摘要目的:探讨先天性心脏病(CHD)室间隔缺损(VSD)患儿体外循环(CPB)术前、术后早期和术后(15.61±4.51)个月肠道菌群的变化特征。方法:采取前瞻性研究。2021年1月至2022年1月于广州市妇女儿童医疗中心纳入13例计划行CPB术的VSD患儿和10例年龄和性别匹配的健康婴儿作为CPB前对照组，于CPB前和CPB后早期采集粪便样本。同期纳入18例性别、CHD类型和手术方式匹配的CPB后(15.61±4.51)个月的患儿和8名年龄和性别匹配的健康幼儿作为CPB后远期对照组，并采集粪便样本。对所有粪便样本进行16S rRNA测序，采用alpha和beta多样性特征比较、参数或非参数检验方法和LEfSe分析以比较组间菌群的差异。结果:与CPB前对照组相比，CPB前组有显著差异的群落结构，Enterobacteriaceae和 Shigella增加， Bifidobacterium减少(均 P<0.05)。从CPB前到CPB后早期菌群多样性均无明显变化(均 P>0.05)，除 Clostridium和 Streptococcus外(均 P<0.05)，其余高丰度的物种组间相对丰度差异均无统计学意义(均 P>0.05)。与CPB后早期组比较，CPB后(15.61±4.51)个月组的短链脂肪酸产生菌显著增加(均 P<0.05)，群落结构接近CPB后远期对照组的模式(均 P>0.05)。 结论:VSD患儿在CPB前已存在肠道菌群失调，CPB对其肠道菌群无明显影响，CPB后(15.61±4.51)个月VSD患儿的菌群模式改善，并趋于正常。

abstractsObjective:To explore the characteristics of gut microbiota in the preoperative, short-term postoperative and long-term postoperative period at (15.61±4.51) months in children with ventricular septal defect (VSD) of congenital heart disease (CHD) treated with cardiopulmonary bypass (CPB).Methods:A prospective study was conducted.In Guangzhou Women and Children′s Medical Center, 13 patients with VSD who were scheduled for CPB and additional 10 age- and gender-matched healthy infants as pre-CPB control group from January 2021 to January 2022 were enrolled.Fecal samples were collected at pre- and early post-CPB.Meanwhile, 18 gender- and CHD diagnosis and operation-matched patients at (15.61±4.51) months after CPB and 8 healthy age- and gender-matched children as long-term control group after CPB were also enrolled, and fecal samples were collected.16S rRNA sequencing of fecal samples from all subjects were performed and comparing the differences in gut microbiota between two groups via comparing alpha and beta diversity, parameter test or nonparametric test, and LEfSe analysis.Results:Compared with those of pre-CPB control group, there was a significant difference in the composition of gut microbiota in the preoperative period of VSD children, with significantly increased abundances of Enterobacteriaceae and Shigella, and decreased abundance of Bifidobacterium (all P<0.05). The diversity of gut microbiota was comparable in VSD children before CPB and in the short period time after CPB (all P>0.05), except for the abundances of Clostridium and Streptococcus (all P<0.05), and there was no significant difference in the relative abundances of other highly abundant gut bacteria between the two periods (all P>0.05). Compared with that in VSD children in the short period time after CPB, the abundances of short-chain fatty acids-producing microbes were significantly higher at (15.61±4.51) months postoperatively (all P<0.05), and the gut bacteria profile was similar to that of the long-term control group after CPB (all P>0.05). Conclusions:Gut microbiota imbalance exists in VSD children before CPB.The gut microbiota profile is not influenced by CPB, which returns normal at (15.61±4.51) months postoperatively.