Department of Pediatrics, Division of Infectious Disease, McMaster University, Hamilton;
Department of Pathology and Laboratory Medicine, Division of Microbiology, University of Ottawa, Ottawa, Ontario.
Can J Infect Dis Med Microbiol. 2014 May;25(3):151-4. doi: 10.1155/2014/757963.
Community-acquired pneumonia (CAP) complicated by parapneumonic effusion/empyema is an infectious syndrome commonly encountered by physicians caring for children in Canada.
To investigate the incremental benefit of novel molecular testing for the microbiological diagnosis of pediatric CAP complicated by parapneumonic effusion/empyema in Canada.
A convenience sample of pleural fluid from 56 children who had been admitted to hospital in Ontario with CAP complicated by parapneumonic effusion between 2009 and 2011 was examined. Multiple uniplex real-time polymerase chain reaction (PCR) testing was performed on these pleural fluids and compared with traditional culture-based testing of blood and pleural fluid samples.
Molecular methods detected a pathogen in 82% of cases, whereas traditional cultures of blood and pleural fluids detected a pathogen in only 25%. The majority of parapneumonic effusions were associated with pneumococcal infection; Streptococcus pneumoniae was detected in 62% of the samples using molecular methods but in only 14% of samples using culture-based methods. Streptococcus pyogenes, detected in 16% of samples using PCR, was the second most common pathogen found. No patients were found to have empyema caused by Staphylococcus aureus.
The results showed that multiple uniplex real-time PCR performed substantially better than traditional culture methods for microbiological diagnosis of CAP complicated by effusion/ empyema. S pneumoniae and S pyogenes were found to be responsible for the majority of infections. The approach detected pathogens in a similar proportion of pleural fluid samples as previously reported nested PCR assays; furthermore, the real-time closed-well approach also minimized the risk of nonspecificity due to cross-contamination relative to nested PCR.
Real-time PCR for the detection of bacterial DNA in pleural fluids has the potential to better define the microbiological cause of pediatric CAP. This approach could help clinicians provide targeted antimicrobial therapy.
社区获得性肺炎（CAP）合并脓胸/积脓是加拿大儿科医生常见的感染综合征。
调查新型分子检测在加拿大儿科 CAP 合并脓胸/积脓的微生物学诊断中的额外益处。
对 2009 年至 2011 年间安大略省因 CAP 合并脓胸/积脓住院的 56 名儿童的胸腔积液进行了方便抽样。对这些胸腔积液进行了多种单重实时聚合酶链反应（PCR）检测，并与血液和胸腔积液样本的传统培养检测进行了比较。
分子方法在 82%的病例中检测到病原体，而传统的血液和胸腔积液培养仅在 25%的病例中检测到病原体。大多数脓胸与肺炎链球菌感染有关；分子方法检测到 62%的样本中有 S. pneumoniae，但仅在 14%的样本中通过培养方法检测到。PCR 检测到 16%的样本中有酿脓链球菌，是第二常见的病原体。未发现金黄色葡萄球菌引起的积脓。
结果表明，多重单重实时 PCR 比传统的培养方法在 CAP 合并胸腔积液/积脓的微生物学诊断中要好得多。S. pneumoniae 和 S. pyogenes 被发现是大多数感染的病原体。该方法在胸腔积液样本中的检测病原体比例与先前报道的嵌套 PCR 检测相似；此外，实时闭孔方法还最大限度地减少了由于交叉污染而导致非特异性的风险，这与嵌套 PCR 相比。
实时 PCR 检测胸腔积液中的细菌 DNA 有可能更好地确定儿科 CAP 的微生物病因。这种方法可以帮助临床医生提供靶向抗菌治疗。
