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Leleiwi I, Kokkinias K, Kim Y, Baniasad M, Shaffer M, Sabag-Daigle A, Daly RA, Flynn RM, Wysocki VH, Ahmer BMM, Borton MA, Wrighton KC. Gut microbiome carbon and sulfur metabolisms support Salmonella during pathogen infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.16.575907. [PMID: 38293109 PMCID: PMC10827160 DOI: 10.1101/2024.01.16.575907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Salmonella enterica serovar Typhimurium is a pervasive enteric pathogen and an ongoing global threat to public health. Ecological studies in the Salmonella impacted gut remain underrepresented in the literature, discounting the microbiome mediated interactions that may inform Salmonella physiology during colonization and infection. To understand the microbial ecology of Salmonella remodeling of the gut microbiome, here we performed multi-omics approaches on fecal microbial communities from untreated and Salmonella -infected mice. Reconstructed genomes recruited metatranscriptomic and metabolomic data providing a strain-resolved view of the expressed metabolisms of the microbiome during Salmonella infection. This data informed possible Salmonella interactions with members of the gut microbiome that were previously uncharacterized. Salmonella- induced inflammation significantly reduced the diversity of transcriptionally active members in the gut microbiome, yet increased gene expression was detected for 7 members, with Luxibacter and Ligilactobacillus being the most active. Metatranscriptomic insights from Salmonella and other persistent taxa in the inflamed microbiome further expounded the necessity for oxidative tolerance mechanisms to endure the host inflammatory responses to infection. In the inflamed gut lactate was a key metabolite, with microbiota production and consumption reported amongst transcriptionally active members. We also showed that organic sulfur sources could be converted by gut microbiota to yield inorganic sulfur pools that become oxidized in the inflamed gut, resulting in thiosulfate and tetrathionate that supports Salmonella respiration. Advancement of pathobiome understanding beyond inferences from prior amplicon-based approaches can hold promise for infection mitigation, with the active community outlined here offering intriguing organismal and metabolic therapeutic targets.
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Leleiwi I, Rodriguez-Ramos J, Shaffer M, Sabag-Daigle A, Kokkinias K, Flynn RM, Daly RA, Kop LFM, Solden LM, Ahmer BMM, Borton MA, Wrighton KC. Exposing new taxonomic variation with inflammation - a murine model-specific genome database for gut microbiome researchers. MICROBIOME 2023; 11:114. [PMID: 37210515 PMCID: PMC10199544 DOI: 10.1186/s40168-023-01529-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 03/21/2023] [Indexed: 05/22/2023]
Abstract
BACKGROUND The murine CBA/J mouse model widely supports immunology and enteric pathogen research. This model has illuminated Salmonella interactions with the gut microbiome since pathogen proliferation does not require disruptive pretreatment of the native microbiota, nor does it become systemic, thereby representing an analog to gastroenteritis disease progression in humans. Despite the value to broad research communities, microbiota in CBA/J mice are not represented in current murine microbiome genome catalogs. RESULTS Here we present the first microbial and viral genomic catalog of the CBA/J murine gut microbiome. Using fecal microbial communities from untreated and Salmonella-infected, highly inflamed mice, we performed genomic reconstruction to determine the impacts on gut microbiome membership and functional potential. From high depth whole community sequencing (~ 42.4 Gbps/sample), we reconstructed 2281 bacterial and 4516 viral draft genomes. Salmonella challenge significantly altered gut membership in CBA/J mice, revealing 30 genera and 98 species that were conditionally rare and unsampled in non-inflamed mice. Additionally, inflamed communities were depleted in microbial genes that modulate host anti-inflammatory pathways and enriched in genes for respiratory energy generation. Our findings suggest decreases in butyrate concentrations during Salmonella infection corresponded to reductions in the relative abundance in members of the Alistipes. Strain-level comparison of CBA/J microbial genomes to prominent murine gut microbiome databases identified newly sampled lineages in this resource, while comparisons to human gut microbiomes extended the host relevance of dominant CBA/J inflammation-resistant strains. CONCLUSIONS This CBA/J microbiome database provides the first genomic sampling of relevant, uncultivated microorganisms within the gut from this widely used laboratory model. Using this resource, we curated a functional, strain-resolved view on how Salmonella remodels intact murine gut communities, advancing pathobiome understanding beyond inferences from prior amplicon-based approaches. Salmonella-induced inflammation suppressed Alistipes and other dominant members, while rarer commensals like Lactobacillus and Enterococcus endure. The rare and novel species sampled across this inflammation gradient advance the utility of this microbiome resource to benefit the broad research needs of the CBA/J scientific community, and those using murine models for understanding the impact of inflammation on the gut microbiome more generally. Video Abstract.
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Affiliation(s)
- Ikaia Leleiwi
- Department of Cell and Molecular Biology, The Colorado State University, Fort Collins, CO USA
- Department of Soil and Crop Sciences, The Colorado State University, Fort Collins, CO USA
| | - Josué Rodriguez-Ramos
- Department of Soil and Crop Sciences, The Colorado State University, Fort Collins, CO USA
- Graduate Degree Program in Ecology, The Colorado State University, Fort Collins, CO USA
| | - Michael Shaffer
- Department of Soil and Crop Sciences, The Colorado State University, Fort Collins, CO USA
| | - Anice Sabag-Daigle
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH USA
| | - Katherine Kokkinias
- Department of Soil and Crop Sciences, The Colorado State University, Fort Collins, CO USA
- Department of Microbiology, Immunology, and Pathology, The Colorado State University, Fort Collins, CO USA
| | - Rory M. Flynn
- Department of Soil and Crop Sciences, The Colorado State University, Fort Collins, CO USA
| | - Rebecca A. Daly
- Department of Soil and Crop Sciences, The Colorado State University, Fort Collins, CO USA
| | - Linnea F. M. Kop
- Department of Microbiology, RIBES, Radbound University, Nijmegen, The Netherlands
- Department of Microbiology and Biophysics, The Ohio State University, Columbus, OH USA
| | - Lindsey M. Solden
- Department of Soil and Crop Sciences, The Colorado State University, Fort Collins, CO USA
| | - Brian M. M. Ahmer
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH USA
| | - Mikayla A. Borton
- Department of Soil and Crop Sciences, The Colorado State University, Fort Collins, CO USA
| | - Kelly C. Wrighton
- Department of Cell and Molecular Biology, The Colorado State University, Fort Collins, CO USA
- Department of Soil and Crop Sciences, The Colorado State University, Fort Collins, CO USA
- Graduate Degree Program in Ecology, The Colorado State University, Fort Collins, CO USA
- Department of Microbiology, Immunology, and Pathology, The Colorado State University, Fort Collins, CO USA
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Sabag-Daigle A, Boulanger EF, Thirugnanasambantham P, Law JD, Bogard AJ, Behrman EJ, Gopalan V, Ahmer BMM. Identification of Small-Molecule Inhibitors of the Salmonella FraB Deglycase Using a Live-Cell Assay. Microbiol Spectr 2023; 11:e0460622. [PMID: 36809033 PMCID: PMC10100877 DOI: 10.1128/spectrum.04606-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/18/2023] [Indexed: 02/23/2023] Open
Abstract
Nontyphoidal salmonellosis is one of the most significant foodborne diseases in the United States and globally. There are no vaccines available for human use to prevent this disease, and only broad-spectrum antibiotics are available to treat complicated cases of the disease. However, antibiotic resistance is on the rise and new therapeutics are needed. We previously identified the Salmonella fraB gene, that mutation of causes attenuation of fitness in the murine gastrointestinal tract. The FraB gene product is encoded in an operon responsible for the uptake and utilization of fructose-asparagine (F-Asn), an Amadori product found in several human foods. Mutations in fraB cause an accumulation of the FraB substrate, 6-phosphofructose-aspartate (6-P-F-Asp), which is toxic to Salmonella. The F-Asn catabolic pathway is found only in the nontyphoidal Salmonella serovars, a few Citrobacter and Klebsiella isolates, and a few species of Clostridium; it is not found in humans. Thus, targeting FraB with novel antimicrobials is expected to be Salmonella specific, leaving the normal microbiota largely intact and having no effect on the host. We performed high-throughput screening (HTS) to identify small-molecule inhibitors of FraB using growth-based assays comparing a wild-type Salmonella and a Δfra island mutant control. We screened 224,009 compounds in duplicate. After hit triage and validation, we found three compounds that inhibit Salmonella in an fra-dependent manner, with 50% inhibitory concentration (IC50) values ranging from 89 to 150 μM. Testing these compounds with recombinant FraB and synthetic 6-P-F-Asp confirmed that they are uncompetitive inhibitors of FraB with Ki' (inhibitor constant) values ranging from 26 to 116 μM. IMPORTANCE Nontyphoidal salmonellosis is a serious threat in the United States and globally. We have recently identified an enzyme, FraB, that when mutated renders Salmonella growth defective in vitro and unfit in mouse models of gastroenteritis. FraB is quite rare in bacteria and is not found in humans or other animals. Here, we have identified small-molecule inhibitors of FraB that inhibit the growth of Salmonella. These could provide the foundation for a therapeutic to reduce the duration and severity of Salmonella infections.
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Affiliation(s)
- Anice Sabag-Daigle
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA
| | - Erin F. Boulanger
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA
| | | | - Jamison D. Law
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - Alex J. Bogard
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - Edward J. Behrman
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - Venkat Gopalan
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - Brian M. M. Ahmer
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA
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Thirugnanasambantham P, Kovvali S, Cool A, Gao Y, Sabag-Daigle A, Boulanger EF, Mitton-Fry M, Capua AD, Behrman EJ, Wysocki VH, Lindert S, Ahmer BMM, Gopalan V. Serendipitous Discovery of a Competitive Inhibitor of FraB, a Salmonella Deglycase and Drug Target. Pathogens 2022; 11:1102. [PMID: 36297159 PMCID: PMC9609667 DOI: 10.3390/pathogens11101102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/18/2022] [Accepted: 09/20/2022] [Indexed: 11/01/2023] Open
Abstract
Although salmonellosis, an infectious disease, is a significant global healthcare burden, there are no Salmonella-specific vaccines or therapeutics for humans. Motivated by our finding that FraB, a Salmonella deglycase responsible for fructose-asparagine catabolism, is a viable drug target, we initiated experimental and computational efforts to identify inhibitors of FraB. To this end, our recent high-throughput screening initiative yielded almost exclusively uncompetitive inhibitors of FraB. In parallel with this advance, we report here how a separate structural and computational biology investigation of FrlB, a FraB paralog, led to the serendipitous discovery that 2-deoxy-6-phosphogluconate is a competitive inhibitor of FraB (KI ~ 3 μM). However, this compound was ineffective in inhibiting the growth of Salmonella in a liquid culture. In addition to poor uptake, cellular metabolic transformations by a Salmonella dehydrogenase and different phosphatases likely undermined the efficacy of 2-deoxy-6-phosphogluconate in live-cell assays. These insights inform our ongoing efforts to synthesize non-hydrolyzable/-metabolizable analogs of 2-deoxy-6-phosphogluconate. We showcase our findings largely to (re)emphasize the role of serendipity and the importance of multi-pronged approaches in drug discovery.
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Affiliation(s)
| | - Sravya Kovvali
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Austin Cool
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Yuan Gao
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
- Resource for Native Mass Spectrometry-Guided Structural Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Anice Sabag-Daigle
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210, USA
| | - Erin F. Boulanger
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210, USA
| | - Mark Mitton-Fry
- Department of Medicinal Chemistry and Pharmacognosy, The Ohio State University, Columbus, OH 43210, USA
| | - Angela Di Capua
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
- Resource for Native Mass Spectrometry-Guided Structural Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Edward J. Behrman
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Vicki H. Wysocki
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
- Resource for Native Mass Spectrometry-Guided Structural Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Steffen Lindert
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Brian M. M. Ahmer
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210, USA
| | - Venkat Gopalan
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
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Abstract
Accumulation of phosphorylated intermediates during cellular metabolism can have wide-ranging toxic effects on many organisms, including humans and the pathogens that infect them. These toxicities can be induced by feeding an upstream metabolite (a sugar, for instance) while simultaneously blocking the appropriate metabolic pathway with either a mutation or an enzyme inhibitor. Here, we survey the toxicities that can arise in the metabolism of glucose, galactose, fructose, fructose-asparagine, glycerol, trehalose, maltose, mannose, mannitol, arabinose, and rhamnose. Select enzymes in these metabolic pathways may serve as novel therapeutic targets. Some are conserved broadly among prokaryotes and eukaryotes (e.g., glucose and galactose) and are therefore unlikely to be viable drug targets. However, others are found only in bacteria (e.g., fructose-asparagine, rhamnose, and arabinose), and one is found in fungi but not in humans (trehalose). We discuss what is known about the mechanisms of toxicity and how resistance is achieved in order to identify the prospects and challenges associated with targeted exploitation of these pervasive metabolic vulnerabilities.
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Abdelhamid AG, Yousef AE. Natural Antimicrobials Suitable for Combating Desiccation-Resistant Salmonella enterica in Milk Powder. Microorganisms 2021; 9:421. [PMID: 33670672 PMCID: PMC7923161 DOI: 10.3390/microorganisms9020421] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 02/04/2021] [Accepted: 02/14/2021] [Indexed: 01/01/2023] Open
Abstract
Some Salmonella enterica strains survive well in low-water activity (low-aw) foods and cause frequent salmonellosis outbreaks in these products. Methods are needed to overcome such desiccation-resistant Salmonella and to improve the safety of low-aw foods. Building on a recent finding, we hypothesized that natural antimicrobial food additives, which are active against cytoplasmic membrane, could overcome this desiccation resistance phenomenon, and thus, sensitize the pathogen to drying and mild processing. Food additives were screened for the ability to cause leakage of intracellular potassium ions; retention of these ions is vital for protecting Salmonella against desiccation. Two antimicrobial food additives, carvacrol and thymol, caused considerable potassium leakage from the desiccation-resistant S. enterica serovars, Tennessee and Livingstone. Thus, carvacrol and thymol were investigated for their ability to sensitize the desiccation-adapted S. enterica to heat treatment. The combined use of food additives, at their minimum inhibitory concentrations, with heat treatment at 55 °C for 15 min caused 3.1 ± 0.21 to more than 5.5 log colony forming unit (CFU)/mL reduction in desiccation-adapted S. enterica, compared to 2.4 ± 0.53-3.2 ± 0.11 log CFU/mL reduction by sole heat treatment. Carvacrol was the additive that caused the greatest potassium leakage and sensitization of Salmonella to heat; hence, the application of this compound was investigated in a food model against Salmonella Typhimurium ASD200. Addition of carvacrol at 200 or 500 ppm into liquid milk followed by spray-drying reduced the strain's population by 0.9 ± 0.02 and 1.3 ± 0.1 log CFU/g, respectively, compared to 0.6 ± 0.02 log CFU/g reduction for non-treated spray-dried milk. Additionally, freeze-drying of milk treated with high levels of carvacrol (5000 ppm) reduced the population of Salmonella Typhimurium ASD200 by more than 4.5 log CFU/g, compared to 1.1 ± 0.4 log CFU/g reduction for the freeze-dried untreated milk. These findings suggest that carvacrol can combat desiccation-resistant S. enterica, and thus, potentially improve the safety of low-aw foods.
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Affiliation(s)
- Ahmed G. Abdelhamid
- Department of Food Science and Technology, The Ohio State University, 2015 Fyffe Court, Columbus, OH 43210, USA;
- Botany and Microbiology Department, Faculty of Science, Benha University, Benha 13518, Egypt
| | - Ahmed E. Yousef
- Department of Food Science and Technology, The Ohio State University, 2015 Fyffe Court, Columbus, OH 43210, USA;
- Department of Microbiology, The Ohio State University, 105 Biological Sciences Building, 484 West 12th Avenue, Columbus, OH 43210, USA
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Gut AM, Vasiljevic T, Yeager T, Donkor ON. Salmonella infection - prevention and treatment by antibiotics and probiotic yeasts: a review. MICROBIOLOGY-SGM 2018; 164:1327-1344. [PMID: 30136920 DOI: 10.1099/mic.0.000709] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Global Salmonella infection, especially in developing countries, is a health and economic burden. The use of antibiotic drugs in treating the infection is proving less effective due to the alarming rise of antibiotic-resistant strains of Salmonella, the effects of antibiotics on normal gut microflora and antibiotic-associated diarrhoea, all of which bring a growing need for alternative treatments, including the use of probiotic micro-organisms. However, there are issues with probiotics, including their potential to be opportunistic pathogens and antibiotic-resistant carriers, and their antibiotic susceptibility if used as complementary therapy. Clinical trials, animal trials and in vitro investigations into the prophylactic and therapeutic efficacies of probiotics have demonstrated antagonistic properties against Salmonella and other enteropathogenic bacteria. Nonetheless, there is a need for further studies into the potential mechanisms, efficacy and mode of delivery of yeast probiotics in Salmonella infections. This review discusses Salmonella infections and treatment using antibiotics and probiotics.
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Affiliation(s)
- Abraham Majak Gut
- 1Institute for Sustainable Industries and Livable Cities, College of Health and Biomedicine, Victoria University, Werribee Campus, PO Box 14428, Melbourne, Victoria 8001, Australia
| | - Todor Vasiljevic
- 1Institute for Sustainable Industries and Livable Cities, College of Health and Biomedicine, Victoria University, Werribee Campus, PO Box 14428, Melbourne, Victoria 8001, Australia
| | - Thomas Yeager
- 2Institute for Sustainable Industries and Livable Cities, College of Engineering and Science, Victoria University, Werribee Campus, PO Box 14428, Melbourne, Victoria 8001, Australia
| | - Osaana N Donkor
- 1Institute for Sustainable Industries and Livable Cities, College of Health and Biomedicine, Victoria University, Werribee Campus, PO Box 14428, Melbourne, Victoria 8001, Australia
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Salmonella-Mediated Inflammation Eliminates Competitors for Fructose-Asparagine in the Gut. Infect Immun 2018; 86:IAI.00945-17. [PMID: 29483291 DOI: 10.1128/iai.00945-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 02/20/2018] [Indexed: 01/05/2023] Open
Abstract
Salmonella enterica elicits intestinal inflammation to gain access to nutrients. One of these nutrients is fructose-asparagine (F-Asn). The availability of F-Asn to Salmonella during infection is dependent upon Salmonella pathogenicity islands 1 and 2, which in turn are required to provoke inflammation. Here, we determined that F-Asn is present in mouse chow at approximately 400 pmol/mg (dry weight). F-Asn is also present in the intestinal tract of germfree mice at 2,700 pmol/mg (dry weight) and in the intestinal tract of conventional mice at 9 to 28 pmol/mg. These findings suggest that the mouse intestinal microbiota consumes F-Asn. We utilized heavy-labeled precursors of F-Asn to monitor its formation in the intestine, in the presence or absence of inflammation, and none was observed. Finally, we determined that some members of the class Clostridia encode F-Asn utilization pathways and that they are eliminated from highly inflamed Salmonella-infected mice. Collectively, our studies identify the source of F-Asn as the diet and that Salmonella-mediated inflammation is required to eliminate competitors and allow the pathogen nearly exclusive access to this nutrient.
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An Attenuated Salmonella enterica Serovar Typhimurium Strain and Galacto-Oligosaccharides Accelerate Clearance of Salmonella Infections in Poultry through Modifications to the Gut Microbiome. Appl Environ Microbiol 2018; 84:AEM.02526-17. [PMID: 29269490 DOI: 10.1128/aem.02526-17] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 12/14/2017] [Indexed: 01/18/2023] Open
Abstract
Salmonella is estimated to cause one million foodborne illnesses in the United States every year. Salmonella-contaminated poultry products are one of the major sources of salmonellosis. Given the critical role of the gut microbiota in Salmonella transmission, a manipulation of the chicken intestinal microenvironment could prevent animal colonization by the pathogen. In Salmonella, the global regulator gene fnr (fumarate nitrate reduction) regulates anaerobic metabolism and is essential for adapting to the gut environment. This study tested the hypothesis that an attenuated Fnr mutant of Salmonella enterica serovar Typhimurium (attST) or prebiotic galacto-oligosaccharides (GOS) could improve resistance to wild-type Salmonella via modifications to the structure of the chicken gut microbiome. Intestinal samples from a total of 273 animals were collected weekly for 9 weeks to evaluate the impact of attST or prebiotic supplementation on microbial species of the cecum, duodenum, jejunum, and ileum. We next analyzed changes to the gut microbiome induced by challenging the animals with a wild-type Salmonella serovar 4,[5],12:r:- (Nalr) strain and determined the clearance rate of the virulent strain in the treated and control groups. Both GOS and the attenuated Salmonella strain modified the gut microbiome but elicited alterations of different taxonomic groups. The attST produced significant increases of Alistipes and undefined Lactobacillus, while GOS increased Christensenellaceae and Lactobacillus reuteri The microbiome structural changes induced by both treatments resulted in a faster clearance after a Salmonella challenge.IMPORTANCE With an average annual incidence of 13.1 cases/100,000 individuals, salmonellosis has been deemed a nationally notifiable condition in the United States by the Centers for Disease Control and Prevention (CDC). Earlier studies demonstrated that Salmonella is transmitted by a subset of animals (supershedders). The supershedder phenotype can be induced by antibiotics, ascertaining an essential role for the gut microbiota in Salmonella transmission. Consequently, modulation of the gut microbiota and modification of the intestinal microenvironment could assist in preventing animal colonization by the pathogen. Our study demonstrated that a manipulation of the chicken gut microbiota by the administration of an attenuated Salmonella strain or prebiotic galacto-oligosaccharides (GOS) can promote resistance to Salmonella colonization via increases of beneficial microorganisms that translate into a less hospitable gut microenvironment.
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Borton MA, Sabag-Daigle A, Wu J, Solden LM, O’Banion BS, Daly RA, Wolfe RA, Gonzalez JF, Wysocki VH, Ahmer BMM, Wrighton KC. Chemical and pathogen-induced inflammation disrupt the murine intestinal microbiome. MICROBIOME 2017; 5:47. [PMID: 28449706 PMCID: PMC5408407 DOI: 10.1186/s40168-017-0264-8] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 04/11/2017] [Indexed: 05/06/2023]
Abstract
BACKGROUND Salmonella is one of the most significant food-borne pathogens to affect humans and agriculture. While it is well documented that Salmonella infection triggers host inflammation, the impacts on the gut environment are largely unknown. A CBA/J mouse model was used to evaluate intestinal responses to Salmonella-induced inflammation. In parallel, we evaluated chemically induced inflammation by dextran sodium sulfate (DSS) and a non-inflammation control. We profiled gut microbial diversity by sequencing 16S ribosomal ribonucleic acid (rRNA) genes from fecal and cecal samples. These data were correlated to the inflammation marker lipocalin-2 and short-chain fatty acid concentrations. RESULTS We demonstrated that inflammation, chemically or biologically induced, restructures the chemical and microbial environment of the gut over a 16-day period. We observed that the ten mice within the Salmonella treatment group had a variable Salmonella relative abundance, with three high responding mice dominated by >46% Salmonella at later time points and the remaining seven mice denoted as low responders. These low- and high-responding Salmonella groups, along with the chemical DSS treatment, established an inflammation gradient with chemical and low levels of Salmonella having at least 3 log-fold lower lipocalin-2 concentration than the high-responding Salmonella mice. Total short-chain fatty acid and individual butyrate concentrations each negatively correlated with inflammation levels. Microbial communities were also structured along this inflammation gradient. Low levels of inflammation, regardless of chemical or biological induction, enriched for Akkermansia spp. in the Verrucomicrobiaceae and members of the Bacteroidetes family S24-7. Relative to the control or low inflammation groups, high levels of Salmonella drastically decreased the overall microbial diversity, specifically driven by the reduction of Alistipes and Lachnospiraceae in the Bacteroidetes and Firmicutes phyla, respectively. Conversely, members of the Enterobacteriaceae and Lactobacillus were positively correlated to high levels of Salmonella-induced inflammation. CONCLUSIONS Our results show that enteropathogenic infection and intestinal inflammation are interrelated factors modulating gut homeostasis. These findings may prove informative with regard to prophylactic or therapeutic strategies to prevent disruption of microbial communities, or promote their restoration.
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Affiliation(s)
- Mikayla A. Borton
- Department of Microbiology, The Ohio State University, 484 W. 12th Avenue, 440 Biological Sciences Building, Columbus, OH 43210 USA
| | - Anice Sabag-Daigle
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210 USA
- Center for Microbial Interface Biology, The Ohio State University, Columbus, OH 43210 USA
| | - Jikang Wu
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210 USA
| | - Lindsey M. Solden
- Department of Microbiology, The Ohio State University, 484 W. 12th Avenue, 440 Biological Sciences Building, Columbus, OH 43210 USA
| | - Bridget S. O’Banion
- Department of Microbiology, The Ohio State University, 484 W. 12th Avenue, 440 Biological Sciences Building, Columbus, OH 43210 USA
| | - Rebecca A. Daly
- Department of Microbiology, The Ohio State University, 484 W. 12th Avenue, 440 Biological Sciences Building, Columbus, OH 43210 USA
| | - Richard A. Wolfe
- Department of Microbiology, The Ohio State University, 484 W. 12th Avenue, 440 Biological Sciences Building, Columbus, OH 43210 USA
| | - Juan F. Gonzalez
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210 USA
- Center for Microbial Interface Biology, The Ohio State University, Columbus, OH 43210 USA
| | - Vicki H. Wysocki
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210 USA
| | - Brian M. M. Ahmer
- Department of Microbiology, The Ohio State University, 484 W. 12th Avenue, 440 Biological Sciences Building, Columbus, OH 43210 USA
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210 USA
- Center for Microbial Interface Biology, The Ohio State University, Columbus, OH 43210 USA
| | - Kelly C. Wrighton
- Department of Microbiology, The Ohio State University, 484 W. 12th Avenue, 440 Biological Sciences Building, Columbus, OH 43210 USA
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11
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Abstract
For the important foodborne pathogen Salmonella enterica to cause disease or persist in pigs, it has evolved an intricate set of interactions between itself, the host, and the indigenous microflora of the host. S. enterica must evade the host's immune system and must also overcome colonization resistance mediated by the pig's indigenous microflora. The inflammatory response against S. enterica provides the bacteria with unique metabolites and is thus exploited by S. enterica for competitive advantage. During infection, changes in the composition of the indigenous microflora occur that have been associated with a breakdown in colonization resistance. Healthy pigs that are low-level shedders of S. enterica also exhibit alterations in their indigenous microflora similar to those in ill animals. Here we review the literature on the interactions that occur between swine, S. enterica, and the indigenous microflora and discuss methods to reduce or prevent colonization of pigs with S. enterica.
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Affiliation(s)
- Hyeun Bum Kim
- Department of Animal Resources Science, Dankook University, Cheonan, Chungnam, South Korea 31116;
| | - Richard E Isaacson
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, Minnesota 55108;
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