Eggerthella

Metal Dependencies#

Eggerthella lenta relies on several metal cofactors for its diverse reductase enzymes.

Iron: Required for electron transport chains in anaerobic respiration. E. lenta uses iron-containing oxidoreductases for its dehydroxylation reactions. Cobalt: The cardiac glycoside reductase (Cgr) operon that inactivates digoxin requires cobalamin (vitamin B12) as a cofactor, linking cobalt availability to drug metabolism.

Molybdenum: Molybdopterin-dependent enzymes participate in the reductive metabolism that defines the genus.

Unlike many strict anaerobes that are sensitive to Heavy Metals, Eggerthella appears to be metal-tolerant. In multiple sclerosis cohorts, E. lenta expands precisely when metal-sensitive Clostridia are depleted—a pattern consistent with Cadmium, Lead, and Nickel exposure selectively removing competitors (,^{[1]Dysbiosis in the Gut Microbiota of Patients with Multiple Sclerosis, with a Striking Depletion of Species Belonging to Clostridia XIVa and IV ClustersSachiko Miyake, Sangwan Kim, Wataru Suda et al. · 2015Open reference 1 ↓} cross-sectional).

Key Enzymes and Virulence Factors#

Dopamine dehydroxylase: E. lenta converts dopamine to m-tyramine through dehydroxylation, forming the second step of an interspecies relay where Enterococcus faecalis first converts L-DOPA to dopamine via tyrosine decarboxylase (TyrDC). This two-step pathway significantly reduces levodopa bioavailability in Parkinson's disease patients (,^{[2]Maini Rekdal 2019 -- Discovery and Inhibition of an Interspecies Gut Bacterial Pathway for Levodopa MetabolismVayu Maini Rekdal, Emily N Bess, Jordan E Bisanz et al. · 2019Open reference 2 ↓} in-vitro).

Cardiac glycoside reductase (Cgr): Inactivates digoxin in the gut lumen, reducing drug efficacy. This enzyme is strain-specific—only E. lenta strains carrying the Cgr operon metabolize digoxin (,^{[3]Microbiome-Drug Interactions: A Critical Review of Pharmacokinetic and Pharmacodynamic ModulationRamya Sree Maddu, Aarthi Saima Ghanta, Veeresh Pratap · 2025Open reference 3 ↓} expert-opinion).

Beta-glucuronidase: Deconjugates glucuronidated estrogens, returning active estrogen to the circulation. This activity connects Eggerthella to the Estrobolome and estrogen-dependent conditions.

Enriched in:#

Multiple sclerosis: Significantly increased in Japanese MS patients alongside Streptococcus thermophilus; expansion coincides with depletion of Treg-inducing Clostridia (,^{[1]Dysbiosis in the Gut Microbiota of Patients with Multiple Sclerosis, with a Striking Depletion of Species Belonging to Clostridia XIVa and IV ClustersSachiko Miyake, Sangwan Kim, Wataru Suda et al. · 2015Open reference 1 ↓} cross-sectional, n=40). Also reported enriched in European MS cohorts (,^{[6]Feeding the gut microbiome: impact on multiple sclerosisMatteo Bronzini, Alessandro Maglione, Rachele Rosso et al. · 2023Open reference 6 ↓} expert-opinion).

Chronic kidney disease: Consistently enriched in CKD; contributes to uremic toxin generation (indoxyl sulfate, p-cresyl sulfate) that accelerates renal decline (,^{[4]Wehedy et al. 2022 — The Human Microbiome in CKD: A Double-Edged SwordWehedy, Ghali, Matboli · 2022Open reference 4 ↓} expert-opinion).

Premature ovarian insufficiency: Abundance significantly increased in POI patients; reversed by hormone replacement therapy. E. lenta induced ovarian fibrosis when administered to mice, an effect ameliorated by estrogen (,^{[7]Hormone Replacement Therapy Reverses Gut Microbiome and Serum Metabolome Alterations in Premature Ovarian InsufficiencyJiang L, Fei H, Tong J et al. · 2021Open reference 7 ↓} animal-model).

Hashimoto's thyroiditis: Identified among genera with significant differences between HT progression stages (,^{[8]Analysis of gut microbiota diversity in Hashimoto's thyroiditis patientsLiu J, Qin X, Lin B et al. · 2022Open reference 8 ↓} cross-sectional).