黏菌素细菌药物敏感性检测方法学评价

Evaluation of the methods for testing colistin susceptibility

目的评估黏菌素肉汤纸片洗脱法(CBDE)和黏菌素琼脂试验法(CAT)检测细菌对黏菌素敏感性结果的可靠性。方法收集临床分离的非重复分离菌株486株,采用CLSI 2020年版推荐的CBDE和CAT测定上述临床分菌株对黏菌素的敏感性,以肉汤微量稀释法(BMD)为标准对照,观察CBDE和CAT测定细菌对黏菌素敏感性的基本一致率(EA)、分类一致率(CA)、重大误差(ME)和非常重大误差(VME)。结果采用BMD、CBDE和CAT测定277株肠杆菌目细菌对黏菌素的敏感率分别为93.5%、93.1%和93.1%;105株铜绿假单胞菌的敏感率均为96.2%;104株鲍曼不动杆菌的敏感率分别为99.0%、98.1%和99.0%。与BMD测定结果相比,CBDE和CAT检测肠杆菌目细菌对黏菌素敏感性的EA分别为90.3%和96.8%、CA均为99.6%、ME均为0.4%、VME均为0。同样与BMD比较,CBDE和CAT检测铜绿假单胞菌对黏菌素敏感性的EA分别为96.2%和93.3%、CA均为100%、ME和VME均为0。而与BMD结果相比,CBDE和CAT检测鲍曼不动杆菌对黏菌素敏感性的EA分别为87.5%和99.0%、CA分别为99.0%和100%、ME分别为1.0%和0、VME均为0。结论CBDE和CAT可用于临床实验室常规检测肠杆菌目细菌和铜绿假单胞菌对黏菌素的敏感性;因鲍曼不动杆菌CBDE与BMD比较EA为87.5%(不符合≥90%的可接受率),故不建议推荐,可以选择CAT检测鲍曼不动杆菌对黏菌素的敏感性。

Objective To evaluate the accuracy and reliability of colistin broth disc elution(CBDE)and colistin agar test(CAT)methods for testing the in vitro colistin susceptibility.Methods A total of 486 nonduplicate clinical isolates were collected.The CBDE and CAT methods recommended by CLSI 2020 edition were used to determine the susceptibility of these clinical isolates to colistin.The broth microdilution method(BMD)recommended by CLSI was used as control.The essential agreement(EA),classification consistency(CA),major error(ME),and very major error(VME)rates of CBDE and CAT methods in determining colistin susceptibility were observed.Results Overall,93.5%,93.1%and 93.1%of the 277 Enterobacterales strains were susceptible to colistin determined by BMD,CBDE and CAT,respectively.Majority(96.2%)of the 105 P.aeruginosa strains were susceptible to colistin.And 99.0%,98.1%and 99.0%of the 104 A.baumannii strains were susceptible to colistin determined by BMD,CBDE and CAT,respectively.Compared with BMD,CBDE and CAT methods provided EA of 90.3%and 96.8%in susceptibility of Enterobacterales to colistin,respectively.The corresponding CA was 99.6%,ME 0.4%,and VME 0 for both CBDE and CAT.Similarly,compared with BMD,CBDE and CAT methods provided EA of 96.2%and 93.3%in susceptibility of P.aeruginosa to colistin,respectively.The corresponding CA was 100%,ME and VME were 0.For A.baumannii strains,CBDE and CAT methods resulted in EA of 87.5%and 99.0%in colistin susceptibility compared with BMD.The corresponding CA was 99.0%and 100%,ME 1.0%and 0,and VME 0,respectively.Conclusions CBDE and CAT can be used to routinely determine the susceptibility of Enterobacterales and P.aeruginosa to colistin in clinical laboratories.For A.baumannii,EA of 87.5%between CBDE and BMD does not satisfy the acceptance criteria of≥90%.CAT is recommended for testing the susceptibility of A.baumannii to colistin.