Evaluation of growth and sporulation of a non-toxigenic strain of Clostridioides difficile (Z31) and its shelf viability

Abstract

The oral administration of non-toxigenic strains of Clostridioides difficile (NTCD) is currently showing promising results for the prevention of Clostridioides difficile infection (CDI) in humans and animals, and is being considered as a possible commercial product to be used in the near future. The aim of this work was to evaluate five culture media for the growth and sporulation of one NTCD (Z31) and evaluate the viability of a lyophilized spore solution of NTCD Z31 stored at 4°C or at 25°C for 2 years. Reinforced clostridial medium (RCM) and brain heart infusion broth (BHI) provided the highest production of NTCD Z31 spores. In the first 6 months of the storage of the lyophilized solution, a reduction in spore count of approximately 0.3 Log 10 CFU/ mL was observed; however, no further significant reduction in spore count was observed up to 24 months. No difference in spore concentration was found between the two storage temperatures from 6 to 24 months of storage. The present work showed BHI and RCM to be the best choices for the growth and sporulation of NTCD Z31 and suggested that the spores of NTCD Z31 are stable for up to 2 years under both temperature conditions.

Non-Toxigenic Clostridioides difficile Strain E4 (NTCD-E4) Prevents Establishment of Primary C. difficile Infection by Epidemic PCR Ribotype 027 in an In Vitro Human Gut Model

“…As phylogenetically divergent NTCD strains have demonstrated in vitro and in vivo efficacy in CDI prevention [ 21 , 24 , 63 , 79 , 80 ], it remains a possibility that as of yet uncharacterized factors determine the efficacy of NTCD for the prevention of CDI by virulent strains.…”