Background. Metagenomic next-generation sequencing (mNGS) has made a revolution in the mode of pathogen identification. We decided to explore the diagnostic value of blood and bronchoalveolar lavage fluid (BALF) as mNGS samples in pneumonia. Methods. We retrospectively reviewed 467 mNGS results and assessed the diagnostic performance of paired blood and BALF mNGS in 39 patients with pneumonia. Results. For bacteria and fungi, 16 patients had culture-confirmed pathogen diagnosis, while 13 patients were culture-negative. BALF mNGS was more sensitive than blood mNGS (81.3% vs. 25.0%, ), and the specificity in BALF and blood mNGS was not statistically significant different (76.9% vs. 84.6%, ). For 10 patients without culture test, treatments were changed in 2 patients. For viruses, Epstein-Barr virus was positive in blood mNGS in 9 patients. Human adenovirus was detected in both BALF and blood mNGS in 3 patients. Conclusion. Our study suggests that BALF mNGS is more sensitive than blood mNGS in detecting bacteria and fungi, but blood also has advantages to identify the pathogens of pneumonia, especially for some viruses.

中文翻译：

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肺炎中的血液和支气管肺泡灌洗液宏基因组下一代测序。

背景。宏基因组下一代测序（mNGS）在病原体鉴定模式上发生了一场革命。我们决定探索血液和支气管肺泡灌洗液 (BALF) 作为 mNGS 样本在肺炎中的诊断价值。方法。我们回顾性审查了 467 个 mNGS 结果，并评估了配对血液和 BALF mNGS 在 39 名肺炎患者中的诊断性能。结果。对于细菌和真菌，16例患者培养确诊为病原体，13例患者培养阴性。BALF mNGS 比血液 mNGS 更敏感（81.3% vs. 25.0%，)，而 BALF 和血液 mNGS 的特异性差异无统计学意义（76.9% vs. 84.6%，）。10例未进行培养试验，2例改变治疗方案。对于病毒，9 名患者的血液 mNGS 中 Epstein-Barr 病毒呈阳性。在 3 名患者的 BALF 和血液 mNGS 中均检测到人腺病毒。结论。我们的研究表明，BALF mNGS 在检测细菌和真菌方面比血液 mNGS 更敏感，但血液在识别肺炎病原体方面也有优势，尤其是对某些病毒。