Lactobacillus rhamnosus GG and Saccharomyces cerevisiae boulardii exert synergistic antipathogenic activity in vitro against enterotoxigenic Escherichia coli

Abstract

Short-term colonic in vitro batch incubations were performed to elucidate the possible synergistic effects of Lactobacillus rhamnosus GG (CNCM-I-4798) and Saccharomyces cerevisiae boulardii (CNCM-I-1079) (associated in Smebiocta/Smectaflora Protect®) on the colonic microbial fermentation process, as well as their antipathogenic activity against enterotoxigenic Escherichia coli (LMG2092) (ETEC). These incubations adequately simulate the native microbiota and environmental conditions of the proximal colon of both adult and toddler donors, including the colonic mucosal layer. Results indicated that both strains were capable of growing together without showing antagonistic effects. Co-cultivation of both strains resulted in increased butyrate (stimulated by L. rhamnosus GG), propionate (stimulated by S. boulardii), and ethanol (produced by S. boulardii) production compared to the control incubations, revealing the additive effect of both strains. After inoculation of ETEC under simulated dysbiotic conditions, a 40 and 46% reduction in the concentration of ETEC was observed upon addition of both strains during the experiments with the adult and toddler donor, respectively. Furthermore, ETEC toxin levels decreased upon S. boulardii inoculation, probably due to proteolytic activity of this strain, with a synergistic effect being observed upon co-cultivation of L. rhamnosus GG and S. boulardii resulting in a reduction of 57 and 46% for the adult and toddler donor, respectively. Altogether, the results suggest that both probiotics together may help microbiota functionality, in both adults and toddlers and under healthy or impaired conditions, which could be of great interest when the colonic microbiota is dysbiotic and therefore sensitive to pathogenic invasion such as during antibiotic treatment.

Lacticaseibacillus rhamnosus GG and Saccharomyces cerevisiae boulardii supplementation exert protective effects on human gut microbiome following antibiotic administration in vitro

“…Furthermore, co-dosing L. rhamnosus GG and S. boulardii resulted in superior SCFA recovery compared to the antibiotic control, accompanied by a stronger increase in abundance of Bifidobacteriaceae. This confirmed previous results from our research group, which demonstrated that combination of L. rhamnosus GG and S. boulardii improved microbiota functionality under impaired conditions (Moens et al, 2019). Donor B instead was characterised by a higher abundance of Veillonellaceae in its healthy state, levels of which were drastically reduced following antibiotic dosage in the control arm, while supplementation of the different probiotic test strains preserved Veillonellaceae levels, indicating a potential protective effect of L. rhamnosus GG and S. boulardii on Veillonellaceae levels during antibiotic dosage for this particular donor.…”

2′FL and LNnT Exert Antipathogenic Effects against C. difficile ATCC 9689 In Vitro, Coinciding with Increased Levels of Bifidobacteriaceae and/or Secondary Bile Acids

“…Briefly, sterile 100 mL antibiotic flasks, already containing 250 mg of HMO test product were filled with 49 mL RCM to which 1 mL of freshly prepared C. difficile culture and 20 µL of freshly prepared fecal slurry was administered. The fecal slurries were prepared from freshly collected fecal samples of three different healthy human donors (A, B and C) as described by Moens et al [ 50 ]. The donors had no history of gastrointestinal disorders, and they did not consume antibiotics in the 3 months preceding the study.…”

“…At the start of the experiment, a fecal sample from donor A was collected and a 1:5 ( w / v ) fecal slurry of fecal sample was made in anaerobic phosphate buffer. This buffer was prepared as described by Moens et al [ 50 ]. This slurry was inoculated at 5 vol% in the colon regions containing a nutritional medium exclusively.…”

Fructans with Varying Degree of Polymerization Enhance the Selective Growth of Bifidobacterium animalis subsp. lactis BB-12 in the Human Gut Microbiome In Vitro

“…A dose corresponding with 10 9 CFU of the BB-12 strain was co-administered, reaching a concentration 1.5 × 10 7 CFU/mL at start of the incubation. A sterile anaerobic fecal suspension was prepared from a freshly collected fecal sample of a healthy human donor as described by Moens et al [31] and inoculated at 10% (v/v) into the reactors to provide the BB-12 strain with necessary co-factors to perform substrate breakdown. A blank incubation was included, where BB-12 strain was administered without co-supplementation of fructans.…”