Background
The gastrointestinal microbiota is an important line of defense against colonization with antimicrobial resistant (AR) bacteria. In this post hoc analysis of the Phase 3 ECOSPOR III trial, we assessed impact of a microbiota-based oral therapeutic (fecal microbiota spores, live [VOWSTTM Oral Spores; VOS, formerly SER-109]) compared with placebo, on AR gene (ARG) abundance in patients with recurrent Clostridioides difficile infection (rCDI).
Methods
Adults with rCDI were randomized to receive VOS or placebo orally for 3 days following standard-of-care antibiotics. ARG and taxonomic profiles were generated using whole metagenomic sequencing of stool at baseline and Weeks 1, 2, 8, and 24 post-treatment.
Results
Baseline (n=151) and serial post-treatment stool samples collected through 24 weeks (total n=472) from 182 patients (59.9% female; mean age 65.5 years) in ECOSPOR III as well as 68 stool samples obtained at a single timepoint from a healthy cohort were analyzed. Baseline ARG abundance was similar between arms and significantly elevated vs. the healthy cohort. By Week 1, there was a greater decline in ARG abundance in VOS vs. placebo (p=0.003) in association with marked decline of Proteobacteria and repletion of spore-forming Firmicutes, as compared with baseline. We observed abundance of Proteobacteria and non-spore forming Firmicutes were associated with ARG abundance, while spore-forming Firmicutes abundance was negatively associated.
Conclusions
This proof-of-concept analysis suggests that microbiome remodeling with Firmicutes spores may be a potential novel approach to reduce ARG colonization in the gastrointestinal tract.