacter baumannii at different concentrations of glucose so as to provide theoretical evidence for the prevention and treatment of infections in patients with diabetes.METHODS Clinical isolates of multidrug-resistant A.baumannii,which were screened from Apr.2012 to Oct.2013 by MIC determination method and cultured in glucose tryptone soya broth at different concentrations,were measured for absorbance values at 570 nm.The shape and thickness of formed biofilms under different concentrations and times were observed and measured by confocal laser scanning microscopy（CLSM）.The statistical data of film formation ability under different concentrations were processed by using Kruskal-Wallis H test and t test.RESULTS The 30 clinical isolates of multidrug-resistant A.baumannii showed a resistance of 96.7%to ceftazidime,piperacillin and amikacin.The biofilm formation ability data showed that there were differences in absorbance values at the glucose concentrations of 11.1-30.0mmol/L compared with sugarfree group（P〈0.05）.However,there was no significant difference in the absorbance value between each group at the glucose concentration≥11.1mmol/L.CLSM observation showed that when the glucose concentration was11.1-30.0mmol/L,the fluorescence intensity of multidrug-resistant A.baumannii was the strongest at around24 h,and maintained at 48 h,which was advanced by 24 hthan the sugar-free group.Biofilm thickness data by statistical analysis showed the film thickness reached the maximum value at 12-36 hof sugar culture.There was significant difference in film thickness by sugar culture compared to sugar-free culture（P〈0.05）.CONCLUSION For multidrug-resistant A.baumannii at the condition of glucose concentrations≥ 11.1mmol/L,the ability of biofilm formation was significantly enhanced,the biofilm thickness was increased,and the biofilm formation cycle was significantly shorter.