Pediatr Infect Dis J. 2018 Feb;37(2):153-156. doi: 10.1097/INF.0000000000001772.
The widespread uptake of pneumococcal vaccines has substantially reduced the incidence of invasive pneumococcal disease, such that pneumococcal bacteremia in children is now considered a relatively rare event. The objective of this study was to ascertain the clinical utility of a Streptococcus pneumoniae real-time polymerase chain reaction (PCR) assay compared with standard blood culture for the diagnosis of pneumococcal bacteremia in children in the post-vaccine era.
A systematic retrospective review of laboratory and patient records from Children's University Hospital, Temple Street, during a 6-year period was performed. Paired blood PCR and blood culture specimens from children younger than 16 years of age were investigated. Statistical analysis was performed to measure the diagnostic accuracy of PCR versus routine bacterial culture techniques.
More than 1900 PCR test requests were examined from 2010 to 2015, of which 1561 paired PCR and blood culture specimens met criteria for inclusion in the statistical analysis. The PCR assay demonstrated high specificity (99%, confidence interval 95%: 98.81%-99.69%); however, the sensitivity was low compared with that of blood culture (47%, confidence interval 95%: 21.27%-73.41%). Investigation of 10 PCR-positive/culture-negative cases revealed that these cases ranged from definite, probable, and possible significance, indicating a low false positivity rate associated with the assay.
This study demonstrates the limited utility of blood PCR testing for S. pneumoniae in pediatric patients without radiographic evidence pneumonia or empyema. Moreover, we report that PCR may be a useful diagnostic tool when blood cultures are negative because of antimicrobial therapy before sampling. Given that the incidence of pneumococcal disease has decreased considerably in recent years, justification of S. pneumoniae PCR requisition is necessary. Hence, new guidelines for pediatric pneumococcal blood PCR testing have been introduced at the Irish Meningitis and Sepsis Reference Laboratory.
肺炎球菌疫苗的广泛应用大大降低了侵袭性肺炎球菌病的发病率，以至于儿童中肺炎球菌菌血症现在被认为是一种相对罕见的事件。本研究的目的是确定肺炎链球菌实时聚合酶链反应（PCR）检测与标准血培养相比，在疫苗接种后时代诊断儿童肺炎球菌菌血症的临床实用性。
对 6 年来都柏林圣三一儿童医院的实验室和患者记录进行了系统的回顾性审查。研究了年龄在 16 岁以下的儿童的配对血 PCR 和血培养标本。统计分析用于测量 PCR 与常规细菌培养技术的诊断准确性。
在 2010 年至 2015 年期间，检查了超过 1900 次 PCR 检测请求，其中 1561 次 PCR 和血培养配对标本符合纳入统计分析的标准。该 PCR 检测法显示出很高的特异性（99%，置信区间 95%：98.81%-99.69%）；然而，与血培养相比，敏感性较低（47%，置信区间 95%：21.27%-73.41%）。对 10 例 PCR 阳性/培养阴性的病例进行调查发现，这些病例的意义从明确、可能到可能，表明该检测的假阳性率较低。
本研究表明，在没有放射影像学证据肺炎或积脓的儿科患者中，血液 PCR 检测对 S. pneumoniae 的应用有限。此外，我们报告说，由于在采样前进行了抗菌治疗，当血培养为阴性时，PCR 可能是一种有用的诊断工具。鉴于近年来肺炎球菌病的发病率已大大降低，有必要对 S. pneumoniae PCR 申请进行正当化。因此，爱尔兰脑膜炎和败血症参考实验室引入了儿科肺炎球菌血 PCR 检测的新指南。
