快速筛查革兰阴性杆菌β内酰胺酶

目的应用Cica-Beta-Test试剂盒快速筛查革兰阴性杆菌β内酰胺酶:超广谱β内酰胺酶(ESBILs)、金属β内酰胺酶(MBLs)和染色体介导头孢菌素酶(AmpC酶),为临床抗感染治疗提供耐药依据。方法收集2010年1月至2011年3月上海交通大学医学院附属仁济医院临床分离革兰阴性杆菌共110株,其中头孢噻肟和(或)头孢他啶不敏感大肠埃希菌、肺炎克雷伯菌和奇异变形杆菌各20株,多重耐药鲍曼不动杆菌20株和阴沟肠杆菌30株。其中大肠埃希菌、肺炎克雷伯菌和奇异变形杆菌用美国CLSI推荐方法确证产ESBLs;对鲍曼不动杆菌用聚合酶链反应(PCR)法检测其MBLs和AmpC酶耐药基因;对阴沟肠杆菌用表型筛选法(三维试验法)检测其AmpC酶;对所有菌株应用Cica-Beta-Test试剂盒快速筛查ESBLs、MBLs和AmpC酶。根据检测结果对试剂盒进行评估。结果应用Cica-Beta-Test试剂盒检测110株临床分离菌未发现假阳性,确诊试验总符合率为92.0%(92/100),其中与PCR法比较检测MBLs和AmpC酶结果符合率为100%;与CLSI推荐ESBLs双纸片确诊试验比较,符合率为86.7%(52/60)。30株阴沟肠杆菌用AmpC酶表型筛选法比较符合率为86.7%(26/30)。结论 Cica-Beta-Test试剂盒可对各种革兰阴性杆菌产生的β内酰胺酶进行筛查及初步分型,简便、快速,灵敏度高,准确率高,尤其能对CLSI未推荐方法的耐药革兰阴性杆菌进行β内酰胺酶快速筛查意义更大。

Quick screening test of beta-lactamase in gram-negative bacilli

Objective To screen and differentiate the various beta-lactamases produced by gram-negative bacilli using a novel kit (Cica-Beta Test) and to provide reference for clinical antimicrobial therapy.Methods A total of 110 clinical strains of gram-negative bacilli were collected from Renji Hospital from January 2010 to March 2011,of which there were 20 strains of Escherichia coli,Klebsiella pneumoniae and Proteus mirabilis each.All of these strains were not sensitive to cefotaxime and/or ceftazidime. There were also 20 strains of multiple resistant Acinetobacter baumannii and 30 strains of Enterobacter cloacae.Extended -spectrum beta-lactamases(ESBLs) produced by Escherichia coli,Klebsiella pneumoniae and Proteus mirabilis were determined by the method recommended by the Clinical and Laboratory Standards Institute(CLSI).Metallo-beta-lactamases and AmpC beta-lactamases genes were detected by PCR in Acinetobacter baumannii.We used phenotype screening method(threedimensional method) to identify the AmpC beta-lactamases produced by Enterobacter cloacae.Cica-Beta-Test kit was applied to all the strains as a quick screening test of ESBLs,MBLs and AmpC beta-lactamases.We evaluated the novel kit according to the results.Results No false-positive result was found by the application of Cica-Beta-Test.The overall agreement rate with the final confirmation test was 92%(92/100) while the agreement with PCR was 100%in the detection of MBLs and AmpC betalactamases. The agreement of Cica-Beta-Test result with the ESBLs double disc diffusion method recommended by the CLSI was 86.7%(52/60).The agreement with the phenotype screening method was 86.7%(26/30) in the detection of AmpC betalactamases in the 30 strains of Enterobacter cloacae.Conclusions The Cica-Beta-Test kit is a convenient,quick,highly sensitive and accurate method compared to traditional methods in terms of rapid identifying and differentiating a range of beta-lactamas- ??es,especially for rapid screening of beta-lactamases in the resistant strains of gram-negative bacilli for which no reference method is available from CLSI.