Differential modulation of post-antibiotic colonization resistance to by two probiotic strains.

Probiotics are often consumed after antibiotic treatment to prevent antibiotic-associated diarrheal disease, most commonly caused by . However, the impact of probiotic bacteria on the post-antibiotic gut microbiota is undetermined and often overlooked. Here, we examined the effect of a single dose of probiotic NCFM and Lg-36 on colonization resistance against in an antibiotic-treated mouse model.

The curated Lactobacillus acidophilus NCFM genome provides insights into strain specificity and microevolution.

Background: The advent of next generation sequencing technologies has enabled a surge in the number of whole genome sequences in public databases, and our understanding of the composition and evolution of bacterial genomes. Besides model organisms and pathogens, some attention has been dedicated to industrial bacteria, notably members of the Lactobacillaceae family that are commonly studied and formulated as probiotic bacteria. Of particular interest is Lactobacillus acidophilus NCFM, an extensively studied strain that has been widely commercialized for decades and is being used for the delivery of vaccines and therapeutics.

Bile salt hydrolases shape the bile acid landscape and restrict Clostridioides difficile growth in the murine gut.

Bile acids (BAs) mediate the crosstalk between human and microbial cells and influence diseases including Clostridioides difficile infection (CDI). While bile salt hydrolases (BSHs) shape the BA pool by deconjugating conjugated BAs, the basis for their substrate selectivity and impact on C. difficile remain elusive.

Impact of Pomegranate on Probiotic Growth, Viability, Transcriptome and Metabolism.

Despite rising interest in understanding intestinal bacterial survival in situ, relatively little attention has been devoted to deciphering the interaction between bacteria and functional food ingredients. Here, we examined the interplay between diverse beneficial species and a pomegranate (POM) extract and determined the impact of this functional ingredient on bacterial growth, cell survival, transcription and target metabolite genesis. Three commercially available probiotic strains ( NCFM, GG and Lp-115) were used in growth assays and flow cytometry analysis, indicating differential responses to the presence of POM extract across the three strains.

Probiotic colonization dynamics after oral consumption of VSL#3 by antibiotic-treated mice.

The ability of probiotic strains to provide health benefits to the host partially hinges on the survival of gastrointestinal passage and temporary colonization of the digestive tract. This study aims to investigate the colonization profile of individual probiotic strains comprising the commercial product VSL#3 and determine their impact on the host intestinal microbiota. Using a cefoperazone-treated mouse model of antibiotic treatment, we investigated the impact of oral gavage with ~10 CFU commercial VSL#3 product on the intestinal microbiota using 16S-based amplicon sequencing over 7 days.

Metabolomic Analysis of , and Strains in the Presence of Pomegranate Extract.

species are prominent inhabitants of the human gastrointestinal tract that contribute to maintaining a balanced microbial environment that positively influences host health. These bacterial populations can be altered through use of probiotic supplements or dietary changes which in turn affect the host health. Utilizing polyphenolic compounds to selectively stimulate the growth of commensal bacteria can have a positive effect on the host through the production of numerous metabolites that are biologically active.

bile salt hydrolase substrate specificity governs bacterial fitness and host colonization.

Primary bile acids (BAs) are a collection of host-synthesized metabolites that shape physiology and metabolism. BAs transit the gastrointestinal tract and are subjected to a variety of chemical transformations encoded by indigenous bacteria. The resulting microbiota-derived BA pool is a mediator of host-microbiota interactions.

S-layer associated proteins contribute to the adhesive and immunomodulatory properties of Lactobacillus acidophilus NCFM.

Background: Surface layers (S-layers) are two-dimensional crystalline arrays of repeating proteinaceous subunits that form the outermost layer of many bacterial cell envelopes. Within the Lactobacillus genus, S-layer presence is frequently associated with probiotic-relevant properties such as improved adherence to host epithelial cells and modulation of the immune response. However, recent studies have demonstrated that certain S-layer functions may be supplemented by a novel subset of proteins embedded within its lattice, termed S-layer associated proteins (SLAPs).

Genomic characterization of Lactobacillus fermentum DSM 20052.

Background: Lactobacillus fermentum, a member of the lactic acid bacteria complex, has recently garnered increased attention due to documented antagonistic properties and interest in assessing the probiotic potential of select strains that may provide human health benefits. Here, we genomically characterize L. fermentum using the type strain DSM 20052 as a canonical representative of this species.

Deletion of S-Layer Associated Ig-Like Domain Protein Disrupts the Cell Surface.

Bacterial surface-layers (S-layers) are crystalline arrays of repeating proteinaceous subunits that coat the exterior of many cell envelopes. S-layers have demonstrated diverse functions in growth and survival, maintenance of cell integrity, and mediation of host interactions. Additionally, S-layers can act as scaffolds for the outward display of auxiliary proteins and glycoproteins.

The Bile Salt Hydrolase Repertoire Reveals Niche-Specific Adaptation.

Various species have been reported to deconjugate bile acids in the gastrointestinal tract (GIT) through the action of bile salt hydrolase (BSH) proteins. This function contributes to altering the gut microbiota composition and bile metabolism and detoxification and to lowering cholesterol levels. Here, we investigated the BSH repertoire across 170 sequenced species.

Investigating the Effect of Growth Phase on the Surface-Layer Associated Proteome of Using Quantitative Proteomics.

Bacterial surface-layers (S-layers) are semi-porous crystalline arrays that self-assemble to form the outermost layer of some cell envelopes. S-layers have been shown to act as scaffolding structures for the display of auxiliary proteins externally. These S-layer associated proteins have recently gained attention in probiotics due to their direct physical contact with the intestinal mucosa and potential role in cell proliferation, adhesion, and immunomodulation.

CRISPR-based engineering of next-generation lactic acid bacteria.

The advent of CRISPR-based technologies has opened new avenues for the development of next-generation food microorganisms and probiotics with enhanced functionalities. Building off two decades of functional genomics studies unraveling the genetic basis for food fermentations and host-probiotic interactions, CRISPR technologies offer a wide range of opportunities to engineer commercially-relevant Lactobacillus and Bifidobacteria. Endogenous CRISPR-Cas systems can be repurposed to enhance gene expression or provide new features to improve host colonization and promote human health.

Deletion of Lipoteichoic Acid Synthase Impacts Expression of Genes Encoding Cell Surface Proteins in .

NCFM is a well-characterized probiotic microorganism, supported by a decade of genomic and functional phenotypic investigations. deficient in lipoteichoic acid (LTA), a major immunostimulant in Gram-positive bacteria, has been shown to shift immune system responses in animal disease models. However, the pleiotropic effects of removing LTA from the cell surface in lactobacilli are unknown.

Multivalent Chromosomal Expression of the Clostridium botulinum Serotype A Neurotoxin Heavy-Chain Antigen and the Bacillus anthracis Protective Antigen in Lactobacillus acidophilus.

Unlabelled: Clostridium botulinum and Bacillus anthracis produce potent toxins that cause severe disease in humans. New and improved vaccines are needed for both of these pathogens. For mucosal vaccine delivery using lactic acid bacteria, chromosomal expression of antigens is preferred over plasmid-based expression systems, as chromosomal expression circumvents plasmid instability and the need for antibiotic pressure.

Differential proteome and cellular adhesion analyses of the probiotic bacterium Lactobacillus acidophilus NCFM grown on raffinose - an emerging prebiotic.

Whole cell and surface proteomes were analyzed together with adhesive properties of the probiotic bacterium Lactobacillus acidophilus NCFM (NCFM) grown on the emerging prebiotic raffinose, exemplifying a synbiotic. Adhesion of NCFM to mucin and intestinal HT-29 cells increased three-fold after culture with raffinose versus glucose, as also visualized by scanning electron microscopy. Comparative proteomics using 2D-DIGE showed 43 unique proteins to change in relative abundance in whole cell lysates from NCFM grown on raffinose compared to glucose.

Occurrence and activity of a type II CRISPR-Cas system in Lactobacillus gasseri.

Bacteria encode clustered regularly interspaced short palindromic repeats (CRISPRs) and CRISPR-associated genes (cas), which collectively form an RNA-guided adaptive immune system against invasive genetic elements. In silico surveys have revealed that lactic acid bacteria harbour a prolific and diverse set of CRISPR-Cas systems. Thus, the natural evolutionary role of CRISPR-Cas systems may be investigated in these ecologically, industrially, scientifically and medically important microbes.

Sortase-deficient lactobacilli: effect on immunomodulation and gut retention.

Surface proteins of probiotic microbes, including Lactobacillus acidophilus and Lactobacillus gasseri, are believed to promote retention in the gut and mediate host-bacterial communications. Sortase, an enzyme that covalently couples a subset of extracellular proteins containing an LPXTG motif to the cell surface, is of particular interest in characterizing bacterial adherence and communication with the mucosal immune system. A sortase gene, srtA, was identified in L.

Identification of extracellular surface-layer associated proteins in Lactobacillus acidophilus NCFM.

Bacterial surface (S-) layers are crystalline arrays of self-assembling, proteinaceous subunits called S-layer proteins (Slps), with molecular masses ranging from 40 to 200 kDa. The S-layer-forming bacterium Lactobacillus acidophilus NCFM expresses three major Slps: SlpA (46 kDa), SlpB (47 kDa) and SlpX (51 kDa). SlpA has a demonstrated role in adhesion to Caco-2 intestinal epithelial cells in vitro, and has been shown to modulate dendritic cell (DC) and T-cell functionalities with murine DCs.

Influence of exposure time on gene expression by human intestinal epithelial cells exposed to Lactobacillus acidophilus.

Analysis of global temporal gene expression by human intestinal cells when exposed to Lactobacillus acidophilus revealed induction of immune-related pathways and NF-κB target genes after a 1-h exposure, compared to a 4- or 8-h exposure. Additionally, an L. acidophilus derivative expressing covalently bound flagellin resulted in increased induction of il8, cxc1, and cxcl2 compared to the parent L.