分析绵阳地区3～5岁儿童的口腔微生物菌群结构，探究其对患龋的影响。

对2023年3月～6月绵阳地区10所幼儿园的136例3～5岁儿童进行口腔流行病学调查，筛选患龋儿童和口腔健康儿童各68例，分别作为观察组和对照组。收集两组儿童唾液样本，提取其全基因组脱氧核糖核酸（DNA）并进行16S核糖体脱氧核糖核酸（16S rDNA）高通量测序，采用独立样本t检验、PCoA、非参数协方差分析（PERMANOVA）、相似性分析（ANOSIM）、Wilcoxon秩和检验比较两组儿童口腔样本微生物菌群多样性、物种组成结构、优势菌群及功能差异。

α多样性分析结果显示，观察组儿童Shannon指数（3.02 ± 0.70）和Simpson指数（0.86 ± 0.35）显著高于对照组（2.70 ± 0.46、0.67 ± 0.15），差异均有统计学意义（t = 3.150、P = 0.002，t = 4.115、P < 0.001）；主坐标分析（PCoA）显示两组儿童口腔菌群呈现显著分离（F = 3.428、P < 0.001），且对照组与观察组间的Bray-Curtis距离（0.58 ± 0.22）显著高于组内（R = 0.659，P = 0.003）。属层级水平上，观察组儿童唾液样本中的链球菌属、纤毛菌属、巨球形菌属和普雷沃菌属丰度显著高于对照组，嗜血杆菌属、梭杆菌属、志贺菌和大肠埃希菌属丰度显著低于对照组（P均< 0.05）；种层级水平上，观察组儿童的副流感嗜血杆菌丰度显著低于对照组，纤毛菌IK040、产黑普雷沃菌、洛氏普雷沃菌丰度显著高于对照组，差异均有统计学意义（P均< 0.05）。观察组儿童磷酸戊糖途径、丙酮酸代谢和丙脂酸代谢丰度显著低于对照组，差异均有统计学意义（P均< 0.05）。

与健康儿童相比，龋病儿童口腔微生物菌群多样性增加，结构紊乱。

To explore the structure of oral microflora in children aged 3 to 5 years old in Mianyang area, and to analyze its effect on dental caries.

An oral epidemiological survey was conducted on 136 children aged 3 to 5 years old in 10 kindergartens in Mianyang from March to June 2023. Total of 68 children with caries and 68 children with oral health were selected as observation group and control group, respectively. Saliva samples of both groups were collected, and the whole genomic DNA was extracted and sequenced with 16s ribosomal DNA (16S rDNA). Independent sample t-test, permutational multivariate analysis of variance (PERMANOVA), analysis of similarity (ANOSIM) and Wilcoxon rank sum test were used to compare the diversity of microflora, species composition, dominant flora and functional differences between the two groups.

The results of α diversity analysis showed that the Shannon index (3.02 ± 0.70) and Simpson index (0.86 ± 0.35) of the observation group were significantly higher than those of the control group (2.70 ± 0.46; 0.67 ± 0.15), with significant differences (t = 3.150, P = 0.002; t = 4.115, P < 0.001). Principal coordinate analysis (PCoA) showed that the oral flora of both groups were significantly separated (F = 3.428, P < 0.001), and the Bray-Curtis distance between the control group and the observation group (0.58 ± 0.22) was significantly higher than that of the group (R = 0.659, P = 0.003). At the level of genera, the abundance of Streptococcus, Leptotrichia, Megasphaera and Prevotella in saliva samples of the observation group were significantly higher than those of the control group, while the abundance of Haemophilus, Fusobacterium and Escherichia-Shigella of the observation group were significantly lower than those of the control group, with significant differences (all P < 0.05). At the species level, the abundance of Haemophilus parainfluenzae of the observation group was significantly lower than that of the control group, while the abundance of Leptotrichia_IK040, Prevotella melaninogenica and Prevotella loescheii of the observation group were significantly higher than those of the control group, with significant differences (all P < 0.05). The abundance of pentose phosphate pathway, pyruvate metabolism and propanoate metabolism of the observation group were significantly lower than those of the control group (all P < 0.05).

Compared with healthy children, children with caries have increased oral microbial flora diversity and structural disturbances.