The study of endometriosis and adenomyosis related microbiota in female lower genital tract in Northern Chinese population

Background Endometriosis is a chronic disease that affects women in reproductive age, and adenomyosis was known as “endometriosis in the uterus”. Endometriosis is an immune-dysfunction-related disease, contributing to the diversity of microbiota in the lower genital tract. Endometriosis is also an infection-related disease, the number of bacteria may contribute to some unknown mechanisms. Presently, the feature of microbiota between endometriosis patients and normal people is not fully understood. Methods To identify the microbiota differences and features of endometriosis patients, 298 samples from the cervical canal, posterior fornix of the vagina and uterine cavity were analyzed by 16s-rRNA sequencing. Raw data were filtered, analyzed, and visualized. We conducted diversity analysis, statistical data of microbiota abundance, biomarker identification, random forest, and environmental factors analysis. Results Alpha diversity was not distinctive in endometriosis and adenomyosis patients. Posterior fornix near cervix was a better sampling location to analyze the dysmenorrhea-related microbiota feature; few dysmenorrhea-related bacteria were identified. Endometrial bacteria is controversial, and the result of 16s-rRNA sequencing was not good enough to conduct further analysis. Anaerococcus was a possible biomarker of adenomyosis-endometriosis patients. The identified bacteria were representative only in specific periods during the menstrual cycle. GnRH-a treatment impacted microbiota feature the most compared with other environmental factors. Conclusion This study provided us with a new concept of endometriosis and bacteria; different microbiota features may relate to endometriosis. The bacterial involvement should be considered in the future study of endometriosis. New non-invasive diagnosis and therapeutic methods through bacterial medication are prospective.