Dysbiosis of vaginal and peritoneal fluid microbiota in patients with cervical lesions

This study aimed to characterize disturbances in vaginal microbiota among patients with squamous intraepithelial lesions (SIL) or cervical cancer (CC), and to identify specific bacterial genera with potential as diagnostic or prognostic biomarkers. We also explored microbiota of peritoneal fluid in CC patients across different pathological subtypes.

A total of 76 participants were enrolled, including 44 SIL and 32 CC patients, further classified into four groups: low-grade SIL (LSIL; n = 14), high-grade SIL (HSIL; n = 30), squamous cell carcinoma (SCC; n = 18) and adenocarcinoma (ADC; n = 14). Vaginal secretions were collected from all participants, and free peritoneal fluid was obtained from 16 SCC and 12 ADC patients. Vaginal HPV status was monitored semiannually over two years in 25 HSIL patients. Microbial composition was analyzed using 16 S rRNA gene sequencing.

Vaginal bacterial abundance was significantly higher in the CC group than in the SIL group. A non-significant decrease in Lactobacillus abundance (SIL: 60.89% vs. CC: 52.37%; p = 0.247) and an increase in anaerobic bacteria including Prevotella (SIL: 0.14% vs. CC: 0.79%; p < 0.001) and Sneathia (SIL: 0.21% vs. CC: 1.57%; p = 0.097) were observed in CC patients. Lactobacillus abundance was negatively correlated with these anaerobic genera. Among HSIL patients, those who cleared HPV infection had a significantly higher abundance of Atopobium (5.25% vs. 0.65%; p = 0.022). Furthermore, ADC patients showed significantly higher microbial abundance in both vaginal and peritoneal fluid samples compared to SCC patients. LEfSe analysis indicated that Prevotella was the most distinguishing genus in the ADC group.

Our study suggests that vaginal microbiota diversity may be associated with the severity of cervical lesions. Additionally, ADC patients showed heightened microbial diversity in both vaginal and peritoneal fluid microbiota compared to SCC patients.