Koyama Tsutomu, Shimizu Kimihiro, Mishima Shuji, Matsuoka Shunichiro, Takeda Tetsu, Miura Kentaro, Agatsuma Hiroyuki, Eguchi Takashi, Hamanaka Kazutoshi, Yoshida Kazuo
Division of General Thoracic Surgery, Department of Surgery, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.
Department of General Thoracic Surgery, Japanese Red Cross Suwa Hospital, Suwa, Nagano, Japan.
J Thorac Dis. 2024 Nov 30;16(11):7329-7341. doi: 10.21037/jtd-24-933. Epub 2024 Nov 29.
While the relationship between gut microbiota and gastrointestinal cancer has been elucidated, the relationship between lung microbiota and lung cancer remains unclear. Previous study findings are inconclusive due to the possibility of contamination by upper airway microbiota in samples obtained from the oropharynx, such as saliva and sputum, and bronchoalveolar lavage fluid (BALF) collected during bronchoscopy. Therefore, this study aimed to detect pure lung microbiota in patients with lung cancer using BALF samples from resected lung specimens. Additionally, we aimed to evaluate the lung microbiota to clarify their relationship with lung cancer and aid in postoperative pneumonia (POP) prevention and treatment.
This prospective cohort study enrolled patients with clinically suspected lung cancer who underwent surgical resection at the Department of Thoracic Surgery, Japanese Red Cross Suwa Hospital, between April 2020 and March 2022. BALF from resected lung specimens collected under sterile conditions were used for high-throughput next-generation sequencing (NGS) and bacterial culture analyses. Pure lung microbiota were identified, and their abundance ratio was analyzed. Additionally, we performed α-diversity analysis and explored the relationship between microbiota and POP by comparing our findings with previous literature.
Among samples collected from 54 included cases, bacteria were detected in 13 samples (24.1%) via bacterial culture and in all samples via NGS. Candidate Phylum OD1 bacteria (OD1) was present in a large proportion of samples (phylum level). The major bacteria genera, with a relative abundance ratio (each bacterial read amount/total bacterial read amount) >1% in at least one sample, included , and . Additionally, bacteria widely recognized as pathogens of POP were detected.
Our lung microbiota sampling method eliminated contamination from upper airway microbiota, allowing detection of pure lung microbiota. This study provides baseline data on pure lung microbiota and highlights the need for further research to explore the role of OD1 in lung cancer, which was previously unreported in lung microbiota. Although the pathogens of POP can be aspirated post-hospitalization, they could already exist as lung microbiota pre-hospitalization. Further investigation is needed to substantiate our results and hypothesis.
虽然肠道微生物群与胃肠道癌症之间的关系已得到阐明，但肺部微生物群与肺癌之间的关系仍不清楚。由于从口咽获取的样本（如唾液、痰液）以及支气管镜检查期间收集的支气管肺泡灌洗液（BALF）可能受到上呼吸道微生物群的污染，以往的研究结果尚无定论。因此，本研究旨在使用来自切除肺标本的BALF样本检测肺癌患者的纯净肺部微生物群。此外，我们旨在评估肺部微生物群，以阐明它们与肺癌的关系，并有助于预防和治疗术后肺炎（POP）。
这项前瞻性队列研究纳入了2020年4月至2022年3月期间在日本红十字诹访医院胸外科接受手术切除的临床疑似肺癌患者。在无菌条件下收集的切除肺标本的BALF用于高通量下一代测序（NGS）和细菌培养分析。鉴定纯净的肺部微生物群，并分析其丰度比。此外，我们进行了α多样性分析，并通过将我们的研究结果与以往文献进行比较，探讨了微生物群与POP之间的关系。
在从54例纳入病例中收集的样本中，通过细菌培养在13个样本（24.1%）中检测到细菌，通过NGS在所有样本中均检测到细菌。候选门OD1细菌（OD1）在大部分样本（门水平）中存在。主要细菌属中，至少在一个样本中相对丰度比（每个细菌读数/总细菌读数）>1%的包括 ，以及 。此外，还检测到被广泛认为是POP病原体的细菌。
我们的肺部微生物群采样方法消除了上呼吸道微生物群的污染，从而能够检测到纯净的肺部微生物群。本研究提供了关于纯净肺部微生物群的基线数据，并强调需要进一步研究以探索OD1在肺癌中的作用，OD1此前在肺部微生物群中未被报道。虽然POP的病原体可能在住院后被吸入，但它们可能在住院前就已作为肺部微生物群存在。需要进一步研究来证实我们的结果和假设。
