Project description:Background: Probiotic-like bacteria treatment has been described to be associated with gut microbiota modifications. Goal: To decipher if the effects of the tested probiotic-like bacteria are due to the bacteria itself or due to the effects of the bacteria on the gut microbiota. Methodology: In this study, gut microbiota has been analyzed from feces samples of subjects with metabolic syndrome and treated with one of the 2 tested probiotic-like bacteria or with the placebo during 3months.
Project description:Escherichia coli Nissle 1917 (EcN) is a probiotic used for treatment of intestinal disorders. EcN improves gastrointestinal homeostasis and microbiota balance; however little is known about how this probiotic delivers effector molecules to the host. Outer membrane vesicles (OMVs) are constitutively produced by gram-negative bacteria and have a relevant role in bacteria-host interactions. Here we performed proteomic analysis of EcN OMVs. Using 1D SDSD-PAGE and highly sensitive LC-MS/MS analysis we identified 192 EcN vesicular proteins with high confidence in three independent experiments. Of these proteins, 18 were encoded by strain-linked genes and 57 were common to pathogen-derived OMVs. These proteins may contribute to the ability of this probiotic to colonize the human gut as they fulfil functions related to adhesion to host tissues, immune modulation or bacterial survival in host niches. This study describes the first global OMV proteome of a probiotic strain and provides evidence that probiotic-derived OMVs contain proteins that can target these vesicles to the host and mediate their beneficial effects on intestinal function.
Project description:<p>A mechanistic understanding of the health benefits conferred by consumption of probiotic bacteria has been limited by our knowledge of the resident gut microbiota and its interaction with the host. We used fecal samples from a study of twelve healthy individuals aged 65-80 to characterize the structure and functional dynamics of the gut microbiota associated with consumption of the single-organism probiotic, Lactobacillus rhamnosus GG ATCC 53103 (LGG). Samples were collected prior to probiotic consumption (day 0), on day 28 immediately after consuming 10^10 CFU of LGG twice daily for 28 days and day 56, one month after stopping LGG consumption. Our integrative approach incorporated bacterial 16S rRNA gene sequencing, whole-community expression profiling using RNA-seq, and metagenomic sequencing. We highlight the value of combinatorial 'omics methods and concomitant high-resolution informatics to probe the role that probiotics may play on the structure and function of the resident microbiota.</p>
Project description:Bacteria that colonize the human gut must withstand a variety of stressors, including detergent-like compounds known as bile acids. Here, we investigated how bile acids found in the human cecum and colon impact the behavior of the probiotic strain Escherichia coli Nissle 1917 (EcN). We found that lithocholic acid (LCA), which is a microbiota-derived secondary bile acid, promotes the formation of a distinctive surface-coating biofilm by EcN, including on an organoid-derived model of the human colonic epithelium. Mechanistic investigations, including RNA-sequencing, revealed that LCA upregulates the production of several components of flagella, which are essential for LCA-induced biofilm formation and form part of the biofilm extracellular matrix.
Project description:Modulation of gut microbiota through probiotic supplementation is an interesting strategy to prevent obesity We use microarrays to study the global genome expression of C. elegans fed with the probiotic strain Bifidobacterium animalis sbsp. lactis CECT 8145
Project description:Rapidly growing antibiotic resistance among gastrointestinal pathogens, and the ability of antibiotics to induce the virulence of these pathogens makes it increasingly difficult to rely on antibiotics to treat gastrointestinal infections. The probiotic E. coli strain Nissle 1917 (EcN) is the active component of the pharmaceutical preparation Mutaflor® and has been successfully used in the treatment of gastrointestinal disorders. Gut bacteriophages are dominant players in maintaining the microbial homeostasis in the gut, however, their interaction with incoming probiotic bacteria remains to be at conception. The presence of bacteriophages in the gut makes it inevitable for any probiotic bacteria to be phage resistant, in order to survive and successfully colonize the gut. This study addresses the phage resistance of EcN, specifically against lytic T4 phage infection. From various experiments we could show that i) EcN is resistant towards T4 phage infection, ii) EcN’s K5 polysaccharide capsule plays a crucial role in T4 phage resistance and iii) EcN’s lipopolysaccharide (LPS) inactivates T4 phages and notably, treatment with the antibiotic polymyxin B which neutralizes the LPS destroyed the phage inactivation ability of isolated LPS from EcN. Our results further indicate that N-acetylglucosamine at the distal end of O6 antigen in EcN’s LPS could be the interacting partner with T4 phages. From our findings, we have reported for the first time, the role of EcN’s K5 capsule and LPS in its defense against T4 phages. In addition, by inactivating the T4 phages, EcN also protects E. coli K-12 strains from phage infection in tri-culture experiments. The combination of the identified properties is not found in other tested commensal E. coli strains. Furthermore, our research highlights phage resistance as an additional safety feature of EcN, a clinically successful probiotic E. coli strain.