Moore Nicholas M, Cantón Rafael, Carretto Edoardo, Peterson Lance R, Sautter Robert L, Traczewski Maria M
Departments of Pathology and Medical Laboratory Science, Rush University Medical Center, Chicago, Illinois, USA
Servicio de Microbiología, Hospital Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain.
J Clin Microbiol. 2017 Jul;55(7):2268-2275. doi: 10.1128/JCM.00137-17. Epub 2017 May 17.
Carbapenemase-producing organisms (CPO) have been identified by global health leaders as an urgent threat. Detection of patients with gastrointestinal carriage of CPO is necessary to interrupt their spread within health care facilities. In this multisite study, we assessed the performance of the Xpert Carba-R test, a rapid real-time quantitative PCR (qPCR) assay that detects five families of carbapenemase genes (, , , , and ) directly from rectal swab specimens. Using dual swabs, specimens from 755 patients were collected and tested prospectively. An additional 432 contrived specimens were prepared by seeding well-characterized carbapenem-susceptible and -nonsusceptible strains into a rectal swab matrix and inoculating them onto swabs prior to testing. Antimicrobial susceptibility testing, broth enriched culture, and DNA sequencing were performed by a central laboratory blind to the Xpert Carba-R results. The Xpert Carba-R assay demonstrated a positive percentage of agreement (PPA) between 60 and 100% for four targets (, , , and ) and a negative percentage of agreement (NPA) ranging between 98.9 and 99.9% relative to the reference method (culture and sequencing of any carbapenem-nonsusceptible isolate). There were no prospective -positive samples. Contrived specimens demonstrated a PPA between 95 and 100% and an NPA of 100% for all targets. Testing of rectal swabs directly using the Xpert Carba-R assay is effective for rapid detection and identification of CPO from hospitalized patients.
产碳青霉烯酶微生物（CPO）已被全球卫生领域的领导者认定为一种紧迫威胁。检测携带CPO的胃肠道患者对于阻断其在医疗机构内的传播至关重要。在这项多中心研究中，我们评估了Xpert Carba - R检测的性能，这是一种快速实时定量PCR（qPCR）检测方法，可直接从直肠拭子标本中检测五类碳青霉烯酶基因（、、、和）。我们使用双拭子前瞻性地收集并检测了755例患者的标本。另外还制备了432份人工标本，方法是将特征明确的对碳青霉烯敏感和不敏感的菌株接种到直肠拭子基质中，并在检测前将其接种到拭子上。由对Xpert Carba - R结果不知情的中央实验室进行抗菌药物敏感性检测、肉汤富集培养和DNA测序。相对于参考方法（对任何碳青霉烯不敏感分离株进行培养和测序），Xpert Carba - R检测对四个靶点（、、、和）的阳性百分一致率（PPA）在60%至100%之间，阴性百分一致率（NPA）在98.9%至99.9%之间。没有前瞻性阳性样本。人工标本对所有靶点的PPA在95%至100%之间，NPA为100%。直接使用Xpert Carba - R检测对直肠拭子进行检测对于从住院患者中快速检测和鉴定CPO是有效的。
