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Abstract：
BACKGROUND: Rapid antimicrobial susceptibility testing (AST) for bloodstream infections (BSIs) facilitates the optimization of antimicrobial therapy, preventing antimicrobial resistance and improving patient outcomes. QMAC-dRAST (QuantaMatrix Inc., Korea) is a rapid AST platform based on microfluidic chip technology that performs AST directly using positive blood culture broth (PBCB). This study evaluated the performance of QMAC-dRAST for Gram-negative bacteria using PBCB and subcultured colony isolates, comparing it with that of VITEK 2 (bioMérieux, France) using broth microdilution (BMD) as the reference method.
METHODS: We included 141 Gram-negative blood culture isolates from patients with BSI and 12 carbapenemase-producing clinical isolates of Enterobacterales spiked into blood culture bottles. QMAC-dRAST performance was evaluated using PBCB and colony isolates, whereas VITEK 2 and BMD were tested only on colony isolates.
RESULTS: For PBCB, QMAC-dRAST achieved 92.1% categorical agreement (CA), 95.3% essential agreement (EA), with 1.8% very major errors (VMEs), 3.5% major errors (MEs), and 5.2% minor errors (mEs). With colony isolates, it exhibited 92.5% CA and 95.1% EA, with 2.0% VMEs, 3.2% MEs, and 4.8% mEs. VITEK 2 showed 94.1% CA and 96.0% EA, with 4.3% VMEs, 0.4% MEs, and 4.3% mEs. QMAC-dRAST yielded elevated error rates for specific antimicrobial agents, with high VMEs for carbapenems and aminoglycosides. The median time to result for QMAC-dRAST was 5.9 h for PBCB samples and 6.1 h for subcultured colony isolates.
CONCLUSIONS: The QMAC-dRAST system demonstrated considerable strengths and comparable performance to the VITEK 2 system; however, challenges were discerned with specific antimicrobial agents, underlining a necessity for improvement.
METHODS: We included 141 Gram-negative blood culture isolates from patients with BSI and 12 carbapenemase-producing clinical isolates of Enterobacterales spiked into blood culture bottles. QMAC-dRAST performance was evaluated using PBCB and colony isolates, whereas VITEK 2 and BMD were tested only on colony isolates.
RESULTS: For PBCB, QMAC-dRAST achieved 92.1% categorical agreement (CA), 95.3% essential agreement (EA), with 1.8% very major errors (VMEs), 3.5% major errors (MEs), and 5.2% minor errors (mEs). With colony isolates, it exhibited 92.5% CA and 95.1% EA, with 2.0% VMEs, 3.2% MEs, and 4.8% mEs. VITEK 2 showed 94.1% CA and 96.0% EA, with 4.3% VMEs, 0.4% MEs, and 4.3% mEs. QMAC-dRAST yielded elevated error rates for specific antimicrobial agents, with high VMEs for carbapenems and aminoglycosides. The median time to result for QMAC-dRAST was 5.9 h for PBCB samples and 6.1 h for subcultured colony isolates.
CONCLUSIONS: The QMAC-dRAST system demonstrated considerable strengths and comparable performance to the VITEK 2 system; however, challenges were discerned with specific antimicrobial agents, underlining a necessity for improvement.
摘要：
背景：血流感染（BSIs）的快速抗菌药物敏感性测试（AST）有助于优化抗菌治疗，预防抗菌素耐药性并改善患者预后。QMAC-dRAST(QuantaMatrixInc.，韩国）是基于微流控芯片技术的快速AST平台，直接使用阳性血培养肉汤（PBCB）进行AST。本研究使用PBCB和传代培养的菌落分离物评估了QMAC-dRAST对革兰氏阴性菌的性能，将其与VITEK2(bioMérieux，法国）使用肉汤微量稀释（BMD）作为参考方法。
方法：我们纳入了141个来自BSI患者的革兰氏阴性血培养分离株和12个产碳青霉烯酶的肠杆菌临床分离株，这些临床分离株被添加到血培养瓶中。使用PBCB和菌落分离物评估QMAC-dRAST性能，而VITEK2和BMD仅在菌落分离株上进行测试。
结果：对于PBCB，QMAC-dRAST达成了92.1%的分类协议(CA)，95.3%基本协议(EA)，1.8%的非常大错误(VME)，3.5%主要错误(ME)，和5.2%的小错误(mE)。有了菌落分离株，它表现出92.5%的CA和95.1%的EA，2.0%的中小微企业，3.2%的MEs，和4.8%的MEE。VITEK2显示94.1%CA和96.0%EA，4.3%的中小微企业，0.4%MEs，和4.3%的MES。QMAC-dRAST对特定的抗菌剂产生了较高的错误率，碳青霉烯类和氨基糖苷类具有较高的VME。PBCB样品获得QMAC-dRAST的中位时间为5.9h，传代培养的菌落分离株为6.1h。
结论：QMAC-dRAST系统表现出与VITEK2系统相当的优势和性能；然而，挑战被识别为特定的抗微生物剂，强调改进的必要性。
方法：我们纳入了141个来自BSI患者的革兰氏阴性血培养分离株和12个产碳青霉烯酶的肠杆菌临床分离株，这些临床分离株被添加到血培养瓶中。使用PBCB和菌落分离物评估QMAC-dRAST性能，而VITEK2和BMD仅在菌落分离株上进行测试。
结果：对于PBCB，QMAC-dRAST达成了92.1%的分类协议(CA)，95.3%基本协议(EA)，1.8%的非常大错误(VME)，3.5%主要错误(ME)，和5.2%的小错误(mE)。有了菌落分离株，它表现出92.5%的CA和95.1%的EA，2.0%的中小微企业，3.2%的MEs，和4.8%的MEE。VITEK2显示94.1%CA和96.0%EA，4.3%的中小微企业，0.4%MEs，和4.3%的MES。QMAC-dRAST对特定的抗菌剂产生了较高的错误率，碳青霉烯类和氨基糖苷类具有较高的VME。PBCB样品获得QMAC-dRAST的中位时间为5.9h，传代培养的菌落分离株为6.1h。
结论：QMAC-dRAST系统表现出与VITEK2系统相当的优势和性能；然而，挑战被识别为特定的抗微生物剂，强调改进的必要性。
