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Song W, Zhang S, Majzoub ME, Egan S, Kjelleberg S, Thomas T. The impact of interspecific competition on the genomic evolution of Phaeobacter inhibens and Pseudoalteromonas tunicata during biofilm growth. Environ Microbiol 2024; 26:e16553. [PMID: 38062568 DOI: 10.1111/1462-2920.16553] [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: 08/21/2023] [Accepted: 11/24/2023] [Indexed: 01/30/2024]
Abstract
Interspecific interactions in biofilms have been shown to cause the emergence of community-level properties. To understand the impact of interspecific competition on evolution, we deep-sequenced the dispersal population of mono- and co-culture biofilms of two antagonistic marine bacteria (Phaeobacter inhibens 2.10 and Pseudoalteromononas tunicata D2). Enhanced phenotypic and genomic diversification was observed in the P. tunicata D2 populations under both mono- and co-culture biofilms in comparison to P. inhibens 2.10. The genetic variation was exclusively due to single nucleotide variants and small deletions, and showed high variability between replicates, indicating their random emergence. Interspecific competition exerted an apparent strong positive selection on a subset of P. inhibens 2.10 genes (e.g., luxR, cobC, argH, and sinR) that could facilitate competition, while the P. tunicata D2 population was genetically constrained under competition conditions. In the absence of interspecific competition, the P. tunicata D2 replicate populations displayed high levels of mutations affecting the same genes involved in cell motility and biofilm formation. Our results show that interspecific biofilm competition has a complex impact on genomic diversification, which likely depends on the nature of the competing strains and their ability to generate genetic variants due to their genomic constraints.
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Affiliation(s)
- Weizhi Song
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, Faculty of Science, The University of New South Wales, Kensington, New South Wales, Australia
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - Shan Zhang
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, Faculty of Science, The University of New South Wales, Kensington, New South Wales, Australia
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - Marwan E Majzoub
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, Faculty of Science, The University of New South Wales, Kensington, New South Wales, Australia
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - Suhelen Egan
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, Faculty of Science, The University of New South Wales, Kensington, New South Wales, Australia
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - Staffan Kjelleberg
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, Faculty of Science, The University of New South Wales, Kensington, New South Wales, Australia
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Kensington, New South Wales, Australia
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Torsten Thomas
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, Faculty of Science, The University of New South Wales, Kensington, New South Wales, Australia
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Kensington, New South Wales, Australia
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2
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Song X, Kong SJ, Seo S, Prabhakar RG, Shamoo Y. Methyl halide transferase-based gas reporters for quantification of filamentous bacteria in microdroplet emulsions. Appl Environ Microbiol 2023; 89:e0076423. [PMID: 37699129 PMCID: PMC10537575 DOI: 10.1128/aem.00764-23] [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: 05/10/2023] [Accepted: 07/19/2023] [Indexed: 09/14/2023] Open
Abstract
The application of microfluidic techniques in experimental and environmental studies is a rapidly emerging field. Water-in-oil microdroplets can serve readily as controllable micro-vessels for studies that require spatial structure. In many applications, it is useful to monitor cell growth without breaking or disrupting the microdroplets. To this end, optical reporters based on color, fluorescence, or luminescence have been developed. However, optical reporters suffer from limitations when used in microdroplets such as inaccurate readings due to strong background interference or limited sensitivity during early growth stages. In addition, optical detection is typically not amenable to filamentous or biofilm-producing organisms that have significant nonlinear changes in opacity and light scattering during growth. To overcome such limitations, we show that volatile methyl halide gases produced by reporter cells expressing a methyl halide transferase (MHT) can serve as an alternative nonoptical detection approach suitable for microdroplets. In this study, an MHT-labeled Streptomyces venezuelae reporter strain was constructed and characterized. Protocols were established for the encapsulation and incubation of S. venezuelae in microdroplets. We observed the complete life cycle for S. venezuelae including the vegetative expansion of mycelia, mycelial fragmentation, and late-stage sporulation. Methyl bromide (MeBr) production was detected by gas chromatography-mass spectrometry (GC-MS) from S. venezuelae gas reporters incubated in either liquid suspension or microdroplets and used to quantitatively estimate bacterial density. Overall, using MeBr production as a means of quantifying bacterial growth provided a 100- to 1,000-fold increase in sensitivity over optical or fluorescence measurements of a comparable reporter strain expressing fluorescent proteins. IMPORTANCE Quantitative measurement of bacterial growth in microdroplets in situ is desirable but challenging. Current optical reporter systems suffer from limitations when applied to filamentous or biofilm-producing organisms. In this study, we demonstrate that volatile methyl halide gas production can serve as a quantitative nonoptical growth assay for filamentous bacteria encapsulated in microdroplets. We constructed an S. venezuelae gas reporter strain and observed a complete life cycle for encapsulated S. venezuelae in microdroplets, establishing microdroplets as an alternative growth environment for Streptomyces spp. that can provide spatial structure. We detected MeBr production from both liquid suspension and microdroplets with a 100- to 1,000-fold increase in signal-to-noise ratio compared to optical assays. Importantly, we could reliably detect bacteria with densities down to 106 CFU/mL. The combination of quantitative gas reporting and microdroplet systems provides a valuable approach to studying fastidious organisms that require spatial structure such as those found typically in soils.
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Affiliation(s)
- Xinhao Song
- Department of BioSciences, Rice University, Houston, Texas, USA
| | - Sarah J. Kong
- Department of BioSciences, Rice University, Houston, Texas, USA
| | - Seokju Seo
- Department of BioSciences, Rice University, Houston, Texas, USA
| | | | - Yousif Shamoo
- Department of BioSciences, Rice University, Houston, Texas, USA
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3
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Mehta HH, Song X, Shamoo Y. Intracellular Experimental Evolution of Francisella tularensis Subsp. holarctica Live Vaccine Strain (LVS) to Antimicrobial Resistance. ACS Infect Dis 2023; 9:308-321. [PMID: 36662533 PMCID: PMC9996545 DOI: 10.1021/acsinfecdis.2c00483] [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: 01/21/2023]
Abstract
In vitro experimental evolution has complemented clinical studies as an excellent tool to identify genetic changes responsible for the de novo evolution of antimicrobial resistance. However, the in vivo context for adaptation contributes to the success of particular evolutionary trajectories, especially in intracellular niches where the adaptive landscape of virulence and resistance are strongly coupled. In this work, we designed an ex vivo evolution approach to identify evolutionary trajectories responsible for antibiotic resistance in the Live Vaccine Strain (LVS) of Francisella tularensis subsp. holarctica while being passaged to increasing ciprofloxacin (CIP) and doxycycline (DOX) concentrations within macrophages. Overall, adaptation within macrophages advanced much slower when compared to previous in vitro evolution studies reflecting a limiting capacity for the expansion of adaptive mutations within the macrophage. Longitudinal genomic analysis identified resistance conferring gyrase mutations outside the Quinolone Resistance Determining Region. Strikingly, FupA/B mutations that are uniquely associated with in vitro CIP resistance in Francisella were not observed ex vivo, reflecting the coupling of intracellular survival and resistance during intracellular adaptation. To our knowledge, this is the first experimental study demonstrating the ability to conduct experimental evolution to antimicrobial resistance within macrophages. The results provide evidence of differences in mutational profiles of populations adapted to the same antibiotic in different environments/cellular compartments and underscore the significance of host mediated stress during resistance evolution.
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Affiliation(s)
- Heer H Mehta
- Department of BioSciences, Rice University, Houston, Texas 77005, United States
| | - Xinhao Song
- Department of BioSciences, Rice University, Houston, Texas 77005, United States
| | - Yousif Shamoo
- Department of BioSciences, Rice University, Houston, Texas 77005, United States
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Brepoels P, Appermans K, Pérez-Romero CA, Lories B, Marchal K, Steenackers HP. Antibiotic Cycling Affects Resistance Evolution Independently of Collateral Sensitivity. Mol Biol Evol 2022; 39:6884036. [PMID: 36480297 PMCID: PMC9778841 DOI: 10.1093/molbev/msac257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 10/13/2022] [Accepted: 11/17/2022] [Indexed: 12/13/2022] Open
Abstract
Antibiotic cycling has been proposed as a promising approach to slow down resistance evolution against currently employed antibiotics. It remains unclear, however, to which extent the decreased resistance evolution is the result of collateral sensitivity, an evolutionary trade-off where resistance to one antibiotic enhances the sensitivity to the second, or due to additional effects of the evolved genetic background, in which mutations accumulated during treatment with a first antibiotic alter the emergence and spread of resistance against a second antibiotic via other mechanisms. Also, the influence of antibiotic exposure patterns on the outcome of drug cycling is unknown. Here, we systematically assessed the effects of the evolved genetic background by focusing on the first switch between two antibiotics against Salmonella Typhimurium, with cefotaxime fixed as the first and a broad variety of other drugs as the second antibiotic. By normalizing the antibiotic concentrations to eliminate the effects of collateral sensitivity, we demonstrated a clear contribution of the evolved genetic background beyond collateral sensitivity, which either enhanced or reduced the adaptive potential depending on the specific drug combination. We further demonstrated that the gradient strength with which cefotaxime was applied affected both cefotaxime resistance evolution and adaptation to second antibiotics, an effect that was associated with higher levels of clonal interference and reduced cost of resistance in populations evolved under weaker cefotaxime gradients. Overall, our work highlights that drug cycling can affect resistance evolution independently of collateral sensitivity, in a manner that is contingent on the antibiotic exposure pattern.
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Affiliation(s)
| | | | - Camilo Andres Pérez-Romero
- Department of Information Technology and the Department of Plant Biotechnology, Biochemistry and Bioinformatics, Ghent University, Ghent, Belgium
| | - Bram Lories
- Department of Microbial and Molecular Systems, Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Leuven, Belgium
| | - Kathleen Marchal
- Department of Information Technology and the Department of Plant Biotechnology, Biochemistry and Bioinformatics, Ghent University, Ghent, Belgium
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Rodríguez‐Pastor R, Shafran Y, Knossow N, Gutiérrez R, Harrus S, Zaman L, Lenski RE, Barrick JE, Hawlena H. A road map for in vivo evolution experiments with blood-borne parasitic microbes. Mol Ecol Resour 2022; 22:2843-2859. [PMID: 35599628 PMCID: PMC9796859 DOI: 10.1111/1755-0998.13649] [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: 11/07/2021] [Revised: 03/14/2022] [Accepted: 05/13/2022] [Indexed: 01/07/2023]
Abstract
Laboratory experiments in which blood-borne parasitic microbes evolve in their animal hosts offer an opportunity to study parasite evolution and adaptation in real time and under natural settings. The main challenge of these experiments is to establish a protocol that is both practical over multiple passages and accurately reflects natural transmission scenarios and mechanisms. We provide a guide to the steps that should be considered when designing such a protocol, and we demonstrate its use via a case study. We highlight the importance of choosing suitable ancestral genotypes, treatments, number of replicates per treatment, types of negative controls, dependent variables, covariates, and the timing of checkpoints for the experimental design. We also recommend specific preliminary experiments to determine effective methods for parasite quantification, transmission, and preservation. Although these methodological considerations are technical, they also often have conceptual implications. To this end, we encourage other researchers to design and conduct in vivo evolution experiments with blood-borne parasitic microbes, despite the challenges that the work entails.
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Affiliation(s)
- Ruth Rodríguez‐Pastor
- Jacob Blaustein Center for Scientific Cooperation, The Jacob Blaustein Institutes for Desert ResearchBen‐Gurion University of the NegevMidreshet Ben‐GurionIsrael
| | - Yarden Shafran
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert ResearchBen‐Gurion University of the NegevMidreshet Ben‐GurionIsrael
| | - Nadav Knossow
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert ResearchBen‐Gurion University of the NegevMidreshet Ben‐GurionIsrael
| | - Ricardo Gutiérrez
- Koret School of Veterinary Medicine, Faculty of Agricultural, Nutritional and Environmental SciencesThe Hebrew University of JerusalemRehovotIsrael
| | - Shimon Harrus
- Koret School of Veterinary Medicine, Faculty of Agricultural, Nutritional and Environmental SciencesThe Hebrew University of JerusalemRehovotIsrael
| | - Luis Zaman
- Department of Ecology and Evolutionary Biology, The Center for the Study of Complex Systems (CSCS)University of MichiganAnn ArborMichiganUSA
| | - Richard E. Lenski
- Department of Microbiology and Molecular GeneticsMichigan State UniversityEast LansingMichiganUSA
| | - Jeffrey E. Barrick
- Department of Molecular BiosciencesThe University of Texas AustinAustinTexasUSA
| | - Hadas Hawlena
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert ResearchBen‐Gurion University of the NegevMidreshet Ben‐GurionIsrael
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6
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Biofilm antimicrobial susceptibility through an experimental evolutionary lens. NPJ Biofilms Microbiomes 2022; 8:82. [PMID: 36257971 PMCID: PMC9579162 DOI: 10.1038/s41522-022-00346-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 10/04/2022] [Indexed: 11/19/2022] Open
Abstract
Experimental evolution experiments in which bacterial populations are repeatedly exposed to an antimicrobial treatment, and examination of the genotype and phenotype of the resulting evolved bacteria, can help shed light on mechanisms behind reduced susceptibility. In this review we present an overview of why it is important to include biofilms in experimental evolution, which approaches are available to study experimental evolution in biofilms and what experimental evolution has taught us about tolerance and resistance in biofilms. Finally, we present an emerging consensus view on biofilm antimicrobial susceptibility supported by data obtained during experimental evolution studies.
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Evolution of Enterococcus faecium in Response to a Combination of Daptomycin and Fosfomycin Reveals Distinct and Diverse Adaptive Strategies. Antimicrob Agents Chemother 2022; 66:e0233321. [PMID: 35543524 PMCID: PMC9211409 DOI: 10.1128/aac.02333-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Infections caused by vancomycin-resistant Enterococcus faecium (VREfm) are an important public health threat. VREfm isolates have become increasingly resistant to the front-line antibiotic daptomycin (DAP). As such, the use of DAP combination therapies with other antibiotics like fosfomycin (FOS) has received increased attention. Antibiotic combinations could extend the efficacy of currently available antibiotics and potentially delay the onset of further resistance. We investigated the potential for E. faecium HOU503, a clinical VREfm isolate that is DAP and FOS susceptible, to develop resistance to a DAP-FOS combination. Of particular interest was whether the genetic drivers for DAP-FOS resistance might be epistatic and, thus, potentially decrease the efficacy of a combinatorial approach in either inhibiting VREfm or in delaying the onset of resistance. We show that resistance to DAP-FOS could be achieved by independent mutations to proteins responsible for cell wall synthesis for FOS and in altering membrane dynamics for DAP. However, we did not observe genetic drivers that exhibited substantial cross-drug epistasis that could undermine the DAP-FOS combination. Of interest was that FOS resistance in HOU503 was largely mediated by changes in phosphoenolpyruvate (PEP) flux as a result of mutations in pyruvate kinase (pyk). Increasing PEP flux could be a readily accessible mechanism for FOS resistance in many pathogens. Importantly, we show that HOU503 was able to develop DAP resistance through a variety of biochemical mechanisms and was able to employ different adaptive strategies. Finally, we showed that the addition of FOS can prolong the efficacy of DAP and slow down DAP resistance in vitro.
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8
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Santos-Lopez A, Fritz MJ, Lombardo JB, Burr AHP, Heinrich VA, Marshall CW, Cooper VS. Evolved resistance to a novel cationic peptide antibiotic requires high mutation supply. Evol Med Public Health 2022; 10:266-276. [PMID: 35712084 PMCID: PMC9198447 DOI: 10.1093/emph/eoac022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 05/21/2022] [Indexed: 01/30/2023] Open
Abstract
Background and Objectives A key strategy for resolving the antibiotic resistance crisis is the development of new drugs with antimicrobial properties. The engineered cationic antimicrobial peptide WLBU2 (also known as PLG0206) is a promising broad-spectrum antimicrobial compound that has completed Phase I clinical studies. It has activity against Gram-negative and Gram-positive bacteria including infections associated with biofilm. No definitive mechanisms of resistance to WLBU2 have been identified. Methodology Here, we used experimental evolution under different levels of mutation supply and whole genome sequencing (WGS) to detect the genetic pathways and probable mechanisms of resistance to this peptide. We propagated populations of wild-type and hypermutator Pseudomonas aeruginosa in the presence of WLBU2 and performed WGS of evolved populations and clones. Results Populations that survived WLBU2 treatment acquired a minimum of two mutations, making the acquisition of resistance more difficult than for most antibiotics, which can be tolerated by mutation of a single target. Major targets of resistance to WLBU2 included the orfN and pmrB genes, previously described to confer resistance to other cationic peptides. More surprisingly, mutations that increase aggregation such as the wsp pathway were also selected despite the ability of WLBU2 to kill cells growing in a biofilm. Conclusions and implications The results show how experimental evolution and WGS can identify genetic targets and actions of new antimicrobial compounds and predict pathways to resistance of new antibiotics in clinical practice.
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Affiliation(s)
- Alfonso Santos-Lopez
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, 15219 USA
- Present address: Department of Microbiology, Hospital Universitario Ramon y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- Present address: Department of Microbial Biology, National Center of Biotechnology (CNB), Madrid, Spain
| | - Melissa J Fritz
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, 15219 USA
| | - Jeffrey B Lombardo
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, 15219 USA
| | - Ansen H P Burr
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, 15219 USA
| | - Victoria A Heinrich
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, 15219 USA
| | - Christopher W Marshall
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, 15219 USA
- Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Present address: Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
| | - Vaughn S Cooper
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, 15219 USA
- Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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Seo S, Disney-McKeethen S, Prabhakar RG, Song X, Mehta HH, Shamoo Y. Identification of Evolutionary Trajectories Associated with Antimicrobial Resistance Using Microfluidics. ACS Infect Dis 2022; 8:242-254. [PMID: 34962128 PMCID: PMC10022597 DOI: 10.1021/acsinfecdis.1c00564] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In vitro experimental evolution of pathogens to antibiotics is commonly used for the identification of clinical biomarkers associated with antibiotic resistance. Microdroplet emulsions allow exquisite control of spatial structure, species complexity, and selection microenvironments for such studies. We investigated the use of monodisperse microdroplets in experimental evolution. Using Escherichia coli adaptation to doxycycline, we examined how changes in environmental conditions such as droplet size, starting lambda value, selection strength, and incubation method affected evolutionary outcomes. We also examined the extent to which emulsions could reveal potentially new evolutionary trajectories and dynamics associated with antimicrobial resistance. Interestingly, we identified both expected and unexpected evolutionary trajectories including large-scale chromosomal rearrangements and amplification that were not observed in suspension culture methods. As microdroplet emulsions are well-suited for automation and provide exceptional control of conditions, they can provide a high-throughput approach for biomarker identification as well as preclinical evaluation of lead compounds.
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Affiliation(s)
- Seokju Seo
- Department of BioSciences, Rice University, Houston, Texas 77005, United States
| | | | | | - Xinhao Song
- Department of BioSciences, Rice University, Houston, Texas 77005, United States
| | - Heer H Mehta
- Department of BioSciences, Rice University, Houston, Texas 77005, United States
| | - Yousif Shamoo
- Department of BioSciences, Rice University, Houston, Texas 77005, United States
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10
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Lewis JA, Morran LT. Advantages of laboratory natural selection in the applied sciences. J Evol Biol 2021; 35:5-22. [PMID: 34826161 DOI: 10.1111/jeb.13964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 11/29/2022]
Abstract
In the past three decades, laboratory natural selection has become a widely used technique in biological research. Most studies which have utilized this technique are in the realm of basic science, often testing hypotheses related to mechanisms of evolutionary change or ecological dynamics. While laboratory natural selection is currently utilized heavily in this setting, there is a significant gap with its usage in applied studies, especially when compared to the other selection experiment methodologies like artificial selection and directed evolution. This is despite avenues of research in the applied sciences which seem well suited to laboratory natural selection. In this review, we place laboratory natural selection in context with other selection experiments, identify the characteristics which make it well suited for particular kinds of applied research and briefly cover key examples of the usefulness of selection experiments within applied science. Finally, we identify three promising areas of inquiry for laboratory natural selection in the applied sciences: bioremediation technology, identifying mechanisms of drug resistance and optimizing biofuel production. Although laboratory natural selection is currently less utilized in applied science when compared to basic research, the method has immense promise in the field moving forward.
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Affiliation(s)
- Jordan A Lewis
- Population Biology, Ecology, and Evolution Graduate Program, Emory University, Atlanta, Georgia, USA
| | - Levi T Morran
- Population Biology, Ecology, and Evolution Graduate Program, Emory University, Atlanta, Georgia, USA.,Department of Biology, Emory University, Atlanta, Georgia, USA
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11
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Daptomycin Resistance in Enterococcus faecium Can Be Delayed by Disruption of the LiaFSR Stress Response Pathway. Antimicrob Agents Chemother 2021; 65:AAC.01317-20. [PMID: 33468468 DOI: 10.1128/aac.01317-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 01/08/2021] [Indexed: 01/01/2023] Open
Abstract
LiaFSR signaling plays a major role in mediating daptomycin (DAP) resistance in enterococci, and the lack of a functional LiaFSR pathway leads to DAP hypersusceptibility. Using in vitro experimental evolution, we evaluated how Enterococcus faecium with a liaR response regulator gene deletion evolved DAP resistance. We found that knocking out LiaFSR signaling significantly delayed the onset of resistance, but resistance could emerge eventually through various alternate mechanisms that were influenced by the environment.
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12
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Ahmed S, Sony SA, Chowdhury MB, Ullah MM, Paul S, Hossain T. Retention of antibiotic activity against resistant bacteria harbouring aminoglycoside-N-acetyltransferase enzyme by adjuvants: a combination of in-silico and in-vitro study. Sci Rep 2020; 10:19381. [PMID: 33168871 PMCID: PMC7653040 DOI: 10.1038/s41598-020-76355-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/27/2020] [Indexed: 01/08/2023] Open
Abstract
Interference with antibiotic activity and its inactivation by bacterial modifying enzymes is a prevailing mode of bacterial resistance to antibiotics. Aminoglycoside antibiotics become inactivated by aminoglycoside-6′-N-acetyltransferase-Ib [AAC(6′)-Ib] of gram-negative bacteria which transfers an acetyl group from acetyl-CoA to the antibiotic. The aim of the study was to disrupt the enzymatic activity of AAC(6′)-Ib by adjuvants and restore aminoglycoside activity as a result. The binding affinities of several vitamins and chemical compounds with AAC(6′)-Ib of Escherichia coli, Klebsiella pneumoniae, and Shigella sonnei were determined by molecular docking method to screen potential adjuvants. Adjuvants having higher binding affinity with target enzymes were further analyzed in-vitro to assess their impact on bacterial growth and bacterial modifying enzyme AAC(6′)-Ib activity. Four compounds—zinc pyrithione (ZnPT), vitamin D, vitamin E and vitamin K-exhibited higher binding affinity to AAC(6′)-Ib than the enzyme’s natural substrate acetyl-CoA. Combination of each of these adjuvants with three aminoglycoside antibiotics—amikacin, gentamicin and kanamycin—were found to significantly increase the antibacterial activity against the selected bacterial species as well as hampering the activity of AAC(6′)-Ib. The selection process of adjuvants and the use of those in combination with aminoglycoside antibiotics promises to be a novel area in overcoming bacterial resistance.
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Affiliation(s)
- Shamim Ahmed
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Shahjalal University of Science and Technology, Sylhet, 3114, Bangladesh.
| | - Sabrina Amita Sony
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Shahjalal University of Science and Technology, Sylhet, 3114, Bangladesh
| | - Md Belal Chowdhury
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Shahjalal University of Science and Technology, Sylhet, 3114, Bangladesh
| | - Md Mahib Ullah
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Shahjalal University of Science and Technology, Sylhet, 3114, Bangladesh
| | - Shatabdi Paul
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Shahjalal University of Science and Technology, Sylhet, 3114, Bangladesh
| | - Tanvir Hossain
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Shahjalal University of Science and Technology, Sylhet, 3114, Bangladesh
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Mehta HH, Shamoo Y. Pathogenic Nocardia: A diverse genus of emerging pathogens or just poorly recognized? PLoS Pathog 2020; 16:e1008280. [PMID: 32134995 PMCID: PMC7058287 DOI: 10.1371/journal.ppat.1008280] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Heer H. Mehta
- Department of BioSciences, Rice University, Houston, Texas, United States of America
- * E-mail:
| | - Yousif Shamoo
- Department of BioSciences, Rice University, Houston, Texas, United States of America
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14
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Tilocca B, Cao A, Migheli Q. Scent of a Killer: Microbial Volatilome and Its Role in the Biological Control of Plant Pathogens. Front Microbiol 2020; 11:41. [PMID: 32117096 PMCID: PMC7018762 DOI: 10.3389/fmicb.2020.00041] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 01/09/2020] [Indexed: 11/29/2022] Open
Abstract
The use of synthetic fungicides represents the most common strategy to control plant pathogens. Excessive and/or long-term distribution of chemicals is responsible for increased levels of environmental pollution, as well as adverse health consequence to humans and animals. These issues are deeply influencing public perception, as reflected by the increasing demand for safer and eco-friendly agricultural commodities and their by-products. A steadily increasing number of research efforts is now devoted to explore the use of safer and innovative approaches to control plant pathogens. The use of microorganisms as biological control agents (BCAs) represents one of the most durable and promising strategies. Among the panoply of microbial mechanisms exerted by BCAs, the production of volatile organic compounds (VOCs) represents an intriguing issue, mostly exploitable in circumstances where a direct contact between the pathogen and its antagonist is not practicable. VOCs are potentially produced by all living microorganisms, and may be active in the biocontrol of phytopathogenic oomycetes, fungi, and bacteria by means of antimicrobial activity and/or other cross-talk interactions. Their biological effects, the reduced residuals in the environment and on agricultural commodities, and the ease of application in different agricultural systems make the use of VOCs a promising and sustainable approach to replace synthetic fungicides in the control of plant pathogens. In this review, we focus on VOCs produced by bacteria and fungi and on their role in the cross-talk existing between the plant pathogens and their host. Biologic systemic effect of the microbial volatile blends on both pathogen and host plant cells is also briefly reviewed.
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Affiliation(s)
- Bruno Tilocca
- Department of Health Sciences, University “Magna Græcia” of Catanzaro, Catanzaro, Italy
- Dipartimento di Agraria and NRD-Nucleo di Ricerca sulla Desertificazione, Università degli Studi di Sassari, Sassari, Italy
| | - Aocheng Cao
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Quirico Migheli
- Dipartimento di Agraria and NRD-Nucleo di Ricerca sulla Desertificazione, Università degli Studi di Sassari, Sassari, Italy
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Environment Shapes the Accessible Daptomycin Resistance Mechanisms in Enterococcus faecium. Antimicrob Agents Chemother 2019; 63:AAC.00790-19. [PMID: 31332078 DOI: 10.1128/aac.00790-19] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 07/16/2019] [Indexed: 02/07/2023] Open
Abstract
Daptomycin binds to bacterial cell membranes and disrupts essential cell envelope processes, leading to cell death. Bacteria respond to daptomycin by altering their cell envelopes to either decrease antibiotic binding to the membrane or by diverting binding away from septal targets. In Enterococcus faecalis, daptomycin resistance is typically coordinated by the three-component cell envelope stress response system, LiaFSR. Here, studying a clinical strain of multidrug-resistant Enterococcus faecium containing alleles associated with activation of the LiaFSR signaling pathway, we found that specific environments selected for different evolutionary trajectories, leading to high-level daptomycin resistance. Planktonic environments favored pathways that increased cell surface charge via yvcRS upregulation of dltABCD and mprF, causing a reduction in daptomycin binding. Alternatively, environments favoring complex structured communities, including biofilms, evolved both diversion and repulsion strategies via divIVA and oatA mutations, respectively. Both environments subsequently converged on cardiolipin synthase (cls) mutations, suggesting the importance of membrane modification across strategies. Our findings indicate that E. faecium can evolve diverse evolutionary trajectories to daptomycin resistance that are shaped by the environment to produce a combination of resistance strategies. The accessibility of multiple and different biochemical pathways simultaneously suggests that the outcome of daptomycin exposure results in a polymorphic population of resistant phenotypes, making E. faecium a recalcitrant nosocomial pathogen.
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16
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Wencewicz TA. Crossroads of Antibiotic Resistance and Biosynthesis. J Mol Biol 2019; 431:3370-3399. [PMID: 31288031 DOI: 10.1016/j.jmb.2019.06.033] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/20/2019] [Accepted: 06/27/2019] [Indexed: 12/14/2022]
Abstract
The biosynthesis of antibiotics and self-protection mechanisms employed by antibiotic producers are an integral part of the growing antibiotic resistance threat. The origins of clinically relevant antibiotic resistance genes found in human pathogens have been traced to ancient microbial producers of antibiotics in natural environments. Widespread and frequent antibiotic use amplifies environmental pools of antibiotic resistance genes and increases the likelihood for the selection of a resistance event in human pathogens. This perspective will provide an overview of the origins of antibiotic resistance to highlight the crossroads of antibiotic biosynthesis and producer self-protection that result in clinically relevant resistance mechanisms. Some case studies of synergistic antibiotic combinations, adjuvants, and hybrid antibiotics will also be presented to show how native antibiotic producers manage the emergence of antibiotic resistance.
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Affiliation(s)
- Timothy A Wencewicz
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA.
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The Essential Role of Hypermutation in Rapid Adaptation to Antibiotic Stress. Antimicrob Agents Chemother 2019; 63:AAC.00744-19. [PMID: 31036684 DOI: 10.1128/aac.00744-19] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 04/19/2019] [Indexed: 12/22/2022] Open
Abstract
A common outcome of antibiotic exposure in patients and in vitro is the evolution of a hypermutator phenotype that enables rapid adaptation by pathogens. While hypermutation is a robust mechanism for rapid adaptation, it requires trade-offs between the adaptive mutations and the more common "hitchhiker" mutations that accumulate from the increased mutation rate. Using quantitative experimental evolution, we examined the role of hypermutation in driving the adaptation of Pseudomonas aeruginosa to colistin. Metagenomic deep sequencing revealed 2,657 mutations at ≥5% frequency in 1,197 genes and 761 mutations in 29 endpoint isolates. By combining genomic information, phylogenetic analyses, and statistical tests, we showed that evolutionary trajectories leading to resistance could be reliably discerned. In addition to known alleles such as pmrB, hypermutation allowed identification of additional adaptive alleles with epistatic relationships. Although hypermutation provided a short-term fitness benefit, it was detrimental to overall fitness. Alarmingly, a small fraction of the colistin-adapted population remained colistin susceptible and escaped hypermutation. In a clinical population, such cells could play a role in reestablishing infection upon withdrawal of colistin. We present here a framework for evaluating the complex evolutionary trajectories of hypermutators that applies to both current and emerging pathogen populations.
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Pathogenic Nocardia cyriacigeorgica and Nocardia nova Evolve To Resist Trimethoprim-Sulfamethoxazole by both Expected and Unexpected Pathways. Antimicrob Agents Chemother 2018; 62:AAC.00364-18. [PMID: 29686152 DOI: 10.1128/aac.00364-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 04/15/2018] [Indexed: 12/12/2022] Open
Abstract
Nocardia spp. are Gram-positive opportunistic pathogens that affect largely immunocompromised patients, leading to serious pulmonary or systemic infections. Combination therapy using the folate biosynthesis pathway inhibitors trimethoprim (TMP) and sulfamethoxazole (SMX) is commonly used as an antimicrobial therapy. Not surprisingly, as antibiotic therapies for nocardiosis can extend for many months, resistance to TMP-SMX has emerged. Using experimental evolution, we surveyed the genetic basis of adaptation to TMP-SMX across 8 strains of Nocardia nova and 2 strains of Nocardia cyriacigeorgica By employing both continuous experimental evolution to provide longitudinal information on the order of changes and characterization of resistant endpoint isolates, we observe changes that are consistent with modifications of two enzymes of the folate biosynthesis pathway: dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) (FolP), with the mutations often being clustered near the active site of the enzymes. While changes to DHFR and DHPS might be expected, we also noted that mutations in a previously undescribed homolog of DHPS (DHPS2 or FolP2) that was annotated as being "nonfunctional" were also sufficient to generate TMP-SMX resistance, which serves as a cautionary tale for the use of automated annotation by investigators and for the future discovery of drugs against this genus. Additionally, folP2 overlapped glucosyl-3-phosphoglycerate synthase. Remarkably, an adaptive frameshift mutation within the overlapping region resulted in a new in-frame fusion to the downstream gene to produce a potentially new bifunctional enzyme. How a single potentially bifunctional DHPS2 enzyme might confer resistance is unclear. However, it highlights the unexpected ways in which adaptive evolution finds novel solutions for selection.
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