流式细胞术检测抗生素最低抑菌浓度

目的　建立一种流式细胞术 (FCM )快速检测抗生素最低抑菌浓度 (MIC)的方法 ,与常规药敏试验结果进行比较 ,探讨其应用价值。方法　取 2 0株肠杆菌科细菌 ,用碘化丙啶 (PI)染色 ,分别检测阴性对照管和MIC浓度抗生素作用管的平均荧光强度 (MFI) ,计算两者比值 ,据此 ,设定流式细胞药敏试验 (FCST)检测MIC的判断值 ,根据设定的判断值对 2 8株临床分离细菌同时进行常规药敏和FCST双盲测定。结果　 2 0株肠杆菌科细菌测得的MFI比值 x为 2 .0 7,CV为 0 .3 1;将MFI大于阴性对照细菌 2倍 (增加 10 0 % )的最低药物浓度定义为该菌的MIC ,2 8株临床菌株FCST所测得的MIC与常规药敏试验相比r=0 .92 ,(P <0 .0 0 1) ,回归方程为 :Y =1.4X -0 .48。结论　FCST与常规药敏试验结果有显著相关性 ,并且具有快速、稳定、准确、便于自动化等优点 ,有着较大的临床应用前景。

Measure MICs of antibiotic by Flow cytometry

Objective A fast method for measuring antibiotic minimal inhibitory concentrations (MICs) by Flow cytometry (FCM) was developed and its application value was studied by comparing with the conventional method. Methods Twenty strains of Enterbacteriaceae were taken a nd fluorescence labeled by propidium iodide (PI), mean fluorescence intensity (M FI) of negative control and reaction tube for drug MIC was read respectively. Ac cording to the judgement level of MIC by Flow cytometry susceptibility testing ( FCST), 28 clinical isolates were double-blind examined at the same time by conv entional method and FCST. Results The mean of MFI of 20 b acteria strains was 2.07, and the coefficient of variation was 0.31; The MIC was defined as the lowest concentration of drug that showed an increase of 100% in MFI compared to that of the negative control. Comparing the MICs of FCST and con ventional method in 28 clinical strains, we found the correlation coefficient wa s 0.92 (P values< 0.001 ). The regression equation is Y=1.4X-0.48. Conclusion The correlation of results for FCST and convention al method was notable, and FCST is rapid, accurate, stabile and convenient for a utomatization, and so has a good clinical application foreground.