Bacterial microbiome analysis of vaginal, cervical, and endometrial samples in patients with adenomyosis during the window of implantation

Troha, Nika (author), Zorec, Tomaž Mark (author), Hošnjak, Lea (author), Strašek Smrdel, Katja (author), Celar Šturm, Andraž (author), Šalamun, Vesna (author), Frković-Grazio, Snježana (author), Vrtačnik-Bokal, Eda (author), Poljak, Mario (author)

Adenomyosis is a chronic gynecological condition affecting a substantial portion of women of reproductive age. With symptoms including abnormal uterine bleeding, chronic pelvic pain (CPP), dysmenorrhea, and infertility, poor response to symptomatic treatment and unfavorable outcomes of assisted reproductive technologies, it remains a significant diagnostic and therapeutic challenge. Here, we analyzed microbial compositions of the reproductive tract of women with adenomyosis (n = 33) in comparison with healthy controls (n = 31). Vaginal, cervical, and endometrial samples were collected using minimally invasive transcervical sampling techniques on the 22nd day of the menstrual cycle, during the so-called window of implantation. 16S rRNA was amplified and recorded using the next generation sequencing. Bioinformatic and statistical analysis focused on quantitative taxonomical characterization of the specimens’ microbiomes. Vaginal bacterial microbiome composition was consistent across the three anatomical sites. Compared with the control group, adenomyosis was associated with Lactobacillus iners, whereas Lactobacillus gasseri and Gardnerella vaginalis were negatively associated with adenomyosis and its clinical symptoms. G. vaginalis, typically considered a pathogen, was highlighted as an important dominant microbiome replacement for lactobacilli, more so in healthy women than in women with adenomyosis. Anaerococcus prevotii, Peptoniphilus grossensis, and Peptrostreptococcus anaerobius also showed weak correlation to adenomyosis. Differences in taxa abundance were detected in association with adenomyosis clinical symptoms. L. iners was associated with dysmenorrhea, heavy menstrual bleeding (HMB), as well as CPP. Prevotella disiens, Prevotella timonesis, and Dialister micraerophilus were associated with dysmenorrhea and Peptoniphilus grossensis with HMB, respectively. L. gasseri and L. jensenii appeared to anticorrelate with these symptoms.

• Language: English
• Keywords: adenomyosis, reproductive tract, microbiome, Lactobacillus iners, Lactobacillus gasseri, Gardnerella vaginalis, window of implantation, infertility, reproductive health
• Typology: 1.01 - Original Scientific Article
• Organization: MF - Faculty of Medicine
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: 19 str.
• Numbering: Vol. 14, iss.4, art. e02791-25
• PID: 20.500.12556/RUL-184384
• UDC: 61
• ISSN on article: 2165-0497
• DOI: 10.1128/spectrum.02791-25
• COBISS.SI-ID: 269348355
• Publication date in RUL: 06.07.2026

Record is a part of a journal

• Title: Microbiology spectrum
• Shortened title: Microbiol. spectr.
• Publisher: ASM
• ISSN: 2165-0497
• COBISS.SI-ID: 4526968

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: adenomioza, mikrobiom rodil, implantacijsko okno

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P3-0083
• Name: Odnosi parazitskega obstajanja