Department of Pulmonary and Critical Care Medicine, The First Hospital of Qinhuangdao, Qinhuangdao, China.
Department of Respiratory Diseases, The First Medical Center, Chinese PLA General Hospital, Beijing, China.
Ann Palliat Med. 2022 May;11(5):1725-1735. doi: 10.21037/apm-21-3474.
Metagenomic next-generation sequencing (mNGS) exerts a vital part in accurately diagnosing pulmonary infection. However, the diagnostic value of different samples obtained by virtual bronchoscopic navigation (VBN) combined with mNGS for pathogen detection in infections located in the peripheral lung field (PLF) is still unclear.
Patients infected from July 2018 to February of the following year were carefully analyzed and divided into two parts, namely, non-infectious disease group and the infectious disease group. Then bronchial expansion tests were performed for each subject, collected liquid specimens and tissue standards, and conducted regular mNGS and microbiological detection and analysis. The value of mNGS and culture in pathogen detection was compared, at the same time, the performance of tissue mNGS and bronchoalveolar lavage fluid (BALF) mNGS in the diagnosis process was compared. When discrete variables were processed, Pearson χ2 and Fisher's exact test could be used to perform categorical variables analysis. Continuous variables were analyzed and compared by Mann-Whitney U test.
After mNGS diagnosis, Acinetobacter baumannii, Pseudomonas aeruginosa and Rothia mucilaginosa were the bacterial species showing the highest abundances. In addition, mNGS achieved the sensitivities in the detection of pathogens in tissues and BALF of 72.9% and 81.4%, respectively, and it is higher than conventional culture. Bacterial diagnostic sensitivity was significantly different between BALF and tissue using mNGS (95.0% vs. 62.5%, P=0.03). The sensitivity and specificity of BALF in detecting fungal infections were not significantly different from those of mNGS. A consistency test showed that these two methods had some degree of consistency (k=0.673, P=0.000).
This study showed that the mNGS in BALF samples and the mNGS in tissue samples which could be used to test for pathogens in the lungs. The sensitivity will increase when mNGS is combined with culture. Also, mNGS of BALF and tissues had some degree of consistency to detect fungal infections, whereas mNGS of BALF had better sensitivity to detect bacterial infection than mNGS of tissues.
宏基因组下一代测序（mNGS）在准确诊断肺部感染方面发挥着重要作用。然而，虚拟支气管导航（VBN）联合 mNGS 获得的不同样本对位于肺外周区（PLF）感染的病原体检测的诊断价值尚不清楚。
对 2018 年 7 月至次年 2 月期间感染的患者进行仔细分析，分为非传染性疾病组和传染性疾病组。然后对每位患者进行支气管扩张试验，采集液体标本和组织标准，并进行常规 mNGS 和微生物检测分析。比较 mNGS 和培养在病原体检测中的价值，同时比较组织 mNGS 和支气管肺泡灌洗液（BALF）mNGS 在诊断过程中的性能。处理离散变量时，可使用 Pearson χ2 和 Fisher 精确检验进行分类变量分析。连续变量采用 Mann-Whitney U 检验进行分析和比较。
mNGS 诊断后，鲍曼不动杆菌、铜绿假单胞菌和粘质罗氏菌是丰度最高的细菌种。此外，mNGS 检测组织和 BALF 中病原体的灵敏度分别为 72.9%和 81.4%，高于常规培养。BALF 和组织中使用 mNGS 检测细菌的诊断灵敏度差异有统计学意义（95.0% vs. 62.5%，P=0.03）。BALF 检测真菌感染的灵敏度和特异性与 mNGS 无显著差异。一致性检验显示，两种方法具有一定的一致性（k=0.673，P=0.000）。
本研究表明，BALF 样本中的 mNGS 以及可用于检测肺部病原体的组织中的 mNGS 具有较高的灵敏度。联合培养可提高 mNGS 的灵敏度。此外，BALF 和组织的 mNGS 对检测真菌感染有一定的一致性，而 BALF 的 mNGS 对检测细菌感染的灵敏度优于组织的 mNGS。
