Centre for Gut Microbiota Research, The Chinese University of Hong Kong, Shatin, Hong Kong.
Department of Microbiology, The Chinese University of Hong Kong, Shatin, Hong Kong.
Gut. 2020 Nov;69(11):1998-2007. doi: 10.1136/gutjnl-2019-319635. Epub 2020 Feb 12.
Fusobacteria are not common nor relatively abundant in non-colorectal cancer (CRC) populations, however, we identified multiple taxa nearly absent in western and rural populations to be comparatively more prevalent and relatively abundant in southern Chinese populations. We investigated whether these represented known or novel lineages in the genus, and assessed their genomes for features implicated in development of cancer.
Prevalence and relative abundances of fusobacterial species were calculated from 3157 CRC and non-CRC gut metagenomes representing 16 populations from various biogeographies. Microbial genomes were assembled and compared with existing reference genomes to assess novel fusobacterial diversity. Phylogenetic distribution of virulence genes implicated in CRC was investigated.
Irrespective of CRC disease status, southern Chinese populations harboured increased prevalence (maximum 39% vs 7%) and relative abundances (average 0.4% vs 0.04% of gut community) of multiple recognised and novel fusobacterial taxa phylogenetically distinct from . Genomes assembled from southern Chinese gut metagenomes increased existing fusobacterial diversity by 14.3%. Homologues of the FadA adhesin linked to CRC were consistently detected in several monophyletic lineages sister to and inclusive of and , but not . We also detected increased prevalence and relative abundances of in CRC compared with non-CRC cohorts, which together with distribution of FadA homologues supports a possible association with gut disease.
The proportion of fusobacteria in guts of southern Chinese populations are higher compared with several western and rural populations in line with the notion of environment/biogeography driving human gut microbiome composition. Several non-nucleatum taxa possess FadA homologues and were enriched in CRC cohorts; whether this imposes a risk in developing CRC and other gut diseases deserves further investigation.
梭菌在非结直肠癌（CRC）人群中并不常见或相对较少，但我们发现，在西方和农村人群中几乎不存在的多个分类群在中国人中更为普遍和相对丰富。我们调查了这些是否代表了该属中的已知或新谱系，并评估了它们的基因组中与癌症发展相关的特征。
从代表来自不同生物地理区域的 16 个人群的 3157 个 CRC 和非 CRC 肠道宏基因组中计算了梭菌物种的流行率和相对丰度。组装微生物基因组并与现有参考基因组进行比较，以评估新的梭菌多样性。调查了与 CRC 相关的、涉及毒力的基因的系统发育分布。
无论 CRC 疾病状态如何，中国南方人群都存在更高的流行率（最高为 39%，而 7%为非 CRC）和相对丰度（肠道社区的平均 0.4%，而 0.04%为非 CRC）。从中国南方肠道宏基因组组装的基因组增加了现有的梭菌多样性 14.3%。与. 属内姐妹群和包含. 属内姐妹群的多个梭菌分类群中一致检测到与 CRC 相关的 FadA 粘附素的同源物，但在. 属中没有检测到。我们还检测到 CRC 中与非 CRC 队列相比，. 属的流行率和相对丰度增加，这与 FadA 同源物的分布一起支持了与肠道疾病的可能关联。
与几个西方和农村人群相比，中国南方人群肠道中梭菌的比例较高，这符合环境/生物地理学驱动人类肠道微生物组组成的观点。几个非核梭菌分类群具有 FadA 同源物，并且在 CRC 队列中富集；这是否会增加 CRC 和其他肠道疾病的风险值得进一步研究。
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