Bacteroides fragilis metabolises exopolysaccharides produced by bifidobacteria. Issue 1 (December 2016)

• Record Type: Journal Article
• Authors: Rios-Covian, David; Cuesta, Isabel; Alvarez-Buylla, Jorge; Ruas-Madiedo, Patricia; Gueimonde, Miguel; de los Reyes-Gavilán, Clara
• Is Part Of: BMC microbiology. Volume 16:Issue 1(2016)
• Page Start: 1
• Page End: 8
• Publication Date: 2016-12
• Subjects: Bacteroides fragilis -- Exopolysaccharides -- Bifidobacterium -- MALLS -- Heteropolysaccharides; Microbiology -- Periodicals; 579.05
• DOI: 10.1186/s12866-016-0773-9
• Languages: English
• ISSNs: 1471-2180

Abstract

Abstract Background Bacteroides fragilis is the most frequent species at the human intestinal mucosal surface, it contributes to the maturation of the immune system although is also considered as an opportunistic pathogen. SomeBifidobacterium strains produce exopolysaccharides (EPS), complex carbohydrate polymers that promote changes in the metabolism ofB. fragilis when this microorganism grows in their presence. To demonstrate thatB. fragilis can use EPS from bifidobacteria as fermentable substrates, purified EPS fractions from two strains, Bifidobacterium longum E44 andBifidobacterium animalis subsp.lactis R1, were added as the sole carbon source in cultures ofB. fragilis DSMZ 2151 in a minimal medium. Bacterial counts were determined during incubation and the evolution of organic acids, short chain fatty acids (SCFA) and evolution of EPS fractions was analysed by chromatography. Results Growth ofB. fragilis at early stages of incubation was slower in EPS than with glucose, microbial levels remaining higher in EPS at prolonged incubation times. A shift in metabolite production byB. fragilis occurred from early to late stages of growth, leading to the increase in the production of propionate and acetate whereas decrease lactate formation. The amount of the two peaks with different molar mass of the EPS E44 clearly decreased along incubation whereas a consumption of the polymer R1 was not so evident. Conclusions This report demonstrates thatB. fragilis can consume some EPS from bifidobacteria, with a concomitant release of SCFA and organic acids, suggesting a role for these biopolymers in bacteria-bacteria cross-talk within the intestine.