Infectious Diseases Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Policlinico di Sant'Orsola, Bologna, Italy; Department of Medical and Surgical Sciences, Alma Mater Studiorum University of Bologna, Bologna, Italy.
Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy; Microbiology and Virology Unit, Careggi University Hospital, Florence, Italy.
Clin Microbiol Infect. 2022 Sep;28(9):1290.e1-1290.e4. doi: 10.1016/j.cmi.2022.03.013. Epub 2022 Mar 17.
In this study we investigated the rate of susceptibility testing discrepancies between semi-automated and reference systems with carbapenem-resistant Enterobacterales (CRE) and the impact of alleged errors by semi-automated systems on guiding targeted therapy for CRE bloodstream infection (BSI).
This was a multicentre, retrospective study enrolling patients with monomicrobial BSI caused by CRE from January 2013 to December 2016. Nonduplicate isolates from index blood cultures tested locally with semi-automated systems were centralized at a referral laboratory and retested with a reference broth microdilution or agar dilution method.
We enrolled 366 patients with CRE-BSI; 220 (60%) were male, and the median age was 67 years (interquartile range, 54-76 years). When compared with the results of the reference methods, those of the semi-automated systems exhibited variable rates of very major errors (VMEs; i.e. false susceptibilities) and major errors (MEs; i.e. false resistances). The highest rates of VMEs were observed with fosfomycin (14%) and colistin (13.9%), and the highest rates of MEs were observed with gentamicin (21%), fosfomycin (7.7%), and tigecycline (34%). Overall, VMEs and MEs led clinicians to prescribe or confirm ineffective therapy in 25 of 341 patients (7%). Receipt of ineffective therapy supported by a misleading susceptibility test was associated with higher 30-day mortality rates by Kaplan-Meier survival curves rates compared with receipt of active therapy (56% vs. 26%; p = 0.002), and the difference was confirmed after adjustment for confounders in a Cox regression model (adjusted hazard ratio: 2.91; 95% CI, 1.62-5.22; p < 0.001).
MEs and VMEs were relatively common with semi-automated susceptibility testing systems. VMEs were associated with inappropriate use of antibiotics and poorer outcomes.
本研究旨在调查半自动化系统与碳青霉烯类耐药肠杆菌科（CRE）之间药敏试验差异的发生率，并评估半自动化系统假阳性结果对指导 CRE 血流感染（BSI）靶向治疗的影响。
这是一项多中心、回顾性研究，纳入 2013 年 1 月至 2016 年 12 月期间由 CRE 引起的单一致病菌血流感染患者。对当地半自动化系统检测的血培养指数非重复分离株进行集中，并在参考肉汤微量稀释或琼脂稀释法中进行重新检测。
我们共纳入 366 例 CRE-BSI 患者；220 例（60%）为男性，中位年龄为 67 岁（四分位间距，54-76 岁）。与参考方法相比，半自动化系统的检测结果存在不同程度的非常大误差（VME；即假敏感）和大误差（ME；即假耐药）。VME 发生率最高的是磷霉素（14%）和黏菌素（13.9%），ME 发生率最高的是庆大霉素（21%）、磷霉素（7.7%）和替加环素（34%）。总体而言，25 例（7%）341 例患者因 VME 和 ME 而接受或确认无效治疗。在 Kaplan-Meier 生存曲线中，接受误导性药敏试验支持的无效治疗的患者 30 天死亡率更高，与接受有效治疗的患者相比（56%比 26%；p=0.002），且在 Cox 回归模型中校正混杂因素后差异仍然存在（校正后的危险比：2.91；95%CI，1.62-5.22；p<0.001）。
半自动化药敏试验系统中 ME 和 VME 较为常见。VME 与抗生素不合理使用和较差的预后有关。
