Novel probiotic Bifidobacterium longum subsp. infantis CECT 7210 strain active against rotavirus infections

Abstract

Rotavirus is the leading cause of severe acute gastroenteritis among children worldwide. It is well known that breast-feeding and vaccination afford infants protection. Since breast-feeding has drastically decreased in developed countries, efforts have been focused on the potential use of probiotics as preventive agents. In this study, a novel Bifidobacterium longum subsp. infantis strain was isolated from infant feces and selected, based on its capacity to inhibit in vitro rotavirus Wa replication (up to 36.05% infectious foci reduction) and also to protect cells from virus infection (up to 48.50% infectious foci reduction) in both MA-104 and HT-29 cell lines. Furthermore, studies using a BALB/c mouse model have proved that this strain provides preliminary in vivo protection against rotavirus infection. The strain has been deposited in the Spanish Type Culture Collection under the accession number CECT 7210. This novel strain has the main properties required of a probiotic, such as resistance to gastrointestinal juices, biliary salts, NaCl, and low pH, as well as adhesion to intestinal mucus and sensitivity to antibiotics. The food safety status has been confirmed by the absence of undesirable metabolite production and in acute ingestion studies of mice. Overall, these results demonstrate that Bifidobacterium longum subsp. infantis CECT 7210 can be considered a probiotic able to inhibit rotavirus infection.

Fig. 1.

Data obtained by BFM medium plate counts from mouse feces at different times in the study. *, significantly different from control group at 10 h (P < 0.01).

Fig. 2.

Rotavirus antigen shedding in feces of mice fed with the selected probiotic compared with a placebo (control group). Results are given as the mean value ± standard deviation of triplicate absorbance values at 492 nm, converted to FFU/mg with the aid of a standard curve, which reflects the viral shedding for each mouse group. *, significantly different from control group (P < 0.01); **, significantly different from control group (P < 0.05).

Fig. 3.

Bifidobacteria counts in feces of immunocompetent mice (a) and in immunosupressed mice (b).