-
PLoS Pathogens Dec 2020
Review
Topics: Bacterial Infections; Bacteroides fragilis; Genetic Variation; Humans; Microbiota
PubMed: 33301530
DOI: 10.1371/journal.ppat.1009056 -
Nature Feb 2024Bacteria in the gastrointestinal tract produce amino acid bile acid amidates that can affect host-mediated metabolic processes; however, the bacterial gene(s)...
Bacteria in the gastrointestinal tract produce amino acid bile acid amidates that can affect host-mediated metabolic processes; however, the bacterial gene(s) responsible for their production remain unknown. Herein, we report that bile salt hydrolase (BSH) possesses dual functions in bile acid metabolism. Specifically, we identified a previously unknown role for BSH as an amine N-acyltransferase that conjugates amines to bile acids, thus forming bacterial bile acid amidates (BBAAs). To characterize this amine N-acyltransferase BSH activity, we used pharmacological inhibition of BSH, heterologous expression of bsh and mutants in Escherichia coli and bsh knockout and complementation in Bacteroides fragilis to demonstrate that BSH generates BBAAs. We further show in a human infant cohort that BBAA production is positively correlated with the colonization of bsh-expressing bacteria. Lastly, we report that in cell culture models, BBAAs activate host ligand-activated transcription factors including the pregnane X receptor and the aryl hydrocarbon receptor. These findings enhance our understanding of how gut bacteria, through the promiscuous actions of BSH, have a significant role in regulating the bile acid metabolic network.
Topics: Humans; Acyltransferases; Amidohydrolases; Amines; Bacteroides fragilis; Bile Acids and Salts; Biocatalysis; Cohort Studies; Escherichia coli; Gastrointestinal Microbiome; Ligands; Pregnane X Receptor; Receptors, Aryl Hydrocarbon; Transcription Factors; Infant; Cell Culture Techniques
PubMed: 38326609
DOI: 10.1038/s41586-023-06990-w -
Journal of Microbiology and... Mar 2020Enterotoxigenic (ETBF) is the main pathogen causing severe inflammatory diseases and colorectal cancer. Its biofilm plays a key role in the development of colorectal...
Enterotoxigenic (ETBF) is the main pathogen causing severe inflammatory diseases and colorectal cancer. Its biofilm plays a key role in the development of colorectal cancer. The objective of this study was to determine the antagonistic effects of cell-free supernatants (CFS) derived from against the growth and biofilm of ETBF. Our data showed that CFS inhibited the growth of in planktonic culture. In addition, CFS exhibited an antibiofilm effect by inhibiting biofilm development, disassembling preformed biofilms and reducing the metabolic activity of cells in biofilms. Using confocal laser scanning microscopy, we found that CFS significantly suppressed the proteins and extracellular nucleic acids among the basic biofilm components. Furthermore, CFS significantly downregulated the expression of virulence- and efflux pump-related genes including and in . Our findings suggest that can be used as biotherapeutic agent by inhibiting the growth and biofilm of ETBF.
Topics: Anti-Bacterial Agents; Bacteroides fragilis; Biofilms; Clostridium butyricum; Gene Expression; Gene Expression Regulation, Bacterial; Probiotics
PubMed: 32066216
DOI: 10.4014/jmb.2001.01027 -
PloS One 2017We have developed 22 mouse IgG1 monoclonal antibodies (mAbs) against Bacteroides fragilis zinc metalloprotease toxins 1 and 2 (BFT1 and BFT2). Mice were immunized with...
We have developed 22 mouse IgG1 monoclonal antibodies (mAbs) against Bacteroides fragilis zinc metalloprotease toxins 1 and 2 (BFT1 and BFT2). Mice were immunized with recombinant BFT1 or BFT2 proteins with metalloprotease activity. Eight of the mAbs bind specifically to BFT1. One mAb, 2H6, binds specifically to BFT2. The remaining 13 mAbs bind to both BFT1 and BFT2. The eight BFT1-specific mAbs recognize at least five different epitopes on the toxin. Four of the BFT1-specific mAbs neutralized rBFT1 metalloprotease activity. Only one of these four mAbs, 1D9, neutralizes the cytotoxic effect of BFT1. Here, we describe the development of enzyme-linked immunosorbent assays (ELISAs) to detect BFT1 or BFT2 toxin in an isotype-specific manner. The sandwich ELISAs have a detection limit of 20 to 40 ng/ml when purified recombinant BFT protein is diluted into PBS. The sandwich ELISA can be used to distinguish and quantify levels of rBFT1 and rBFT2 in stool. This ELISA can be an important tool to investigate the association between BFT expression by enterotoxigenic B. fragilis and diseases such as diarrhea, inflammatory bowel disease and colorectal cancer.
Topics: Animals; Antibodies, Monoclonal; Antibody Specificity; Bacteroides Infections; Bacteroides fragilis; Diarrhea; Enterotoxins; Enzyme-Linked Immunosorbent Assay; Epitopes; Feces; Humans; Metalloendopeptidases; Mice
PubMed: 28257448
DOI: 10.1371/journal.pone.0173128 -
FEMS Microbiology Letters Jul 2007Bacteroides fragilis is considered an important clinical pathogen and the most common anaerobe isolated from human and animal clinical specimens; enterotoxigenic strains...
Bacteroides fragilis is considered an important clinical pathogen and the most common anaerobe isolated from human and animal clinical specimens; enterotoxigenic strains produce diarrhea. The presence of enterotoxigenic (ETBF) and nonenterotoxigenic B. fragilis in stool samples from calves with or without acute diarrhea and the antimicrobial susceptibility of the strains were evaluated. The stool samples were plated onto a selective B. fragilis-bile-esculin agar, and incubated anaerobically (10% CO(2)/90% N(2)), at 37 degrees C, for 72 h. Species of the B. fragilis group were identified by using the API 32-A kit. Enterotoxigenic strains were detected by PCR and the cytotoxic assay. From 54 diarrhea and 54 nondiarrhea stools, 124 and 92 members of the B. fragilis group, respectively, were recovered. Only two ETBF strains were isolated from two different diarrhea samples and the bft gene was detected in both. Moreover, the bft gene was detected in DNA from four different diarrheal stools samples but no ETBF strain was recovered. All the bacteria were susceptible to chloramphenicol, imipenem, moxifloxacin, piperacillin/tazobactam, metronidazole and tigecycline. Most of the isolates from both calves with and without diarrhea were resistant to all metals. Our results are of concern, and suggest the need to increase the surveillance of antibiotic and metal resistance of this microbial group isolated from animal production such as calves.
Topics: Anaerobiosis; Animals; Anti-Bacterial Agents; Bacterial Typing Techniques; Bacteroides Infections; Bacteroides fragilis; Cattle; Cattle Diseases; Cell Line; Culture Media; DNA, Bacterial; Diarrhea; Drug Resistance, Bacterial; Feces; Female; Genes, Bacterial; Humans; Metalloendopeptidases; Metals; Microbial Sensitivity Tests; Polymerase Chain Reaction; Temperature
PubMed: 17488333
DOI: 10.1111/j.1574-6968.2007.00732.x -
Research in Microbiology Mar 2021The exposure of Bacteroides fragilis to highly oxygenated tissues induces an oxidative stress due to a shift from the reduced condition of the gastrointestinal tract to... (Review)
Review
The exposure of Bacteroides fragilis to highly oxygenated tissues induces an oxidative stress due to a shift from the reduced condition of the gastrointestinal tract to an aerobic environment of host tissues. The potent and effective responses to reactive oxygen species (ROS) make the B. fragilis tolerant to atmospheric oxygen for several days. The response to oxidative stress in B. fragilis is a complicated event that is induced and regulated by different agents. In this review, we will focus on the B. fragilis response to oxidative stress and present an overview of the regulators of responses to oxidative stress in this bacterium.
Topics: Bacterial Proteins; Bacteroides fragilis; Drug Resistance, Multiple, Bacterial; Ferritins; Gastrointestinal Tract; Gene Expression Regulation, Bacterial; Oxidative Stress; Reactive Oxygen Species; SOS Response, Genetics; Sigma Factor; Stress, Physiological; Transcription Factors; Virulence
PubMed: 33485914
DOI: 10.1016/j.resmic.2021.103798 -
Microbiology Spectrum Feb 2022Three difficult-to-cultivate, strictly anaerobic strains, AN20, AN421, and AN502, were analyzed within a project studying possible probiotics for newly hatched chickens....
Three difficult-to-cultivate, strictly anaerobic strains, AN20, AN421, and AN502, were analyzed within a project studying possible probiotics for newly hatched chickens. Phylogenetic analyses showed that strains AN20, AN421, and AN502 formed two well-separated phylogenetic lineages in all phylogenetic and phylogenomic trees comprising members of the family . Comparison to reference genomes of type species Bacteroides fragilis NCTC 9343, Phocaeicola abscessus CCUG 55929, and Capsularis zoogleoformans ATCC 33285 showed low relatedness based on the calculated genome-to-genome distance and orthologous average nucleotide identity. Analysis of fatty acid profiles showed iso-C, anteiso-C, C, C, and iso-C 3OH as the major fatty acids for all three strains and additionally C 3OH for AN421 and AN502. A specific combination of respiratory quinones different from related taxa was found in analyzed strains, MK-5 plus MK-11 in strain AN20 and MK-5 plus MK-10 in strains AN421 and AN502. Strains AN421 and AN502 harbor complete CRISPR loci with CRISPR array, type II-C, accompanied by a set of genes (, , and ) in close proximity. Interestingly, strain AN20 was found to harbor two copies of gene with >95% similarity to of B. fragilis, suggesting a horizontal gene transfer between these taxa. In summary, three isolates characterized in this study represent two novel species, which we proposed to be classified in two novel genera of the family , for which the names sp. nov. (AN20 = CCM 9041 = DSM 111154) and sp. nov. (AN421= CCM 9040 = DSM 111155) are proposed. This study represents follow-up research on three difficult-to-cultivate anaerobic isolates originally isolated within a project focused on strains that are able to stably colonize newly hatched chickens, thus representing possible probiotics. This project is exceptional in that it successfully isolates several miscellaneous strains that required modified and richly supplemented anaerobic media, as information on many gut-colonizing bacteria is based predominantly on metagenomic studies. Superior colonization of newly hatched chickens by spp., spp., or related taxa can be considered of importance for development of future probiotics. Although different experiments can also be performed with provisionally characterized isolates, precise taxonomical definition is necessary for subsequent broad communication. The aim of this study is therefore to thoroughly characterize these isolates that represent novel genera and precisely determine their taxonomic position among related taxa to facilitate further research and communication involving these strains.
Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Bacterial Typing Techniques; Bacteroidaceae; Bacteroides fragilis; Cecum; Chickens; Drug Resistance, Bacterial; Drug Resistance, Microbial; Phylogeny; RNA, Ribosomal, 16S
PubMed: 35170999
DOI: 10.1128/spectrum.01954-21 -
International Journal of Environmental... Sep 2020The aim of this study was to evaluate the applicability of markers specific to group (BFG) bacteria as indicators of anthropogenic pollution of surface waters. In...
The aim of this study was to evaluate the applicability of markers specific to group (BFG) bacteria as indicators of anthropogenic pollution of surface waters. In addition, the impact of wastewater treatment plants (WWTPs) on the spread of genes specific to fecal indicator bacteria and genes encoding antimicrobial resistance in water bodies was also determined. Samples of hospital wastewater (HWW), untreated wastewater (UWW), and treated wastewater (TWW) evacuated from a WWTP were collected, and samples of river water were taken upstream (URW) and downstream (DRW) from the wastewater discharge point to determine, by qPCR, the presence of genes specific to BFG, and , and the abundance of 11 antibiotic resistance genes (ARGs) and two integrase genes. The total number of bacterial cells (TCN) in the examined samples was determined by fluorescence in situ hybridization (FISH). Genes specific to BFG predominated among the analyzed indicator microorganisms in HWW, and their copy numbers were similar to those of genes specific to and in the remaining samples. The abundance of genes specific to BFG was highly correlated with the abundance of genes characteristic of and , all analyzed ARGs and I genes. The results of this study indicate that genes specific to BFG can be used in analyses of human fecal pollution, and as indicators of environmental contamination with ARGs. A significant increase in the copy numbers of genes specific to BFG, , and seven out of the 11 analyzed ARGs was noted in samples of river water collected downstream from the wastewater discharge point, which suggests that WWTPs are an important source of these genes in riparian environments.
Topics: Anti-Bacterial Agents; Bacteria; Bacteroides fragilis; Drug Resistance, Microbial; Escherichia coli; Genes, Bacterial; Humans; In Situ Hybridization, Fluorescence; Polymerase Chain Reaction; Wastewater
PubMed: 33003501
DOI: 10.3390/ijerph17197137 -
Journal of Hazardous Materials Jul 2020The aim of this study was to determine the effect of the activated sludge process on the abundance of anaerobic bacteria of the phylum Bacteroidetes, with special...
Environmental fate of Bacteroidetes, with particular emphasis on Bacteroides fragilis group bacteria and their specific antibiotic resistance genes, in activated sludge wastewater treatment plants.
The aim of this study was to determine the effect of the activated sludge process on the abundance of anaerobic bacteria of the phylum Bacteroidetes, with special emphasis on Bacteroides fragilis group (BFG) bacteria, in twelve full-scale wastewater treatment plants. The composition of bacterial phyla and classes in wastewater samples were analyzed by next-generation sequencing. The presence of specific to BFG bacteria genes and the abundance of ARGs and genes encoding class 1 integrase in wastewater samples were determined by qPCR. Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes were dominant bacterial phyla in wastewater samples. Next-generation sequencing revealed similar proportions of Bacteroidia (<1.0-8.2 % of all bacteria) in wastewater influents and effluents, which suggest that these microorganisms are not completely eliminated in the activated sludge process. The average copy numbers of specific to BFG bacteria gene, were 10, and 10 copies in 1 mL of wastewater influents and effluents, respectively. The results revealed a correlation between the abundance of BFG bacteria and BFG-specific genes encoding resistance to antibiotics. The observed changes in the prevalence of BFG-specific genes and ARGs in untreated and treated wastewater indicate that the activated sludge process decreases the number of gene copies in the effluent evacuated to the environment.
Topics: Bacteroides fragilis; Base Sequence; DNA, Bacterial; Drug Resistance, Bacterial; Genes, Bacterial; Sewage; Water Purification
PubMed: 32224375
DOI: 10.1016/j.jhazmat.2020.122544 -
Journal of Bacteriology Oct 2011Xylose is rarely described as a component of bacterial glycans. UDP-xylose is the nucleotide-activated form necessary for incorporation of xylose into glycans and is...
Xylose is rarely described as a component of bacterial glycans. UDP-xylose is the nucleotide-activated form necessary for incorporation of xylose into glycans and is synthesized by the decarboxylation of UDP-glucuronic acid (UDP-GlcA). Enzymes with UDP-GlcA decarboxylase activity include those that lead to the formation of UDP-xylose as the end product (Uxs type) and those synthesizing UDP-xylose as an intermediate (ArnA and RsU4kpxs types). In this report, we identify and confirm the activities of two Uxs-type UDP-GlcA decarboxylases of Bacteroides fragilis, designated BfUxs1 and BfUxs2. Bfuxs1 is located in a conserved region of the B. fragilis genome, whereas Bfuxs2 is in the heterogeneous capsular polysaccharide F (PSF) biosynthesis locus. Deletion of either gene separately does not result in the loss of a detectable phenotype, but deletion of both genes abrogates PSF synthesis, strongly suggesting that they are functional paralogs and that the B. fragilis NCTC 9343 PSF repeat unit contains xylose. UDP-GlcA decarboxylases are often annotated incorrectly as NAD-dependent epimerases/dehydratases; therefore, their prevalence in bacteria is underappreciated. Using available structural and mutational data, we devised a sequence pattern to detect bacterial genes encoding UDP-GlcA decarboxylase activity. We identified 826 predicted UDP-GlcA decarboxylase enzymes in diverse bacterial species, with the ArnA and RsU4kpxs types confined largely to proteobacterial species. These data suggest that xylose, or a monosaccharide requiring a UDP-xylose intermediate, is more prevalent in bacterial glycans than previously appreciated. Genes encoding BfUxs1-like enzymes are highly conserved in Bacteroides species, indicating that these abundant intestinal microbes may synthesize a conserved xylose-containing glycan.
Topics: Bacteroides fragilis; Blotting, Western; Carboxy-Lyases; Chromatography, High Pressure Liquid; Computational Biology; Electrophoresis, Polyacrylamide Gel; Genome, Bacterial; Polysaccharides, Bacterial; Xylose
PubMed: 21804000
DOI: 10.1128/JB.05337-11