Ampicillin Inactivation in the Caecum of Axenic, Gnotoxenic and Conventional Lambs: Interaction with Resistant or Sensitive Escherichia coli

Coste, Marguerite; Gouet, Ph.; Escoula, Louis

doi:10.1099/00221287-130-6-1325

Cited by 3 publications

(2 citation statements)

References 15 publications

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“…1. Human beings or ordinary animals, provided with a means of isolating part of the gut contents, by sachets (16), filter (9), capsules containing a gel (38), re-entrant cannula (22) or ileostomy (28). The most widely used and also the simplest procedure is to collect faeces, which serve as the basis for a model.…”

Section: Classification Of Experimental Modelsmentioning

confidence: 99%

Microbial ecology of the intestine. In vitro, in vivo and mathematical models

Corpet¹

1989

Rev. Sci. Tech. OIE

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using models, which include in vitro and in vivo experimental procedures and mathematical models. This review proposes a classification of experimental models. A distinction can be made between ordinary, heteroxenic and gnotoxenic animals, continuous culture of a complex flora in a chemostat, and static cultures prepared by incubating faeces or a medium.The value of these models is demonstrated by some examples, with reference to the degree of conservation of the original ecosystem, and whether they throw light on its functioning.For in vivo models, the composition of the flora and its metabolic activity are described, whether in the case of a homologous flora or a heteroxenic model.In vitro interactions in a chemostat containing certain strains, or inoculated with a complex mixture of pure strains, are compared with interactions occurring in vivo.Mathematical models of actual in vitro and in vivo systems are presented, together with the criteria which make it possible to assess their plausibility.It may be concluded that the use of heteroxenic animals permits the study of bacterial populations, that the use of continuous culture facilitates an understanding of the metabolism of bacteria of the microflora, and that mathematical models make it possible to comprehend the mechanisms involved in a microbial ecosystem.A simple account of Monod's mathematical model is appended.

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Section: Classification Of Experimental Modelsmentioning

confidence: 99%

Microbial ecology of the intestine. In vitro, in vivo and mathematical models

Corpet¹

1989

Rev. Sci. Tech. OIE

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“…1. Homme ou animal conventionnel, avec dispositif permettant d'isoler une partie de son contenu digestif : sachets (16), filtre (9), capsules contenant un gel (38), canule réentrante (22), iléostomie (28). Le système le plus utilisé et le plus simple est la collection des fèces, ce qui est le «degré zéro» du modèle.…”

Section: Typologie Des Modèles Expérimentauxunclassified

Etude de l'écologie microbienne de l'intestin : modèles in vitro, in vivo et mathématiques

Corpet¹

1989

Rev. Sci. Tech. OIE

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Etude de l'écologie microbienne de l'intestin : modèles in vitro, in vivo et mathématiques D.e. corpet * Résumé : L'étude de l'écologie microbienne ne progresse que grâce à l'utilisation de modèles : modèles expérimentaux in vitro et in vivo, et modèles mathématiques. Dans cet article de synthèse, une typologie des modèles expérimentaux est proposée. Nous y distinguons notamment les modèles animaux conventionnels, hétéroxéniques et gnotoxéniques, les cultures continues d'une flore complexe en chémostat, et les cultures statiques, réalisées par incubation de fèces ou de milieu. L'intérêt de ces modèles d'étude est ensuite examiné sur des exemples, en cherchant à savoir s'ils conservent les propriétés de l'écosystème qu'ils simulent, et s'ils permettent d'en expliquer le fonctionnement. Pour les modèles in vivo, la composition de la flore et son activité métabolique sont décrites dans le cas d'une flore homologue, et dans celui d'un modèle hétéroxénique. Les interactions in vitro dans un chémostat contenant quelques souches, ou inoculé avec un mélange complexe de souches pures, sont comparées avec celles qui existent in vivo.Les modélisations mathématiques de systèmes réels in vitro et in vivo sont présentées, avec les critères permettant de juger qu'un modèle est plausible.En conclusion, l'utilisation d'animaux hétéroxéniques permet l'étude des populations bactériennes, l'utilisation de culture continue facilite l'approche du métabolisme des bactéries de la microflore, et l'utilisation de modèles mathématiques permet de comprendre les mécanismes qui interviennent dans l'écosystème microbien. Une description simple du modèle mathématique de Monod est proposée en annexe.MOTS-CLÉS : Animaux hétéroxéniques -Bactériologie -Culture continue -Ecosystème microbien -Flore intestinale -Modèles expérimentaux -Modèles mathématiques.

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Phage-delivered CRISPR-Cas9 for strain-specific depletion and genomic deletions in the gut microbiome

Lam

Spanogiannopoulos

Soto-Perez

et al. 2020

Preprint

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AbstractThe recognition that the gut microbiome has a profound influence on human health and disease has spurred efforts to manipulate gut microbial community structure and function. Though various strategies for microbiome engineering have been proposed, methods for phage-based genetic manipulation of resident members of the gut microbiota in vivo are currently lacking. Here, we show that bacteriophage can be used as a vector for delivery of plasmid DNA to bacteria colonizing the gastrointestinal tract, using filamentous phage M13 and Escherichia coli engrafted in the gut microbiota of mice. We employ M13 to deliver CRISPR-Cas9 for sequence-specific targeting of E. coli leading to depletion of one strain of a pair of fluorescently marked isogenic strains competitively colonizing the gut. We further show that when mice are colonized by a single E. coli strain, it is possible for M13-delivered CRISPR-Cas9 to induce genomic deletions that encompass the targeted gene. Our results suggest that rather than being developed for use as an antimicrobial in the gut microbiome, M13-delivered CRISPR-Cas9 may be better suited for targeted genomic deletions in vivo that harness the robust DNA repair response of bacteria. With improved methods to mitigate undesired escape mutations, we envision these strategies may be developed for targeted removal of strains or genes present in the gut microbiome that are detrimental to the host. These results provide a highly adaptable platform for in vivo microbiome engineering using phage and a proof-of-concept for the establishment of phage-based tools for a broader panel of human gut bacteria.

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Ampicillin Inactivation in the Caecum of Axenic, Gnotoxenic and Conventional Lambs: Interaction with Resistant or Sensitive Escherichia coli

Cited by 3 publications

References 15 publications

Microbial ecology of the intestine. In vitro, in vivo and mathematical models

Microbial ecology of the intestine. In vitro, in vivo and mathematical models

Etude de l'écologie microbienne de l'intestin : modèles in vitro, in vivo et mathématiques

Phage-delivered CRISPR-Cas9 for strain-specific depletion and genomic deletions in the gut microbiome

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