与培养法相比，对尼日利亚发热儿童干血斑进行肺炎链球菌的分子检测
Molecular Detection of Streptococcus pneumoniae on Dried Blood Spots from Febrile Nigerian Children Compared to Culture.
作者信息
Iroh Tam Pui-Ying, Hernandez-Alvarado Nelmary, Schleiss Mark R, Hassan-Hanga Fatimah, Onuchukwu Chuma, Umoru Dominic, Obaro Stephen K
机构信息
Division of Pediatric Infectious Diseases and Immunology, University of Minnesota Masonic Children's Hospital, Minneapolis, Minnesota, United States of America.
Center for Infectious Diseases, Microbiology and Translational Research, Minneapolis, Minnesota, United States of America.
出版信息
PLoS One. 2016 Mar 23;11(3):e0152253. doi: 10.1371/journal.pone.0152253. eCollection 2016.
BACKGROUND
Nigeria has one of the highest burdens of pneumococcal disease in the world, but accurate surveillance is lacking. Molecular detection of infectious pathogens in dried blood spots (DBS) is an ideal method for surveillance of infections in resource-limited settings because of its low cost, minimal blood volumes involved, and ease of storage at ambient temperature. Our study aim was to evaluate a Streptococcus pneumoniae real-time polymerase chain reaction (rt-PCR) assay on DBS from febrile Nigerian children on Whatman 903 and FTA filter papers, compared to the gold standard of culture.
METHODS
Between September 2011 to May 2015, blood was collected from children 5 years of age or under who presented to six hospital study sites throughout northern and central Nigeria with febrile illness, and inoculated into blood culture bottles or spotted onto Whatman 903 or FTA filter paper. Culture and rt-PCR were performed on all samples.
RESULTS
A total of 537 DBS specimens from 535 children were included in the study, of which 15 were culture-positive for S. pneumoniae. The rt-PCR assay detected S. pneumoniae in 12 DBS specimens (2.2%). One positive rt-PCR result was identified in a culture-negative specimen from a high-risk subject, and two positive rt-PCR results were negative on repeat testing. Six culture-confirmed cases of S. pneumoniae bacteremia were missed. Compared to culture, the overall sensitivities of Whatman 903 and FTA DBS for detection of S. pneumoniae were 57.1% (95% CI 18.4-90.1%) and 62.5% (95% CI 24.5-91.5%), respectively. Nonspecific amplification was noted in an additional 22 DBS (4.1%). Among these, six were positive for a non-S. pneumoniae pathogen on culture.
CONCLUSIONS
Rt-PCR was able to detect S. pneumoniae from clinical DBS specimens, including from a culture-negative specimen. Our findings show promise of this approach as a surveillance diagnostic, but also raise important cautionary questions. Several DBS specimens were detected as S. pneumoniae by rt-PCR despite growth of a non-S. pneumoniae pathogen on culture. A precise definition of what constitutes a positive result is required to avoid falsely over-identifying specimens.
背景
尼日利亚是世界上肺炎球菌疾病负担最高的国家之一，但缺乏准确的监测。由于成本低、所需血量少且易于在室温下储存，干血斑（DBS）中感染病原体的分子检测是在资源有限环境中监测感染的理想方法。我们的研究目的是评估在Whatman 903和FTA滤纸上对尼日利亚发热儿童的DBS进行肺炎链球菌实时聚合酶链反应（rt-PCR）检测，并与培养的金标准进行比较。
方法
2011年9月至2015年5月期间，从尼日利亚北部和中部六个医院研究地点出现发热疾病的5岁及以下儿童中采集血液，接种到血培养瓶中或点样到Whatman 903或FTA滤纸上。对所有样本进行培养和rt-PCR检测。
结果
该研究共纳入了来自535名儿童的537份DBS标本，其中15份肺炎链球菌培养阳性。rt-PCR检测在12份DBS标本中检测到肺炎链球菌（2.2%）。在一名高危受试者的培养阴性标本中鉴定出一个rt-PCR阳性结果，两次重复检测中有两个rt-PCR阳性结果为阴性。漏检了6例培养确诊的肺炎链球菌菌血症病例。与培养相比，Whatman 903和FTA DBS检测肺炎链球菌的总体敏感性分别为57.1%（95%CI 18.4 - 90.1%）和62.5%（95%CI 24.5 - 91.5%）。在另外22份DBS中发现非特异性扩增（4.1%）。其中，6份在培养时对非肺炎链球菌病原体呈阳性。
结论
rt-PCR能够从临床DBS标本中检测到肺炎链球菌，包括来自培养阴性的标本。我们的研究结果显示了这种方法作为监测诊断方法的前景，但也提出了重要的警示问题。尽管培养时非肺炎链球菌病原体生长，但仍有几份DBS标本被rt-PCR检测为肺炎链球菌。需要对阳性结果的构成进行精确界定，以避免错误地过度鉴定标本。
Zotero 插件