Effect of Fructooligosaccharide Metabolism on Chicken Colonization by an Extra-Intestinal Pathogenic Escherichia coli Strain

Abstract

Extra-intestinal pathogenic Escherichia coli (ExPEC) strains cause many diseases in humans and animals. While remaining asymptomatic, they can colonize the intestine for subsequent extra-intestinal infection and dissemination in the environment. We have previously identified the fos locus, a gene cluster within a pathogenicity island of the avian ExPEC strain BEN2908, involved in the metabolism of short-chain fructooligosaccharides (scFOS). It is assumed that these sugars are metabolized by the probiotic bacteria of the microbiota present in the intestine, leading to a decrease in the pathogenic bacterial population. However, we have previously shown that scFOS metabolism helps BEN2908 to colonize the intestine, its reservoir. As the fos locus is located on a pathogenicity island, one aim of this study was to investigate a possible role of this locus in the virulence of the strain for chicken. We thus analysed fos gene expression in extracts of target organs of avian colibacillosis and performed a virulence assay in chickens. Moreover, in order to understand the involvement of the fos locus in intestinal colonization, we monitored the expression of fos genes and their implication in the growth ability of the strain in intestinal extracts of chicken. We also performed intestinal colonization assays in axenic and Specific Pathogen-Free (SPF) chickens. We demonstrated that the fos locus is not involved in the virulence of BEN2908 for chickens and is strongly involved in axenic chicken cecal colonization both in vitro and in vivo . However, even if the presence of a microbiota does not inhibit the growth advantage of BEN2908 in ceca in vitro , overall, growth of the strain is not favoured in the ceca of SPF chickens. These findings indicate that scFOS metabolism by an ExPEC strain can contribute to its fitness in ceca but this benefit is fully dependent on the bacteria present in the microbiota.

Nutraceuticals Induced Structural Changes in Broiler Gastrointestinal Tract Microbiota

“…This technology was designed to achieve high weight gain while producing quality meat. We obtained, that under our experimental conditions diet enriched in FOSs, anthocyanins and synbiotics did not alter growth performance during the production stages supporting the estimations of other data [57,91,92]. Furthermore, based on our findings plant derived nutraceuticals have been shown to strengthen the positive correlations between body weight gain and the beneficious Bacteroidales, Campylobacteriales, Corynebacteriales and Pseudomonadales associated with increased absorption of nutrients through the improvement of the integrity of the intestinal epithelia [78,[93][94][95].…”

“…Health-promoting probiotic bacteria can ferment prebiotics which are undigestible and non-absorbable for the host and convert them to lactic acid and short-chain fatty acids (SCFAs) [50][51][52][53][54][55][56][57][58][59][60]. SCFA producing bacteria may directly enhance the absorption of some nutrients [61][62][63][64][65][66].…”

Metabolism of Fructooligosaccharides in Lactobacillus plantarum ST-III via Differential Gene Transcription and Alteration of Cell Membrane Fluidity

“…Although the main targets for prebiotic FOS are bifidobacteria and lactobacilli, other members of the GIT microbiota have also been demonstrated to consume FOStype fructans and even to be stimulated by their ingestion (47,48). Basically, two metabolic routes of FOS metabolism exist in bacteria in the GIT.…”

Prebiotics and gut microbiota in chickens

“…A gene cluster, called the fos locus, has been identified in the genome of avian extraintestinal E. coli (ExPEC) that encodes proteins involved in FOS metabolism (Schouler et al 2009;Porcheron et al 2011). The products of the gene cluster provided a strong growth advantage for the ExPEC strains to colonize the chicken intestine (Porcheron et al 2012). Growth of undesirable bacteria can suppress the beneficial effects provided by probiotic-mediated utilization of FOS.…”