Dry alginate beads for fecal microbiota transplantation: From model strains to fecal samples.

Clostridioides difficile infection (CDI) is a critical nosocomial infection with more than 124,000 cases per year in Europe and a mortality rate of 15-17 %. The standard of care (SoC) is antibiotic treatment. Unfortunately, the relapse rate is high (∼35 %) and SoC is significantly less effective against recurrent infection (rCDI). Fecal microbiota transplantation (FMT) is a recommended treatment against rCDI from the second recurrence episode and has an efficacy of 90 %. The formulation of diluted donor stool deserves innovation because its actual administration routes deserve optimization (naso-duodenal/jejunal tubes, colonoscopy, enema or several voluminous oral capsules). Encapsulation of model bacteria strains in gel beads were first investigated. Then, the encapsulation method was applied to diluted stools. Robust spherical gel beads were obtained. The mean particle size was around 2 mm. A high loading of viable microorganisms was obtained for model strains and fecal samples. For plate-counting, values ranged from 1015 to 1017 CFU/g for single and mixed model strains, and 106 to 108 CFU/g for fecal samples. This corresponded to a viability of 30 % to 60 % as assessed by flow cytometry. This novel formulation is promising as the technology is applicable to both model strains and bacteria contained in the gut microbiota.

Fecal microbiota transplantation: a review on current formulations in Clostridioides difficile infection and future outlooks.

INTRODUCTION: The role of the gut microbiota in health and the pathogenesis of several diseases has been highlighted in recent years. Even though the precise mechanisms involving the microbiome in these ailments are still unclear, microbiota-modulating therapies have been developed. Fecal microbiota transplantation (FMT) has shown significant results against Clostridioides difficile infection (CDI), and its potential has been investigated for other diseases. Unfortunately, the technical aspects of the treatment make it difficult to implement. Pharmaceutical technology approaches to encapsulate microorganisms could play an important role in providing this treatment and render the treatment modalities easier to handle. AREAS COVERED: After an overview of CDI, this narrative review aims to discuss the current formulations for FMT and specifically addresses the technical aspects of the treatment. This review also distinguishes itself by focusing on the hurdles and emphasizing the possible improvements using pharmaceutical technologies. EXPERT OPINION: FMT is an efficient treatment for recurrent CDI. However, its standardization is overlooked. The approach of industrial and hospital preparations of FMT are different, but both show promise in their respective methodologies. Novel FMT formulations could enable further research on dysbiotic diseases in the future.