3种方法测定替加环素对鲍曼不动杆菌的体外药敏结果比较

Comparison of Three Methods in Vitro Susceptibility Test of Tigecycline Against Acinetobacter baumannii

比较替加环素对鲍曼不动杆菌的体外药敏试验不同方法之间的差异。分别采用微量肉汤稀释法、琼脂稀释法和K-B法测定119株临床分离鲍曼不动杆菌对替加环素的敏感性,比较不同检测方法结果的差异。微量肉汤稀释法MIC500.5μg/m L、MIC901μg/m L,FDA/EUCAST的耐药率0.0%（0/119）/0.0%（0/119）,中介率0.0%（0/119）/5.0%（6/119）,敏感率100%（119/119）/95.0%（113/119）;琼脂稀释法MIC501μg/m L、MIC904μg/m L,FDA/EUCAST耐药率11.7%（14/119）/45.4%（54/119）,中介率33.6%（40/119）/21.0%（25/119）,敏感率54.7%（65/119）/33.6%（40/119）;K-B法Jone/EUCAST的敏感率47.1%（56/119）/31.9%（38/119）、中介率48.74%（58/119）/31.9%（38/119）,耐药率4.2%（5/119）/36.2%（43/119）。替加环素对鲍曼不动杆菌体的外药敏实验中,微量肉汤稀释法、琼脂稀释法和K-B法之间存在差异。以微量肉汤稀释法为参考方法,MH琼脂稀释法总误差41.2%-60.5%,K-B法总误差47.9%-63.9%。

To evaluate different tigecyclin susceptibility testing methods for Acinetobacter baumannii. A total of 119 clinical A.baumannii isolates were collected and tigecycline susceptibilities were tested by the broth microdilution,agar dilution and disk diffusion. The results of three test methods were compared. The MIC_(50) and MIC90values obtained by broth microdilution method were0.5 μg/m L,1 μg/m L respectively,the(FDA/EUCAST breakpoint) susceptible rates were 100%(119/119)/95.0%(113/119),intermediate rates were 0.0%(0/119)/5.0%(6/119)and resistant rates were 0.0%(0/119)/0.0%(0/119). The MIC_(50) and MIC90values obtained by agar dilution method were2 μg/m L,4 μg/m L respectively,the(FDA/EUCAST breakpoint) susceptible rates were 54.7%(65/119)/33.6%(40/119),intermediate rates were 33.6%(40/119)/21.0%(25/119)and resistant rates were 11.7%(14/119)/45.4%(54/119).The disk diffusion method(FDA/EUCAST breakpoint)resistant rates were 4.2%(5/119)/36.2%(43/119),intermediate rates were 48.74%(58/119)/31.9%(38/119)and susceptible rates were 47.1%(56/119)/31.9%(38/119). There were significant differences on susceptible rates among broth microdilution(BDM),agar dilution(ADM) and disk diffusion. As broth microdilution method was reference method,the total error rates of agar dilution method were 41.2%~60.5% and the total error rates of disk diffusion were 47.9%~63.9%.