Cui Wenjie, Lu Rongqi, Huang Shaolong, Ma Ruirui, Wang Qing, Liu Yali
Department of Laboratory Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
Department of Laboratory Medicine, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing University, Nanjing, China.
J Antimicrob Chemother. 2025 Sep 3;80(9):2530-2540. doi: 10.1093/jac/dkaf264.
Evaluate the performance of broth microdilution (BMD) and gradient diffusion (Etest) methods in anti-microbial susceptibility testing (AST) of Burkholderia cepacia complex (BCC) isolates, with a particular focus on the impact of transitioning from CLSI MIC breakpoints to epidemiological cut-off values (ECVs) in the 2025 guidelines.
A total of 90 clinical BCC isolates were collected and identified to the species-level using MALDI-TOF mass spectrometry. AST was performed using BMD and Etest for minocycline, meropenem, trimethoprim-sulfamethoxazole, ceftazidime and levofloxacin. Results were interpreted using 2024 MIC breakpoints and re-analysed with 2025 ECVs. Categorical agreement (CA), essential agreement (EA) and classification errors (VME, ME, MI, WT-ME and NWT-VME) were calculated. In addition, species-stratified analysis was also conducted and medical records of 44 patients were reviewed to assess the correlation between in vitro susceptibility and clinical outcomes.
Under CLSI 2024 MIC breakpoints, CA between Etest and BMD varied, highest for trimethoprim-sulfamethoxazole (94.4%) and lowest for meropenem (12.2%). EA for all agents was below the 90% threshold. Using CLSI 2025 ECVs, CA improved for all agents except trimethoprim-sulfamethoxazole, but error rates remained unacceptable for all except minocycline. Species-specific resistance patterns were observed. Among 44 clinical cases, only 40.9% showed concordance between in vitro susceptibility and treatment outcomes.
Although the adoption of ECVs improved CA for some agents, MIC-level discrepancies between Etest and BMD persisted. Species-specific resistance patterns and the low concordance with clinical outcomes (40.9%) highlight the limitations of AST alone in guiding BCC treatment decisions.
评估肉汤微量稀释法（BMD）和梯度扩散法（Etest）在洋葱伯克霍尔德菌复合体（BCC）分离株抗菌药物敏感性试验（AST）中的性能，特别关注2025年指南中从临床和实验室标准研究所（CLSI）的最低抑菌浓度（MIC）断点转换为流行病学截断值（ECV）的影响。
共收集90株临床BCC分离株，使用基质辅助激光解吸电离飞行时间质谱（MALDI-TOF）进行种水平鉴定。采用BMD和Etest对米诺环素、美罗培南、复方磺胺甲恶唑、头孢他啶和左氧氟沙星进行AST。结果根据2024年MIC断点进行解释，并使用2025年ECV重新分析。计算分类一致性（CA）、基本一致性（EA）和分类错误（VME、ME、MI、WT-ME和NWT-VME）。此外，还进行了种属分层分析，并回顾了44例患者的病历，以评估体外药敏与临床结局之间的相关性。
在CLSI 2024年MIC断点下，Etest和BMD之间的CA各不相同，复方磺胺甲恶唑最高（94.4%），美罗培南最低（12.2%）。所有药物的EA均低于90%阈值。使用CLSI 2025年ECV，除复方磺胺甲恶唑外，所有药物的CA均有所改善，但除米诺环素外，所有药物的错误率仍然不可接受。观察到种属特异性耐药模式。在44例临床病例中，只有40.9%的病例显示体外药敏与治疗结局一致。
虽然采用ECV改善了某些药物的CA，但Etest和BMD之间的MIC水平差异仍然存在。种属特异性耐药模式以及与临床结局的低一致性（40.9%）突出了单独使用AST指导BCC治疗决策的局限性。
