Objective: To use metagenomic sequencing to compare the differences in intestinal microbiota species and metabolic pathways in patients with hepatitis B cirrhosis with or without ascites and further explore the correlation between the differential microbiota and clinical indicators and metabolic pathways. Methods: 20 hepatitis B cirrhosis cases [10 without ascites (HBLC-WOA), 10 with ascites (HBLC-WA), and 5 healthy controls (HC)] were selected from the previously studied 16S rRNA samples. Metagenome sequencing was performed on the intestinal microbiota samples. The Kruskal-Wallis rank sum test and Spearman test were used to identify and analyse differential intestinal microbiota populations, metabolic pathways, and their correlations. Results: (1) The overall structure of the intestinal microbiota differed significantly among the three groups (R = 0.19, P = 0.018). The HC group had the largest abundance of Firmicutes and the lowest abundance of Proteobacteria at the genus level. Firmicutes abundance was significantly decreased (P(fdr) < 0.01), while Proteobacteria abundance was significantly increased (P(fdr) < 0.01) in patients with cirrhosis accompanied by ascites; (2) LEfSe analysis revealed that 29 intestinal microbiota (18 in the HBLC-WA group and 11 in the HBLC-WOA group) played a significant role in the disease group. The unclassified Enterobacteriaceae and Klebsiella species in the HBLC-WA group and Enterobacteriaceae in the HBLC-WOA group were positively correlated with the Child-Turcotte-Pugh (CTP) score, prothrombin time, and international normalized ratio score and negatively correlated with albumin and hemoglobin levels (P < 0.05). Escherichia and Shigella in the HBLC-WA group were positively correlated with CTP scores (P < 0.05); (3) The correlation analysis results between the KEGG pathway and 29 specific intestinal microbiota revealed that Enterobacteriaceae and arachidonic acid, α-linolenic acid, glycerolipid metabolism, and fatty acid degradation were positively correlated in the lipid metabolism pathway, while most Enterobacteriaceae were positively correlated with branched-chain amino acid degradation and negatively correlated with aromatic amino acid biosynthesis in the amino acid metabolic pathway. Conclusion: A significant increment of Enterobacteriaceae in the intestines of HBLC-WA patients influenced hepatic reserve function and was associated with amino acid and lipid metabolic pathways. Therefore, attention should be paid to controlling the intestinal microbiota to prevent complications and improve the prognosis in patients with hepatitis B cirrhosis, especially in those with ascites.
目的： 采用宏基因组测序比较乙型肝炎肝硬化伴或不伴有腹水患者肠道菌群物种及代谢通路差异，并探讨差异菌群与临床指标及代谢通路间相关性。 方法： 在前期16S rRNA研究样本中选择20例乙型肝炎肝硬化（HBLC）患者[10例无腹水(HBLC-WOA)，10例伴腹水(HBLC-WA)]及5名健康人作为健康对照（HC），对其肠道菌群样本进行宏基因组测序。采用Kruskal–Wallis秩和检验及Spearman检验发现差异菌群及代谢通路并分析其相关性。 结果： （1）3组间肠道菌群的总体结构存在显著差异（R = 0.19, P = 0.018）；在门水平上，HC组厚壁菌门的丰度最高，而变形菌门的丰度较低；肝硬化患者伴随腹水的出现，厚壁菌门丰度显著下降（P(fdr) < 0.01)，而变形菌门丰度显著增加（P(fdr) < 0.01);（2）LEfSe分析表明29个菌属（HBLC-WA组18个，HBLC-WOA组11个）在疾病组中发挥主要作用。肠道菌群与临床变量的相关性分析结果显示，HBLC-WA组的未分类肠杆菌、克雷伯菌属以及HBLC-WOA组的肠杆菌属与Child-Turcotte-Pugh（CTP）评分、凝血酶原时间、国际标准化比值评分呈正相关，与白蛋白、血红蛋白水平呈负相关（P值均< 0.05）；且HBLC-WA组的埃希菌属和志贺菌属与CTP评分呈正相关（P < 0.05）;（3）关键差异KEGG通路与29个特定菌属相关性分析结果显示，在脂质代谢通路中，肠杆菌科菌属与花生四烯酸、α-亚麻酸、甘油脂代谢及脂肪酸降解呈正相关；在氨基酸代谢通路中，多数肠杆菌科菌属与支链氨基酸降解正相关，与芳香族氨基酸生物合成呈负相关。 结论： 肠杆菌科细菌在HBLC-WA患者肠道中明显增加，影响肝脏的储备功能，并与脂质、氨基酸代谢通路密切相关。因此，对乙型肝炎肝硬化患者尤其是伴有腹水的患者应注意调节肠道菌群，预防并发症，改善患者的预后。.
Keywords: Ascites; Hepatitis B; Intestinal flora; Liver cirrhosis; Metagenomics.