The gut microbiota is a complex ecosystem, which is essential for the metabolism, health and immunity of host. Many diseases have been shown to be closely related to the alteration of intestinal flora. Aeromonas veronii as a conditioned pathogen can cause disease in Yangtze finless porpoise through intestinal infections. However, it is not clear whether the disease caused by Aeromonas veronii is related to changes of intestinal flora. In the current study, the diversity and composition of gut microbiota in the healthy and Aeromonas veronii-infected Yangtze finless porpoise were evaluated by high-throughput sequencing to further investigate the potential association between intestinal flora alteration and pathogen invasion. A total of 127,3276 high-quality sequences were achieved and 2465 operational taxonomic units (OTUs) were in common among all samples. The results of alpha diversity showed that there was no obvious difference in richness and diversity between healthy and Aeromonas veronii-infected Yangtze finless porpoise. Firmicutes, Bacteroidetes and Proteobacteria were the most dominant phyla in all samples. In addition, the healthy Yangtze finless porpoise exhibited higher abundance of Firmicutes and Fusobacteria than Aeromonas veronii-infected Yangtze finless porpoise, while, the level of Proteobacteria was decreased. At the genus level, Paeniclostridium and Paraclostridium were the predominant bacteria genera in the CK (healthy Yangtze finless porpoise) group. In the DIS (Aeromonas veronii-infected Yangtze finless porpoise) group, Lactobacillus and unidentified_Enterobacteriaceae were the dominant bacteria genera and the proportion of Paeniclostridium, Paraclostridium, Terrisporobacter, Cetobacterium, Candidatus Arthromitus, Terrabacter and Dechloromonas were reduced. In conclusion, our results showed that Aeromonas veronii infection can alter the gut microbiota of the Yangtze finless porpoise by affecting the number of harmful bacteria and beneficial bacteria.

中文翻译：

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健康人和维罗纳气单胞菌感染的长江无鳍海豚的微生物群落结构比较分析。

肠道菌群是一个复杂的生态系统，对于宿主的代谢，健康和免疫至关重要。已显示许多疾病与肠道菌群的变化密切相关。维罗纳气单胞菌作为条件性病原体可通过肠道感染在长江无鳍海豚中引起疾病​​。但是，尚不清楚由维罗纳气单胞菌引起的疾病是否与肠道菌群的变化有关。在本研究中，通过高通量测序对健康的和经气单胞菌感染的长江无鳍海豚的肠道菌群的多样性和组成进行了评估，以进一步研究肠道菌群改变与病原体入侵之间的潜在关联。总共127 在所有样本中，共获得3276个高质量序列，共有2465个操作分类单位（OTU）。α多样性的结果表明，健康的和感染了维氏气单胞菌的长江无鳍海豚的丰富度和多样性没有明显差异。在所有样品中，硬毛菌，拟杆菌属和变形杆菌是最主要的门。此外，健康的长江无鳍海豚表现出比沙门氏菌感染的长江无鳍海豚更多的硬毛和梭状芽胞杆菌，而其变形杆菌水平却降低了。在属水平上，Pa虫和副梭菌是CK（健康的长江无鳍海豚）组的主要细菌属。在DIS（感染了Aeromonas veronii的长江无鳍海豚）组中，乳酸杆菌和未鉴定的肠杆菌科是主要的细菌属，并且减少了草杆菌，副梭菌，Terrisporobacter，头孢杆菌，假丝酵母​​，Terrabacter和Dechloromonas的比例。总而言之，我们的结果表明，Veronii气单胞菌感染可以通过影响有害细菌和有益细菌的数量来改变长江无鳍海豚的肠道菌群。