Ivagnes Vittorio, De Maio Flavio, Baccani Ilaria, Antonelli Alberto, Menchinelli Giulia, Rosato Roberto, Cafaro Giordana, Santarelli Giulia, Falletta Federico, D'Inzeo Tiziana, Sanguinetti Maurizio, Spanu Teresa, De Angelis Giulia, Rossolini Gian Maria, Posteraro Brunella
Dipartimento di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Università Cattolica del Sacro Cuore, Rome, Italy.
Dipartimento di Scienze di Laboratorio ed Ematologiche, Fondazione Policlinico Universitario A. Gemelli Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rome, Italy.
Front Cell Infect Microbiol. 2025 Jun 3;15:1597700. doi: 10.3389/fcimb.2025.1597700. eCollection 2025.
Accurate detection of β-lactam resistance genes in bloodstream infections is critical for guiding antimicrobial therapy. This study evaluates the Alifax Gram-negative resistance (GNR) microchip assay for detecting β-lactam resistance genes directly from positive blood cultures (PBCs) for Gram-negative (GN) bacteria, including Enterobacterales, , and .
Simulated (n=146) and clinical (n=106) GN-PBC samples were tested for , , , , -like, -like, -ESBL, group, and -like genes using the GNR microchip assay. Whole-genome sequencing (WGS) served as the reference assay for simulated samples and, selectively, for clinical samples. The bioMérieux BioFire Blood Culture Identification 2 (BCID2) panel assay was used as a comparator for clinical samples.
The GNR microchip assay correctly identified 203 (99.5%) of 204 β-lactam resistance genes in simulated samples. One sample tested false negative for a -ESBL gene but true positive for a gene. In clinical samples, GNR results were concordant with BCID2 for 113 (100%) of 113 genes included in both assays. Additionally, the GNR assay detected bla -like (n=6), -like (n=5), and -ESBL (n=2), which are not targeted by BCID2, all confirmed by WGS. In two β-lactam-resistant samples but negative by the GNR assay, WGS confirmed the absence of acquired β-lactam resistance genes, suggesting alternative resistance mechanisms.
The GNR microchip assay demonstrated high concordance and broader β-lactam resistance gene coverage compared to BCID2, supporting its potential role in routine diagnostics. Further validation in larger, prospective studies is warranted.
准确检测血流感染中的β-内酰胺抗性基因对于指导抗菌治疗至关重要。本研究评估了Alifax革兰氏阴性菌抗性（GNR）微芯片检测法，用于直接从革兰氏阴性（GN）菌的阳性血培养物（PBC）中检测β-内酰胺抗性基因，包括肠杆菌科细菌、 、 和 。
使用GNR微芯片检测法对模拟（n = 146）和临床（n = 106）GN-PBC样本进行 、 、 、 、 样、 样、 型超广谱β-内酰胺酶（ESBL）、 组和 样基因检测。全基因组测序（WGS）用作模拟样本以及部分临床样本的参考检测方法。生物梅里埃公司的BioFire血培养鉴定2（BCID2）检测板检测法用作临床样本的比较方法。
GNR微芯片检测法在模拟样本中正确鉴定出204个β-内酰胺抗性基因中的203个（99.5%）。一个样本对 型ESBL基因检测为假阴性，但对 基因检测为真阳性。在临床样本中，GNR检测结果与BCID2对两种检测法均包含的113个基因中的113个（100%）一致。此外，GNR检测法检测到BCID2未靶向的bla 样（n = 6）、 样（n = 5）和 型ESBL（n = 2）基因，所有这些均经WGS确认。在两个对β-内酰胺耐药的 样本中，GNR检测法结果为阴性，但WGS确认不存在获得性β-内酰胺抗性基因，提示存在其他耐药机制。
与BCID2相比，GNR微芯片检测法显示出高度一致性和更广泛的β-内酰胺抗性基因覆盖范围，支持其在常规诊断中的潜在作用。有必要在更大规模的前瞻性研究中进行进一步验证。
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