评价一种实时 PCR 检测方法，用于检测和定量怀疑患有晚发性败血症的早产儿血液中的细菌 DNA。
Evaluation of a real-time PCR assay for detection and quantification of bacterial DNA directly in blood of preterm neonates with suspected late-onset sepsis.
机构信息
Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1117, 1081HV, Amsterdam, The Netherlands.
Department of Pediatrics, VU University Medical Center, De Boelelaan 1117, 1081HV, Amsterdam, The Netherlands.
出版信息
Crit Care. 2018 Apr 22;22(1):105. doi: 10.1186/s13054-018-2010-4.
BACKGROUND
Rapid and accurate diagnosis of neonatal sepsis is highly warranted because of high associated morbidity and mortality. The aim of this study was to evaluate the performance of a novel multiplex PCR assay for diagnosis of late-onset sepsis and to investigate the value of bacterial DNA load (BDL) determination as a measure of infection severity.
METHODS
This cross-sectional study was conducted in a neonatal intensive care unit. Preterm and/or very low birth weight infants suspected for late-onset sepsis were included. Upon suspicion of sepsis, a whole blood sample was drawn for multiplex PCR to detect the eight most common bacteria causing neonatal sepsis, as well as for blood culture. BDL was determined in episodes with a positive multiplex PCR.
RESULTS
In total, 91 episodes of suspected sepsis were investigated, and PCR was positive in 53 (58%) and blood culture in 60 (66%) episodes, yielding no significant difference in detection rate (p = 0.17). Multiplex PCR showed a sensitivity of 77%, specificity of 81%, positive predictive value of 87%, and negative predictive value of 68% compared with blood culture. Episodes with discordant results of PCR and blood culture included mainly detection of coagulase-negative staphylococci (CoNS). C-reactive protein (CRP) level and immature to total neutrophil (I/T) ratio were lower in these episodes, indicating less severe disease or even contamination. Median BDL was high (4.1 log cfu Eq/ml) with a wide range, and was it higher in episodes with a positive blood culture than in those with a negative blood culture (4.5 versus 2.5 log cfu Eq/ml; p < 0.0001). For CoNS infection episodes BDL and CRP were positively associated (p = 0.004), and for Staphylococcus aureus infection episodes there was a positive association between BDL and I/T ratio (p = 0.049).
CONCLUSIONS
Multiplex PCR provides a powerful assay to enhance rapid identification of the causative pathogen in late-onset sepsis. BDL measurement may be a useful indicator of severity of infection.
背景
由于新生儿败血症相关的高发病率和死亡率，快速准确的诊断是非常必要的。本研究旨在评估一种新型多重 PCR 检测方法对晚发性败血症的诊断性能，并探讨细菌 DNA 载量（BDL）测定作为感染严重程度的衡量标准的价值。
方法
本横断面研究在新生儿重症监护病房进行。纳入疑似晚发性败血症的早产儿和/或极低出生体重儿。怀疑败血症时，采集全血进行多重 PCR 检测以检测引起新生儿败血症的八种最常见细菌，同时进行血培养。在多重 PCR 阳性的发作中确定 BDL。
结果
共调查了 91 例疑似败血症的发作，PCR 阳性 53 例（58%），血培养阳性 60 例（66%），检测率无显著差异（p=0.17）。与血培养相比，多重 PCR 的敏感性为 77%，特异性为 81%，阳性预测值为 87%，阴性预测值为 68%。PCR 和血培养结果不一致的发作主要包括凝固酶阴性葡萄球菌（CoNS）的检测。这些发作中的 C 反应蛋白（CRP）水平和未成熟中性粒细胞与总中性粒细胞（I/T）比值较低，表明疾病较轻甚至污染。中位 BDL 较高（4.1log cfuEq/ml），范围较宽，血培养阳性的发作中 BDL 高于血培养阴性的发作（4.5 与 2.5 log cfuEq/ml；p<0.0001）。对于 CoNS 感染发作，BDL 与 CRP 呈正相关（p=0.004），对于金黄色葡萄球菌感染发作，BDL 与 I/T 比值呈正相关（p=0.049）。
结论
多重 PCR 提供了一种强大的检测方法，可增强对晚发性败血症病原体的快速鉴定。BDL 测量可能是感染严重程度的有用指标。
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