儿童癌症患者中性粒细胞减少性发热期菌血症的诊断：微生物学和分子方法。

Diagnosis of bacteremia in febrile neutropenic episodes in children with cancer: microbiologic and molecular approach.

机构信息

Department of Pediatrics, Hospital L. Calvo Mackenna, Faculty of Medicine, Universidad de Chile, Santiago, Chile.

出版信息

Pediatr Infect Dis J. 2011 Nov;30(11):957-61. doi: 10.1097/INF.0b013e31822a37d7.

DOI:10.1097/INF.0b013e31822a37d7

PMID:21768922

Abstract

BACKGROUND

Bacterial isolation using conventional microbiologic techniques rarely surpasses 25% in children with clinical and laboratory findings indicative of an invasive bacterial infection. The aim of this study was to determine the role of real-time polymerase chain reaction (RT-PCR) from whole blood samples compared with automated blood cultures (BC) in detection of relevant microorganisms causing bacteremia in episodes of high-risk febrile neutropenia (HRFN) in children with cancer.

METHODS

Children presenting with HRFN at 6 hospitals in Santiago, Chile, were invited to participate. Blood samples were obtained at admission for BC, and at admission and 24 hours for RT-PCR targeting DNA of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa causing bacteremia in children with HRFN.

RESULTS

A total of 177 HRFN episodes were evaluated from May 2009 to August 2010, of which 29 (16.3%) had positive BC, 9 (5%) positive for 1 of the 3 selected bacterial species: 5 for E. coli, 3 for S. aureus, and 1 for P. aeruginosa. RT-PCR detected 39 bacteria in 36 episodes (20%): 14 E. coli, 20 S. aureus, and 5 P. aeruginosa. The sensitivity, specificity, and positive and negative predictive values of RT-PCR compared with BC were 56%, 80%, 13%, and 97%. The final clinical diagnosis was compatible with an invasive bacterial infection in 30/36 (83%) RT-PCR-positive episodes.

CONCLUSIONS

In our series, RT-PCR significantly improved detection of the most relevant bacteria associated with HRFN episodes. Large number of patients and close clinical monitoring, in addition to improved RT-PCR techniques will be required to fully recommend RT-PCR-based diagnosis for the routine workup of children with cancer, fever, and neutropenia.

摘要

背景

使用传统微生物学技术进行细菌分离，在临床和实验室检查提示有侵袭性细菌感染的儿童中，其阳性率很少超过 25%。本研究旨在确定实时聚合酶链反应（RT-PCR）与自动血培养（BC）相比，在检测导致癌症患儿高危发热性中性粒细胞减少症（HRFN）发作时菌血症的相关微生物中的作用。

方法

邀请智利圣地亚哥的 6 家医院出现 HRFN 的患儿参加。在入院时采集 BC 血样，在入院时和 24 小时时采集针对引起 HRFN 患儿菌血症的大肠杆菌、金黄色葡萄球菌和铜绿假单胞菌 DNA 的 RT-PCR 血样。

结果

2009 年 5 月至 2010 年 8 月，共评估了 177 例 HRFN 发作，其中 29 例（16.3%）BC 阳性，9 例（5%）3 种选定细菌中的 1 种阳性：5 例为大肠杆菌，3 例为金黄色葡萄球菌，1 例为铜绿假单胞菌。RT-PCR 在 36 个发作中检测到 39 个细菌（20%）：14 个大肠杆菌，20 个金黄色葡萄球菌，5 个铜绿假单胞菌。与 BC 相比，RT-PCR 的敏感性、特异性、阳性和阴性预测值分别为 56%、80%、13%和 97%。36 例 RT-PCR 阳性发作中，30 例（83%）最终临床诊断为侵袭性细菌感染。