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Gut Microbes

Peter Allan Dobranowski, Chris Tang, Jean Philippe Sauvé, Susan Christine Menzies, Laura May Sly
Inflammatory bowel disease, encompassing both ulcerative colitis and Crohn's disease, is characterized by chronic, relapsing-remitting gastrointestinal inflammation of unknown etiology. SHIP deficient mice develop fully penetrant, spontaneous ileitis at 6 weeks of age, and thus offer a tractable model of Crohn's disease-like inflammation. Since disruptions to the microbiome are implicated in the pathogenesis of Crohn's disease, we conducted a 16S rRNA gene survey of the ileum, cecum, colon, and stool contents of SHIP+/+ and SHIP-/- mice...
February 13, 2019: Gut Microbes
Lucy E Blandford, Emma L Johnston, Jeremy D Sanderson, William G Wade, Alistair J Lax
Bacteroides fragilis is a member of the normal microbiota of the lower gastrointestinal tract, but some strains produce the putative tumourigenic B. fragilis toxin (BFT). In addition, B. fragilis can produce multiple capsular polysaccharides that comprise a microcapsule layer, including an immunomodulatory, zwitterionic, polysaccharide A (PSA) capable of stimulating anti-inflammatory interleukin-10 (IL-10) production. It is known that the PSA promoter can undergo inversion, thereby regulating the expression of PSA...
February 7, 2019: Gut Microbes
Samir Patel, Daniel M Wall, Antonio Castillo, Beth A McCormick
SifA is a bi-functional Type III Secretion System (T3SS) effector protein that plays an important role in Salmonella virulence. The N-terminal domain of SifA binds SifA-Kinesin-Interacting-Protein (SKIP), and via an interaction with kinesin, forms tubular membrane extensions called Sif filaments (Sifs) that emanate from the Salmonella Containing Vacuole (SCV). The C-terminal domain of SifA harbors a WxxxE motif that functions to mimic active host cell GTPases. Taken together, SifA functions in inducing endosomal tubulation in order to maintain the integrity of the SCV and promote bacterial dissemination...
February 6, 2019: Gut Microbes
Stefano Leo, Vladimir Lazarevic, Nadia Gaïa, Candice Estellat, Myriam Girard, Sophie Matheron, Laurence Armand-Lefèvre, Antoine Andremont, Jacques Schrenzel, Etienne Ruppé
The risk of acquisition of multidrug-resistant Enterobacteriaceae (MRE) and of occurrence of diarrhea is high when traveling to tropical regions. The relationships between these phenomena and the composition of human gut microbiota have not yet been assessed. Here, we investigated the dynamics of changes of metabolically active microbiota by sequencing total RNA from fecal samples taken before and after travel to tropical regions. We included 43 subjects who could provide fecal samples before and after a travel to tropical regions...
February 3, 2019: Gut Microbes
Pedro Henrique Q S Medeiros, Solanka E Ledwaba, David T Bolick, Natasa Giallourou, Lauren K Yum, Deiziane V S Costa, Reinaldo B Oriá, Eileen M Barry, Jonathan R Swann, Aldo Ângelo M Lima, Hervé Agaisse, Richard L Guerrant
Shigella is one of the major enteric pathogens worldwide. We present a murine model of S. flexneri infection and investigate the role of zinc deficiency (ZD). C57BL/6 mice fed either standard chow (HC) or ZD diets were pretreated with an antibiotic cocktail and received S. flexneri strain 2457T orally. Antibiotic pre-treated ZD mice showed higher S. flexneri colonization than non-treated mice. ZD mice showed persistent colonization for at least 50 days post-infection (pi). S. flexneri-infected mice showed significant weight loss, diarrhea and increased levels of fecal MPO and LCN in both HC and ZD fed mice...
February 3, 2019: Gut Microbes
Jacqueline C Whittemore, Jennifer E Stokes, Joshua M Price, Jan S Suchodolski
Reduction in antibiotic-associated gastrointestinal signs (AAGS) in people co-administered probiotics is believed to result from shifts in the microbiome and metabolome. Amelioration of AAGS in cats secondary to synbiotic administration has recently been demonstrated. Thus, the aim of this randomized, double-blinded, placebo-controlled trial was to characterize associated changes in the fecal microbiome and metabolome. Sixteen healthy research cats received clindamycin with food, followed 1 h later by either a placebo or synbiotic, daily for 21 days...
February 1, 2019: Gut Microbes
Alyssa Dalton, Christine Mermier, Micah Zuhl
The microbiome in the gut is a diverse environment, housing the majority of our bacterial microbes. This microecosystem has a symbiotic relationship with the surrounding multicellular organism, and a balance and diversity of specific phyla of bacteria support general health. When gut bacteria diversity diminishes, there are systemic consequences, such as gastrointestinal and psychological distress. This pathway of communication is known as the microbiome-gut-brain axis. Interventions such as probiotic supplementation that influence microbiome also improve both gut and brain disorders...
January 31, 2019: Gut Microbes
Faith D Ihekweazu, Tatiana Y Fofanova, Karen Queliza, Dorottya Nagy-Szakal, Christopher J Stewart, Melinda A Engevik, Kristina G Hulten, Nina Tatevian, David Y Graham, James Versalovic, Joseph F Petrosino, Richard Kellermayer
BACKGROUND AND AIMS: Bacteriotherapy aimed at addressing dysbiosis may be therapeutic for Inflammatory Bowel Diseases (IBDs). We sought to determine if defined Bacteroides-based bacteriotherapy could be an effective and consistent alternative to fecal microbiota transplantation (FMT) in a murine model of IBD. METHODS: We induced experimental colitis in 8- 12-week-old C57BL/6 mice using 2-3% dextran sodium sulfate. Mice were simultaneously treated by oral gavage with a triple-Bacteroides cocktail, individual Bacteroides strains, FMT using stool from healthy donor mice, or their own stool as a control...
January 21, 2019: Gut Microbes
Aline Machiavelli, Rubens T Delgado Duarte, Maria M de Souza Pires, Carlos R Zarate-Bladés, Aguinaldo R Pinto
HIV-exposed but uninfected (HEU) children represent a growing population and show a significantly higher number of infectious diseases, several immune alterations, compromised growth, and increased mortality rates when compared to HIV-unexposed children. Considering the impact that the gut microbiota has on general host homeostasis and immune system development and modulation, we hypothesized that HEU children present altered gut microbiota that is linked to the increased morbidity and the immune system disorders faced by them...
January 18, 2019: Gut Microbes
Solenne Marion, Nicolas Studer, Lyne Desharnais, Laure Menin, Stéphane Escrig, Anders Meibom, Siegfried Hapfelmeier, Rizlan Bernier-Latmani
The human gut hosts trillions of microorganisms that exert a profound influence on human biology. Gut bacteria communicate with their host by secreting small molecules that can signal to distant organs in the body. Bile acids are one class of these signaling molecules, synthesized by the host and chemically transformed by the gut microbiota. Among bile acid metabolizers, bile acid 7-dehydroxylating bacteria are commensals of particular importance as they carry out the 7-dehydroxylation of liver-derived primary bile acids to 7-dehydroxylated bile acids...
December 27, 2018: Gut Microbes
Michael J Davoren, Jared Liu, Jocelyn Castellanos, Norma I Rodríguez-Malavé, Robert H Schiestl
Probiotics are considered to have multiple beneficial effects on the human gastrointestinal tract, including immunomodulation, pathogen inhibition, and improved host nutrient metabolism. However, extensive characterization of these properties is needed to define suitable clinical applications for probiotic candidates. Lactobacillus johnsonii 456 (LBJ 456) was previously demonstrated to have anti-inflammatory and anti-genotoxic effects in a mouse model. Here, we characterize its resistance to gastric and bile acids as well as its ability to inhibit gut pathogens and adhere to host mucosa...
December 22, 2018: Gut Microbes
Nick W Smith, Paul R Shorten, Eric H Altermann, Nicole C Roy, Warren C McNabb
Hydrogen plays a key role in many microbial metabolic pathways in the human gastrointestinal tract (GIT) that have an impact on human nutrition, health and wellbeing. Hydrogen is produced by many members of the GIT microbiota, and may be subsequently utilized by cross-feeding microbes for growth and in the production of larger molecules. Hydrogenotrophic microbes fall into three functional groups: sulfate-reducing bacteria, methanogenic archaea and acetogenic bacteria, which can convert hydrogen into hydrogen sulfide, methane and acetate, respectively...
December 18, 2018: Gut Microbes
Michael B Burns, Ran Blekhman
Although the gut microbiome has been linked to colorectal cancer (CRC) development, associations of microbial taxa with CRC status are often inconsistent across studies. We have recently shown that tumor genomics, a factor that is rarely incorporated in analyses of the CRC microbiome, has a strong effect on the composition of the microbiota. Here, we discuss these results in the wider context of studies characterizing interaction between host genetics and the microbiome, and describe the implications of our findings for understanding the role of the microbiome in CRC...
December 17, 2018: Gut Microbes
(no author information available yet)
No abstract text is available yet for this article.
November 30, 2018: Gut Microbes
Luisa De Sordi, Marta Lourenço, Laurent Debarbieux
Viruses that infect bacteria, or bacteriophages, are among the most abundant entities in the gut microbiome. However, their role and the mechanisms by which they infect bacteria in the intestinal tract remain poorly understood. We recently reported that intestinal bacteria are an evolutionary force, driving the expansion of the bacteriophage host range by boosting the genetic variability of these viruses. Here, we expand these observations by studying antagonistic bacteriophage-bacteria coevolution dynamics and revealing that bacterial genetic variability is also increased under the pressure of bacteriophage predation...
2019: Gut Microbes
Katherine Z Sanidad, Hang Xiao, Guodong Zhang
Triclosan (TCS) is an antimicrobial compound incorporated into more than 2,000 consumer products. This compound is frequently detected in the human body and causes ubiquitous contamination in the environment, raising concerns about its impact on human health and environmental pollution. Our recent research showed that exposure to TCS exaggerates colonic inflammation and exacerbates development of colitis-associated colon tumorigenesis, via gut microbiome-dependent mechanisms. In this review, we discussed recent research about TCS, as well as other consumer antimicrobials, on the gut microbiome and gut health...
November 20, 2018: Gut Microbes
Delphine Sterlin, Claire Fieschi, Marion Malphettes, Martin Larsen, Guy Gorochov, Jehane Fadlallah
In a recently published article we report the metagenomic analysis of human gut microbiomes evolved in the absence of immunoglobulin A (IgA). We show that human IgA deficiency is not associated with massive quantitative perturbations of gut microbial ecology. While our study underlines a rather expected pathobiont expansion, we at the same time highlight a less expected depletion in some typically beneficial symbionts. We also show that IgM partially supply IgA deficiency, explaining the relatively mild clinical phenotype associated with the early steps of this condition...
November 18, 2018: Gut Microbes
Piu Saha, Xia Xiao, Beng San Yeoh, Qiuyan Chen, Bhuvana Katkere, Girish Soorappa Kirimanjeswara, Matam Vijay-Kumar
Enterobactin (Ent), a prototypical bacterial siderophore known for its unparalleled affinity for iron, is widely conserved among members of the Enterobacteriaceae family of Gram-negative bacteria. In this study, we demonstrated that, aside from mediating iron acquisition, Ent also dampened the macrophages (MΦs) antimicrobial responses against intracellular infection by Salmonella enterica serovar Typhimurium. Accordingly, the loss of Ent expression (ΔentB) in Salmonella demoted their survivability against MΦs...
November 18, 2018: Gut Microbes
Jacqueline A Barnett, Deanna L Gibson
Water is a fundamental part of any in vivo microbiome experiment however, it is also one of the most overlooked and underreported variables within the literature. Currently there is no established standard for drinking water quality set by the Canadian Council on Animal Care. Most water treatment methods focus on inhibiting bacterial growth within the water while prolonging the shelf-life of bottles once poured. When reviewing the literature, it is clear that some water treatment methods, such as water acidification, alter the gut microbiome of experimental animals resulting in dramatic differences in disease phenotype progression...
November 15, 2018: Gut Microbes
Brendan A Daisley, Marc Monachese, Mark Trinder, Jordan E Bisanz, John A Chmiel, Jeremy P Burton, Gregor Reid
Heavy metals are highly toxic elements that contaminate the global food supply and affect human and wildlife health. Purification technologies are often too expensive or not practically applicable for large-scale implementation, especially in impoverished nations where heavy metal contamination is widespread. Lactobacillus rhamnosus GR-1 (LGR-1) was shown in previous work to reduce heavy metal bioaccumulation in a Tanzanian cohort of women and children through indeterminant mechanisms. Here, it was hypothesized that LGR-1 could sequester the heavy metals lead (Pb) and cadmium (Cd), thereby reducing their absorption across intestinal epithelium...
November 14, 2018: Gut Microbes
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