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Barton A, Hill J, O'Connor D, Jones C, Jones E, Camara S, Shrestha S, Jin C, Gibani MM, Dobinson HC, Waddington C, Darton TC, Blohmke CJ, Pollard AJ. Early transcriptional responses to human enteric fever challenge. Infect Immun 2023; 91:e0010823. [PMID: 37725060 PMCID: PMC10581002 DOI: 10.1128/iai.00108-23] [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: 03/23/2023] [Accepted: 06/29/2023] [Indexed: 09/21/2023] Open
Abstract
Enteric fever, caused by oral infection with typhoidal Salmonella serovars, presents as a non-specific febrile illness preceded by an incubation period of 5 days or more. The enteric fever human challenge model provides a unique opportunity to investigate the innate immune response during this incubation period, and how this response is altered by vaccination with the Vi polysaccharide or conjugate vaccine. We find that on the same day as ingestion of typhoidal Salmonella, there is already evidence of an immune response, with 199 genes upregulated in the peripheral blood transcriptome 12 hours post-challenge (false discovery rate <0.05). Gene sets relating to neutrophils, monocytes, and innate immunity were over-represented (false discovery rate <0.05). Estimating cell proportions from gene expression data suggested a possible increase in activated monocytes 12 hours post-challenge (P = 0.036, paired Wilcoxon signed-rank test). Furthermore, plasma TNF-α rose following exposure (P = 0.011, paired Wilcoxon signed-rank test). There were no significant differences in gene expression (false discovery rate <0.05) in the 12 hours response between those who did and did not subsequently develop clinical or blood culture confirmed enteric fever or between vaccination groups. Together, these results demonstrate early perturbation of the peripheral blood transcriptome after enteric fever challenge and provide initial insight into early mechanisms of protection.
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Affiliation(s)
- Amber Barton
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Jennifer Hill
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Daniel O'Connor
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Claire Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Elizabeth Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Susana Camara
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Sonu Shrestha
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Celina Jin
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
- Department of Pathology, Royal Melbourne Hospital, Melbourne, Australia
- Infectious Diseases and Immune Defence Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Malick M. Gibani
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
- Department of Infectious Disease, Imperial College, London, United Kingdom
| | - Hazel C. Dobinson
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Claire Waddington
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
- Department of Infectious Disease, Imperial College, London, United Kingdom
| | - Thomas C. Darton
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
- Department of Infection, Immunity and Cardiovascular Disease and The Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, United Kingdom
| | - Christoph J. Blohmke
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Andrew J. Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
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Lentsch V, Aslani S, Echtermann T, Preet S, Cappio Barazzone E, Hoces D, Moresi C, Kümmerlen D, Slack E. "EvoVax" - A rationally designed inactivated Salmonella Typhimurium vaccine induces strong and long-lasting immune responses in pigs. Vaccine 2023; 41:5545-5552. [PMID: 37517910 DOI: 10.1016/j.vaccine.2023.07.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 07/25/2023] [Accepted: 07/25/2023] [Indexed: 08/01/2023]
Abstract
Salmonella enterica subspecies enterica serovar Typhimurium (S.Tm) poses a considerable threat to public health due to its zoonotic potential. Human infections are mostly foodborne, and pork and pork products are ranked among the top culprits for transmission. In addition, the high percentage of antibiotic resistance, especially in monophasic S.Tm, limits treatment options when needed. Better S.Tm control would therefore be of benefit both for farm animals and for safety of the human food chain. A promising pre-harvest intervention is vaccination. In this study we tested safety and immunogenicity of an oral inactivated S.Tm vaccine, which has been recently shown to generate an "evolutionary trap" and to massively reduce S.Tm colonization and transmission in mice. We show that this vaccine is highly immunogenic and safe in post-weaning pigs and that administration of a single oral dose results in a strong and long-lasting serum IgG response. This has several advantages over existing - mainly live - vaccines against S.Tm, both in improved seroconversion and reduced risk of vaccine-strain persistence and reversion to virulence.
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Affiliation(s)
- Verena Lentsch
- Institute for Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Selma Aslani
- Institute for Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Thomas Echtermann
- Division of Swine Medicine, Department for Farm Animals, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Swapan Preet
- Institute for Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | | | - Daniel Hoces
- Institute for Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Claudia Moresi
- Institute for Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Dolf Kümmerlen
- Division of Swine Medicine, Department for Farm Animals, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Emma Slack
- Institute for Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland; Botnar Research Centre for Child Health, Basel, Switzerland.
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Santelices J, Ou M, Maegawa GHB, Hercik K, Edelmann MJ. USP8 inhibition regulates autophagy flux and controls Salmonella infection. Front Cell Infect Microbiol 2023; 13:1070271. [PMID: 37026055 PMCID: PMC10072284 DOI: 10.3389/fcimb.2023.1070271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 02/13/2023] [Indexed: 04/08/2023] Open
Abstract
Introduction Ubiquitination is an important protein modification that regulates various essential cellular processes, including the functions of innate immune cells. Deubiquitinases are enzymes responsible for removing ubiquitin modification from substrates, and the regulation of deubiquitinases in macrophages during infection with Salmonella Typhimurium and Yersinia enterocolitica remains unknown. Methods To identify deubiquitinases regulated in human macrophages during bacterial infection, an activity-based proteomics screen was conducted. The effects of pharmacological inhibition of the identified deubiquitinase, USP8, were examined, including its impact on bacterial survival within macrophages and its role in autophagy regulation during Salmonella infection. Results Several deubiquiitnases were differentially regulated in infected macrophages. One of the deubiquitinases identified was USP8, which was downregulated upon Salmonella infection. Inhibition of USP8 was associated with a decrease in bacterial survival within macrophages, and it was found to play a distinct role in regulating autophagy during Salmonella infection. The inhibition of USP8 led to the downregulation of the p62 autophagy adaptor. Discussion The findings of this study suggest a novel role of USP8 in regulating autophagy flux, which restricts intracellular bacteria, particularly during Salmonella infection.
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Affiliation(s)
- John Santelices
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, United States
| | - Mark Ou
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, United States
| | - Gustavo H. B. Maegawa
- Department of Pediatrics and Genetics, Columbia University Irving Medical Center, Vagelos Physicians and Surgeons College of Medicine, New York, NY, United States
| | - Kamil Hercik
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czechia
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defense, Hradec Kralove, Czechia
| | - Mariola J. Edelmann
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, United States
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Hoces D, Greter G, Arnoldini M, Stäubli ML, Moresi C, Sintsova A, Berent S, Kolinko I, Bansept F, Woller A, Häfliger J, Martens E, Hardt WD, Sunagawa S, Loverdo C, Slack E. Fitness advantage of Bacteroides thetaiotaomicron capsular polysaccharide in the mouse gut depends on the resident microbiota. eLife 2023; 12:81212. [PMID: 36757366 PMCID: PMC10014078 DOI: 10.7554/elife.81212] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 02/08/2023] [Indexed: 02/10/2023] Open
Abstract
Many microbiota-based therapeutics rely on our ability to introduce a microbe of choice into an already-colonized intestine. In this study, we used genetically barcoded Bacteroides thetaiotaomicron (B. theta) strains to quantify population bottlenecks experienced by a B. theta population during colonization of the mouse gut. As expected, this reveals an inverse relationship between microbiota complexity and the probability that an individual wildtype B. theta clone will colonize the gut. The polysaccharide capsule of B. theta is important for resistance against attacks from other bacteria, phage, and the host immune system, and correspondingly acapsular B. theta loses in competitive colonization against the wildtype strain. Surprisingly, the acapsular strain did not show a colonization defect in mice with a low-complexity microbiota, as we found that acapsular strains have an indistinguishable colonization probability to the wildtype strain on single-strain colonization. This discrepancy could be resolved by tracking in vivo growth dynamics of both strains: acapsular B.theta shows a longer lag phase in the gut lumen as well as a slightly slower net growth rate. Therefore, as long as there is no niche competitor for the acapsular strain, this has only a small influence on colonization probability. However, the presence of a strong niche competitor (i.e., wildtype B. theta, SPF microbiota) rapidly excludes the acapsular strain during competitive colonization. Correspondingly, the acapsular strain shows a similarly low colonization probability in the context of a co-colonization with the wildtype strain or a complete microbiota. In summary, neutral tagging and detailed analysis of bacterial growth kinetics can therefore quantify the mechanisms of colonization resistance in differently-colonized animals.
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Affiliation(s)
- Daniel Hoces
- Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH ZurichZürichSwitzerland
| | - Giorgia Greter
- Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH ZurichZürichSwitzerland
| | - Markus Arnoldini
- Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH ZurichZürichSwitzerland
| | - Melanie L Stäubli
- Institute of Microbiology, Department of Biology, ETH ZurichZurichSwitzerland
| | - Claudia Moresi
- Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH ZurichZürichSwitzerland
| | - Anna Sintsova
- Institute of Microbiology, Department of Biology, ETH ZurichZurichSwitzerland
| | - Sara Berent
- Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH ZurichZürichSwitzerland
| | - Isabel Kolinko
- Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH ZurichZürichSwitzerland
| | - Florence Bansept
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine (IBPS), Laboratoire Jean Perrin (LJP)ParisFrance
| | - Aurore Woller
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine (IBPS), Laboratoire Jean Perrin (LJP)ParisFrance
| | - Janine Häfliger
- Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH ZurichZürichSwitzerland
| | - Eric Martens
- Department of Microbiology and Immunology, University of Michigan Medical SchoolAnn ArborUnited States
| | - Wolf-Dietrich Hardt
- Institute of Microbiology, Department of Biology, ETH ZurichZurichSwitzerland
| | - Shinichi Sunagawa
- Institute of Microbiology, Department of Biology, ETH ZurichZurichSwitzerland
| | - Claude Loverdo
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine (IBPS), Laboratoire Jean Perrin (LJP)ParisFrance
| | - Emma Slack
- Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH ZurichZürichSwitzerland
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5
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Singh Y, Saxena A, Singh SP, Verma MK, Kumar A, Kumar A, Mrigesh M, Saxena MK. Calcium phosphate adjuvanted nanoparticles of outer membrane proteins of Salmonella Typhi as a candidate for vaccine development against Typhoid fever. J Med Microbiol 2022; 71. [PMID: 35476604 DOI: 10.1099/jmm.0.001529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Introduction. The conventional adjuvants used in vaccines have limitations like induction of an imbalanced Th1 and Th2 immune response. To overcome this limitation, novel adjuvants and newer forms of existing adjuvants like calcium phosphate nanoparticles are being tested.Hypothesis/Gap Statement. Calcium phosphate adjuvanted outer membrane proteins vaccine may work as an efficient, safe and cost effective vaccine against Salmonella Typhi.Aim. Our goals were to evaluate the potential of calcium phosphate nanoparticles as an adjuvant using outer membrane proteins (Omps) of Salmonella Typhi as antigens for immune response, with montanide (commercially available adjuvant) as control, and its toxicity in rats.Methodology. Calcium phosphate adjuvanted outer membrane proteins nanoparticles were synthesized and characterized. The efficacy of vaccine formulation in mice and toxicity assay were carried out in rats.Results. The calcium phosphate nanoparticles varying in size between 20-50 nm had entrapment efficiency of 41.5% and loading capacity of 54%. The calcium phosphate nanoparticle-Omps vaccine formulation (nanoparticle-Omps) induced a strong humoral immune response, which was significantly higher than the control group for the entire period of study. In the montanide-Omps group the initial very high immune response declined steeply and then remained steady. The immune response induced by nanoparticle-Omps did not change appreciably. The cell mediated immune response as measured by lymphocyte proliferation assay and delayed type hypersensitivity test showed a higher response (P<0.01) for the nanoparticles-Omps group as compared to montanide-Omps group. The bacterial clearance assay also showed higher clearance in the nanoparticles-Omps group as compared to montanide-Omps group (approx 1.4%). The toxicity analysis in rats showed no difference in the values of toxicity biomarkers and blood chemistry parameters, revealing vaccine formulation was non-toxic in rats.Conclusion. Calcium phosphate nanoparticles as adjuvant in vaccines is safe, have good encapsulation and loading capacity and induce a strong cell mediated, humoral and protective immune response.
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Affiliation(s)
- Yashpal Singh
- Department of Molecular Biology & Genetic Engineering, College of Basic Sciences & Humanities, Pantnagar, Uttarakhand, India
| | - Anjani Saxena
- Department of Veterinary Pharmacology & Toxicology, College of Veterinary & Animal Sciences, Pantnagar, Uttarakhand, India
| | - S P Singh
- Department of Veterinary Pharmacology & Toxicology, College of Veterinary & Animal Sciences, Pantnagar, Uttarakhand, India
| | - Manish Kumar Verma
- Department of Veterinary Pharmacology & Toxicology, College of Veterinary & Animal Sciences, Pantnagar, Uttarakhand, India
| | - Arun Kumar
- Department of Veterinary Surgery and Radiology, College of Veterinary & Animal Sciences, Pantnagar, Uttarakhand, India
| | - Avadhesh Kumar
- Department of Veterinary & Animal Husbandry Extension Education, College of Veterinary & Animal Sciences, Pantnagar, Uttarakhand, India
| | - Meena Mrigesh
- Department of Veterinary Anatomy, College of Veterinary & Animal Sciences, Pantnagar, Uttarakhand, India
| | - Mumtesh Kumar Saxena
- Department of Animal Genetics & Breeding, College of Veterinary & Animal Sciences G.B. Pant University of Agriculture & Technology, Pantnagar, Uttarakhand, India
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Abstract
During infection, the rates of pathogen replication, death, and migration affect disease progression, dissemination, transmission, and resistance evolution. Here, we follow the population dynamics of Vibrio cholerae in a mouse model by labeling individual bacteria with one of >500 unique, fitness-neutral genomic tags. Using the changes in tag frequencies and CFU numbers, we inform a mathematical model that describes the within-host spatiotemporal bacterial dynamics. This allows us to disentangle growth, death, forward, and retrograde migration rates continuously during infection. Our model has robust predictive power across various experimental setups. The population dynamics of V. cholerae shows substantial spatiotemporal heterogeneity in replication, death, and migration. Importantly, we find that the niche available to V. cholerae in the host increases with inoculum size, suggesting cooperative effects during infection. Therefore, it is not enough to consider just the likelihood of exposure (50% infectious dose) but rather the magnitude of exposure to predict outbreaks. IMPORTANCE Determining the rates of bacterial migration, replication, and death during infection is important for understanding how infections progress. Separately measuring these rates is often difficult in systems where multiple processes happen simultaneously. Here, we use next-generation sequencing to measure V. cholerae migration, replication, death, and niche size along the mouse gastrointestinal tract. We show that the small intestine of the mouse is a heterogeneous environment, and the population dynamic characteristics change substantially between adjacent gut sections. Our approach also allows us to characterize the effect of inoculum size on these processes. We find that the niche size in mice increases with the infectious dose, hinting at cooperative effects in larger inocula. The dose-response relationship between inoculum size and final pathogen burden is important for the infected individual and is thought to influence the progression of V. cholerae epidemics.
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7
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Mahmutovic A, Gillman AN, Lauksund S, Robson Moe NA, Manzi A, Storflor M, Abel Zur Wiesch P, Abel S. RESTAMP - Rate estimates by sequence-tag analysis of microbial populations. Comput Struct Biotechnol J 2021; 19:1035-1051. [PMID: 33613869 PMCID: PMC7878984 DOI: 10.1016/j.csbj.2021.01.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 01/12/2021] [Accepted: 01/14/2021] [Indexed: 12/31/2022] Open
Abstract
Microbial division rates determine the speed of mutation accumulation and thus the emergence of antimicrobial resistance. Microbial death rates are affected by antibiotic action and the immune system. Therefore, measuring these rates has advanced our understanding of host-pathogen interactions and antibiotic action. Several methods based on marker-loss or few inheritable neutral markers exist that allow estimating microbial division and death rates, each of which has advantages and limitations. Technical bottlenecks, i.e., experimental sampling events, during the experiment can distort the rate estimates and are typically unaccounted for or require additional calibration experiments. In this work, we introduce RESTAMP (Rate Estimates by Sequence Tag Analysis of Microbial Populations) as a method for determining bacterial division and death rates. This method uses hundreds of fitness neutral sequence barcodes to measure the rates and account for experimental bottlenecks at the same time. We experimentally validate RESTAMP and compare it to established plasmid loss methods. We find that RESTAMP has a number of advantages over plasmid loss or previous marker based techniques. (i) It enables to correct the distortion of rate estimates by technical bottlenecks. (ii) Rate estimates are independent of the sequence tag distribution in the starting culture allowing the use of an arbitrary number of tags. (iii) It introduces a bottleneck sensitivity measure that can be used to maximize the accuracy of the experiment. RESTAMP allows studying microbial population dynamics with great resolution over a wide dynamic range and can thus advance our understanding of host-pathogen interactions or the mechanisms of antibiotic action.
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Affiliation(s)
- Anel Mahmutovic
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, 9037 Tromsø, Norway
| | - Aaron Nicholas Gillman
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, 9037 Tromsø, Norway.,Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, PA 16802, USA
| | - Silje Lauksund
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, 9037 Tromsø, Norway
| | - Natasha-Anne Robson Moe
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, 9037 Tromsø, Norway
| | - Aime Manzi
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, 9037 Tromsø, Norway
| | - Merete Storflor
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, 9037 Tromsø, Norway.,Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, PA 16802, USA
| | - Pia Abel Zur Wiesch
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, 9037 Tromsø, Norway.,Centre for Molecular Medicine Norway, Nordic EMBL Partnership, 0318 Oslo, Norway.,Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA.,Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - Sören Abel
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, 9037 Tromsø, Norway.,Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, PA 16802, USA.,Centre for Molecular Medicine Norway, Nordic EMBL Partnership, 0318 Oslo, Norway.,Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA
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8
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Vlazaki M, Price DJ, Restif O. An experimental design tool to optimize inference precision in data-driven mathematical models of bacterial infections in vivo. J R Soc Interface 2020; 17:20200717. [PMID: 33323052 DOI: 10.1098/rsif.2020.0717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The management of bacterial diseases calls for a detailed knowledge about the dynamic changes in host-bacteria interactions. Biological insights are gained by integrating experimental data with mechanistic mathematical models to infer experimentally unobservable quantities. This inter-disciplinary field would benefit from experiments with maximal information content yielding high-precision inference. Here, we present a computationally efficient tool for optimizing experimental design in terms of parameter inference in studies using isogenic-tagged strains. We study the effect of three experimental design factors: number of biological replicates, sampling timepoint selection and number of copies per tagged strain. We conduct a simulation study to establish the relationship between our optimality criterion and the size of parameter estimate confidence intervals, and showcase its application in a range of biological scenarios reflecting different dynamics patterns observed in experimental infections. We show that in low-variance systems with low killing and replication rates, predicting high-precision experimental designs is consistently achieved; higher replicate sizes and strategic timepoint selection yield more precise estimates. Finally, we address the question of resource allocation under constraints; given a fixed number of host animals and a constraint on total inoculum size per host, infections with fewer strains at higher copies per strain lead to higher-precision inference.
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Affiliation(s)
- Myrto Vlazaki
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - David J Price
- Centre for Epidemiology and Biostatistics, University of Melbourne, Grattan Street, Parkville, Victoria 3010, Australia.,The Doherty Institute for Infection and Immunity, 792 Elizabeth Street, Melbourne, Victoria 3000, Australia
| | - Olivier Restif
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
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9
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Antibodies and Protection in Systemic Salmonella Infections: Do We Still Have More Questions than Answers? Infect Immun 2020; 88:IAI.00219-20. [PMID: 32601109 DOI: 10.1128/iai.00219-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Salmonella causes grave systemic infections in humans and other animals and provides a paradigm for other diseases in which the bacteria have both intracellular and extracellular lifestyles. New generations of vaccines rely on the essential contribution of the antibody responses for their protection. The quality, antigen specificity, and functions associated with antibody responses to this pathogen have been elusive for a long time. Recent approaches that combine studies in humans and genetically manipulated experimental models and that exploit awareness of the location and within-host life cycle of the pathogen are shedding light on how humoral immunity to Salmonella operates. However, this area of research remains full of controversy and discrepancies. The overall scenario indicates that antibodies are essential for resistance against systemic Salmonella infections and can express the highest protective function when operating in conjunction with cell-mediated immunity. Antigen specificity, isotype profile, Fc-gamma receptor usage, and complement activation are all intertwined factors that still arcanely influence antibody-mediated protection to Salmonella.
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10
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Jones DR, Rutan BJ, Wargo AR. Impact of Vaccination and Pathogen Exposure Dosage on Shedding Kinetics of Infectious Hematopoietic Necrosis Virus (IHNV) in Rainbow Trout. JOURNAL OF AQUATIC ANIMAL HEALTH 2020; 32:95-108. [PMID: 32443164 PMCID: PMC7540492 DOI: 10.1002/aah.10108] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 04/03/2020] [Accepted: 04/27/2020] [Indexed: 06/11/2023]
Abstract
Vaccine efficacy in preventing clinical disease has been well characterized. However, vaccine impacts on transmission under diverse field conditions, such as variable pathogen exposure dosages, are not fully understood. We evaluated the impacts of vaccination on disease-induced host mortality and shedding of infectious hematopoietic necrosis virus (IHNV) in Rainbow Trout Oncorhynchus mykiss. Fish, in up to three different genetic lines, were exposed to different dosages of IHNV to simulate field variability. Mortality and viral shedding of each individual fish were quantified over the course of infection. As the exposure dosage increased, mortality, number of fish shedding virus, daily virus quantity shed, and total amount of virus shed also increased. Vaccination significantly reduced mortality but had a much smaller impact on shedding, such that vaccinated fish still shed significant amounts of virus, particularly at higher viral exposure dosages. These studies demonstrate that the consideration of pathogen exposure dosage and transmission are critical for robust inference of vaccine efficacy.
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Affiliation(s)
- Darbi R. Jones
- Virginia Institute of Marine ScienceWilliam & MaryPost Office Box 1346, 1370 Greate RoadGloucester PointVirginia23062USA
| | - Barbara J. Rutan
- Virginia Institute of Marine ScienceWilliam & MaryPost Office Box 1346, 1370 Greate RoadGloucester PointVirginia23062USA
| | - Andrew R. Wargo
- Virginia Institute of Marine ScienceWilliam & MaryPost Office Box 1346, 1370 Greate RoadGloucester PointVirginia23062USA
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11
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Rossi O, Vlazaki M, Kanvatirth P, Restif O, Mastroeni P. Within-host spatiotemporal dynamic of systemic salmonellosis: Ways to track infection, reaction to vaccination and antimicrobial treatment. J Microbiol Methods 2020; 176:106008. [PMID: 32707153 DOI: 10.1016/j.mimet.2020.106008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 07/13/2020] [Accepted: 07/17/2020] [Indexed: 12/16/2022]
Abstract
During the last two decades our understanding of the complex in vivo host-pathogen interactions has increased due to technical improvements and new research tools. The rapid advancement of molecular biology, flow cytometry and microscopy techniques, combined with mathematical modelling, have empowered in-depth studies of systemic bacterial infections across scales from single molecules, to cells, to organs and systems to reach the whole organism level. By tracking subpopulations of bacteria in vivo using molecular or fluorescent tags, it has been possible to reconstruct the spread of infection within and between organs, allowing unprecedented quantification of the effects of antimicrobial treatment and vaccination. This review illustrates recent advances in the study of heterogeneous traits of the infection process and illustrate approaches to investigate the reciprocal interactions between antimicrobial treatments, bacterial growth/death as well as inter- and intra-organ spread. We also discuss how vaccines impact the in vivo behaviour of bacteria and how these findings can guide vaccine design and rational antimicrobial treatment.
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Affiliation(s)
- Omar Rossi
- University of Cambridge, Department of Veterinary Medicine, Madingley Road, CB3 0ES Cambridge, UK.
| | - Myrto Vlazaki
- University of Cambridge, Department of Veterinary Medicine, Madingley Road, CB3 0ES Cambridge, UK
| | - Panchali Kanvatirth
- University of Cambridge, Department of Veterinary Medicine, Madingley Road, CB3 0ES Cambridge, UK
| | - Olivier Restif
- University of Cambridge, Department of Veterinary Medicine, Madingley Road, CB3 0ES Cambridge, UK
| | - Pietro Mastroeni
- University of Cambridge, Department of Veterinary Medicine, Madingley Road, CB3 0ES Cambridge, UK.
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12
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Vlazaki M, Huber J, Restif O. Integrating mathematical models with experimental data to investigate the within-host dynamics of bacterial infections. Pathog Dis 2020; 77:5704399. [PMID: 31942996 PMCID: PMC6986552 DOI: 10.1093/femspd/ftaa001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 01/13/2020] [Indexed: 12/23/2022] Open
Abstract
Bacterial infections still constitute a major cause of mortality and morbidity worldwide. The unavailability of therapeutics, antimicrobial resistance and the chronicity of infections due to incomplete clearance contribute to this phenomenon. Despite the progress in antimicrobial and vaccine development, knowledge about the effect that therapeutics have on the host–bacteria interactions remains incomplete. Insights into the characteristics of bacterial colonization and migration between tissues and the relationship between replication and host- or therapeutically induced killing can enable efficient design of treatment approaches. Recently, innovative experimental techniques have generated data enabling the qualitative characterization of aspects of bacterial dynamics. Here, we argue that mathematical modeling as an adjunct to experimental data can enrich the biological insight that these data provide. However, due to limited interdisciplinary training, efforts to combine the two remain limited. To promote this dialogue, we provide a categorization of modeling approaches highlighting their relationship to data generated by a range of experimental techniques in the area of in vivo bacterial dynamics. We outline common biological themes explored using mathematical models with case studies across all pathogen classes. Finally, this review advocates multidisciplinary integration to improve our mechanistic understanding of bacterial infections and guide the use of existing or new therapies.
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Affiliation(s)
- Myrto Vlazaki
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, CB3 0ES, Cambridge, UK
| | - John Huber
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, CB3 0ES, Cambridge, UK
| | - Olivier Restif
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, CB3 0ES, Cambridge, UK
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13
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Intestinal epithelial NAIP/NLRC4 restricts systemic dissemination of the adapted pathogen Salmonella Typhimurium due to site-specific bacterial PAMP expression. Mucosal Immunol 2020; 13:530-544. [PMID: 31953493 PMCID: PMC7181392 DOI: 10.1038/s41385-019-0247-0] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 11/18/2019] [Accepted: 12/10/2019] [Indexed: 02/07/2023]
Abstract
Inflammasomes can prevent systemic dissemination of enteropathogenic bacteria. As adapted pathogens including Salmonella Typhimurium (S. Tm) have evolved evasion strategies, it has remained unclear when and where inflammasomes restrict their dissemination. Bacterial population dynamics establish that the NAIP/NLRC4 inflammasome specifically restricts S. Tm migration from the gut to draining lymph nodes. This is solely attributable to NAIP/NLRC4 within intestinal epithelial cells (IECs), while S. Tm evades restriction by phagocyte NAIP/NLRC4. NLRP3 and Caspase-11 also fail to restrict S. Tm mucosa traversal, migration to lymph nodes, and systemic pathogen growth. The ability of IECs (not phagocytes) to mount a NAIP/NLRC4 defense in vivo is explained by particularly high NAIP/NLRC4 expression in IECs and the necessity for epithelium-invading S. Tm to express the NAIP1-6 ligands-flagella and type-III-secretion-system-1. Imaging reveals both ligands to be promptly downregulated following IEC-traversal. These results highlight the importance of intestinal epithelial NAIP/NLRC4 in blocking bacterial dissemination in vivo, and explain why this constitutes a uniquely evasion-proof defense against the adapted enteropathogen S. Tm.
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14
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Georg P, Sander LE. Innate sensors that regulate vaccine responses. Curr Opin Immunol 2019; 59:31-41. [PMID: 30978666 DOI: 10.1016/j.coi.2019.02.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/07/2019] [Accepted: 02/22/2019] [Indexed: 02/08/2023]
Abstract
Pattern recognition receptors (PRRs) control elemental functions of antigen presenting cells (APCs) and critically shape adaptive immune responses. Wielding a natural adjuvanticity, live attenuated vaccines elicit exceptionally efficient and durable immunity. Commonly used vaccine adjuvants target individual PRRs or bolster the immunogenicity of vaccines via indirect mechanisms of inflammation. Here, we review the impact of innate sensors on immune responses to live attenuated vaccines and commonly used vaccine adjuvants, with a focus on human vaccine responses. We discuss the unique potential of microbial nucleic acids and their corresponding sensing receptors to mimic live attenuated vaccines and promote protective immunity.
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Affiliation(s)
- Philipp Georg
- Department of Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Leif E Sander
- Department of Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
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15
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Vierbuchen T, Stein K, Heine H. RNA is taking its Toll: Impact of RNA-specific Toll-like receptors on health and disease. Allergy 2019; 74:223-235. [PMID: 30475385 DOI: 10.1111/all.13680] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 11/08/2018] [Accepted: 11/20/2018] [Indexed: 12/13/2022]
Abstract
RNA-sensing Toll-like receptors (TLRs) are often described as antiviral receptors of the innate immune system. However, the past decade has shown that the function and relevance of these receptors are far more complex. They were found to be essential for the detection of various bacterial, archaeal, and eukaryotic microorganisms and facilitate the discrimination between dead and living microbes. The cytokine and interferon response profile that is triggered has the potential to improve the efficacy of next-generation vaccines and may prevent the development of asthma and allergy. Nevertheless, the ability to recognize foreign RNA comes with a cost as also damaged host cells can release nucleic acids that might induce an inappropriate immune response. Thus, it is not surprising that RNA-sensing TLRs play a key role in various autoimmune diseases. However, promising new inhibitors and antagonists are on the horizon to improve their treatment.
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Affiliation(s)
- Tim Vierbuchen
- Division of Innate Immunity Research Center Borstel – Leibniz Lung Center Borstel Germany
| | - Karina Stein
- Division of Innate Immunity Research Center Borstel – Leibniz Lung Center Borstel Germany
- Airway Research Center North (ARCN) German Center for Lung Research (DZL) Borstel Germany
| | - Holger Heine
- Division of Innate Immunity Research Center Borstel – Leibniz Lung Center Borstel Germany
- Airway Research Center North (ARCN) German Center for Lung Research (DZL) Borstel Germany
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16
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Ugolini M, Sander LE. Dead or alive: how the immune system detects microbial viability. Curr Opin Immunol 2018; 56:60-66. [PMID: 30366275 DOI: 10.1016/j.coi.2018.09.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 09/19/2018] [Accepted: 09/21/2018] [Indexed: 12/14/2022]
Abstract
Immune detection of microbial viability is increasingly recognized as a potent driver of innate and adaptive immune responses. Here we describe recent mechanistic insights into the process of how the immune system discriminates between viable and non-viable microbial matter. Accumulating evidence suggests a key role for microbial RNA as a widely conserved viability associated PAMP (vita-PAMP) and a molecular signal of increased infectious threat. Toll-like receptor 8 (TLR8) has recently emerged as a critical sensor for viable bacteria, ssRNA viruses, and archaea in human antigen presenting cells (APC). We discuss the role of microbial RNA, and other potential vita-PAMPs in antimicrobial immunity and vaccine responses.
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Affiliation(s)
- Matteo Ugolini
- Max Planck Unit for the Science of Pathogens, Berlin, Germany; Max Planck Institute for Infection Biology, Berlin, Germany
| | - Leif E Sander
- Department of Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany; German Center for Lung Research (DZL), Berlin, Germany.
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17
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Rossi O, Dybowski R, Maskell DJ, Grant AJ, Restif O, Mastroeni P. Within-host spatiotemporal dynamics of systemic Salmonella infection during and after antimicrobial treatment. J Antimicrob Chemother 2018; 72:3390-3397. [PMID: 28962012 PMCID: PMC5890750 DOI: 10.1093/jac/dkx294] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 07/20/2017] [Indexed: 01/23/2023] Open
Abstract
Objectives We determined the interactions between efficacy of antibiotic treatment, pathogen growth rates and between-organ spread during systemic Salmonella infections. Methods We infected mice with isogenic molecularly tagged subpopulations of either a fast-growing WT or a slow-growing ΔaroC Salmonella strain. We monitored viable bacterial numbers and fluctuations in the proportions of each bacterial subpopulation in spleen, liver, blood and mesenteric lymph nodes (MLNs) before, during and after the cessation of treatment with ampicillin and ciprofloxacin. Results Both antimicrobials induced a reduction in viable bacterial numbers in the spleen, liver and blood. This reduction was biphasic in infections with fast-growing bacteria, with a rapid initial reduction followed by a phase of lower effect. Conversely, a slow and gradual reduction of the bacterial load was seen in infections with the slow-growing strain, indicating a positive correlation between bacterial net growth rates and the efficacy of ampicillin and ciprofloxacin. The viable numbers of either bacterial strain remained constant in MLNs throughout the treatment with a relapse of the infection with WT bacteria occurring after cessation of the treatment. The frequency of each tagged bacterial subpopulation was similar in the spleen and liver, but different from that of the MLNs before, during and after treatment. Conclusions In Salmonella infections, bacterial growth rates correlate with treatment efficacy. MLNs are a site with a bacterial population structure different to those of the spleen and liver and where the total viable bacterial load remains largely unaffected by antimicrobials, but can resume growth after cessation of treatment.
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Affiliation(s)
- O Rossi
- University of Cambridge, Department of Veterinary Medicine, Cambridge, UK
| | - R Dybowski
- University of Cambridge, Department of Veterinary Medicine, Cambridge, UK
| | - D J Maskell
- University of Cambridge, Department of Veterinary Medicine, Cambridge, UK
| | - A J Grant
- University of Cambridge, Department of Veterinary Medicine, Cambridge, UK
| | - O Restif
- University of Cambridge, Department of Veterinary Medicine, Cambridge, UK
| | - P Mastroeni
- University of Cambridge, Department of Veterinary Medicine, Cambridge, UK
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18
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Clonal analysis of Salmonella-specific effector T cells reveals serovar-specific and cross-reactive T cell responses. Nat Immunol 2018; 19:742-754. [PMID: 29925993 DOI: 10.1038/s41590-018-0133-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 04/19/2018] [Indexed: 12/20/2022]
Abstract
To tackle the complexity of cross-reactive and pathogen-specific T cell responses against related Salmonella serovars, we used mass cytometry, unbiased single-cell cloning, live fluorescence barcoding, and T cell-receptor sequencing to reconstruct the Salmonella-specific repertoire of circulating effector CD4+ T cells, isolated from volunteers challenged with Salmonella enterica serovar Typhi (S. Typhi) or Salmonella Paratyphi A (S. Paratyphi). We describe the expansion of cross-reactive responses against distantly related Salmonella serovars and of clonotypes recognizing immunodominant antigens uniquely expressed by S. Typhi or S. Paratyphi A. In addition, single-amino acid variations in two immunodominant proteins, CdtB and PhoN, lead to the accumulation of T cells that do not cross-react against the different serovars, thus demonstrating how minor sequence variations in a complex microorganism shape the pathogen-specific T cell repertoire. Our results identify immune-dominant, serovar-specific, and cross-reactive T cell antigens, which should aid in the design of T cell-vaccination strategies against Salmonella.
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19
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Price DJ, Breuzé A, Dybowski R, Mastroeni P, Restif O. An efficient moments-based inference method for within-host bacterial infection dynamics. PLoS Comput Biol 2017; 13:e1005841. [PMID: 29155811 PMCID: PMC5714343 DOI: 10.1371/journal.pcbi.1005841] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 12/04/2017] [Accepted: 10/22/2017] [Indexed: 11/18/2022] Open
Abstract
Over the last ten years, isogenic tagging (IT) has revolutionised the study of bacterial infection dynamics in laboratory animal models. However, quantitative analysis of IT data has been hindered by the piecemeal development of relevant statistical models. The most promising approach relies on stochastic Markovian models of bacterial population dynamics within and among organs. Here we present an efficient numerical method to fit such stochastic dynamic models to in vivo experimental IT data. A common approach to statistical inference with stochastic dynamic models relies on producing large numbers of simulations, but this remains a slow and inefficient method for all but simple problems, especially when tracking bacteria in multiple locations simultaneously. Instead, we derive and solve the systems of ordinary differential equations for the two lower-order moments of the stochastic variables (mean, variance and covariance). For any given model structure, and assuming linear dynamic rates, we demonstrate how the model parameters can be efficiently and accurately estimated by divergence minimisation. We then apply our method to an experimental dataset and compare the estimates and goodness-of-fit to those obtained by maximum likelihood estimation. While both sets of parameter estimates had overlapping confidence regions, the new method produced lower values for the division and death rates of bacteria: these improved the goodness-of-fit at the second time point at the expense of that of the first time point. This flexible framework can easily be applied to a range of experimental systems. Its computational efficiency paves the way for model comparison and optimal experimental design.
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Affiliation(s)
- David J. Price
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Alexandre Breuzé
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
- ENSTA-ParisTech, Palaiseau, France
| | - Richard Dybowski
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Piero Mastroeni
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Olivier Restif
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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20
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Inferring within-host bottleneck size: A Bayesian approach. J Theor Biol 2017; 435:218-228. [PMID: 28919397 DOI: 10.1016/j.jtbi.2017.09.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 08/07/2017] [Accepted: 09/13/2017] [Indexed: 12/21/2022]
Abstract
Recent technical developments in microbiology have led to new discoveries on the within-host dynamics of bacterial infections in laboratory animals. In particular, they have highlighted the importance of stochastic bottlenecks at the onset of invasive disease. A number of approaches exist for bottleneck-size estimation with respect to within-host bacterial infections; however, some are more appropriate than others under certain circumstances. A Bayesian comparison of several approaches is made in terms of the availability of isogenic multitype bacteria (e.g., WITS), knowledge of post-bottleneck dynamics, and the suitability of dilution with monotype bacteria. A sampling approach to bottleneck-size estimation is also introduced. The results are summarised by a guiding flowchart, which we hope will promote the use of quantitative models in microbiology to refine the analysis of animal experiment data.
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21
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Zauberman A, Vagima Y, Tidhar A, Aftalion M, Gur D, Rotem S, Chitlaru T, Levy Y, Mamroud E. Host Iron Nutritional Immunity Induced by a Live Yersinia pestis Vaccine Strain Is Associated with Immediate Protection against Plague. Front Cell Infect Microbiol 2017; 7:277. [PMID: 28680860 PMCID: PMC5478729 DOI: 10.3389/fcimb.2017.00277] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Accepted: 06/06/2017] [Indexed: 12/29/2022] Open
Abstract
Prompt and effective elicitation of protective immunity is highly relevant for cases of rapidly deteriorating fatal diseases, such as plague, which is caused by Yersinia pestis. Here, we assessed the potential of a live vaccine to induce rapid protection against this infection. We demonstrated that the Y. pestis EV76 live vaccine protected mice against an immediate lethal challenge, limiting the multiplication of the virulent pathogen and its dissemination into circulation. Ex vivo analysis of Y. pestis growth in serum derived from EV76-immunized mice revealed that an antibacterial activity was produced rapidly. This activity was mediated by the host heme- and iron-binding proteins hemopexin and transferrin, and it occurred in strong correlation with the kinetics of hemopexin induction in vivo. We suggest a new concept in which a live vaccine is capable of rapidly inducing iron nutritional immunity, thus limiting the propagation of pathogens. This concept could be exploited to design novel therapeutic interventions.
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Affiliation(s)
- Ayelet Zauberman
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological ResearchNess-Ziona, Israel
| | | | | | | | | | | | | | | | - Emanuelle Mamroud
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological ResearchNess-Ziona, Israel
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22
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Dybowski R, Restif O, Goupy A, Maskell DJ, Mastroeni P, Grant AJ. Single passage in mouse organs enhances the survival and spread of Salmonella enterica. J R Soc Interface 2016; 12:20150702. [PMID: 26701880 PMCID: PMC4707846 DOI: 10.1098/rsif.2015.0702] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Intravenous inoculation of Salmonella enterica serovar Typhimurium into mice is a prime experimental model of invasive salmonellosis. The use of wild-type isogenic tagged strains (WITS) in this system has revealed that bacteria undergo independent bottlenecks in the liver and spleen before establishing a systemic infection. We recently showed that those bacteria that survived the bottleneck exhibited enhanced growth when transferred to naive mice. In this study, we set out to disentangle the components of this in vivo adaptation by inoculating mice with WITS grown either in vitro or in vivo. We developed an original method to estimate the replication and killing rates of bacteria from experimental data, which involved solving the probability-generating function of a non-homogeneous birth–death–immigration process. This revealed a low initial mortality in bacteria obtained from a donor animal. Next, an analysis of WITS distributions in the livers and spleens of recipient animals indicated that in vivo-passaged bacteria started spreading between organs earlier than in vitro-grown bacteria. These results further our understanding of the influence of passage in a host on the fitness and virulence of Salmonella enterica and represent an advance in the power of investigation on the patterns and mechanisms of host–pathogen interactions.
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Affiliation(s)
- Richard Dybowski
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - Olivier Restif
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - Alexandre Goupy
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK ENSTA-ParisTech, 828 Boulevard des Maréchaux, Palaiseau 91120, France
| | - Duncan J Maskell
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - Piero Mastroeni
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - Andrew J Grant
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
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Hammami P, Lancelot R, Lesnoff M. Modelling the Dynamics of Post-Vaccination Immunity Rate in a Population of Sahelian Sheep after a Vaccination Campaign against Peste des Petits Ruminants Virus. PLoS One 2016; 11:e0161769. [PMID: 27603710 PMCID: PMC5014330 DOI: 10.1371/journal.pone.0161769] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 08/11/2016] [Indexed: 11/23/2022] Open
Abstract
Background Peste des petits ruminants (PPR) is an acute infectious viral disease affecting domestic small ruminants (sheep and goats) and some wild ruminant species in Africa, the Middle East and Asia. A global PPR control strategy based on mass vaccination—in regions where PPR is endemic—was recently designed and launched by international organizations. Sahelian Africa is one of the most challenging endemic regions for PPR control. Indeed, strong seasonal and annual variations in mating, mortality and offtake rates result in a complex population dynamics which might in turn alter the population post-vaccination immunity rate (PIR), and thus be important to consider for the implementation of vaccination campaigns. Methods In a context of preventive vaccination in epidemiological units without PPR virus transmission, we developed a predictive, dynamic model based on a seasonal matrix population model to simulate PIR dynamics. This model was mostly calibrated with demographic and epidemiological parameters estimated from a long-term follow-up survey of small ruminant herds. We used it to simulate the PIR dynamics following a single PPR vaccination campaign in a Sahelian sheep population, and to assess the effects of (i) changes in offtake rate related to the Tabaski (a Muslim feast following the lunar calendar), and (ii) the date of implementation of the vaccination campaigns. Results The persistence of PIR was not influenced by the Tabaski date. Decreasing the vaccination coverage from 100 to 80% had limited effects on PIR. However, lower vaccination coverage did not provide sufficient immunity rates (PIR < 70%). As a trade-off between model predictions and other considerations like animal physiological status, and suitability for livestock farmers, we would suggest to implement vaccination campaigns in September-October. This model is a first step towards better decision support for animal health authorities. It might be adapted to other species, livestock farming systems or diseases.
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Affiliation(s)
- Pachka Hammami
- UMR Contrôle des Maladies Animales Exotiques et Emergentes (Cmaee), Centre de coopération internationale en recherche agronomique pour le développement (Cirad), Campus international de Baillarguet, 34398 Montpellier, France
- UMR Cmaee 1309, Institut national de la recherche agronomique (Inra), Campus international de Baillarguet, 34398 Montpellier, France
- * E-mail:
| | - Renaud Lancelot
- UMR Contrôle des Maladies Animales Exotiques et Emergentes (Cmaee), Centre de coopération internationale en recherche agronomique pour le développement (Cirad), Campus international de Baillarguet, 34398 Montpellier, France
- UMR Cmaee 1309, Institut national de la recherche agronomique (Inra), Campus international de Baillarguet, 34398 Montpellier, France
| | - Matthieu Lesnoff
- UMR Systèmes d’élevage méditerranéens et tropicaux (Selmet), Cirad, Campus international de Baillarguet, 34398 Montpellier, France
- UMR Selmet, Inra, Campus international de Baillarguet, 34398 Montpellier, France
- UMR Selmet, Montpellier Supagro, Campus international de Baillarguet, 34398 Montpellier, France
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Mastroeni P, Rossi O. Immunology, epidemiology and mathematical modelling towards a better understanding of invasive non-typhoidal Salmonella disease and rational vaccination approaches. Expert Rev Vaccines 2016; 15:1545-1555. [PMID: 27171941 DOI: 10.1080/14760584.2016.1189330] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Invasive non-typhoidal Salmonella (iNTS) infections cause a high burden of lethal sepsis in young children and HIV patients, often associated with malaria, anaemia, malnutrition and sickle-cell disease. Vaccines against iNTS are urgently needed but none are licensed yet. Areas covered: This review illustrates how immunology, epidemiology and within-host pathogen behaviour affect invasive Salmonella infections and highlights how this knowledge can assist the improvement and choice of vaccines. Expert Commentary: Control of iNTS disease requires approaches that reduce transmission and improve diagnosis and treatment. These are often difficult to implement due to the fragile ecology and economies in endemic countries. Vaccines will be key tools in the fight against iNTS disease. To optimise vaccine design, we need to better define protective antigens and mechanisms of resistance to disease in susceptible populations even in those individuals where innate immunity may be impaired by widespread comorbidities.
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Affiliation(s)
- Pietro Mastroeni
- a Department of Veterinary Medicine , University of Cambridge , Cambridge , United Kingdom
| | - Omar Rossi
- a Department of Veterinary Medicine , University of Cambridge , Cambridge , United Kingdom
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25
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Feng Y, Hodiamont CJ, van Hest RM, Brul S, Schultsz C, ter Kuile BH. Development of Antibiotic Resistance during Simulated Treatment of Pseudomonas aeruginosa in Chemostats. PLoS One 2016; 11:e0149310. [PMID: 26872140 PMCID: PMC4752458 DOI: 10.1371/journal.pone.0149310] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 01/29/2016] [Indexed: 11/24/2022] Open
Abstract
During treatment of infections with antibiotics in critically ill patients in the intensive care resistance often develops. This study aims to establish whether under those conditions this resistance can develop de novo or that genetic exchange between bacteria is by necessity involved. Chemostat cultures of Pseudomonas aeruginosa were exposed to treatment regimes with ceftazidime and meropenem that simulated conditions expected in patient plasma. Development of antibiotic resistance was monitored and mutations in resistance genes were searched for by sequencing PCR products. Even at the highest concentrations that can be expected in patients, sufficient bacteria survived in clumps of filamentous cells to recover and grow out after 3 to 5 days. At the end of a 7 days simulated treatment, the minimal inhibitory concentration (MIC) had increased by a factor between 10 and 10,000 depending on the antibiotic and the treatment protocol. The fitness costs of resistance were minimal. In the resistant strains, only three mutations were observed in genes associated with beta-lactam resistance. The development of resistance often observed during patient treatment can be explained by de novo acquisition of resistance and genetic exchange of resistance genes is not by necessity involved. As far as conclusions based on an in vitro study using P. aeruginosa and only two antibiotics can be generalized, it seems that development of resistance can be minimized by treating with antibiotics in the highest concentration the patient can endure for the shortest time needed to eliminate the infection.
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Affiliation(s)
- Yanfang Feng
- Department of Molecular Biology and Microbial Food Safety, Swammerdam Institute of Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Caspar J. Hodiamont
- Department of Medical Microbiology, Academic Medical Center, Amsterdam, the Netherlands
| | - Reinier M. van Hest
- Department of Hospital Pharmacy & Clinical Pharmacology, Academic Medical Center, Amsterdam, the Netherlands
| | - Stanley Brul
- Department of Molecular Biology and Microbial Food Safety, Swammerdam Institute of Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Constance Schultsz
- Department of Medical Microbiology, Academic Medical Center, Amsterdam, the Netherlands
- Department of Global Health-Amsterdam Institute for Global Health and Development, Academic Medical Center, Amsterdam, The Netherlands
| | - Benno H. ter Kuile
- Department of Molecular Biology and Microbial Food Safety, Swammerdam Institute of Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
- Office for Risk Assessment and Research Coordination Netherlands Food and Consumer Product Safety Authority, Utrecht, The Netherlands
- * E-mail: ;
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26
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Ruggeri J, Pesciaroli M, Foresti F, Giacomini E, Lazzaro M, Ossiprandi MC, Corradi A, Lombardi G, Pasquali P, Alborali GL. Inactivated Salmonella enterica serovar Typhimurium monophasic variant (S. Typhimurium 1,4,[5],12:i-) in sows is effective to control infection in piglets under field condition. Vet Microbiol 2015; 180:82-9. [PMID: 26260858 DOI: 10.1016/j.vetmic.2015.07.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 07/13/2015] [Accepted: 07/21/2015] [Indexed: 11/28/2022]
Abstract
The monophasic variant of Salmonella enterica serovar Typhimurium, namely Salmonella 1,4,[5],12:i-, has been increasingly responsible for foodborne human cases of disease and is most frequently detected in pork, since the variant is widely spread in pig farms. The aim of this study was to assess the efficacy of an autologous vaccine in decreasing the prevalence of Salmonella 1,4,[5],12:i-, in pigs. The trial was performed in a multisite pig production system of Northern Italy. The autogenous vaccine was prepared from the Salmonella 1,4,[5],12:i- strain isolated from the clinical case occurring in the Farm. Different immunization protocols were applied, ranging from interventions only in sows or piglets, or both. Microbiological analysis was performed to assess faecal shedding in sows and their offspring from birth till end of the production cycle and organ colonization of slaughtered pigs. Body weight of pigs was recorded at different time-points. Humoral immune response was evaluated in serum samples of sows and piglets. S. Typhimurium 1,4,[5],12:i- determines reduction of animal growth and farm production, furthermore, contamination of carcasses at the slaughterhouse. The load of bacteria entering into the food processing chain is differently influenced by the regimen of administration of inactivated vaccine. In particular, a combined vaccination of sows and their offspring was able to improve the weight gain of growing pigs, to limit Salmonella colonization of organs and to reduce the number of carrier pigs, and hence lowering the risk of introducing Salmonella organisms in the slaughter process.
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Affiliation(s)
- J Ruggeri
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, 25124 Brescia, Italy
| | - M Pesciaroli
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, 00161 Rome, Italy, FAO Reference Center for Veterinary Public Health; UCM-UPM, Campus Moncloa, Madrid, Spain
| | | | - E Giacomini
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, 25124 Brescia, Italy
| | - M Lazzaro
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, 25124 Brescia, Italy
| | - M C Ossiprandi
- Department of Veterinary Science, University of Parma, Parma, Italy
| | - A Corradi
- Department of Veterinary Science, University of Parma, Parma, Italy
| | - G Lombardi
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, 25124 Brescia, Italy
| | - P Pasquali
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, 00161 Rome, Italy, FAO Reference Center for Veterinary Public Health.
| | - G L Alborali
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, 25124 Brescia, Italy.
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Downing T. Tackling Drug Resistant Infection Outbreaks of Global Pandemic Escherichia coli ST131 Using Evolutionary and Epidemiological Genomics. Microorganisms 2015; 3:236-67. [PMID: 27682088 PMCID: PMC5023239 DOI: 10.3390/microorganisms3020236] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 04/28/2015] [Accepted: 04/30/2015] [Indexed: 11/16/2022] Open
Abstract
High-throughput molecular screening is required to investigate the origin and diffusion of antimicrobial resistance in pathogen outbreaks. The most frequent cause of human infection is Escherichia coli, which is dominated by sequence type 131 (ST131)-a set of rapidly radiating pandemic clones. The highly infectious clades of ST131 originated firstly by a mutation enhancing conjugation and adhesion. Secondly, single-nucleotide polymorphisms occurred enabling fluoroquinolone-resistance, which is near-fixed in all ST131. Thirdly, broader resistance through beta-lactamases has been gained and lost frequently, symptomatic of conflicting environmental selective effects. This flexible approach to gene exchange is worrying and supports the proposition that ST131 will develop an even wider range of plasmid and chromosomal elements promoting antimicrobial resistance. To stop ST131, deep genome sequencing is required to understand the origin, evolution and spread of antimicrobial resistance genes. Phylogenetic methods that decipher past events can predict future patterns of virulence and transmission based on genetic signatures of adaptation and gene exchange. Both the effect of partial antimicrobial exposure and cell dormancy caused by variation in gene expression may accelerate the development of resistance. High-throughput sequencing can decode measurable evolution of cell populations within patients associated with systems-wide changes in gene expression during treatments. A multi-faceted approach can enhance assessment of antimicrobial resistance in E. coli ST131 by examining transmission dynamics between hosts to achieve a goal of pre-empting resistance before it emerges by optimising antimicrobial treatment protocols.
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Affiliation(s)
- Tim Downing
- School of Biotechnology, Faculty of Science and Health, Dublin City University, Dublin 9, Ireland.
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