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Molteni C, Forni D, Cagliani R, Sironi M. Comparative genomics reveal a novel phylotaxonomic order in the genus Fusobacterium. Commun Biol 2024; 7:1102. [PMID: 39244637 PMCID: PMC11380691 DOI: 10.1038/s42003-024-06825-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Accepted: 09/02/2024] [Indexed: 09/09/2024] Open
Abstract
Fusobacteria have been associated to different diseases, including colorectal cancer (CRC), but knowledge of which taxonomic groups contribute to specific conditions is incomplete. We analyzed the genetic diversity and relationships within the Fusobacterium genus. We report recent and ancestral recombination in core genes, indicating that fusobacteria have mosaic genomes and emphasizing that taxonomic demarcation should not rely on single genes/gene regions. Across databases, we found ample evidence of species miss-classification and of undescribed species, which are both expected to complicate disease association. By focusing on a lineage that includes F. periodonticum/pseudoperiodonticum and F. nucleatum, we show that genomes belong to four modern populations, but most known species/subspecies emerged from individual ancestral populations. Of these, the F. periodonticum/pseudoperiodonticum population experienced the lowest drift and displays the highest genetic diversity, in line with the less specialized distribution of these bacteria in oral sites. A highly drifted ancestral population instead contributed genetic ancestry to a new species, which includes genomes classified within the F. nucleatum animalis diversity in a recent CRC study. Thus, evidence herein calls for a re-analysis of F. nucleatum animalis features associated to CRC. More generally, our data inform future molecular profiling approaches to investigate the epidemiology of Fusobacterium-associated diseases.
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Affiliation(s)
- Cristian Molteni
- Scientific Institute IRCCS E. MEDEA, Bioinformatics, Bosisio Parini, Italy.
| | - Diego Forni
- Scientific Institute IRCCS E. MEDEA, Bioinformatics, Bosisio Parini, Italy
| | - Rachele Cagliani
- Scientific Institute IRCCS E. MEDEA, Bioinformatics, Bosisio Parini, Italy
| | - Manuela Sironi
- Scientific Institute IRCCS E. MEDEA, Bioinformatics, Bosisio Parini, Italy
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2
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Kellgren T, Dwibedi C, Widerström M, Sundell D, Öhrman C, Sjödin A, Monsen T, Rydén P, Johansson A. Completed genome and emergence scenario of the multidrug-resistant nosocomial pathogen Staphylococcus epidermidis ST215. BMC Microbiol 2024; 24:215. [PMID: 38890594 PMCID: PMC11186124 DOI: 10.1186/s12866-024-03367-5] [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: 03/24/2024] [Accepted: 06/10/2024] [Indexed: 06/20/2024] Open
Abstract
BACKGROUND A multidrug-resistant lineage of Staphylococcus epidermidis named ST215 is a common cause of prosthetic joint infections and other deep surgical site infections in Northern Europe, but is not present elsewhere. The increasing resistance among S. epidermidis strains is a global concern. We used whole-genome sequencing to characterize ST215 from healthcare settings. RESULTS We completed the genome of a ST215 isolate from a Swedish hospital using short and long reads, resulting in a circular 2,676,787 bp chromosome and a 2,326 bp plasmid. The new ST215 genome was placed in phylogenetic context using 1,361 finished public S. epidermidis reference genomes. We generated 10 additional short-read ST215 genomes and 11 short-read genomes of ST2, which is another common multidrug-resistant lineage at the same hospital. We studied recombination's role in the evolution of ST2 and ST215, and found multiple recombination events averaging 30-50 kb. By comparing the results of antimicrobial susceptibility testing for 31 antimicrobial drugs with the genome content encoding antimicrobial resistance in the ST215 and ST2 isolates, we found highly similar resistance traits between the isolates, with 22 resistance genes being shared between all the ST215 and ST2 genomes. The ST215 genome contained 29 genes that were historically identified as virulence genes of S. epidermidis ST2. We established that in the nucleotide sequence stretches identified as recombination events, virulence genes were overrepresented in ST215, while antibiotic resistance genes were overrepresented in ST2. CONCLUSIONS This study features the extensive antibiotic resistance and virulence gene content in ST215 genomes. ST215 and ST2 lineages have similarly evolved, acquiring resistance and virulence through genomic recombination. The results highlight the threat of new multidrug-resistant S. epidermidis lineages emerging in healthcare settings.
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Affiliation(s)
- Therese Kellgren
- Department of Mathematics and Mathematical Statistics, Umeå University, Umeå, SE, 90187, Sweden
| | - Chinmay Dwibedi
- Department of Clinical Microbiology and Molecular Infection Medicine Sweden (MIMS), Umeå University, 90185, Umeå, Sweden
| | - Micael Widerström
- Department of Clinical Microbiology, Umeå University, 90185, Umeå, Sweden.
| | - David Sundell
- Division of CBRN Defence and Security, Swedish Defense Research Agency, 90182, Umeå, SE, Sweden
| | - Caroline Öhrman
- Division of CBRN Defence and Security, Swedish Defense Research Agency, 90182, Umeå, SE, Sweden
| | - Andreas Sjödin
- Division of CBRN Defence and Security, Swedish Defense Research Agency, 90182, Umeå, SE, Sweden
| | - Tor Monsen
- Department of Clinical Microbiology, Umeå University, 90185, Umeå, Sweden
| | - Patrik Rydén
- Department of Mathematics and Mathematical Statistics, Umeå University, Umeå, SE, 90187, Sweden
| | - Anders Johansson
- Department of Clinical Microbiology and Molecular Infection Medicine Sweden (MIMS), Umeå University, 90185, Umeå, Sweden
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3
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Souza SSR, Smith JT, Marcovici MM, Eckhardt EM, Hansel NB, Martin IW, Andam CP. Demographic fluctuations in bloodstream Staphylococcus aureus lineages configure the mobile gene pool and antimicrobial resistance. NPJ ANTIMICROBIALS AND RESISTANCE 2024; 2:14. [PMID: 38725655 PMCID: PMC11076216 DOI: 10.1038/s44259-024-00032-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 03/08/2024] [Indexed: 05/12/2024]
Abstract
Staphylococcus aureus in the bloodstream causes high morbidity and mortality, exacerbated by the spread of multidrug-resistant and methicillin-resistant S. aureus (MRSA). We aimed to characterize the circulating lineages of S. aureus from bloodstream infections and the contribution of individual lineages to resistance over time. Here, we generated 852 high-quality short-read draft genome sequences of S. aureus isolates from patient blood cultures in a single hospital from 2010 to 2022. A total of 80 previously recognized sequence types (ST) and five major clonal complexes are present in the population. Two frequently detected lineages, ST5 and ST8 exhibited fluctuating demographic structures throughout their histories. The rise and fall in their population growth coincided with the acquisition of antimicrobial resistance, mobile genetic elements, and superantigen genes, thus shaping the accessory genome structure across the entire population. These results reflect undetected selective events and changing ecology of multidrug-resistant S. aureus in the bloodstream.
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Affiliation(s)
- Stephanie S. R. Souza
- Department of Biological Sciences, University at Albany, State University of New York, Albany, New York, NY USA
| | - Joshua T. Smith
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH USA
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA USA
| | - Michael M. Marcovici
- Department of Biological Sciences, University at Albany, State University of New York, Albany, New York, NY USA
| | - Elissa M. Eckhardt
- Dartmouth-Hitchcock Medical Center and Dartmouth College Geisel School of Medicine, Lebanon, NH USA
| | - Nicole B. Hansel
- Dartmouth-Hitchcock Medical Center and Dartmouth College Geisel School of Medicine, Lebanon, NH USA
| | - Isabella W. Martin
- Dartmouth-Hitchcock Medical Center and Dartmouth College Geisel School of Medicine, Lebanon, NH USA
| | - Cheryl P. Andam
- Department of Biological Sciences, University at Albany, State University of New York, Albany, New York, NY USA
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4
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Lagerstrom KM, Scales NC, Hadly EA. Impressive pan-genomic diversity of E. coli from a wild animal community near urban development reflects human impacts. iScience 2024; 27:109072. [PMID: 38375235 PMCID: PMC10875580 DOI: 10.1016/j.isci.2024.109072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 11/22/2023] [Accepted: 01/26/2024] [Indexed: 02/21/2024] Open
Abstract
Human and domesticated animal waste infiltrates global freshwater, terrestrial, and marine environments, widely disseminating fecal microbes, antibiotics, and other chemical pollutants. Emerging evidence suggests that guts of wild animals are being invaded by our microbes, including Escherichia coli, which face anthropogenic selective pressures to gain antimicrobial resistance (AMR) and increase virulence. However, wild animal sources remain starkly under-represented among genomic sequence repositories. We sequenced whole genomes of 145 E. coli isolates from 55 wild and 13 domestic animal fecal samples, averaging 2 (ranging 1-7) isolates per sample, on a preserve imbedded in a human-dominated landscape in California Bay Area, USA, to assess AMR, virulence, and pan-genomic diversity. With single nucleotide polymorphism analyses we predict potential transmission routes. We illustrate the usefulness of E. coli to aid our understanding of and ability to surveil the emergence of zoonotic pathogens created by the mixing of human and wild bacteria in the environment.
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Affiliation(s)
| | - Nicholas C. Scales
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA, USA
| | - Elizabeth A. Hadly
- Department of Biology, Stanford University, Stanford, CA, USA
- Stanford Woods Institute for the Environment, Stanford University, Stanford, CA, USA
- Center for Innovation in Global Health, Stanford University, Stanford, CA, USA
- Department of Earth Systems Science, Stanford University, Stanford, CA, USA
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5
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Liu Z, Good BH. Dynamics of bacterial recombination in the human gut microbiome. PLoS Biol 2024; 22:e3002472. [PMID: 38329938 PMCID: PMC10852326 DOI: 10.1371/journal.pbio.3002472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 12/14/2023] [Indexed: 02/10/2024] Open
Abstract
Horizontal gene transfer (HGT) is a ubiquitous force in microbial evolution. Previous work has shown that the human gut is a hotspot for gene transfer between species, but the more subtle exchange of variation within species-also known as recombination-remains poorly characterized in this ecosystem. Here, we show that the genetic structure of the human gut microbiome provides an opportunity to measure recent recombination events from sequenced fecal samples, enabling quantitative comparisons across diverse commensal species that inhabit a common environment. By analyzing recent recombination events in the core genomes of 29 human gut bacteria, we observed widespread heterogeneities in the rates and lengths of transferred fragments, which are difficult to explain by existing models of ecological isolation or homology-dependent recombination rates. We also show that natural selection helps facilitate the spread of genetic variants across strain backgrounds, both within individual hosts and across the broader population. These results shed light on the dynamics of in situ recombination, which can strongly constrain the adaptability of gut microbial communities.
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Affiliation(s)
- Zhiru Liu
- Department of Applied Physics, Stanford University, Stanford, California, United States of America
| | - Benjamin H. Good
- Department of Applied Physics, Stanford University, Stanford, California, United States of America
- Department of Biology, Stanford University, Stanford, California, United States of America
- Chan Zuckerberg Biohub–San Francisco, San Francisco, California, United States of America
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6
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Mah JC, Lohmueller KE, Garud N. Inference of the demographic histories and selective effects of human gut commensal microbiota over the course of human history. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.09.566454. [PMID: 38014007 PMCID: PMC10680615 DOI: 10.1101/2023.11.09.566454] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Despite the importance of gut commensal microbiota to human health, there is little knowledge about their evolutionary histories, including their population demographic histories and their distributions of fitness effects (DFE) of new mutations. Here, we infer the demographic histories and DFEs of 27 of the most highly prevalent and abundant commensal gut microbial species in North Americans over timescales exceeding human generations using a collection of lineages inferred from a panel of healthy hosts. We find overall reductions in genetic variation among commensal gut microbes sampled from a Western population relative to an African rural population. Additionally, some species in North American microbiomes display contractions in population size and others expansions, potentially occurring at several key historical moments in human history. DFEs across species vary from highly to mildly deleterious, with accessory genes experiencing more drift compared to core genes. Within genera, DFEs tend to be more congruent, reflective of underlying phylogenetic relationships. Taken together, these findings suggest that human commensal gut microbes have distinct evolutionary histories, possibly reflecting the unique roles of individual members of the microbiome.
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7
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Lee IPA, Eldakar OT, Gogarten JP, Andam CP. Recombination as an enforcement mechanism of prosocial behavior in cooperating bacteria. iScience 2023; 26:107344. [PMID: 37554437 PMCID: PMC10405257 DOI: 10.1016/j.isci.2023.107344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/11/2023] [Accepted: 07/06/2023] [Indexed: 08/10/2023] Open
Abstract
Prosocial behavior is ubiquitous in nature despite the relative fitness costs carried by cooperative individuals. However, the stability of cooperation in populations is fragile and often maintained through enforcement. We propose that homologous recombination provides such a mechanism in bacteria. Using an agent-based model of recombination in bacteria playing a public goods game, we demonstrate how changes in recombination rates affect the proportion of cooperating cells. In our model, recombination converts cells to a different strategy, either freeloading (cheaters) or cooperation, based on the strategies of neighboring cells and recombination rate. Increasing the recombination rate expands the parameter space in which cooperators outcompete freeloaders. However, increasing the recombination rate alone is neither sufficient nor necessary. Intermediate benefits of cooperation, lower population viscosity, and greater population size can promote the evolution of cooperation from within populations of cheaters. Our findings demonstrate how recombination influences the persistence of cooperative behavior in bacteria.
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Affiliation(s)
- Isaiah Paolo A. Lee
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA
- National Institute of Molecular Biology and Biotechnology, University of the Philippines–Diliman, Quezon City 1101, Philippines
| | - Omar Tonsi Eldakar
- Department of Biological Sciences, Nova Southeastern University, Fort Lauderdale, FL 33328, USA
| | - J. Peter Gogarten
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Cheryl P. Andam
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA
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8
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Birzu G, Muralidharan HS, Goudeau D, Malmstrom RR, Fisher DS, Bhaya D. Hybridization breaks species barriers in long-term coevolution of a cyanobacterial population. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.06.543983. [PMID: 37333348 PMCID: PMC10274767 DOI: 10.1101/2023.06.06.543983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Bacterial species often undergo rampant recombination yet maintain cohesive genomic identity. Ecological differences can generate recombination barriers between species and sustain genomic clusters in the short term. But can these forces prevent genomic mixing during long-term coevolution? Cyanobacteria in Yellowstone hot springs comprise several diverse species that have coevolved for hundreds of thousands of years, providing a rare natural experiment. By analyzing more than 300 single-cell genomes, we show that despite each species forming a distinct genomic cluster, much of the diversity within species is the result of hybridization driven by selection, which has mixed their ancestral genotypes. This widespread mixing is contrary to the prevailing view that ecological barriers can maintain cohesive bacterial species and highlights the importance of hybridization as a source of genomic diversity.
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Affiliation(s)
- Gabriel Birzu
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
| | | | - Danielle Goudeau
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Rex R. Malmstrom
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Daniel S. Fisher
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - Devaki Bhaya
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
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9
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Noll N, Molari M, Shaw LP, Neher RA. PanGraph: scalable bacterial pan-genome graph construction. Microb Genom 2023; 9:mgen001034. [PMID: 37278719 PMCID: PMC10327495 DOI: 10.1099/mgen.0.001034] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 04/14/2023] [Indexed: 06/07/2023] Open
Abstract
The genomic diversity of microbes is commonly parameterized as SNPs relative to a reference genome of a well-characterized, but arbitrary, isolate. However, any reference genome contains only a fraction of the microbial pangenome, the total set of genes observed in a given species. Reference-based approaches are thus blind to the dynamics of the accessory genome, as well as variation within gene order and copy number. With the widespread usage of long-read sequencing, the number of high-quality, complete genome assemblies has increased dramatically. In addition to pangenomic approaches that focus on the variation in the sets of genes present in different genomes, complete assemblies allow investigations of the evolution of genome structure and gene order. This latter problem, however, is computationally demanding with few tools available that shed light on these dynamics. Here, we present PanGraph, a Julia-based library and command line interface for aligning whole genomes into a graph. Each genome is represented as a path along vertices, which in turn encapsulate homologous multiple sequence alignments. The resultant data structure succinctly summarizes population-level nucleotide and structural polymorphisms and can be exported into several common formats for either downstream analysis or immediate visualization.
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Affiliation(s)
- Nicholas Noll
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA, USA
| | - Marco Molari
- Swiss Institute of Bioinformatics, Basel, Switzerland
- Biozentrum, University of Basel, Basel, Switzerland
| | - Liam P. Shaw
- Department of Biology, University of Oxford, Oxford, UK
| | - Richard A. Neher
- Swiss Institute of Bioinformatics, Basel, Switzerland
- Biozentrum, University of Basel, Basel, Switzerland
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10
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Walsh SK, Imrie RM, Matuszewska M, Paterson GK, Weinert LA, Hadfield JD, Buckling A, Longdon B. The host phylogeny determines viral infectivity and replication across Staphylococcus host species. PLoS Pathog 2023; 19:e1011433. [PMID: 37289828 PMCID: PMC10284401 DOI: 10.1371/journal.ppat.1011433] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 06/21/2023] [Accepted: 05/18/2023] [Indexed: 06/10/2023] Open
Abstract
Virus host shifts, where a virus transmits to and infects a novel host species, are a major source of emerging infectious disease. Genetic similarity between eukaryotic host species has been shown to be an important determinant of the outcome of virus host shifts, but it is unclear if this is the case for prokaryotes where anti-virus defences can be transmitted by horizontal gene transfer and evolve rapidly. Here, we measure the susceptibility of 64 strains of Staphylococcaceae bacteria (48 strains of Staphylococcus aureus and 16 non-S. aureus species spanning 2 genera) to the bacteriophage ISP, which is currently under investigation for use in phage therapy. Using three methods-plaque assays, optical density (OD) assays, and quantitative (q)PCR-we find that the host phylogeny explains a large proportion of the variation in susceptibility to ISP across the host panel. These patterns were consistent in models of only S. aureus strains and models with a single representative from each Staphylococcaceae species, suggesting that these phylogenetic effects are conserved both within and among host species. We find positive correlations between susceptibility assessed using OD and qPCR and variable correlations between plaque assays and either OD or qPCR, suggesting that plaque assays alone may be inadequate to assess host range. Furthermore, we demonstrate that the phylogenetic relationships between bacterial hosts can generally be used to predict the susceptibility of bacterial strains to phage infection when the susceptibility of closely related hosts is known, although this approach produced large prediction errors in multiple strains where phylogeny was uninformative. Together, our results demonstrate the ability of bacterial host evolutionary relatedness to explain differences in susceptibility to phage infection, with implications for the development of ISP both as a phage therapy treatment and as an experimental system for the study of virus host shifts.
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Affiliation(s)
- Sarah K. Walsh
- Centre for Ecology and Conservation; Faculty of Environment, Science, and Economy; Biosciences; University of Exeter; Cornwall; United Kingdom
- Environment and Sustainability Institute; University of Exeter; Cornwall; United Kingdom
| | - Ryan M. Imrie
- Centre for Ecology and Conservation; Faculty of Environment, Science, and Economy; Biosciences; University of Exeter; Cornwall; United Kingdom
| | - Marta Matuszewska
- Department of Medicine; University of Cambridge; Cambridge; United Kingdom
| | - Gavin K. Paterson
- Royal (Dick) School of Veterinary Studies and the Roslin Institute; University of Edinburgh;Edinburgh; United Kingdom
| | - Lucy A. Weinert
- Department of Veterinary Medicine; University of Cambridge; Cambridge; United Kingdom
| | - Jarrod D. Hadfield
- Institute of Evolutionary Biology; The University of Edinburgh; Edinburgh; United Kingdom
| | - Angus Buckling
- Centre for Ecology and Conservation; Faculty of Environment, Science, and Economy; Biosciences; University of Exeter; Cornwall; United Kingdom
- Environment and Sustainability Institute; University of Exeter; Cornwall; United Kingdom
| | - Ben Longdon
- Centre for Ecology and Conservation; Faculty of Environment, Science, and Economy; Biosciences; University of Exeter; Cornwall; United Kingdom
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11
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Zarras C, Karampatakis T, Pappa S, Iosifidis E, Vagdatli E, Roilides E, Papa A. Genetic Characterization of Carbapenem-Resistant Klebsiella pneumoniae Clinical Isolates in a Tertiary Hospital in Greece, 2018-2022. Antibiotics (Basel) 2023; 12:976. [PMID: 37370295 DOI: 10.3390/antibiotics12060976] [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: 05/04/2023] [Revised: 05/23/2023] [Accepted: 05/25/2023] [Indexed: 06/29/2023] Open
Abstract
BACKGROUND Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a serious public health issue. The study aimed to identify the antimicrobial resistance and accessory genes, the clonal relatedness, and the evolutionary dynamics of selected CRKP isolates recovered in an adult and pediatric intensive care unit of a tertiary hospital in Greece. METHODS Twenty-four CRKP isolates recovered during 2018-2022 were included in the study. Next-generation sequencing was performed using the Ion Torrent PGM Platform. The identification of the plasmid content, MLST, and antimicrobial resistance genes, as well as the comparison of multiple genome alignments and the identification of core genome single-nucleotide polymorphism sites, were performed using various bioinformatics software. RESULTS The isolates belonged to eight sequence types: 11, 15, 30, 35, 39, 307, 323, and 512. A variety of carbapenemases (KPC, VIM, NDM, and OXA-48) and resistance genes were detected. CRKP strains shared visually common genomic regions with the reference strain (NTUH-K2044). ST15, ST323, ST39, and ST11 CRKP isolates presented on average 17, 6, 16, and 866 recombined SNPs, respectively. All isolates belonging to ST15, ST323, and ST39 were classified into distinct phylogenetic branches, while ST11 isolates were assigned to a two-subclade branch. For large CRKP sets, the phylogeny seems to change approximately every seven SNPs. CONCLUSIONS The current study provides insight into the genetic characterization of CRKP isolates in the ICUs of a tertiary hospital. Our results indicate clonal dispersion of ST15, ST323, and ST39 and highly diverged ST11 isolates.
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Affiliation(s)
- Charalampos Zarras
- Department of Microbiology, Medical Faculty, School of Health Sciences, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece
- Microbiology Department, Hippokration General Hospital, 546 42 Thessaloniki, Greece
| | - Theodoros Karampatakis
- Department of Microbiology, Medical Faculty, School of Health Sciences, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece
| | - Styliani Pappa
- Department of Microbiology, Medical Faculty, School of Health Sciences, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece
| | - Elias Iosifidis
- Infectious Disease Unit, 3rd Department of Pediatrics, Medical Faculty, School of Health Sciences, Hippokration General Hospital, 546 42 Thessaloniki, Greece
| | - Eleni Vagdatli
- Microbiology Department, Hippokration General Hospital, 546 42 Thessaloniki, Greece
| | - Emmanuel Roilides
- Infectious Disease Unit, 3rd Department of Pediatrics, Medical Faculty, School of Health Sciences, Hippokration General Hospital, 546 42 Thessaloniki, Greece
| | - Anna Papa
- Department of Microbiology, Medical Faculty, School of Health Sciences, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece
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12
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Ikhimiukor OO, Souza SSR, Marcovici MM, Nye GJ, Gibson R, Andam CP. Leaky barriers to gene sharing between locally co-existing coagulase-negative Staphylococcus species. Commun Biol 2023; 6:482. [PMID: 37137974 PMCID: PMC10156822 DOI: 10.1038/s42003-023-04877-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 04/26/2023] [Indexed: 05/05/2023] Open
Abstract
Coagulase-negative Staphylococcus (CoNS) are opportunistic pathogens implicated in many human and animal infections. The evolutionary history of CoNS remains obscure because of the historical lack of recognition for their clinical importance and poor taxonomic sampling. Here, we sequenced the genomes of 191 CoNS isolates representing 15 species sampled from diseased animals diagnosed in a veterinary diagnostic laboratory. We found that CoNS are important reservoirs of diverse phages, plasmids and mobilizable genes encoding antimicrobial resistance, heavy metal resistance, and virulence. Frequent exchange of DNA between certain donor-recipient partners suggests that specific lineages act as hubs of gene sharing. We also detected frequent recombination between CoNS regardless of their animal host species, indicating that ecological barriers to horizontal gene transfer can be surmounted in co-circulating lineages. Our findings reveal frequent but structured patterns of transfer that exist within and between CoNS species, which are driven by their overlapping ecology and geographical proximity.
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Affiliation(s)
- Odion O Ikhimiukor
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY, USA.
| | - Stephanie S R Souza
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY, USA
| | - Michael M Marcovici
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY, USA
| | - Griffin J Nye
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, USA
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME, USA
| | - Robert Gibson
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, USA
- New Hampshire Veterinary Diagnostic Laboratory, Durham, NH, USA
| | - Cheryl P Andam
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY, USA.
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13
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Huisman JS, Vaughan TG, Egli A, Tschudin-Sutter S, Stadler T, Bonhoeffer S. The effect of sequencing and assembly on the inference of horizontal gene transfer on chromosomal and plasmid phylogenies. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210245. [PMID: 35989605 PMCID: PMC9393563 DOI: 10.1098/rstb.2021.0245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 03/30/2022] [Indexed: 12/12/2022] Open
Abstract
The spread of antibiotic resistance genes on plasmids is a threat to human and animal health. Phylogenies of bacteria and their plasmids contain clues regarding the frequency of plasmid transfer events, as well as the co-evolution of plasmids and their hosts. However, whole genome sequencing data from diverse ecological or clinical bacterial samples are rarely used to study plasmid phylogenies and resistance gene transfer. This is partially due to the difficulty of extracting plasmids from short-read sequencing data. Here, we use both short- and long-read sequencing data of 24 clinical extended-spectrum [Formula: see text]-lactamase (ESBL)-producing Escherichia coli to estimate chromosomal and plasmid phylogenies. We compare the impact of different sequencing and assembly methodologies on these phylogenies and on the inference of horizontal gene transfer. We find that chromosomal phylogenies can be estimated robustly with all methods, whereas plasmid phylogenies have more variable topology and branch lengths across the methods used. Specifically, hybrid methods that use long reads to resolve short-read assemblies (HybridSPAdes and Unicycler) perform better than those that started from long reads during assembly graph generation (Canu). By contrast, the inference of plasmid and antibiotic resistance gene transfer using a parsimony-based criterion is mostly robust to the choice of sequencing and assembly method. This article is part of a discussion meeting issue 'Genomic population structures of microbial pathogens'.
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Affiliation(s)
- Jana S. Huisman
- Department of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerland
- Department of Biosystems Science and Engineering, ETH Zurich, 4058 Basel, Switzerland
- Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Timothy G. Vaughan
- Department of Biosystems Science and Engineering, ETH Zurich, 4058 Basel, Switzerland
- Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Adrian Egli
- Division of Clinical Microbiology, University Hospital Basel, Petersgraben 4, 4031 Basel, Switzerland
- Department of Biomedicine, University of Basel, Hebelstrasse 20, 4031 Basel, Switzerland
| | - Sarah Tschudin-Sutter
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Petersgraben 4, 4031 Basel, Switzerland
- Department of Clinical Research, University of Basel, Schanzenstrasse 55, 4031 Basel, Switzerland
| | - Tanja Stadler
- Department of Biosystems Science and Engineering, ETH Zurich, 4058 Basel, Switzerland
- Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Sebastian Bonhoeffer
- Department of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerland
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14
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Leducq JB, Sneddon D, Santos M, Condrain-Morel D, Bourret G, Cecilia Martinez-Gomez N, Lee JA, Foster JA, Stolyar S, Jesse Shapiro B, Kembel SW, Sullivan JM, Marx CJ. Comprehensive phylogenomics of Methylobacterium reveals four evolutionary distinct groups and underappreciated phyllosphere diversity. Genome Biol Evol 2022; 14:6652236. [PMID: 35906926 PMCID: PMC9364378 DOI: 10.1093/gbe/evac123] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/25/2022] [Indexed: 11/13/2022] Open
Abstract
Methylobacterium is a group of methylotrophic microbes associated with soil, fresh water, and particularly the phyllosphere, the aerial part of plants that has been well-studied in terms of physiology but whose evolutionary history and taxonomy are unclear. Recent work has suggested that Methylobacterium is much more diverse than thought previously, questioning its status as an ecologically and phylogenetically coherent taxonomic genus. However, taxonomic and evolutionary studies of Methylobacterium have mostly been restricted to model species, often isolated from habitats other than the phyllosphere, and have yet to utilize comprehensive phylogenomic methods to examine gene trees, gene content, or synteny. By analyzing 189 Methylobacterium genomes from a wide range of habitats, including the phyllosphere, we inferred a robust phylogenetic tree while explicitly accounting for the impact of horizontal gene transfer. We showed that Methylobacterium contains four evolutionarily distinct groups of bacteria (namely A, B, C, D), characterized by different genome size, GC content, gene content and genome architecture, revealing the dynamic nature of Methylobacterium genomes. In addition to recovering 59 described species, we identified 45 candidate species, mostly phyllosphere-associated, stressing the significance of plants as a reservoir of Methylobacterium diversity. We inferred an ancient transition from a free-living lifestyle to association with plant roots in Methylobacteriaceae ancestor, followed by phyllosphere association of three of the major groups (A, B, D), whose early branching in Methylobacterium history has been heavily obscured by HGT. Together, our work lays the foundations for a thorough redefinition of Methylobacterium taxonomy, beginning with the abandonment of Methylorubrum.
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Affiliation(s)
- Jean-Baptiste Leducq
- Université Laval - Quebec City (QC) Canada.,University of Idaho - Moscow (ID) US
| | | | | | | | | | | | | | | | | | - B Jesse Shapiro
- Université de Montréal - Montreal (QC) Canada.,McGill University - Montreal (QC) Canada
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15
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Demographic Expansions and the Emergence of Host Specialization in Genetically Distinct Ecotypes of the Tick-Transmitted Bacterium Anaplasma phagocytophilum. Appl Environ Microbiol 2022; 88:e0061722. [PMID: 35867580 PMCID: PMC9317897 DOI: 10.1128/aem.00617-22] [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: 01/13/2023] Open
Abstract
In Europe, genetically distinct ecotypes of the tick-vectored bacterium Anaplasma phagocytophilum circulate among mammals in three discrete enzootic cycles. To date, potential ecological factors that contributed to the emergence of these divergent ecotypes have been poorly studied. Here, we show that the ecotype that predominantly infects roe deer (Capreolus capreolus) is evolutionarily derived. Its divergence from a host generalist ancestor occurred after the last glacial maximum as mammal populations, including roe deer, recolonized the European mainland from southern refugia. We also provide evidence that this host specialist ecotype's effective population size (Ne) has tracked changes in the population of its roe deer host. Specifically, both host and bacterium have undergone substantial increases in Ne over the past 1,500 years. In contrast, we show that while it appears to have undergone a major population expansion starting ~3,500 years ago, in the past 500 years, the contemporary host generalist ecotype has experienced a substantial reduction in genetic diversity levels, possibly as a result of reduced opportunities for transmission between competent hosts. IMPORTANCE The findings of this study reveal specific events important for the evolution of host specialization in a naturally occurring, obligately intracellular bacterial pathogen. Specifically, they show that host range shifts and the emergence of host specialization may occur during periods of population growth in a generalist ancestor. Our results also demonstrate the close correlation between demographic patterns in host and pathogen for a specialist system. These findings have important relevance for understanding the evolution of host range diversity. They may inform future work on host range dynamics, and they provide insights for understanding the emergence of pathogens that have human and veterinary health implications.
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16
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Qin X, Chiang CWK, Gaggiotti OE. KLFDAPC: a supervised machine learning approach for spatial genetic structure analysis. Brief Bioinform 2022; 23:bbac202. [PMID: 35649387 PMCID: PMC9294434 DOI: 10.1093/bib/bbac202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 04/05/2022] [Accepted: 04/29/2022] [Indexed: 12/30/2022] Open
Abstract
Geographic patterns of human genetic variation provide important insights into human evolution and disease. A commonly used tool to detect and describe them is principal component analysis (PCA) or the supervised linear discriminant analysis of principal components (DAPC). However, genetic features produced from both approaches could fail to correctly characterize population structure for complex scenarios involving admixture. In this study, we introduce Kernel Local Fisher Discriminant Analysis of Principal Components (KLFDAPC), a supervised non-linear approach for inferring individual geographic genetic structure that could rectify the limitations of these approaches by preserving the multimodal space of samples. We tested the power of KLFDAPC to infer population structure and to predict individual geographic origin using neural networks. Simulation results showed that KLFDAPC has higher discriminatory power than PCA and DAPC. The application of our method to empirical European and East Asian genome-wide genetic datasets indicated that the first two reduced features of KLFDAPC correctly recapitulated the geography of individuals and significantly improved the accuracy of predicting individual geographic origin when compared to PCA and DAPC. Therefore, KLFDAPC can be useful for geographic ancestry inference, design of genome scans and correction for spatial stratification in GWAS that link genes to adaptation or disease susceptibility.
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Affiliation(s)
- Xinghu Qin
- Centre for Biological Diversity, Sir Harold Mitchell Building, University of St Andrews, Fife, KY16 9TF, UK
| | - Charleston W K Chiang
- Center for Genetic Epidemiology, Department of Population and Public Health Sciences, Keck School of Medicine & Department of Quantitative and Computational Biology, University of Southern California, USA
| | - Oscar E Gaggiotti
- Centre for Biological Diversity, Sir Harold Mitchell Building, University of St Andrews, Fife, KY16 9TF, UK
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17
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Preska Steinberg A, Lin M, Kussell E. Core genes can have higher recombination rates than accessory genes within global microbial populations. eLife 2022; 11:78533. [PMID: 35801696 PMCID: PMC9444244 DOI: 10.7554/elife.78533] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 06/30/2022] [Indexed: 11/24/2022] Open
Abstract
Recombination is essential to microbial evolution, and is involved in the spread of antibiotic resistance, antigenic variation, and adaptation to the host niche. However, assessing the impact of homologous recombination on accessory genes which are only present in a subset of strains of a given species remains challenging due to their complex phylogenetic relationships. Quantifying homologous recombination for accessory genes (which are important for niche-specific adaptations) in comparison to core genes (which are present in all strains and have essential functions) is critical to understanding how selection acts on variation to shape species diversity and genome structures of bacteria. Here, we apply a computationally efficient, non-phylogenetic approach to measure homologous recombination rates in the core and accessory genome using >100,000 whole genome sequences from Streptococcus pneumoniae and several additional species. By analyzing diverse sets of sequence clusters, we show that core genes often have higher recombination rates than accessory genes, and for some bacterial species the associated effect sizes for these differences are pronounced. In a subset of species, we find that gene frequency and homologous recombination rate are positively correlated. For S. pneumoniae and several additional species, we find that while the recombination rate is higher for the core genome, the mutational divergence is lower, indicating that divergence-based homologous recombination barriers could contribute to differences in recombination rates between the core and accessory genome. Homologous recombination may therefore play a key role in increasing the efficiency of selection in the most conserved parts of the genome.
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Affiliation(s)
| | - Mingzhi Lin
- Department of Biology, New York University, New York, United States
| | - Edo Kussell
- Department of Biology, New York University, New York, United States
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18
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Abstract
Bacteria have evolved numerous strategies to use resources efficiently. However, bacterial economies depend on both the physiological context of the organisms as well as their growth state - whether they are growing, non-growing or reinitiating growth. In this essay, we discuss some of the features that make bacteria efficient under these different conditions and during the transitions between them. We also highlight the many outstanding questions regarding the physiology of non-growing bacterial cells. Lastly, we examine how efficiency is apparent in both the mode and tempo of bacterial evolution.
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Affiliation(s)
- Roberto Kolter
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA.
| | - Nathalie Balaban
- Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Thomas Julou
- Biozentrum and Swiss Institute of Bioinformatics, University of Basel, Basel, CH 4056, Switzerland
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19
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Gene regulation in Escherichia coli is commonly selected for both high plasticity and low noise. Nat Ecol Evol 2022; 6:1165-1179. [PMID: 35726087 DOI: 10.1038/s41559-022-01783-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Accepted: 05/03/2022] [Indexed: 11/08/2022]
Abstract
Bacteria often respond to dynamically changing environments by regulating gene expression. Despite this regulation being critically important for growth and survival, little is known about how selection shapes gene regulation in natural populations. To better understand the role natural selection plays in shaping bacterial gene regulation, here we compare differences in the regulatory behaviour of naturally segregating promoter variants from Escherichia coli (which have been subject to natural selection) to randomly mutated promoter variants (which have never been exposed to natural selection). We quantify gene expression phenotypes (expression level, plasticity and noise) for hundreds of promoter variants across multiple environments and show that segregating promoter variants are enriched for mutations with minimal effects on expression level. In many promoters, we infer that there is strong selection to maintain high levels of plasticity, and direct selection to decrease or increase cell-to-cell variability in expression. Taken together, these results expand our knowledge of how gene regulation is affected by natural selection and highlight the power of comparing naturally segregating polymorphisms to de novo random mutations to quantify the action of selection.
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20
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Annotation-free delineation of prokaryotic homology groups. PLoS Comput Biol 2022; 18:e1010216. [PMID: 35675326 PMCID: PMC9212150 DOI: 10.1371/journal.pcbi.1010216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 06/21/2022] [Accepted: 05/16/2022] [Indexed: 11/19/2022] Open
Abstract
Phylogenomic studies of prokaryotic taxa often assume conserved marker genes are homologous across their length. However, processes such as horizontal gene transfer or gene duplication and loss may disrupt this homology by recombining only parts of genes, causing gene fission or fusion. We show using simulation that it is necessary to delineate homology groups in a set of bacterial genomes without relying on gene annotations to define the boundaries of homologous regions. To solve this problem, we have developed a graph-based algorithm to partition a set of bacterial genomes into Maximal Homologous Groups of sequences (MHGs) where each MHG is a maximal set of maximum-length sequences which are homologous across the entire sequence alignment. We applied our algorithm to a dataset of 19 Enterobacteriaceae species and found that MHGs cover much greater proportions of genomes than markers and, relatedly, are less biased in terms of the functions of the genes they cover. We zoomed in on the correlation between each individual marker and their overlapping MHGs, and show that few phylogenetic splits supported by the markers are supported by the MHGs while many marker-supported splits are contradicted by the MHGs. A comparison of the species tree inferred from marker genes with the species tree inferred from MHGs suggests that the increased bias and lack of genome coverage by markers causes incorrect inferences as to the overall relationship between bacterial taxa. Assuming genes to be the basic evolutionary unit has been commonplace in bacterial genomics. For example, when quantifying the extent of horizontal gene transfer it is common to infer gene trees and reconcile them against a species tree to account for recombination-based processes. We have developed a new method which challenges this assumption by identifying contiguous regions of true homology without regards to gene boundaries and applied it to Enterobacteriaceae, a family of bacteria containing several important human pathogens. Our results show that genes are composed of distinct homologous regions with conflicting phylogenetic histories. We further demonstrate that failing to take account of this conflict, together with the functional biases we show exist among single-copy marker genes, significantly changes the consensus evolutionary tree of Enterobacteriaceae.
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21
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Shikov AE, Malovichko YV, Nizhnikov AA, Antonets KS. Current Methods for Recombination Detection in Bacteria. Int J Mol Sci 2022; 23:ijms23116257. [PMID: 35682936 PMCID: PMC9181119 DOI: 10.3390/ijms23116257] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 05/30/2022] [Accepted: 05/30/2022] [Indexed: 02/05/2023] Open
Abstract
The role of genetic exchanges, i.e., homologous recombination (HR) and horizontal gene transfer (HGT), in bacteria cannot be overestimated for it is a pivotal mechanism leading to their evolution and adaptation, thus, tracking the signs of recombination and HGT events is importance both for fundamental and applied science. To date, dozens of bioinformatics tools for revealing recombination signals are available, however, their pros and cons as well as the spectra of solvable tasks have not yet been systematically reviewed. Moreover, there are two major groups of software. One aims to infer evidence of HR, while the other only deals with horizontal gene transfer (HGT). However, despite seemingly different goals, all the methods use similar algorithmic approaches, and the processes are interconnected in terms of genomic evolution influencing each other. In this review, we propose a classification of novel instruments for both HR and HGT detection based on the genomic consequences of recombination. In this context, we summarize available methodologies paying particular attention to the type of traceable events for which a certain program has been designed.
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Affiliation(s)
- Anton E. Shikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (A.E.S.); (Y.V.M.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
| | - Yury V. Malovichko
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (A.E.S.); (Y.V.M.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
| | - Anton A. Nizhnikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (A.E.S.); (Y.V.M.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
| | - Kirill S. Antonets
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (A.E.S.); (Y.V.M.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
- Correspondence:
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22
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Chen DW, Garud NR. Rapid evolution and strain turnover in the infant gut microbiome. Genome Res 2022; 32:1124-1136. [PMID: 35545448 PMCID: PMC9248880 DOI: 10.1101/gr.276306.121] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 05/06/2022] [Indexed: 11/25/2022]
Abstract
Although the ecological dynamics of the infant gut microbiome have been intensely studied, relatively little is known about evolutionary dynamics in the infant gut microbiome. Here we analyze longitudinal fecal metagenomic data from more than 700 infants and their mothers over the first year of life and find that the evolutionary dynamics in infant gut microbiomes are distinct from those of adults. We find evidence for more than a 10-fold increase in the rate of evolution and strain turnover in the infant gut compared with healthy adults, with the mother-infant transition at delivery being a particularly dynamic period in which gene loss dominates. Within a few months after birth, these dynamics stabilize, and gene gains become increasingly frequent as the microbiome matures. We furthermore find that evolutionary changes in infants show signatures of being seeded by a mixture of de novo mutations and transmissions of pre-evolved lineages from the broader family. Several of these evolutionary changes occur in parallel across infants, highlighting candidate genes that may play important roles in the development of the infant gut microbiome. Our results point to a picture of a volatile infant gut microbiome characterized by rapid evolutionary and ecological change in the early days of life.
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Affiliation(s)
- Daisy W Chen
- Computational and Systems Biology, University of California, Los Angeles, California 90095-1606, USA
- Bioinformatics and Systems Biology Program, University of California, San Diego, California 92093, USA
| | - Nandita R Garud
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California 90095-1606, USA
- Department of Human Genetics, University of California, Los Angeles, California 90095-1606, USA
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23
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Sabin S, Morales-Arce AY, Pfeifer SP, Jensen JD. The impact of frequently neglected model violations on bacterial recombination rate estimation: a case study in Mycobacterium canettii and Mycobacterium tuberculosis. G3 (BETHESDA, MD.) 2022; 12:jkac055. [PMID: 35253851 PMCID: PMC9073693 DOI: 10.1093/g3journal/jkac055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Accepted: 02/28/2022] [Indexed: 12/04/2022]
Abstract
Mycobacterium canettii is a causative agent of tuberculosis in humans, along with the members of the Mycobacterium tuberculosis complex. Frequently used as an outgroup to the M. tuberculosis complex in phylogenetic analyses, M. canettii is thought to offer the best proxy for the progenitor species that gave rise to the complex. Here, we leverage whole-genome sequencing data and biologically relevant population genomic models to compare the evolutionary dynamics driving variation in the recombining M. canettii with that in the nonrecombining M. tuberculosis complex, and discuss differences in observed genomic diversity in the light of expected levels of Hill-Robertson interference. In doing so, we highlight the methodological challenges of estimating recombination rates through traditional population genetic approaches using sequences called from populations of microorganisms and evaluate the likely mis-inference that arises owing to a neglect of common model violations including purifying selection, background selection, progeny skew, and population size change. In addition, we compare performance when full within-host polymorphism data are utilized, versus the more common approach of basing analyses on within-host consensus sequences.
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Affiliation(s)
- Susanna Sabin
- Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA
| | - Ana Y Morales-Arce
- Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA
| | - Susanne P Pfeifer
- Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA
| | - Jeffrey D Jensen
- Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA
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24
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Bowers RM, Nayfach S, Schulz F, Jungbluth SP, Ruhl IA, Sheremet A, Lee J, Goudeau D, Eloe-Fadrosh EA, Stepanauskas R, Malmstrom RR, Kyrpides NC, Dunfield PF, Woyke T. Dissecting the dominant hot spring microbial populations based on community-wide sampling at single-cell genomic resolution. THE ISME JOURNAL 2022; 16:1337-1347. [PMID: 34969995 PMCID: PMC9039060 DOI: 10.1038/s41396-021-01178-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 11/29/2021] [Accepted: 12/10/2021] [Indexed: 02/07/2023]
Abstract
With advances in DNA sequencing and miniaturized molecular biology workflows, rapid and affordable sequencing of single-cell genomes has become a reality. Compared to 16S rRNA gene surveys and shotgun metagenomics, large-scale application of single-cell genomics to whole microbial communities provides an integrated snapshot of community composition and function, directly links mobile elements to their hosts, and enables analysis of population heterogeneity of the dominant community members. To that end, we sequenced nearly 500 single-cell genomes from a low diversity hot spring sediment sample from Dewar Creek, British Columbia, and compared this approach to 16S rRNA gene amplicon and shotgun metagenomics applied to the same sample. We found that the broad taxonomic profiles were similar across the three sequencing approaches, though several lineages were missing from the 16S rRNA gene amplicon dataset, likely the result of primer mismatches. At the functional level, we detected a large array of mobile genetic elements present in the single-cell genomes but absent from the corresponding same species metagenome-assembled genomes. Moreover, we performed a single-cell population genomic analysis of the three most abundant community members, revealing differences in population structure based on mutation and recombination profiles. While the average pairwise nucleotide identities were similar across the dominant species-level lineages, we observed differences in the extent of recombination between these dominant populations. Most intriguingly, the creek's Hydrogenobacter sp. population appeared to be so recombinogenic that it more closely resembled a sexual species than a clonally evolving microbe. Together, this work demonstrates that a randomized single-cell approach can be useful for the exploration of previously uncultivated microbes from community composition to population structure.
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Affiliation(s)
- Robert M. Bowers
- grid.451309.a0000 0004 0449 479XU.S. Department of Energy, Joint Genome Institute, Berkeley, CA USA
| | - Stephen Nayfach
- grid.451309.a0000 0004 0449 479XU.S. Department of Energy, Joint Genome Institute, Berkeley, CA USA
| | - Frederik Schulz
- grid.451309.a0000 0004 0449 479XU.S. Department of Energy, Joint Genome Institute, Berkeley, CA USA
| | - Sean P. Jungbluth
- grid.184769.50000 0001 2231 4551Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA
| | - Ilona A. Ruhl
- grid.22072.350000 0004 1936 7697Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4 Canada ,grid.419357.d0000 0001 2199 3636National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO USA
| | - Andriy Sheremet
- grid.22072.350000 0004 1936 7697Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4 Canada
| | - Janey Lee
- grid.451309.a0000 0004 0449 479XU.S. Department of Energy, Joint Genome Institute, Berkeley, CA USA
| | - Danielle Goudeau
- grid.451309.a0000 0004 0449 479XU.S. Department of Energy, Joint Genome Institute, Berkeley, CA USA
| | - Emiley A. Eloe-Fadrosh
- grid.451309.a0000 0004 0449 479XU.S. Department of Energy, Joint Genome Institute, Berkeley, CA USA
| | - Ramunas Stepanauskas
- grid.296275.d0000 0000 9516 4913Bigelow Laboratory for Ocean Sciences, 60 Bigelow Drive, East Boothbay, ME USA
| | - Rex R. Malmstrom
- grid.451309.a0000 0004 0449 479XU.S. Department of Energy, Joint Genome Institute, Berkeley, CA USA
| | - Nikos C. Kyrpides
- grid.451309.a0000 0004 0449 479XU.S. Department of Energy, Joint Genome Institute, Berkeley, CA USA
| | - Peter F. Dunfield
- grid.22072.350000 0004 1936 7697Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4 Canada
| | - Tanja Woyke
- U.S. Department of Energy, Joint Genome Institute, Berkeley, CA, USA.
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25
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Shalon N, Relman DA, Yaffe E. Precise genotyping of circular mobile elements from metagenomic data uncovers human-associated plasmids with recent common ancestors. Genome Res 2022; 32:986-1003. [PMID: 35414589 PMCID: PMC9104695 DOI: 10.1101/gr.275894.121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 04/01/2022] [Indexed: 11/25/2022]
Abstract
Mobile genetic elements with circular genomes play a key role in the evolution of microbial communities. Their circular genomes correspond to circular walks in metagenome graphs, and yet, assemblies derived from natural microbial communities produce graphs riddled with spurious cycles, complicating the accurate reconstruction of circular genomes. We present DomCycle, an algorithm that reconstructs likely circular genomes based on the identification of so-called 'dominant' graph cycles. In the implementation we leverage paired reads to bridge assembly gaps and scrutinize cycles through a nucleotide-level analysis, making the approach robust to misassembly artifacts. We validated the approach using simulated and real sequencing data. Application of DomCycle to 32 publicly available DNA shotgun sequence data sets from diverse natural environments led to the reconstruction of hundreds of circular mobile genomes. Clustering revealed 20 highly prevalent and cryptic plasmids that have clonal population structures with recent common ancestors. This method facilitates the study of microbial communities that evolve through horizontal gene transfer.
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26
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Recombination resolves the cost of horizontal gene transfer in experimental populations of Helicobacter pylori. Proc Natl Acad Sci U S A 2022; 119:e2119010119. [PMID: 35298339 PMCID: PMC8944584 DOI: 10.1073/pnas.2119010119] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Horizontal gene transfer (HGT)—the transfer of DNA between lineages—is responsible for a large proportion of the genetic variation that contributes to evolution in microbial populations. While HGT can bring beneficial genetic innovation, the transfer of DNA from other species or strains can also have deleterious effects. In this study, we evolve populations of the bacteria Helicobacter pylori and use DNA sequencing to identify over 40,000 genetic variants transferred by HGT. We measure the cost of many of these and find that both strongly beneficial mutations and deleterious mutations are genetic variants transferred by natural transformation. Importantly, we also show how recombination that separates linked beneficial and deleterious mutations resolves the cost of HGT. Horizontal gene transfer (HGT) is important for microbial evolution, yet we know little about the fitness effects and dynamics of horizontally transferred genetic variants. In this study, we evolve laboratory populations of Helicobacter pylori, which take up DNA from their environment by natural transformation, and measure the fitness effects of thousands of transferred genetic variants. We find that natural transformation increases the rate of adaptation but comes at the cost of significant genetic load. We show that this cost is circumvented by recombination, which increases the efficiency of selection by decoupling deleterious and beneficial genetic variants. Our results show that adaptation with HGT, pervasive in natural microbial populations, is shaped by a combination of selection, recombination, and genetic drift not accounted for in existing models of evolution.
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Mallawaarachchi S, Tonkin-Hill G, Croucher NJ, Turner P, Speed D, Corander J, Balding D. Genome-wide association, prediction and heritability in bacteria with application to Streptococcus pneumoniae. NAR Genom Bioinform 2022; 4:lqac011. [PMID: 35211669 PMCID: PMC8862724 DOI: 10.1093/nargab/lqac011] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/06/2022] [Accepted: 02/01/2022] [Indexed: 11/14/2022] Open
Abstract
Whole-genome sequencing has facilitated genome-wide analyses of association, prediction and heritability in many organisms. However, such analyses in bacteria are still in their infancy, being limited by difficulties including genome plasticity and strong population structure. Here we propose a suite of methods including linear mixed models, elastic net and LD-score regression, adapted to bacterial traits using innovations such as frequency-based allele coding, both insertion/deletion and nucleotide testing and heritability partitioning. We compare and validate our methods against the current state-of-art using simulations, and analyse three phenotypes of the major human pathogen Streptococcus pneumoniae, including the first analyses of minimum inhibitory concentrations (MIC) for penicillin and ceftriaxone. We show that the MIC traits are highly heritable with high prediction accuracy, explained by many genetic associations under good population structure control. In ceftriaxone MIC, this is surprising because none of the isolates are resistant as per the inhibition zone criteria. We estimate that half of the heritability of penicillin MIC is explained by a known drug-resistance region, which also contributes a quarter of the ceftriaxone MIC heritability. For the within-host carriage duration phenotype, no associations were observed, but the moderate heritability and prediction accuracy indicate a moderately polygenic trait.
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Affiliation(s)
| | - Gerry Tonkin-Hill
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge CB10 1SA, UK
| | - Nicholas J Croucher
- Faculty of Medicine, School of Public Health, Imperial College, London SW7 2AZ, UK
| | - Paul Turner
- Cambodia-Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap 1710, Cambodia,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7LG, UK
| | - Doug Speed
- Aarhus Institute of Advanced Studies (AIAS), Aarhus University, 8000 Aarhus, Denmark,Bioinformatics Research Centre, Aarhus University, 8000 Aarhus, Denmark,UCL Genetics Institute, University College London, London WC1E 6BT, United Kingdom
| | - Jukka Corander
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge CB10 1SA, UK,Department of Biostatistics, Faculty of Medicine, University of Oslo, 0372 Oslo, Norway,Helsinki Institute of Information Technology, Department of Mathematics and Statistics, University of Helsinki, Helsinki 00014, Finland
| | - David Balding
- Correspondence may also be addressed to David Balding.
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Genomic structure predicts metabolite dynamics in microbial communities. Cell 2022; 185:530-546.e25. [PMID: 35085485 DOI: 10.1016/j.cell.2021.12.036] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 07/16/2021] [Accepted: 12/21/2021] [Indexed: 12/21/2022]
Abstract
The metabolic activities of microbial communities play a defining role in the evolution and persistence of life on Earth, driving redox reactions that give rise to global biogeochemical cycles. Community metabolism emerges from a hierarchy of processes, including gene expression, ecological interactions, and environmental factors. In wild communities, gene content is correlated with environmental context, but predicting metabolite dynamics from genomes remains elusive. Here, we show, for the process of denitrification, that metabolite dynamics of a community are predictable from the genes each member of the community possesses. A simple linear regression reveals a sparse and generalizable mapping from gene content to metabolite dynamics for genomically diverse bacteria. A consumer-resource model correctly predicts community metabolite dynamics from single-strain phenotypes. Our results demonstrate that the conserved impacts of metabolic genes can predict community metabolite dynamics, enabling the prediction of metabolite dynamics from metagenomes, designing denitrifying communities, and discovering how genome evolution impacts metabolism.
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Shoemaker WR, Chen D, Garud NR. Comparative Population Genetics in the Human Gut Microbiome. Genome Biol Evol 2022; 14:evab116. [PMID: 34028530 PMCID: PMC8743038 DOI: 10.1093/gbe/evab116] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2021] [Indexed: 11/13/2022] Open
Abstract
Genetic variation in the human gut microbiome is responsible for conferring a number of crucial phenotypes like the ability to digest food and metabolize drugs. Yet, our understanding of how this variation arises and is maintained remains relatively poor. Thus, the microbiome remains a largely untapped resource, as the large number of coexisting species in the microbiome presents a unique opportunity to compare and contrast evolutionary processes across species to identify universal trends and deviations. Here we outline features of the human gut microbiome that, while not unique in isolation, as an assemblage make it a system with unparalleled potential for comparative population genomics studies. We consciously take a broad view of comparative population genetics, emphasizing how sampling a large number of species allows researchers to identify universal evolutionary dynamics in addition to new genes, which can then be leveraged to identify exceptional species that deviate from general patterns. To highlight the potential power of comparative population genetics in the microbiome, we reanalyze patterns of purifying selection across ∼40 prevalent species in the human gut microbiome to identify intriguing trends which highlight functional categories in the microbiome that may be under more or less constraint.
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Affiliation(s)
- William R Shoemaker
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA
| | - Daisy Chen
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA
| | - Nandita R Garud
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA
- Department of Human Genetics, University of California, Los Angeles, California, USA
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Abstract
Horizontal gene transfer (HGT) is an important factor in bacterial evolution that can act across species boundaries. Yet, we know little about rate and genomic targets of cross-lineage gene transfer and about its effects on the recipient organism's physiology and fitness. Here, we address these questions in a parallel evolution experiment with two Bacillus subtilis lineages of 7% sequence divergence. We observe rapid evolution of hybrid organisms: gene transfer swaps ∼12% of the core genome in just 200 generations, and 60% of core genes are replaced in at least one population. By genomics, transcriptomics, fitness assays, and statistical modeling, we show that transfer generates adaptive evolution and functional alterations in hybrids. Specifically, our experiments reveal a strong, repeatable fitness increase of evolved populations in the stationary growth phase. By genomic analysis of the transfer statistics across replicate populations, we infer that selection on HGT has a broad genetic basis: 40% of the observed transfers are adaptive. At the level of functional gene networks, we find signatures of negative, positive, and epistatic selection, consistent with hybrid incompatibilities and adaptive evolution of network functions. Our results suggest that gene transfer navigates a complex cross-lineage fitness landscape, bridging epistatic barriers along multiple high-fitness paths.
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Jackson LK, Potter B, Schneider S, Fitzgibbon M, Blair K, Farah H, Krishna U, Bedford T, Peek RM, Salama NR. Helicobacter pylori diversification during chronic infection within a single host generates sub-populations with distinct phenotypes. PLoS Pathog 2020; 16:e1008686. [PMID: 33370399 PMCID: PMC7794030 DOI: 10.1371/journal.ppat.1008686] [Citation(s) in RCA: 7] [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: 06/04/2020] [Revised: 01/08/2021] [Accepted: 10/22/2020] [Indexed: 12/15/2022] Open
Abstract
Helicobacter pylori chronically infects the stomach of approximately half of the world's population. Manifestation of clinical diseases associated with H. pylori infection, including cancer, is driven by strain properties and host responses; and as chronic infection persists, both are subject to change. Previous studies have documented frequent and extensive within-host bacterial genetic variation. To define how within-host diversity contributes to phenotypes related to H. pylori pathogenesis, this project leverages a collection of 39 clinical isolates acquired prospectively from a single subject at two time points and from multiple gastric sites. During the six years separating collection of these isolates, this individual, initially harboring a duodenal ulcer, progressed to gastric atrophy and concomitant loss of acid secretion. Whole genome sequence analysis identified 1,767 unique single nucleotide polymorphisms (SNPs) across isolates and a nucleotide substitution rate of 1.3x10-4 substitutions/site/year. Gene ontology analysis identified cell envelope genes among the genes with excess accumulation of nonsynonymous SNPs (nSNPs). A maximum likelihood tree based on genetic similarity clusters isolates from each time point separately. Within time points, there is segregation of subgroups with phenotypic differences in bacterial morphology, ability to induce inflammatory cytokines, and mouse colonization. Higher inflammatory cytokine induction in recent isolates maps to shared polymorphisms in the Cag PAI protein, CagY, while rod morphology in a subgroup of recent isolates mapped to eight mutations in three distinct helical cell shape determining (csd) genes. The presence of subgroups with unique genetic and phenotypic properties suggest complex selective forces and multiple niches within the stomach during chronic infection.
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Affiliation(s)
- Laura K. Jackson
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, WA, United States of America
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
| | - Barney Potter
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
| | - Sean Schneider
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
| | - Matthew Fitzgibbon
- Genomics & Bioinformatics Shared Resource, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
| | - Kris Blair
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, WA, United States of America
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
| | - Hajirah Farah
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA, United States of America
| | - Uma Krishna
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Trevor Bedford
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
| | - Richard M. Peek
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Nina R. Salama
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, WA, United States of America
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA, United States of America
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