Bacteriotherapy
Bacteriotherapy means putting live, protective commensal bacteria onto eczema skin. The idea comes from the Skin Microbiome: lesional AD skin is often dominated by Staphylococcus aureus, while non-lesional skin carries more Coagulase-Negative Staphylococci such as S. epidermidis and S. hominis (Acta Derm Venereol 2020). Transplanted commensals might make anti-staphylococcal compounds or calm inflammation (Ogonowska, Front Microbiol 2021). It differs from oral Probiotics, which are swallowed gut bacteria.
Bacteriotherapy [part-of] Skin Microbiome Bacteriotherapy [opposes] Staphylococcus aureus Bacteriotherapy [relates] Probiotics
Staphylococcus hominis A9. In a double-blind phase 1 trial (Nakatsuji, Nature Medicine 2021), S. hominis A9 or vehicle was applied to the forearm skin of 54 adults with S. aureus-positive AD for 1 week. It met its safety endpoint and reduced S. aureus. Eczema severity did not improve significantly overall. Local improvement appeared only in a post-hoc subgroup whose own S. aureus strain the A9 strain could kill. No children were included.
Coagulase-Negative Staphylococci [part-of] Bacteriotherapy
Roseomonas mucosa. The second approach used Roseomonas mucosa, a Gram-negative bacterium from healthy donors. An open-label NIH trial in 10 adults and 5 children aged 9–14 reported large improvements and no adverse events, but had no placebo arm (Myles, JCI Insight 2018). The placebo-controlled follow-up, FB-401, enrolled 154 people aged 2 and over with mild-to-moderate AD. After 16 weeks, about 58% on FB-401 and 60% on placebo reached EASI-50. It was safe but no better than placebo, and the company stopped development (Dermatology 2024; Clinical Trials Arena 2021). The open-label promise did not hold up once a placebo was used.
Roseomonas mucosa [part-of] Bacteriotherapy EASI [relates] Bacteriotherapy
For toddlers. No bacteriotherapy product is licensed. The only placebo-controlled data that included 2–4-year-olds showed no benefit. For S. aureus in toddler eczema, standard care is still to control inflammation with Topical Corticosteroids and to treat true infection when it occurs (Infected Eczema).
Topical Corticosteroids [relates] Bacteriotherapy
Connections
- Skin Microbiome — S. hominis A9 phase 1 RCT, source: Nakatsuji Nat Med 2021
- Staphylococcus aureus — target of commensal killing, source: Nakatsuji 2021
- Coagulase-Negative Staphylococci — S. hominis A9 is a CoNS strain, source: Nakatsuji 2021
- Roseomonas mucosa — FB-401 phase 2 (ages 2+) failed vs placebo, source: Dermatology 2024
- Probiotics — oral gut bacteria, a different approach, source: Ogonowska 2021
- Infected Eczema — standard care when S. aureus causes true infection, source: NICE NG190