Atopobium parvulum is a Gram-positive obligate anaerobe found primarily in the oral cavity but increasingly detected in gut microbiome studies. It produces hydrogen sulfide (H2S) through cysteine metabolism, contributing to halitosis in the mouth and potentially to mucosal damage when it colonizes the gut.
Metal Dependencies
A. parvulum requires iron for its anaerobic metabolism. Its cysteine desulfhydrase activity generates H2S, which can chelate iron and other metals in the local environment, potentially altering metal bioavailability for neighboring organisms. This places A. parvulum at the intersection of sulfur metabolism and metal ecology.
Ecological Role
In the oral cavity, A. parvulum thrives in anaerobic niches such as tongue biofilms and periodontal pockets, where its H2S output contributes to tissue inflammation. When it translocates to the gut — a phenomenon increasingly documented in inflammatory bowel disease — it may exacerbate mucosal damage through sulfide-mediated inhibition of butyrate oxidation in colonocytes.
Conditions Associated
Enrichment of A. parvulum has been reported in inflammatory bowel disease (particularly Crohn's disease), colorectal cancer, and chronic halitosis. Its oral-to-gut translocation pattern makes it a marker of compromised compartment boundaries, a theme shared with other oral pathobionts like Fusobacterium nucleatum.
Georgina Quaranta, Mauro Pittiruti, Brunella Posteraro et al. (2019). Quaranta 2019 — FMT as a Potential Tool for Female Reproductive Tract Diseases (Review). Frontiers in Immunology. doi:10.3389/fimmu.2019.02653
Ata B, Yildiz S, Turkgeldi E et al. (2019). The Endobiota Study: Comparison of Vaginal, Cervical and Gut Microbiota Between Women with Stage 3/4 Endometriosis and Healthy Controls. Scientific Reports. doi:10.1038/s41598-019-39700-6
Prakash Lingasamy, Vijayachitra Modhukur, Reet Mändar et al. (2024). Lingasamy 2024 — Exploring Immunome and Microbiome Interplay in Reproductive Health. Seminars in Reproductive Medicine. doi:10.1055/s-0043-1778017
Pamela Pruski, Gonçalo D. S. Correia, Holly V. Lewis et al. (2021). Pruski & Correia 2021 — Direct On-Swab Metabolic Profiling of Vaginal Microbiome Host Interactions During Pregnancy and Preterm Birth. Nature Communications. doi:10.1038/s41467-021-26215-w
Asangba AE, Chen J, Goergen KM et al. (2023). Asangba 2023 — Diagnostic and prognostic potential of the microbiome in ovarian cancer treatment response. Scientific Reports. doi:10.1038/s41598-023-27555-x
Qian Yang, Yaping Wang, Xinyi Wei et al. (2020). Yang 2020 — Vaginal Microbiome Alterations in HPV16 Infection by Shotgun Metagenomics. Frontiers in Cellular and Infection Microbiology. doi:10.3389/fcimb.2020.00286
Camila Hernandes, Paola Silveira, Aline Fernanda Rodrigues Sereia et al. (2020). Hernandes 2020 — Microbiome Profile of Deep Endometriosis Patients: Comparison of Vaginal Fluid, Endometrium and Lesion. Diagnostics. doi:10.3390/diagnostics10030163
Rui-Jun Li, Zhu-Ye Jie, Qiang Feng et al. (2021). Network of Interactions Between Gut Microbiome, Host Biomarkers, and Urine Metabolome in Carotid Atherosclerosis. Frontiers in Cellular and Infection Microbiology. doi:10.3389/fcimb.2021.708088