目的 探讨极早产儿（very preterm infant, VPI）无/Ⅰ级支气管肺发育不良（bronchopulmonary dysplasia, BPD）与Ⅱ/Ⅲ级BPD的肠道菌群差异。 方法 前瞻性纳入2023年1月—2024年6月厦门大学附属妇女儿童医院收治的胎龄<32周且出生体重<1 500 g的早产儿，将其分为两组：无/Ⅰ级BPD组（n=52）和Ⅱ/Ⅲ级BPD组（n=41），用高通量测序技术比较两组肠道菌群组成的差异。 结果 Ⅱ/Ⅲ级BPD组变形菌门和克雷伯氏菌属相对丰度显著增加，而厚壁菌门、拟杆菌门和葡萄球菌属相对丰度则显著减少。无/Ⅰ级BPD组肠道菌群变化趋势不明显。出生后第21天Ⅱ/Ⅲ级BPD组链球菌属相对丰度显著低于无/Ⅰ级BPD组（P=0.017）。Ⅱ/Ⅲ级BPD组早产儿肠道菌群α多样性在纠正胎龄36周时显著低于无/Ⅰ级BPD组（P<0.05）。主坐标分析显示，两组早产儿肠道菌群组成结构在纠正胎龄36周时差异有统计学意义（P=0.019）。 结论 Ⅱ/Ⅲ级BPD患儿在生命早期出现肠道菌群多样性降低。链球菌属减少可能与Ⅱ/Ⅲ级BPD的发生相关。

Objective To investigate differences in gut microbiota between very preterm infants with no/grade I bronchopulmonary dysplasia (BPD) and those with grade II/III BPD. Methods A prospective cohort study was conducted at Women and Children's Hospital, School of Medicine, Xiamen University from January 2023 to June 2024. Preterm infants with gestational age <32 weeks and birth weight <1 500 g were categorized into two groups: no/grade I BPD (n=52) and grade II/III BPD (n=41). Gut microbiota composition was compared using high-throughput sequencing. Results The grade II/III BPD group showed significantly increased relative abundances of Proteobacteria and Klebsiella, and significantly decreased relative abundances of Firmicutes, Bacteroidota, and Staphylococcus. No/grade I BPD infants showed no obvious temporal trend in gut microbiota changes. On postnatal day 21, the relative abundance of Streptococcus was significantly lower in the grade II/III BPD group than in the no/grade I BPD group (P=0.017). At 36 weeks of corrected gestational age, alpha diversity in the grade II/III BPD group was significantly lower than in the no/grade I BPD group (P<0.05). Principal coordinates analysis indicated a significant difference in overall gut microbiota composition between the groups at this time point (P=0.019). Conclusions Very preterm infants with grade Ⅱ/Ⅲ BPD show reduced gut microbial diversity early in life. A decrease in Streptococcus may be associated with grade II/III BPD.