Prebiotic Activity of Vaginal Lactobacilli on Bifidobacteria: from Concept to Formulation

Abstract

Bifidobacteria in the gut tract of infants play crucial roles in the prevention of gastrointestinal diseases and the maturation of the immune system. Consequently, strategies to trigger a bifidogenic shift in the infant gut are highly desirable.

Limosilactobacillus vaginalis Exerts Bifidogenic Effects: A Novel Postbiotic Strategy for Infant Prebiotic Supplementation

“…In this regard, we have previously demonstrated that the culture supernatants of vaginal lactobacilli, especially that of L. vaginalis BC17, can stimulate the growth of Bifidobacterium spp., likely due to the secretion of metabolites that can serve as substrates [18]. Instead, in the present work, we focused on L. vaginalis BC17 cells to further investigate the strain's capability to drive a bifidogenic shift in infants' gut.…”

“…infantis DSM20088, B. longum subsp. infantis DSM20090, B. adolescentis DSM20083, B. adolescentis DSM20086, B. angulatum DSM20098) were purchased from DSMZ (Braunschweig, Germany) [18]. L. vaginalis and bifidobacteria were routinely cultured in de Man, Rogosa, and Sharpe broth (MRS, Difco, Detroit, MI, USA) supplemented with L-cysteine 0.05% (w/v) (Merck, Milan, Italy) at 37 • C, in anaerobic jars containing Gas-Pak EZ (Beckton, Dickinson and Co., Milan, Italy).…”

“…Escherichia coli SO107 and Streptococcus agalactiae SO104 were isolated at Sant'Orsola-Malpighi University Hospital of Bologna (Italy) during routine diagnostic procedures [18,19]. Enterotoxigenic E. coli (ETEC), Salmonella enterica, Yersinia enterocolitica, and Enterococcus faecium BC105 belong to the Department of Pharmacy and Biotechnology of University of Bologna [19,20].…”

“…For each experiment, biofilms were detected by crystal violet staining and MTT assay, which enable the quantification of total biofilm biomass and biomass metabolic activity, respectively [19]. Crystal violet staining was performed following the previously reported protocol [18]. Briefly, culture supernatants were removed, adherent cells were washed twice with sterile saline, fixed with 200 µL of absolute ethanol (Merck), and stained with crystal violet (CV, Merck) for 10 min.…”

“…To mimic the passage through the acidic stomach, 1 g of L-HK-BC17 oil suspension with 2 mL of simulated gastric fluid (SGF) (125 mM NaCl, 7 mM KCl, 45 mM NaHCO 3 , 3 g/L pepsin, pH = 3) was incubated under agitation (100 rpm, Certomat ® Sartorius AG, Göttingen, Germany) for 2 h at 37 • C [18]. Afterwards, the oil-in-water emulsion was formed by adding 0.5 g of Tween 80 and 7.5 mL of sterile saline, the pH was adjusted to 6.5 (with NaOH 5 M), and the effects on the planktonic cultures and biofilms of bifidobacteria and pathogens were assessed.…”