BC-GN 快速检测血培养革兰阴性菌及相应耐药基因

Rapid identification of gram-negative bacteria and corresponding resistance determinants from blood cultures by BC-GN assay

目的 评估Verigene革兰阴性血培养（ BC-GN）核酸检测方法对革兰阴性菌及其耐药基因的检测性能和临床实用性. 方法 收集2013年6月—10月浙江大学医学院附属第二医院住院患者非重复革兰阴性菌血培养标本,用BC-GN直接进行菌种鉴定和耐药基因检测,同时以VITEK MS的鉴定、VITEK2 Compact的药物敏感性试验为金标准,PCR和测序方法验证耐药基因,比较BC-GN和常规方法检测结果和时间的差异. 结果 BC-GN的检测范围覆盖临床常见菌,其对大肠埃希菌（13/13）、肺炎克雷伯菌（19/24）、产酸克雷伯菌（9/9）、铜绿假单胞菌（39/39）、黏质沙雷菌（4/5）、肠杆菌属（6/8）、枸橼酸杆菌属（11/11）、变形杆菌属（6/6）、不动杆菌属（24/24）的鉴定均有高准确率,对单一菌感染标本总的准确率高达94.24%;对于2份混合菌感染的标本,BC-GN准确鉴定所有菌种和耐药基因. BC-GN检测比常规方法的鉴定和药物敏感性试验提前42 h获得菌株鉴定和耐药信息.结论 BC-GN在2 h内完成菌株鉴定和耐药基因检测,快速准确,可为临床争取更多有效治疗时间,降低血流感染死亡率.

Objective To evaluate the performance and clinical utility of Verigene gram-negative blood culture （ BC-GN ） assay for a rapid identification of gram-negative bacteria and resistance genes . Methods Non-repetitive blood culture samples containing gram-negative bacteria were collected from inpa-tients in the Second Affiliated Hospital of Zhejiang University School of Medicine from June to October , 2013 .BC-GN assay was performed to identify the species and genetic resistance determinants of gram -nega-tive bacteria directly from the positive blood culture bottles .VITEK MS and the VITEK 2 Compact were used for species identification and antimicrobial susceptibility test , the results of which were considered as gold standards.The resistance genes were further validated by PCR amplification and sequencing analysis .A comparison of the results and time between the BC-GN assay and routine methods was conducted . Results The detection range of BC-GN assay almost covered all of the common gram-negative bacteria .BC-GN assay showed an advantage of high accuracy in the identification of Escherichia coli （13/13）, Klebsiella pneumoniae （19/24）, Klebsiella oxytoca （9/9）, Pseudomonas aeruginosa （39/39）, Serratia marcescens （4/5）, Enterobacter spp.（6/8）, Citrobacter spp.（11/11）, Proteus spp.（6/6） and Acinetobacter spp. （24/24） with an overall accuracy of 94.24%for the identification of mono-microbial blood culture samples . Moreover , BC-GN assay accurately identified all of the bacteria and resistance genes from the two multi -mi-crobial samples .Species identification and resistance profiles could be 42 hours earlier available by using BC-GN assay than those by using routine methods .Conclusion BC-GN assay could simultaneously and ac-curately identify bacteria and resistance determinants from blood cultures within 2 hours.More time for clini-cally effective therapy could be achieved by using BC-GN assay for the reduction of mortality associated with bloodstream infection .