Microbiota of the cervical canal and uterine cavity in hyperplastic diseases of the endometrium: comparative microbiological analysis

Objective: A comprehensive assessment of the microbiota composition in the cervical canal and endometrium in women with various forms of endometrial hyperplastic processes (EHP) – polyp/endometrial hyperplasia in combination with uterine myoma or adenomyosis – compared to patients without endometrial pathology, followed by the analysis of its potential pathogenetic role in hyperplastic changes in the endometrium.

Materials and methods: The study included 100 women of reproductive age, divided into 4 groups depending on the presence and nature of endometrial hyperplastic processes. Microbiological examination included polymerase chain reaction test (PCR test) of samples obtained from the cervical canal, as well as culture-based analysis of aspirates from the uterine cavity. To characterize microbial communities, an assessment of microbial saturation and biological diversity was carried out using alpha diversity indices (Shannon-Wiener diversity, Simpson diversity, Margalef's richness) and subsequent data statistical processing.

Results: We found that microbial richness and taxonomic diversity were significantly higher in the cervical canal compared to the endometrium in all study groups. The maximum frequency of endometrial sterility was observed in the control group (52%). However, this indicator was lower and amounted to 24% (p=0.042) in a combination of hyperplastic changes with adenomyosis. The leading representatives of normobiota were Lactobacillus jensenii, L. crispatus and L. gasseri. Opportunistic microorganisms, including Gardnerella vaginalis, Escherichia coli and Enterococcus faecalis, were more often detected in the endometrium of patients with EHP, which may indicate the presence of disorder in microbial homeostasis and the potential pathogenetic significance of these microorganisms.

Conclusion: The microbiological analysis revealed a decline in species diversity and an increase in the proportion of opportunistic microorganisms in the endometrium of patients with EHP. Such changes may indicate microbial transformation of the intrauterine environment and the supposed participation of microbiota in the pathogenesis of this pathology. The obtained results confirm the relevance of further research aimed at a detailed study of the interaction mechanisms between microbiota and endometrial tissue structures, as well as an assessment of its impact on the prevention and treatment of EHP.