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Altered Schaedler Flora

The Experts below are selected from a list of 144 Experts worldwide ranked by ideXlab platform

Michael J Wannemuehler – 1st expert on this subject based on the ideXlab platform

  • Mouse Genetic Background Affects Transfer of an Antibiotic Resistance Plasmid in the Gastrointestinal Tract.
    mSphere, 2020
    Co-Authors: Zachary R. Stromberg, Michael J Wannemuehler, Graham A. J. Redweik, Melha Mellata

    Abstract:

    ABSTRACT Dissemination of antibiotic resistance (AR) genes, often on plasmids, leads to antibiotic-resistant bacterial infections, which is a major problem for animal and public health. Bacterial conjugation is the primary route of AR gene transfer in the mammalian gastrointestinal tract. Significant gaps in knowledge about which gastrointestinal communities and host factors promote plasmid transfer remain. Here, we used Salmonella enterica serovar Kentucky strain CVM29188 carrying plasmid pCVM29188_146 (harboring streptomycin and tetracycline resistance genes) to assess plasmid transfer to Escherichia coli under in vitro conditions and in various mouse strains with a conventional or defined microbiota. As an initial test, the transfer of pCVM29188_146 to the E. coli strains was confirmed in vitro. Colonization resistance and, therefore, a lack of plasmid transfer were found in wild-type mice harboring a conventional microbiota. Thus, mice harboring the Altered Schaedler Flora (ASF), or ASF mice, were used to probe for host factors in the context of a defined microbiota. To assess the influence of inflammation on plasmid transfer, we compared interleukin-10 gene-deficient 129S6/SvEv ASF mice (proinflammatory environment) to wild-type 129S6/SvEv ASF mice and found no difference in transconjugant yields. In contrast, the mouse strain influenced plasmid transfer, as C3H/HeN ASF mice had significantly lower levels of transconjugants than 129S6/SvEv ASF mice. Although gastrointestinal members were identical between the ASF mouse strains, a few differences from C3H/HeN ASF mice were detected, with C3H/HeN ASF mice having significantly lower abundances of ASF members 356 (Clostridium sp.), 492 (Eubacterium plexicaudatum), and 502 (Clostridium sp.) than 129S6/SvEv ASF mice. Overall, we demonstrate that microbiota complexity and mouse genetic background influence in vivo plasmid transfer. IMPORTANCE Antibiotic resistance is a threat to public health. Many clinically relevant antibiotic resistance genes are carried on plasmids that can be transferred to other bacterial members in the gastrointestinal tract. The current study used a murine model to study the transfer of a large antibiotic resistance plasmid from a foodborne Salmonella strain to a gut commensal E. coli strain in the gastrointestinal tract. We found that different mouse genetic backgrounds and a different diversity of microbial communities influenced the level of Escherichia coli that acquired the plasmid in the gastrointestinal tract. This study suggests that the complexity of the microbial community and host genetics influence plasmid transfer from donor to recipient bacteria.

  • Altered Schaedler Flora mice a defined microbiota animal model to study the microbiota gut brain axis
    Behavioural Brain Research, 2019
    Co-Authors: Alexandra Proctor, Gregory J Phillips, Joshua M Lyte, Mark Lyte, Michael J Wannemuehler

    Abstract:

    Abstract Despite considerable attention, the mechanisms by which the microbiota affect brain function and host behaviour via the gut-brain axis remain undefined. Identifying microbe-specific pathways that influence neuronal function and bi-directional communication between the gut microbiota and the host central nervous system is challenging due to the extreme microbial diversity in the gut of conventionally-reared mice. Herein, we describe the use of the Altered Schaedler Flora (ASF) mouse model as an alternative to conventionally-reared and germ-free animals. Colonized with only 8 bacterial species, use of ASF mice greatly simplifies the examination of microbiota-host interactions. We assessed the extent to which behaviour differed between mice with a limited consortium of bacteria compared with a complex, conventional microbiota. The elevated plus maze and open-field assays were utilized to assess murine behaviour. Histological analysis of ileum and colon was performed to evaluate intestinal morphology, and 16 s rRNA gene taxonomic profiling was performed to determine host-stress induced changes in fecal microbial communities. Behavioural and serum corticosterone differences were observed between ASF and conventionally-reared mice, while no differences were found between the intestinal morphology of these two groups. The stress of the behavioural tests induced significant changes in the ASF fecal microbial community but not in that of the conventionally-reared mice. In contrast to the conventionally-reared mice, the results indicated that the ASF mice displayed a marked anxiogenic-like behaviour. These data indicate that ASF mice represent a unique model to elucidate mechanisms governing microbiota-gut-brain communication affecting behaviour.

  • Pathogenic and non-pathogenic Escherichia coli colonization and host inflammatory response in a defined microbiota mouse model
    Disease Models & Mechanisms, 2018
    Co-Authors: Zachary R. Stromberg, Michael J Wannemuehler, Meghan Wymore Brand, Angelica Van Goor, Graham A. J. Redweik, Melha Mellata

    Abstract:

    Most Escherichia coli strains in the human intestine are harmless. However, enterohemorrhagic E . coli (EHEC) is a foodborne pathogen that causes intestinal disease in humans. Conventionally-reared (CONV) mice are inconsistent models for human infections with EHEC because they are often resistant to E . coli colonization in part due to their gastrointestinal (GI) microbiota. Although antibiotic manipulation of the mouse microbiota has been a common means to overcome colonization resistance, these models have limitations. Currently, there are no licensed treatments for clinical EHEC infections, and thus new tools to study EHEC colonization need to be developed. Here, we used a defined microbiota mouse model consisting of the Altered Schaedler Flora (ASF) to characterize intestinal colonization and compare host responses following colonization with EHEC strain 278F2 or non-pathogenic E . coli strain MG1655. Significantly higher ( P P E. coli MG1655 colonized C3H/HeN ASF mice. In addition, EHEC 278F2 differentially modulated inflammatory-associated genes in colonic tissue of C3H/HeN ASF mice compared to E. coli MG1655 colonized mice. This approach allowed for prolonged colonization of the murine GI tract by pathogenic and non-pathogenic E . coli strains and for evaluation of host inflammatory processes. Overall, this system can be used as a powerful tool for future studies to assess therapeutics, microbe-microbe interactions, and strategies for preventing EHEC infections.

David B Schauer – 2nd expert on this subject based on the ideXlab platform

  • colonization dynamics of Altered Schaedler Flora is influenced by gender aging and helicobacter hepaticus infection in the intestines of swiss webster mice
    Applied and Environmental Microbiology, 2006
    Co-Authors: Zhongming Ge, Yang Feng, Nancy S Taylor, Masahiro Ohtani, Martin F Polz, David B Schauer

    Abstract:

    The distribution and colonization levels of the Altered Schaedler Flora (ASF) in their natural hosts are poorly understood. Intestinal colonization levels of the eight ASF strains in outbred Swiss Webster mice with or without Helicobacter hepaticus infection were characterized by real-time quantitative PCR. All ASF strains were detected in the cecum and colon, but some strains displayed significant variation in colonization levels with host age, gender, and H. hepaticus infection status.

  • spatial distribution and stability of the eight microbial species of the Altered Schaedler Flora in the mouse gastrointestinal tract
    Applied and Environmental Microbiology, 2004
    Co-Authors: Ramahi Sarmarupavtarm, Zhongming Ge, David B Schauer, Martin F Polz

    Abstract:

    The overall complexity of the microbial communities in the gastrointestinal (GI) tracts of mammals has hindered observations of dynamics and interactions of individual bacterial populations. However, such information is crucial for understanding the diverse disease-causing and protective roles that gut microbiota play in their hosts. Here, we determine the spatial distribution, interanimal variation, and persistence of bacteria in the most complex defined-Flora (gnotobiotic) model system to date, viz., mice colonized with the eight strains of the Altered Schaedler Flora (ASF). Quantitative PCR protocols based on the 16S rRNA sequence of each ASF strain were developed and optimized to specifically detect as few as 10 copies of each target. Total numbers of the ASF strains were determined in the different regions of the GI tracts of three C.B-17 SCID mice. Individual strain abundance was dependent on oxygen sensitivity, with microaerotolerant Lactobacillus murinus ASF361 present at 105 to 107 cells/g of tissue in the upper GI tract and obligate anaerobic ASF strains being predominant in the cecal and colonic Flora at 108 to 1010 cells/g of tissue. The variation between the three mice was small for most ASF strains, except for Clostridium sp. strain ASF502 and Bacteroides sp. strain ASF519 in the cecum. A comparison of the relative distribution of the ASF strains in feces and the colon indicated large differences, suggesting that fecal bacterial levels may provide a poor approximation of colonic bacterial levels. All ASF strains were detected by PCR in the feces of C57BL/6 restricted Flora mice, which had been maintained in an isolator without sterile food, water, or bedding for several generations, providing evidence for the stability of these strains in the face of potential competition by bacteria introduced into the gut.

  • phylogeny of the defined murine microbiota Altered Schaedler Flora
    Applied and Environmental Microbiology, 1999
    Co-Authors: Floyd E Dewhirst, Chihching Chien, Bruce J Paster, Rebecca L Ericson, Roger P Orcutt, David B Schauer

    Abstract:

    The “Altered Schaedler Flora” (ASF) was developed for colonizing germfree rodents with a standardized microbiota. The purpose of this study was to identify each of the eight ASF strains by 16S rRNA sequence analysis. Three strains were previously identified asLactobacillus acidophilus (strain ASF 360),Lactobacillus salivarius (strain ASF 361), andBacteroides distasonis (strain ASF 519) based on phenotypic criteria. 16S rRNA analysis indicated that each of the strains differed from its presumptive identity. The 16S rRNA sequence of strain ASF 361 is essentially identical to the 16S rRNA sequences of the type strains of Lactobacillus murinis and Lactobacillus animalis (both isolated from mice), and all of these strains probably belong to a single species. Strain ASF 360 is a novel lactobacillus that clusters with L. acidophilus andLactobacillus lactis. Strain ASF 519 falls into an unnamed genus containing [Bacteroides] distasonis, [Bacteroides] merdae, [Bacteroides] forsythus, and CDC group DF-3. This unnamed genus is in theCytophaga-Flavobacterium-Bacteroides phylum and is most closely related to the genus Porphyromonas. The spiral-shaped strain, strain ASF 457, is in the Flexistipesphylum and exhibits sequence identity with rodent isolates of Robertson. The remaining four ASF strains, which are extremely oxygen-sensitive fusiform bacteria, group phylogenetically with the low-G+C-content gram-positive bacteria (Firmicutes,Bacillus-Clostridium group). ASF 356, ASF 492, and ASF 502 fall into Clostridium cluster XIV of Collins et al. Morphologically, ASF 492 resembles members of this cluster,Roseburia cecicola, and Eubacterium plexicaudatum. The 16S rRNA sequence of ASF 492 is identical to that of E. plexicaudatum. Since the type strain and other viable original isolates of E. plexicaudatum have been lost, strain ASF 492 is a candidate for a neotype strain. Strain ASF 500 branches deeply in the low-G+C-content gram-positive phylogenetic tree but is not closely related to any organisms whose 16S rRNA sequences are currently in the GenBank database. The 16S rRNA sequence information determined in the present study should allow rapid identification of ASF strains and should permit detailed analysis of the interactions of ASF organisms during development of intestinal disease in mice that are coinfected with a variety of pathogenic microorganisms.

Meghan Wymore Brand – 3rd expert on this subject based on the ideXlab platform

  • Pathogenic and non-pathogenic Escherichia coli colonization and host inflammatory response in a defined microbiota mouse model
    Disease Models & Mechanisms, 2018
    Co-Authors: Zachary R. Stromberg, Michael J Wannemuehler, Meghan Wymore Brand, Angelica Van Goor, Graham A. J. Redweik, Melha Mellata

    Abstract:

    Most Escherichia coli strains in the human intestine are harmless. However, enterohemorrhagic E . coli (EHEC) is a foodborne pathogen that causes intestinal disease in humans. Conventionally-reared (CONV) mice are inconsistent models for human infections with EHEC because they are often resistant to E . coli colonization in part due to their gastrointestinal (GI) microbiota. Although antibiotic manipulation of the mouse microbiota has been a common means to overcome colonization resistance, these models have limitations. Currently, there are no licensed treatments for clinical EHEC infections, and thus new tools to study EHEC colonization need to be developed. Here, we used a defined microbiota mouse model consisting of the Altered Schaedler Flora (ASF) to characterize intestinal colonization and compare host responses following colonization with EHEC strain 278F2 or non-pathogenic E . coli strain MG1655. Significantly higher ( P P E. coli MG1655 colonized C3H/HeN ASF mice. In addition, EHEC 278F2 differentially modulated inflammatory-associated genes in colonic tissue of C3H/HeN ASF mice compared to E. coli MG1655 colonized mice. This approach allowed for prolonged colonization of the murine GI tract by pathogenic and non-pathogenic E . coli strains and for evaluation of host inflammatory processes. Overall, this system can be used as a powerful tool for future studies to assess therapeutics, microbe-microbe interactions, and strategies for preventing EHEC infections.

  • Helicobacter bilis Infection Alters Mucosal Bacteria and Modulates Colitis Development in Defined Microbiota Mice
    Inflammatory Bowel Diseases, 2016
    Co-Authors: Todd Atherly, Michael J Wannemuehler, Gregory J Phillips, Meghan Wymore Brand, Alexandra Proctor, Curtis Mosher, Chong Wang, Jesse M. Hostetter, Albert E Jergens

    Abstract:

    Background:Helicobacter bilis infection of C3H/HeN mice harboring the Altered Schaedler Flora (ASF) triggers progressive immune responsiveness and the development of colitis. We sought to investigate temporal alterations in community structure of a defined (ASF-colonized) microbiota in normal and in

  • Attenuation of Colitis by Serum-Derived Bovine Immunoglobulin/Protein Isolate in a Defined Microbiota Mouse Model
    Digestive Diseases and Sciences, 2015
    Co-Authors: Abigail L. Henderson, Michael J Wannemuehler, Meghan Wymore Brand, Ross J. Darling, Kenneth J. Maas, Christopher J. Detzel, Jesse Hostetter, Eric M. Weaver

    Abstract:

    Background The pathogenesis of inflammatory bowel disease (IBD) is complex and multifaceted including genetic predisposition, environmental components, microbial dysbiosis, and inappropriate immune activation to microbial components. Pathogenic bacterial provocateurs like adherent and invasive E. coli have been reported to increase susceptibility to Crohn’s disease. Serum-derived bovine immunoglobulin/protein isolate (SBI) is comprised primarily of immunoglobulins (Igs) that bind to conserved microbial components and neutralize exotoxins. Aim To demonstrate that oral administration of SBI may modulate mucosal inflammation following colonization with E. coli , LF82, and exposure to dextran sodium sulfate (DSS). Methods Defined microbiota mice harboring the Altered Schaedler Flora (ASF) were administered SBI or hydrolyzed collagen twice daily starting 7 days prior to challenge with E. coli LF82 and continuing for the remainder of the experiment. Mice were treated with DSS for 7 days and then evaluated for evidence of local and peripheral inflammation. Results Igs within SBI bound multiple antigens from all eight members of the ASF and E. coli LF82 by western blot analysis. Multiple parameters of LF82/DSS-induced colitis were reduced following administration of SBI, including histological lesion scores, secretion of cytokines and chemokines from cecal biopsies, intestinal fatty acid binding protein (I-FABP) and serum amyloid A from plasma. Conclusions Oral administration of SBI attenuated clinical signs of LF82/DSS-induced colitis in mice. The data are consistent with the hypothesis that SBI immunoglobulin binding of bacterial antigens in the intestinal lumen may inhibit the inflammatory cascades that contribute to IBD, thus attenuating DSS-induced colitis.