Abstract: Objective　To analyze the characteristics and functions of the vaginal microbiota in patients with trichomonal vaginitis (TV) and to explore the association between vaginal microbiota structure and the pathogenesis of TV. Methods　 TV patients admitted to the Gynecology and Obstetrics Outpatient Department of Yixing People's Hospital from October 2024 to January 2025 were selected as the TV group, and non⁃TV patients among female health examination participants at the same hospital during the same period were selected and served as controls. Vaginal secretion samples were collected from both groups. The pH value of vaginal secretions, as well as hydrogen peroxide and leukocyte esterase, were detected using a vaginitis combined detection kit. Total genomic DNA was extracted from the vaginal secretion samples of both groups, and the full⁃length bacterial 16S rRNA gene was amplified by PCR. Purified PCR products were mixed proportionally to construct an amplicon library for single⁃molecule real⁃time sequencing. High⁃quality sequences were clustered into operational taxonomic units (OTUs), and chimeric sequences were simultaneously removed. Representative sequences of OTUs were taxonomically classified, and the microbial composition of each sample was statistically analyzed at different taxonomic levels. Results　A total of 21 TV patients were included in the TV group, and 22 non⁃TV patients among female health examination participants were included in the control group. The pH values of vaginal secretions in the TV group and the control group were 4.593 ± 0.087 and 4.431 ± 0.093, respectively, with a statistically significant difference (t = 6.537, P < 0.01). The positive rates of H2O2 in the two groups were 80.95% (17/21) and 22.72% (5/22), and the positive rates of leukocyte esterase were 80.95% (17/21) and 27.27% (6/22), respectively, with statistically significant differences([χ2] = 14.576、12.445, P < 0.01). Alpha diversity analysis results showed that the median and interquartile range [M（QR）] of the Shannon index for the vaginal microbiota in the TV group was 1.40 (1.41), which was higher than that of the control group (Z = 3.716, P < 0.001); the Simpson index [M（QR）] of the TV group was 0.34 (0.39), which was lower than that of the control group (Z = -3.602, P < 0.001). At the OTU level, the distribution of sample data points in the coordinate space was distant between the TV group and the control group, showing spatial separation. The microbiota health index value of the control group was higher than that of the TV group [1.40 (1.66) vs. -2.36 (2.29); Z = -5.467, P < 0.001], while the microbiota dysbiosis index value was lower than that of the TV group [-1.17 (1.40) vs. 2.06 (2.27); Z = -5.224, P < 0.001]. A total of 281 OTUs were identified. The vaginal microbiota of the TV group contained 62 unique OTUs (accounting for 22.06%), while the control group contained 82 unique OTUs (accounting for 29.18%). The highest relative abundance of Leptotrichia was detected in the TV group, and Lactobacillus was the dominant genus in the control group, with higher relative abundance of Lactobacillus detected in the control group than in the TV group (t = 3.646, P = 0.003). Functional analysis of the vaginal microbiota in both groups showed statistically significant differences in the relative abundances of metabolic pathways such as ABC transporters (t = 3.282, P = 0.002), purine metabolism (t = 2.517, P = 0.014), biosynthesis of secondary metabolites (t = 2.704, P = 0.010), and aminoacyl⁃tRNA biosynthesis (t = 2.201, P = 0.030). Conclusion　The abundance and function of vaginal flora in TV patients undergo changes, which may be closely related to the occurrence and development of TV. This provides assistance for further understanding the microbial mechanism of TV in clinical practice.

Key words: Vaginal microbiota, Trichomonal vaginitis, Vaginal secretion, 16S rRNA gene

摘要： 目的　分析滴虫性阴道炎（trichomonal vaginitis，TV）患者阴道菌群特征及功能，并探讨阴道菌群结构与滴虫性阴道炎发病之间的关联。方法　选取2024年10月—2025年1月就诊于宜兴市第一人民医院妇产科门诊的TV患者作为 TV组；在同一时间段该院的女性健康体检者中，选取未患TV者作为对照组。采集两组研究对象阴道分泌物样本，采用阴道炎联合检测试剂盒检测阴道分泌物pH值以及过氧化氢、白细胞酯酶等。从两组研究对象阴道分泌物样本中提取总基因组DNA，对细菌16S rRNA基因全长进行PCR扩增。纯化后的PCR产物按比例混合，构建扩增子文库，进行单分子实时测序。对高质量序列进行可操作分类单元（operational taxonomic unit，OTU）聚类，并同时去除嵌合体序列。对OTU代表序列进行物种分类，分析不同分类水平下各样本菌群的组成。结果　TV组共纳入21例TV患者，对照组纳入22例未患TV的女性健康体检者。TV组与对照组研究对象阴道分泌物pH值分别为4.593 ± 0.087和4.431 ± 0.093，差异有统计学意义（t = 6.537，P < 0.01）；2组过氧化氢阳性率分别为80.95%（17/21）和22.72%（5/22），白细胞酯酶阳性率分别为80.95%（17/21）和27.27%（6/22），差异均有统计学意义（[χ2] = 14.576、12.445，P均< 0.01）。Alpha多样性分析结果显示，TV组阴道分泌物菌群Shannon指数中位数（四分位数间距）［M（QR）］为1.40（1.41），高于对照组（Z = 3.716，P < 0.001）；TV组Simpson指数M（QR）为0.34（0.39），低于对照组（Z = −3.602，P < 0.001）。在OTU水平，TV组与对照组样本数据点在坐标空间中的分布距离较远，呈空间分离。对照组菌群健康指数值高于TV组［（1.40（1.66）vs. −2.36（2.29）；Z = −5.467，P < 0.001］，而菌群失调指数值低于TV组［−1.17（1.40）vs. 2.06（2.27）；Z = −5.224，P < 0.001］。共鉴定出281个OTU，TV组阴道分泌物菌群包含62个独特OTU（占22.06%），而对照组包含82个独特OTU（占29.18%）。TV组阴道分泌物菌群中纤毛菌属相对丰度最高，对照组中乳酸杆菌属为优势菌属；对照组乳酸菌属相对丰度高于TV组（t = 3.646，P = 0.003）。阴道分泌物菌群功能分析结果显示，两组ABC转运体（t = 3.282，P = 0.002）、嘌呤代谢（t = 2.517，P = 0.014）和次级代谢产物合成（t = 2.704，P = 0.010）、氨酰⁃tRNA合成（t = 2.201，P = 0.030）等代谢通路的相对丰度差异均有统计学意义。结论　TV患者阴道分泌物菌群丰度和菌群功能均发生变化，可能与TV的发生发展密切相关。该发现有助于在临床实践中进一步了解TV的微生物机制。

关键词: 阴道菌群, 滴虫性阴道炎, 阴道分泌物, 16S rRNA基因