VITEK-2Compact高级专家系统检测肠杆菌科碳青霉烯酶的性能评价

Performance evaluation of VITEK-2 Compact advanced expert system detecting carbapenemase in Enterobacteriaceae

目的评价VITEK-2Compact仪器高级专家系统(Advanced expert system,AES)检测肠杆菌科碳青霉烯酶的性能,探讨AES在早期诊断产碳青霉烯酶肠杆菌科细菌中的应用价值。方法以VITEK-2Compact全自动细菌鉴定和药敏系统进行细菌鉴定和药敏试验,筛选2010-2012年非重复临床分离的碳青霉烯类药物敏感性降低的肠杆菌科细菌,PCR检测碳青霉烯酶blaKPC、blaIMP、blaVIM、blaOXA-48及blaNDM-1基因型,阳性结果进行测序并Blast比对确定基因型,以基因测序结果为金标准,分析统计VITEK-2Compact仪器AES检测肠杆菌科碳青霉烯酶的各项性能指标。结果试验共收集62株碳青霉烯类敏感性降低的肠杆菌科细菌,包括肺炎克雷伯菌、阴沟肠杆菌、大肠埃希菌、产酸克雷伯菌,分别占67.74%、19.36%、8.06%、4.84%;AES检测碳青霉烯酶阳性共58株,其中肺炎克雷伯菌、阴沟肠杆菌、大肠埃希菌、产酸克雷伯菌,分别占68.97%、18.97%、6.89%、5.17%;经PCR扩增并测序证实27株为产IMP-4型基因菌株,包括肺炎克雷伯菌21株、阴沟肠杆菌4株、产酸克雷伯菌2株、20株为产IMP-8型基因菌株,包括肺炎克雷伯菌10株、阴沟肠杆菌6株、大肠埃希菌3株、产酸克雷伯菌1株,其他15株为碳青霉烯酶阴性菌株;AES检测肠杆菌科碳青霉烯酶的灵敏度为100.00%、特异性为26.67%,阳性预测值为81.03%、阴性预测值为100.00%,检验效能为82.26%。结论 VITEK-2Compact仪器AES检测肠杆菌科碳青霉烯酶具有良好的灵敏度,临床微生物实验室应将检测信息第一时间提供给临床科室,以便及时采取隔离防护措施。

OBJECTIVE To evaluate the performance of VITEK-2 Compact advanced expert system （AES） for the detection of carbapenemase in Enterobacteriaceae, and to investigate the application value of AES on early diagnosis of Enterobacteriaceae that produces carbapenemase. METHODS The bacterial identification and antibiotic susceptibility tests were performed by VITEK-2 Compact automated system. The non-repetitive clinical isolates of Enterobacteriaceae with reduced susceptibility to carbapenems were selected between 2010 and 2012. The blaK- PC, blalMP, blaVIM, blaOXA-48 and blaNDM-1 genes were amplified by PCR, then positive results were sequenced and blasted to determine genotypes. Since the results of gene sequencing were regarded as the gold standard, the performance index of VITEK-2 Compact AES for the detection of carbapenemase in Enterobacteri- aceae was calculated based on sequencing result. RESULTS Sixty-two E,lterobacteriaceae with reduced susceptibility to carbapenems were collected, including Klebsiella pneumoniae （67. 74%）, Enterobacter cloacae （19. 36%）, Esc[~erichia coli （8. 06%） and Klesbsiella oxytoca （4. 84%）. Fifty-eight Enterobacteriaceae were detected positive with AES, including K. pneurnoniae （68.97%）, E. cloacae （18.97%）, E. coli （6.89%） and K. oxytoca （5. 17%）. The 27 IMP-4 carbapenemase producing isolates were confirmed by PCR amplificationand sequencing, including 21 K. pneumoniae, 4 E. cloacae and 2 K. oxytoca. The 20 IMP-8 carbapenemase producing isolates included by l0 K. pneurnoniae, 6 E. cloacae, 3 E. coli and 1 K. oxytoca, and the other 15 isolates were confirmed to be carbapenemase-negative strains. The sensitivity, specificity, positive predictive value, negative predictive value and test power of AES were 100.0%, 26.67%, 81.03% 100.0%, 82. 26% for the detection of carbapenemase in Enterobacteriaceae. CONCLUSION The VITEK-2 Compact AES reveals great sensitivity for detection o[ carbapenemase in Enterobacteriaceae, and the clinical microbiology laboratory should provide detection in{ormation to clinical departments at the lirst time in order to carry out isolation precautions timely.