Effect of antibiotic pre-treatment on the engraftment efficiency in mice. Mouse FMT

Fecal microbiota transplantation (FMT) is an effective therapy for recurrent Clostridioides difficile infection (rCDI). In addition, it is currently considered as a potential treatment for a wide range of intestinal and systemic diseases. FMT corrects microbiota dysbiosis associated with rCDI and the engraftment of donor microbiota is likely to play a key role in the treatment success. For disease indications other than rCDI, FMT treatment efficacy has been moderate. This may be partly due to stronger resilience of resident host microbiota in patients who do not suffer from rCDI. rCDI patients have typically undergone multiple antibiotic treatments prior to FMT, and present with extensive microbiota dysbiosis. In this study, we addressed the effect of broad-spectrum antibiotics (Ab) as a pre-treatment to FMT for the engraftment of donor microbiota. We conducted a pre-clinical study of FMT between two healthy strains of mice, to mimic interindividual FMT between human subjects.Microbiota composition was assessed by high-throughput 16S rDNA amplicon sequencing. Our results showed that Ab-treatment strongly diminished microbiota before FMT, but didn´t increase the overall similarity of the recipient´s microbiota to that of the donor´s after FMT, as compared to control treatment. However, Bifidobacterium and several other taxa, which were higher in the donor mice, showed increased abundance in recipient mice that were pre-treated with Ab. In conclusion, pre-treatment with broad-spectrum antibiotics didn´t improve the overall engraftment of donor microbiota, but improved the engraftment of specific taxa including Bifidobacterium.