Uterine Microbiota: Residents, Tourists, or Invaders?

Area of Science:

• Reproductive biology and microbiology.

Background:

• The presence and role of bacteria within the human uterus remain debated, with uncertainty regarding whether they are residents, transient visitors, or pathogens.
• Existing research presents discrepancies, necessitating a critical review of the current understanding of uterine microbiota.

Purpose of the Study:

• To provide a historical overview and current status of uterine microbiota research.
• To stimulate discussion and identify research priorities on this controversial topic.
• To examine discrepancies in current reports and explore potential routes of bacterial seeding in the uterus.

Main Methods:

• This study is a comprehensive literature review.
• It critically examines existing reports on uterine microbiota.
• It discusses established and putative routes of bacterial seeding and host-microbiota interactions.

Main Results:

• Current literature presents conflicting findings regarding the composition and function of the uterine microbiota.
• Potential routes for bacterial seeding of the uterus and interactions with other mucosal sites are discussed.
• The need for more rigorous clinical and translational studies is highlighted.

Conclusions:

• Further research is crucial to understand the role of uterine microbiota in reproductive, obstetric, and gynecologic health.
• Investigating host-microbiota interactions is essential to elucidate their impact on the endometrial microenvironment.
• Clarifying the status of uterine bacteria (resident, tourist, or invader) is key to advancing women's health research.