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Beutler M, Eberl C, Garzetti D, Herp S, Münch P, Ring D, Dolowschiak T, Brugiroux S, Schiller P, Hussain S, Basic M, Bleich A, Stecher B. Contribution of bacterial and host factors to pathogen "blooming" in a gnotobiotic mouse model for Salmonella enterica serovar Typhimurium-induced enterocolitis. Infect Immun 2024; 92:e0031823. [PMID: 38189339 PMCID: PMC10863408 DOI: 10.1128/iai.00318-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 12/05/2023] [Indexed: 01/09/2024] Open
Abstract
Inflammation has a pronounced impact on the intestinal ecosystem by driving an expansion of facultative anaerobic bacteria at the cost of obligate anaerobic microbiota. This pathogen "blooming" is also a hallmark of enteric Salmonella enterica serovar Typhimurium (S. Tm) infection. Here, we analyzed the contribution of bacterial and host factors to S. Tm "blooming" in a gnotobiotic mouse model for S. Tm-induced enterocolitis. Mice colonized with the Oligo-Mouse-Microbiota (OMM12), a minimal bacterial community, develop fulminant colitis by day 4 after oral infection with wild-type S. Tm but not with an avirulent mutant. Inflammation leads to a pronounced reduction in overall intestinal bacterial loads, distinct microbial community shifts, and pathogen blooming (relative abundance >50%). S. Tm mutants attenuated in inducing gut inflammation generally elicit less pronounced microbiota shifts and reduction in total bacterial loads. In contrast, S. Tm mutants in nitrate respiration, salmochelin production, and ethanolamine utilization induced strong inflammation and S. Tm "blooming." Therefore, individual Salmonella-specific inflammation-fitness factors seem to be of minor importance for competition against this minimal microbiota in the inflamed gut. Finally, we show that antibody-mediated neutrophil depletion normalized gut microbiota loads but not intestinal inflammation or microbiota shifts. This suggests that neutrophils equally reduce pathogen and commensal bacterial loads in the inflamed gut.
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Affiliation(s)
- Markus Beutler
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Claudia Eberl
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Debora Garzetti
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Simone Herp
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Philipp Münch
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
- Computational Biology of Infection Research, Helmholtz Center for Infection Research, Braunschweig, Germany
- Braunschweig Integrated Center of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
| | - Diana Ring
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Tamas Dolowschiak
- Institute of Microbiology, D-BIOL, ETH Zürich, Zürich, Switzerland
- Institute of Experimental Immunology, University of Zurich, Zürich, Switzerland
| | - Sandrine Brugiroux
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Patrick Schiller
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Saib Hussain
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Marijana Basic
- Institute for Laboratory Animal Science and Central Animal Facility, Hannover Medical School, Hannover, Germany
| | - André Bleich
- Institute for Laboratory Animal Science and Central Animal Facility, Hannover Medical School, Hannover, Germany
| | - Bärbel Stecher
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
- German Center for Infection Research (DZIF), partner site LMU Munich, Munich, Germany
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Forster D, Bittner L, Karkar S, Dunthorn M, Romac S, Audic S, Lopez P, Stoeck T, Bapteste E. Testing ecological theories with sequence similarity networks: marine ciliates exhibit similar geographic dispersal patterns as multicellular organisms. BMC Biol 2015; 13:16. [PMID: 25762112 PMCID: PMC4381497 DOI: 10.1186/s12915-015-0125-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 01/28/2015] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND High-throughput sequencing technologies are lifting major limitations to molecular-based ecological studies of eukaryotic microbial diversity, but analyses of the resulting millions of short sequences remain a major bottleneck for these approaches. Here, we introduce the analytical and statistical framework of sequence similarity networks, increasingly used in evolutionary studies and graph theory, into the field of ecology to analyze novel pyrosequenced V4 small subunit rDNA (SSU-rDNA) sequence data sets in the context of previous studies, including SSU-rDNA Sanger sequence data from cultured ciliates and from previous environmental diversity inventories. RESULTS Our broadly applicable protocol quantified the progress in the description of genetic diversity of ciliates by environmental SSU-rDNA surveys, detected a fundamental historical bias in the tendency to recover already known groups in these surveys, and revealed substantial amounts of hidden microbial diversity. Moreover, network measures demonstrated that ciliates are not globally dispersed, but are structured by habitat and geographical location at intermediate geographical scale, as observed for bacteria, plants, and animals. CONCLUSIONS Currently available 'universal' primers used for local in-depth sequencing surveys provide little hope to exhaust the significantly higher ciliate (and most likely microbial) diversity than previously thought. Network analyses such as presented in this study offer a promising way to guide the design of novel primers and to further explore this vast and structured microbial diversity.
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Affiliation(s)
- Dominik Forster
- Department of Ecology, University of Kaiserslautern, Erwin-Schrödinger-Straße 14, Kaiserslautern, D-67633, Germany.
| | - Lucie Bittner
- Department of Ecology, University of Kaiserslautern, Erwin-Schrödinger-Straße 14, Kaiserslautern, D-67633, Germany.
- CNRS, FR3631, Institut de Biologie Paris-Seine, Paris, F-75005, France.
- Sorbonne Universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine (IBPS), Paris, F-75005, France.
| | - Slim Karkar
- Sorbonne Universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine (IBPS), Paris, F-75005, France.
- CNRS, UMR7138, Institut de Biologie Paris-Seine, Paris, F-75005, France.
| | - Micah Dunthorn
- Department of Ecology, University of Kaiserslautern, Erwin-Schrödinger-Straße 14, Kaiserslautern, D-67633, Germany.
| | - Sarah Romac
- CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, Roscoff, F-29680, France.
- Sorbonne Universités, UPMC Univ Paris 06, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, Roscoff, F-29680, France.
| | - Stéphane Audic
- CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, Roscoff, F-29680, France.
- Sorbonne Universités, UPMC Univ Paris 06, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, Roscoff, F-29680, France.
| | - Philippe Lopez
- Sorbonne Universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine (IBPS), Paris, F-75005, France.
- CNRS, UMR7138, Institut de Biologie Paris-Seine, Paris, F-75005, France.
| | - Thorsten Stoeck
- Department of Ecology, University of Kaiserslautern, Erwin-Schrödinger-Straße 14, Kaiserslautern, D-67633, Germany.
| | - Eric Bapteste
- Sorbonne Universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine (IBPS), Paris, F-75005, France.
- CNRS, UMR7138, Institut de Biologie Paris-Seine, Paris, F-75005, France.
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Network analysis suggests a potentially 'evil' alliance of opportunistic pathogens inhibited by a cooperative network in human milk bacterial communities. Sci Rep 2015; 5:8275. [PMID: 25651890 PMCID: PMC4317708 DOI: 10.1038/srep08275] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 01/02/2015] [Indexed: 12/27/2022] Open
Abstract
The critical importance of human milk to infants and even human civilization has been well established. Yet our understanding of the milk microbiome has been limited to cataloguing OTUs and computation of community diversity. To the best of our knowledge, there has been no report on the bacterial interactions within the milk microbiome. To bridge this gap, we reconstructed a milk bacterial community network based on Hunt et al. Our analysis revealed that the milk microbiome network consists of two disconnected sub-networks. One sub-network is a fully connected complete graph consisting of seven genera as nodes and all of its pair-wise interactions among the bacteria are facilitative or cooperative. In contrast, the interactions in the other sub-network of eight nodes are mixed but dominantly cooperative. Somewhat surprisingly, the only ‘non-cooperative' nodes in the second sub-network are mutually cooperative Staphylococcus and Corynebacterium that include some opportunistic pathogens. This potentially ‘evil' alliance between Staphylococcus and Corynebacterium could be inhibited by the remaining nodes that cooperate with one another in the second sub-network. We postulate that the ‘confrontation' between the ‘evil' alliance and ‘benign' alliance and the shifting balance between them may be responsible for dysbiosis of the milk microbiome that permits mastitis.
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EGN: a wizard for construction of gene and genome similarity networks. BMC Evol Biol 2013; 13:146. [PMID: 23841456 PMCID: PMC3727994 DOI: 10.1186/1471-2148-13-146] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 07/05/2013] [Indexed: 01/11/2023] Open
Abstract
Background Increasingly, similarity networks are being used for evolutionary analyses of molecular datasets. These networks are very useful, in particular for the analysis of gene sharing, lateral gene transfer and for the detection of distant homologs. Currently, such analyses require some computer programming skills due to the limited availability of user-friendly freely distributed software. Consequently, although appealing, the construction and analyses of these networks remain less familiar to biologists than do phylogenetic approaches. Results In order to ease the use of similarity networks in the community of evolutionary biologists, we introduce a software program, EGN, that runs under Linux or MacOSX. EGN automates the reconstruction of gene and genome networks from nucleic and proteic sequences. EGN also implements statistics describing genetic diversity in these samples, for various user-defined thresholds of similarities. In the interest of studying the complexity of evolutionary processes affecting microbial evolution, we applied EGN to a dataset of 571,044 proteic sequences from the three domains of life and from mobile elements. We observed that, in Borrelia, plasmids play a different role than in most other eubacteria. Rather than being genetic couriers involved in lateral gene transfer, Borrelia’s plasmids and their genes act as private genetic goods, that contribute to the creation of genetic diversity within their parasitic hosts. Conclusion EGN can be used for constructing, analyzing, and mining molecular datasets in evolutionary studies. The program can help increase our knowledge of the processes through which genes from distinct sources and/or from multiple genomes co-evolve in lineages of cellular organisms.
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Stecher B, Berry D, Loy A. Colonization resistance and microbial ecophysiology: using gnotobiotic mouse models and single-cell technology to explore the intestinal jungle. FEMS Microbiol Rev 2013; 37:793-829. [PMID: 23662775 DOI: 10.1111/1574-6976.12024] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 04/11/2013] [Accepted: 04/18/2013] [Indexed: 12/14/2022] Open
Abstract
The highly diverse intestinal microbiota forms a structured community engaged in constant communication with itself and its host and is characterized by extensive ecological interactions. A key benefit that the microbiota affords its host is its ability to protect against infections in a process termed colonization resistance (CR), which remains insufficiently understood. In this review, we connect basic concepts of CR with new insights from recent years and highlight key technological advances in the field of microbial ecology. We present a selection of statistical and bioinformatics tools used to generate hypotheses about synergistic and antagonistic interactions in microbial ecosystems from metagenomic datasets. We emphasize the importance of experimentally testing these hypotheses and discuss the value of gnotobiotic mouse models for investigating specific aspects related to microbiota-host-pathogen interactions in a well-defined experimental system. We further introduce new developments in the area of single-cell analysis using fluorescence in situ hybridization in combination with metabolic stable isotope labeling technologies for studying the in vivo activities of complex community members. These approaches promise to yield novel insights into the mechanisms of CR and intestinal ecophysiology in general, and give researchers the means to experimentally test hypotheses in vivo at varying levels of biological and ecological complexity.
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Affiliation(s)
- Bärbel Stecher
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Ludwig-Maximilians-University of Munich, Munich, Germany.
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