Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.
Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy; Microbiology and Virology Unit, Careggi University Hospital, Florence, Italy.
Diagn Microbiol Infect Dis. 2024 Sep;110(1):116436. doi: 10.1016/j.diagmicrobio.2024.116436. Epub 2024 Jul 11.
Antimicrobial susceptibility testing (AST) from blood culture (BC) may take several days, limiting the eventual impact on antimicrobial stewardship. Hence, rapid AST systems represent a valuable support in shorting the time-to-response. In this work, the Quantamatrix dRAST system (dRAST) was evaluated for rapid AST on 100 monomicrobial BCs (50 Gram-negatives and 50 Gram-positives), including several isolates with clinically relevant resistance mechanisms. AST results were provided in 6-hours, on average. Compared to Micronaut (Merlin) system based on broth microdilution, dRAST exhibited an overall categorical agreement of 92.5 %, essential agreement of 89.0 %, and mean bias of 15.9 %. Category overestimation (potentially leading to unnecessary high-dosage treatment or to exclude active agents) and category underestimation (potentially leading to underdosing or using ineffective agents) were observed in 4.3 % and 3.1 % of cases, respectively. Even though several issues were reported, results confirmed the potential contribution of dRAST to shorten the BCs clinical microbiology workflow and management.
血培养（BC）的抗菌药物敏感性测试（AST）可能需要数天时间，这限制了其对抗菌药物管理的最终影响。因此，快速 AST 系统在缩短反应时间方面具有重要的支持作用。在这项工作中，评估了 Quantamatrix dRAST 系统（dRAST）对 100 株单一致病菌 BC（50 株革兰氏阴性菌和 50 株革兰氏阳性菌）的快速 AST，包括几种具有临床相关耐药机制的分离株。AST 结果平均在 6 小时内提供。与基于肉汤微量稀释的 Micronaut（Merlin）系统相比，dRAST 的总体分类一致性为 92.5%，基本一致性为 89.0%，平均偏差为 15.9%。分别有 4.3%和 3.1%的病例出现了分类高估（可能导致不必要的高剂量治疗或排除有效药物）和分类低估（可能导致剂量不足或使用无效药物）。尽管报告了一些问题，但结果证实了 dRAST 有潜力缩短 BC 临床微生物学工作流程和管理。
