Anaerococcus

Anaerococcus is a genus of Gram-positive, obligate anaerobic cocci within the phylum Firmicutes. It is a normal inhabitant of the human vaginal, skin, and gastrointestinal microbiota, but is recognized as an opportunistic pathogen in dysbiotic states, particularly when Lactobacillus-dominant vaginal communities are disrupted.

Anaerococcus enrichment has been documented in the vaginal microbiome of women with endometriosis, where its increased abundance correlates with non-Lactobacillus-dominant community state types (,^{[1]The Vaginal Microbiome as a Tool to Predict rASRM Stage of Disease in Endometriosis: a Pilot StudyPerrotta AR, Borrelli GM, Martins CO et al. · 2020Open reference 1 ↓} cross-sectional;,^{[2]MacSharry 2024 — Endometriosis Specific Vaginal Microbiota Links to Urine and Serum N-GlycomeJohn MacSharry, Zsuzsanna Kovacs, Yongjing Xie et al. · 2024Open reference 2 ↓} cross-sectional).

The genus has also been identified as enriched in HPV-positive cervical cancer, where it contributes to the anaerobic, pro-inflammatory vaginal environment associated with persistent HPV infection and malignant progression (,^{[3]Rashwan et al. 2025 — Insights into the Tripartite Relationship between Cervical Cancer, HPV, and the Vaginal Microbiome: A Mega-AnalysisRashwan HH, Ali MH, Mostafa MM et al. · 2025Open reference 3 ↓} mega-analysis).

These patterns position Anaerococcus as a marker of vaginal Dysbiosis across gynecological conditions.