Effect of short-chain carbohydrates on human intestinal bifidobacteria and Escherichia coli in vitro

Abstract

Plate counts and small subunit (SSU) rRNA abundance were used to study the effects of fructo-oligosaccharides (FOS), fructose, or galacto-oligosaccharides (GOS) on bi®dobac-terial populations in human faecal microbiotas. The bacteria were grown in pHcontrolled anaerobic fermentation vessels. Untreated cultures and fructose-amended fermenters were used as controls. Bi®dobacterium longum, B. adolescentis and B. angulatum comprised the dominant bi®dobacterial populations throughout the experiment. No major differences were found in the four treatments, in terms of viable counts of the organisms or of total populations of bi®dobacteria at any time point. However, large differences were observed with respect to the abundance of bi®dobacterial SSU rRNA between the treatments. Greatest bi®dobacterial SSU rRNA abundance was seen in FOS cultures, with the lowest in the untreated control fermentation. GOS and fructose also increased bi®dobacterial SSU rRNA. Cultures supplemented with FOS and GOS were also associated with lower colony counts and SSU rRNA abundance for Escherichia coli, compared with fructose-supplemented and control fermenters. At the 24-h time point, the untreated control contained 19.8 ìg of enterobacterial SSU rRNA/ml of culture¯uid, compared with 11.4 ìg/ml for the fructose fermentation, and 2.6 and 0.5 ìg/ml for the FOS and GOS culture vessels, respectively.

A Genomic Island of an Extraintestinal Pathogenic Escherichia coli Strain Enables the Metabolism of Fructooligosaccharides, Which Improves Intestinal Colonization

“…They are used commercially in food products and nutritional supplements. In the intestines of humans, rats, horses, pigs, and chicks, FOS stimulate growth of probiotic bacteria, and some studies have found that they inhibit the growth of pathogenic bacteria such as Salmonella enterica serovar Typhimurium and Escherichia coli (4,7,33,42). Genes involved in the assimilation of FOS by probiotic bacteria, such as lactic acid bacteria, have been identified (3,21,39), but so far they have not been found in pathogenic bacteria.…”

Nondigestible Oligosaccharides Enhance Bacterial Colonization Resistance against Clostridium difficile In Vitro

“…Molecular analyses have been used to assess the effects of NDO on colonic bacterial populations (36,38). These methods allow specific groups of bacteria to be targeted with a high degree of confidence without a need to isolate the organisms from complex communities, and they provide an indication of the relative metabolic potentials of different bacterial groups.…”

Bimuno™ and reduction of the bad bacteria that can cause travellers’ diarrhoea - Scientific substantiation of a health claim related to Bimuno™ and reduction of the bad bacteria that can cause travellers’ diarrhoea pursuant to Article 14 of Regulation (EC

“…The applicant identified one unpublished randomised controlled human intervention study (Drakoularakou et al, claimed to be confidential by the applicant), one unpublished nonhuman study (Searle et al, in press, claimed to be confidential by the applicant), three published in-vitro studies (Sharp et al, 2001;Shoaf et al, 2006;Tzortzis et al, 2005) and one review (Cummings et al, 2004) as being pertinent to the health claim.…”

“…As Bimuno TM was not tested in the in vitro studies by Sharp et al (2001) and by Shoaf et al (2006), the Panel considers that these studies are not pertinent to the health claim.…”