Background: Pneumocystis jirovecii pneumonia (PCP) is a serious opportunistic infection in immunocompromised children. Real-time polymerase chain reaction (PCR) is widely used for the diagnosis of PCP due to its good accuracy. However, the diagnostic performance of multiplex real-time PCR on sputum in children with PCP has never been explored.
Methods: Medical records of 63 consecutive pediatric patients were analyzed retrospectively, including 13 cases with PCP and 50 with non-PCP pneumonia. Pneumocystis jirovecii (P. jirovecii) and other co-pathogens detected by multiplex real-time PCR in sputum samples were summarized. Using clinical composite diagnosis as the reference standard, we further compared the diagnostic performance of multiplex real-time PCR to combined serological markers (1,3)-β-D-glucan plus lactate dehydrogenase. Additionally, modifications of antimicrobial treatment for pediatric PCP patients after the report of multiplex real-time PCR results were reviewed.
Results: In children with PCP, nonproductive cough and shortness of breath were more common, lymphocyte count in peripheral blood was markedly lower, and serum levels of (1,3)-β-D-glucan and lactate dehydrogenase were much higher than non-PCP group. Multiplex real-time PCR reached a sensitivity of 100% in diagnosing PCP, which was better than serum (1,3)-β-D-glucan plus lactate dehydrogenase (76.9%). Its specificity (98.0%) significantly surpassed serum (1,3)-β-D-glucan plus lactate dehydrogenase (84.4%). Furthermore, multiplex real-time PCR showed a good performance in identifying co-pathogens in sputum of pediatric PCP patients. Cytomegalovirus, Epstein–Barr virus and Streptococcus pneumoniae were the most common co-pathogens in these patients. Initial antimicrobial treatment was modified in 76.9% of children with PCP after the report of PCR results.
Conclusion: Multiplex real-time PCR on sputum is a diagnostic tool with good performance for the identification of P. jirovecii as well as co-pathogens in children with PCP. Sputum may be an alternative to bronchoalveolar lavage fluid for PCR assay in children when bronchoscopic examination is not feasible.



中文翻译：

---

痰液多重实时聚合酶链反应诊断儿童耶氏肺孢子菌肺炎的回顾性研究

背景： 耶氏肺孢子菌肺炎 (PCP) 是免疫功能低下儿童的一种严重机会性感染。实时聚合酶链反应 (PCR) 因其良好的准确性而被广泛用于 PCP 的诊断。然而，从未探索过多重实时 PCR 对 PCP 儿童痰液的诊断性能。
方法：回顾性分析63例儿科患者的病历，其中PCP肺炎13例，非PCP肺炎50例。Pneumocystis jirovecii ( P. jirovecii) 和其他通过多重实时 PCR 检测的痰液样本中的共病原体进行了总结。以临床复合诊断为参考标准，我们进一步比较了多重实时荧光定量 PCR 与联合血清学标志物 (1,3)-β-D-葡聚糖加乳酸脱氢酶的诊断性能。此外，回顾了多重实时 PCR 结果报告后对儿科 PCP 患者的抗菌治疗的修改。
结果：PCP患儿多见干咳和气短，外周血淋巴细胞计数明显降低，血清(1,3)-β-D-葡聚糖和乳酸脱氢酶水平远高于非PCP组. 多重实时荧光定量 PCR 诊断 PCP 的灵敏度达到 100%，优于血清 (1,3)-β-D-葡聚糖加乳酸脱氢酶 (76.9%)。其特异性（98.0%）显着超过血清（1,3）-β-D-葡聚糖加乳酸脱氢酶（84.4%）。此外，多重实时荧光定量 PCR 在鉴定儿科 PCP 患者痰液中的共病原体方面表现出良好的性能。巨细胞病毒、爱泼斯坦-巴尔病毒和肺炎链球菌是这些患者中最常见的共同病原体。在报告 PCR 结果后，76.9% 的 PCP 儿童进行了初始抗菌治疗。
结论：痰液多重实时荧光定量 PCR 是一种诊断工具，可用于鉴定P. jirovecii以及 PCP 儿童的共同病原体。当支气管镜检查不可行时，痰液可替代支气管肺泡灌洗液用于儿童 PCR 检测。