"Isolation and Characterization of Some Potential Probiotic Candidates for the Control of Clostridium difficile Infection"

Abstract

This study is aimed at the isolation, identification, and characterization of potential probiotic strains capable of inhibiting C. difficile infectionin vitro and in vivo. Twenty isolates were isolated from breast fed infant fecal samples and screened against C. difficile using their cell-free supernatant. Only three isolates showed maximum inhibition from 56.05% to 60.60% thus they were characterized for probiotic properties and safety. The results revealed their tolerance to the GIT conditions and safety profile. They were identified by sequencing 16S rRNA as E. faecalis NM815, E. faecalis NM915 and E. faecium NM1015. Their sequences were submitted to GenBank as KU365166, KU365167 and KU365168 respectively. For in vivo evaluation, a viable mixture of the three strains (109 CFU/ml) was administrated to group of mice (treated group) in daily dose for 14 days, then followed by a challenge with viable C. difficile (105 CFU/ml) in daily dose for 7 days, then a second administration of a viable mixture of the three strains was done daily for 10 days. For control two mice groups were used; control group which was administrated PBS only, untreated group which received PBS instead of the probiotic mixture before and after the challenge with C. difficile. The results obtained from histological analysis in addition to assessment of the toxin A and toxin B gene copies within the mice fecal samples from each group, confirmed the effectiveness of the three potential probiotic strains which expressed as inhibition of C. difficile, reduction in the toxin A and toxin B gene copies and maintenance of the structural integrity of the examined intestinal and liver cellscompared to the untreated groups.