肉汤纸片洗脱法和全自动药敏系统应用于黏菌素药敏试验的方法学评价

Methodological evaluation on application of colistin broth disk elution method and full-automatic antimicrobial sensitivity system in colistin susceptibility test

目的评估黏菌素肉汤纸片洗脱法(CBDE)和全自动药敏系统检测肠杆菌目细菌对黏菌素体外药敏结果的可靠性。方法选取2021年1—6月该院临床分离的肠杆菌目细菌133株,根据欧洲抗菌药物敏感性试验委员会(EUCAST)公布的黏菌素的折点判断标准,使用CBDE和两种全自动药敏系统检测分离株对黏菌素的最低抑菌浓度(MIC),以肉汤微量稀释法(BMD)为参考方法,分析3种方法和BMD的基本一致率(EA)、分类一致率(CA)、重大误差(ME)和非常重大误差(VME)。结果与BMD比较,CBDE、Phoenix NMIC-413和Vitek CompactⅡ-GN335检测大肠埃希菌对黏菌素敏感性的EA分别为98.5%、97.0%和98.5%,CA分别为100.0%、97.0%和98.5%,ME均为0.0%,VME分别为0.0%、28.6%和14.3%。与BMD比较,CBDE、Phoenix NMIC-413和Vitek CompactⅡ-GN335检测肺炎克雷伯菌对黏菌素敏感性的EA分别为97.0%、92.4%和92.4%,CA分别为100.0%、92.4%和92.4%,ME均为0.0%,VME分别为0.0%、10.9%和10.9%。结论CBDE可以作为微生物室检测肠杆菌目细菌对黏菌素敏感性的可靠方法。由全自动药敏分析系统判读为对黏菌素敏感的肠杆菌目细菌需使用BMD进行复核。

Objective To evaluate the reliability of colistin broth disk elusion(CBDE)and full-automatic antimicrobial susceptibility testing(AST)system for detecting the in vitroantimicrobial sensitivity results of Enterobacterales bacteria to colistin.Methods A total of 133 strains of clinically isolated Enterobacterales bacteria were selected from January to June 2021.According to the Breaking Point Criteria of Colistin published by European Committee for Antimicrobial Susceptibility Testing(EUCAST),CBDE and two kinds of full-automatic AST were used to detect the minimum inhibitory concentration(MIC)of the isolated strain to colistin.The broth microdilution(BMD)method was used as the reference method.The essential agreement(EA),category agreement(CA),major error(ME)and very major error(VME)of three methods and BMD were analyzed.Results Compared with BMD,EA of CBDE,Phoenix NMIC-413 and Vitek CompactⅡ-GN335 in detecting the sensitivity of Escherichia coli to colistin were 98.5%,97.0%,and 98.5%,respectively;CA were 100.0%,97.0%,and 98.5%,respectively;ME all were 0.0%,and VME were 0.0%,28.6%,and 14.3%,respectively.Compared with BMD,EA of CBDE,Phoenix NMIC-413 and Vitek CompactⅡ-GN335 indetecting the sensitivity of Klebsiellapneumoniae to colistinby using these three methods were 97.0%,92.4%,and 92.4%,respectively;CA were 100.0%,92.4%and 92.4%,respectively;ME all were 0.0%,VME were 0.0%,10.9%and 10.9%,respectively.Conclusion CBDE could be used as a reliable method for the clinical microbiology laboratory in detecting the antimicrobial sensitivity of Enterobacterales bacteria to colistin.The strains of Enterobacterales bacteria which is judged to be sensitive to colistin by AST system needs to be re-checked by BMD.