1
|
Liu F, Luo Y, Xu T, Lin H, Qiu Y, Li B. Current examining methods and mathematical models of horizontal transfer of antibiotic resistance genes in the environment. Front Microbiol 2024; 15:1371388. [PMID: 38638913 PMCID: PMC11025395 DOI: 10.3389/fmicb.2024.1371388] [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: 01/16/2024] [Accepted: 03/11/2024] [Indexed: 04/20/2024] Open
Abstract
The increasing prevalence of antibiotic resistance genes (ARGs) in the environment has garnered significant attention due to their health risk to human beings. Horizontal gene transfer (HGT) is considered as an important way for ARG dissemination. There are four general routes of HGT, including conjugation, transformation, transduction and vesiduction. Selection of appropriate examining methods is crucial for comprehensively understanding characteristics and mechanisms of different HGT ways. Moreover, combined with the results obtained from different experimental methods, mathematical models could be established and serve as a powerful tool for predicting ARG transfer dynamics and frequencies. However, current reviews of HGT for ARG spread mainly focus on its influencing factors and mechanisms, overlooking the important roles of examining methods and models. This review, therefore, delineated four pathways of HGT, summarized the strengths and limitations of current examining methods, and provided a comprehensive summing-up of mathematical models pertaining to three main HGT ways of conjugation, transformation and transduction. Finally, deficiencies in current studies were discussed, and proposed the future perspectives to better understand and assess the risks of ARG dissemination through HGT.
Collapse
Affiliation(s)
- Fan Liu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, China
| | - Yuqiu Luo
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, China
| | - Tiansi Xu
- School of Environment, Tsinghua University, Beijing, China
| | - Hai Lin
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, China
| | - Yong Qiu
- School of Environment, Tsinghua University, Beijing, China
| | - Bing Li
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, China
| |
Collapse
|
2
|
Risely A, Newbury A, Stalder T, Simmons BI, Top EM, Buckling A, Sanders D. Host- plasmid network structure in wastewater is linked to antimicrobial resistance genes. Nat Commun 2024; 15:555. [PMID: 38228585 PMCID: PMC10791616 DOI: 10.1038/s41467-024-44827-w] [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: 07/19/2023] [Accepted: 01/05/2024] [Indexed: 01/18/2024] Open
Abstract
As mobile genetic elements, plasmids are central for our understanding of antimicrobial resistance spread in microbial communities. Plasmids can have varying fitness effects on their host bacteria, which will markedly impact their role as antimicrobial resistance vectors. Using a plasmid population model, we first show that beneficial plasmids interact with a higher number of hosts than costly plasmids when embedded in a community with multiple hosts and plasmids. We then analyse the network of a natural host-plasmid wastewater community from a Hi-C metagenomics dataset. As predicted by the model, we find that antimicrobial resistance encoding plasmids, which are likely to have positive fitness effects on their hosts in wastewater, interact with more bacterial taxa than non-antimicrobial resistance plasmids and are disproportionally important for connecting the entire network compared to non- antimicrobial resistance plasmids. This highlights the role of antimicrobials in restructuring host-plasmid networks by increasing the benefits of antimicrobial resistance carrying plasmids, which can have consequences for the spread of antimicrobial resistance genes through microbial networks. Furthermore, that antimicrobial resistance encoding plasmids are associated with a broader range of hosts implies that they will be more robust to turnover of bacterial strains.
Collapse
Affiliation(s)
- Alice Risely
- School of Science, Engineering, and Environment, University of Salford, Salford, M5 4WT, UK
| | - Arthur Newbury
- Centre for Ecology & Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, Cornwall, TR10 9FE, UK
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9FE, UK
| | - Thibault Stalder
- Department of Biological Sciences, University of Idaho, Moscow, ID, USA
- Institute for Interdisciplinary Data Sciences, University of Idaho, Moscow, ID, USA
| | - Benno I Simmons
- Centre for Ecology & Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, Cornwall, TR10 9FE, UK
| | - Eva M Top
- Department of Biological Sciences, University of Idaho, Moscow, ID, USA
- Institute for Interdisciplinary Data Sciences, University of Idaho, Moscow, ID, USA
| | - Angus Buckling
- Centre for Ecology & Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, Cornwall, TR10 9FE, UK
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9FE, UK
| | - Dirk Sanders
- Centre for Ecology & Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, Cornwall, TR10 9FE, UK.
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9FE, UK.
| |
Collapse
|
3
|
Li S, Li X, Chang H, Zhong N, Ren N, Ho SH. Comprehensive insights into antibiotic resistance gene migration in microalgal-bacterial consortia: Mechanisms, factors, and perspectives. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 901:166029. [PMID: 37541493 DOI: 10.1016/j.scitotenv.2023.166029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 08/01/2023] [Accepted: 08/01/2023] [Indexed: 08/06/2023]
Abstract
With the overuse of antibiotics, antibiotic resistance gene (ARG) prevalence is gradually increasing. ARGs are considered emerging contaminants that are broadly concentrated and dispersed in most aquatic environments. Recently, interest in microalgal-bacterial biotreatment of antibiotics has increased, as eukaryotes are not the primary target of antimicrobial drugs. Moreover, research has shown that microalgal-bacterial consortia can minimize the transmission of antibiotic resistance in the environment. Unfortunately, reviews surrounding the ARG migration mechanism in microalgal-bacterial consortia have not yet been performed. This review briefly introduces the migration of ARGs in aquatic environments. Additionally, an in-depth summary of horizontal gene transfer (HGT) between cyanobacteria and bacteria and from bacteria to eukaryotic microalgae is presented. Factors influencing gene transfer in microalgal-bacterial consortia are discussed systematically, including bacteriophage abundance, environmental conditions (temperature, pH, and nutrient availability), and other selective pressure conditions including nanomaterials, heavy metals, and pharmaceuticals and personal care products. Furthermore, considering that quorum sensing could be involved in DNA transformation by affecting secondary metabolites, current knowledge surrounding quorum sensing regulation of HGT of ARGs is summarized. In summary, this review gives valuable information to promote the development of practical and innovative techniques for ARG removal by microalgal-bacterial consortia.
Collapse
Affiliation(s)
- Shengnan Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province 150090, China
| | - Xue Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province 150090, China
| | - Haixing Chang
- College of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing 400054, China
| | - Nianbing Zhong
- Liangjiang International College, Chongqing University of Technology, Chongqing 401135, China
| | - Nanqi Ren
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province 150090, China
| | - Shih-Hsin Ho
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province 150090, China.
| |
Collapse
|
4
|
Arbé-Carton K, Rey-Sogo A, Santos-Fernández N, Altube O, Garbisu C, Arana L, Alkorta I. Development of a high-throughput platform to measure plasmid transfer frequency. Front Cell Infect Microbiol 2023; 13:1269732. [PMID: 37886666 PMCID: PMC10598849 DOI: 10.3389/fcimb.2023.1269732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 09/25/2023] [Indexed: 10/28/2023] Open
Abstract
Antibiotic resistance represents one of the greatest threats to global health. The spread of antibiotic resistance genes among bacteria occurs mostly through horizontal gene transfer via conjugation mediated by plasmids. This process implies a direct contact between a donor and a recipient bacterium which acquires the antibiotic resistance genes encoded by the plasmid and, concomitantly, the capacity to transfer the acquired plasmid to a new recipient. Classical assays for the measurement of plasmid transfer frequency (i.e., conjugation frequency) are often characterized by a high variability and, hence, they require many biological and technical replicates to reduce such variability and the accompanying uncertainty. In addition, classical conjugation assays are commonly tedious and time-consuming because they typically involve counting colonies on a large number of plates for the quantification of donors, recipients, and transconjugants (i.e., the bacteria that have received the genetic material by conjugation). Due to the magnitude of the antibiotic resistance problem, it is critical to develop reliable and rapid methods for the quantification of plasmid transfer frequency that allow the simultaneous analysis of many samples. Here, we present the development of a high-throughput, reliable, quick, easy, and cost-effective method to simultaneously accomplish and measure multiple conjugation events in 96-well plates, in which the quantification of donors, recipients, and transconjugants is estimated from the time required to reach a specific threshold value (OD600 value) in the bacterial growth curves. Our method successfully discriminates different plasmid transfer frequencies, yielding results that are equivalent to those obtained by a classical conjugation assay.
Collapse
Affiliation(s)
- Kepa Arbé-Carton
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Ana Rey-Sogo
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Nagore Santos-Fernández
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Oihane Altube
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Carlos Garbisu
- Department of Conservation of Natural Resources, NEIKER-Basque Institute for Agricultural Research and Development, Basque Research and Technology Alliance (BRTA), Derio, Spain
| | - Lide Arana
- Department of Applied Chemistry, University of the Basque Country (UPV/EHU), Donostia, Spain
| | - Itziar Alkorta
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| |
Collapse
|
5
|
Yang J, Wu R, Xia Q, Yu J, Yi LX, Huang Y, Deng M, He WY, Bai Y, Lv L, Burrus V, Wang C, Liu JH. The evolution of infectious transmission promotes the persistence of mcr-1 plasmids. mBio 2023; 14:e0044223. [PMID: 37314200 PMCID: PMC10470590 DOI: 10.1128/mbio.00442-23] [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: 02/22/2023] [Accepted: 04/25/2023] [Indexed: 06/15/2023] Open
Abstract
Conjugative plasmids play a vital role in bacterial evolution and promote the spread of antibiotic resistance. They usually cause fitness costs that diminish the growth rates of the host bacteria. Compensatory mutations are known as an effective evolutionary solution to reduce the fitness cost and improve plasmid persistence. However, whether the plasmid transmission by conjugation is sufficient to improve plasmid persistence is debated since it is an inherently costly process. Here, we experimentally evolved an unstable and costly mcr-1 plasmid pHNSHP24 under laboratory conditions and assessed the effects of plasmid cost and transmission on the plasmid maintenance by the plasmid population dynamics model and a plasmid invasion experiment designed to measure the plasmid's ability to invade a plasmid-free bacterial population. The persistence of pHNSHP24 improved after 36 days evolution due to the plasmid-borne mutation A51G in the 5'UTR of gene traJ. This mutation largely increased the infectious transmission of the evolved plasmid, presumably by impairing the inhibitory effect of FinP on the expression of traJ. We showed that increased conjugation rate of the evolved plasmid could compensate for the plasmid loss. Furthermore, we determined that the evolved high transmissibility had little effect on the mcr-1-deficient ancestral plasmid, implying that high conjugation transfer is vital for maintaining the mcr-1-bearing plasmid. Altogether, our findings emphasized that, besides compensatory evolution that reduces fitness costs, the evolution of infectious transmission can improve the persistence of antibiotic-resistant plasmids, indicating that inhibition of the conjugation process could be useful to combat the spread of antibiotic-resistant plasmids. IMPORTANCE Conjugative plasmids play a key role in the spread of antibiotic resistance, and they are well-adapted to the host bacteria. However, the evolutionary adaptation of plasmid-bacteria associations is not well understood. In this study, we experimentally evolved an unstable colistin resistance (mcr-1) plasmid under laboratory conditions and found that increased conjugation rate was crucial for the persistence of this plasmid. Interestingly, the evolved conjugation was caused by a single-base mutation, which could rescue the unstable plasmid from extinction in bacterial populations. Our findings imply that inhibition of the conjugation process could be necessary for combating the persistence of antibiotic-resistance plasmids.
Collapse
Affiliation(s)
- Jun Yang
- College of Veterinary Medicine National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Renjie Wu
- College of Veterinary Medicine National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs South China Agricultural University, Guangzhou, China
| | - Qiang Xia
- College of Mathematics and Informatics, South China Agricultural University, Guangzhou, China
| | - Jingjing Yu
- College of Veterinary Medicine National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs South China Agricultural University, Guangzhou, China
| | - Ling-Xian Yi
- College of Veterinary Medicine National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs South China Agricultural University, Guangzhou, China
| | - Ying Huang
- College of Veterinary Medicine National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs South China Agricultural University, Guangzhou, China
| | - Meixin Deng
- College of Veterinary Medicine National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs South China Agricultural University, Guangzhou, China
| | - Wan-Yun He
- College of Veterinary Medicine National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs South China Agricultural University, Guangzhou, China
| | - Yuman Bai
- College of Veterinary Medicine National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs South China Agricultural University, Guangzhou, China
| | - Luchao Lv
- College of Veterinary Medicine National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs South China Agricultural University, Guangzhou, China
| | - Vincent Burrus
- Département de biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Chengzhen Wang
- College of Veterinary Medicine National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs South China Agricultural University, Guangzhou, China
| | - Jian-Hua Liu
- College of Veterinary Medicine National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| |
Collapse
|
6
|
Dewan I, Uecker H. A mathematician's guide to plasmids: an introduction to plasmid biology for modellers. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001362. [PMID: 37505810 PMCID: PMC10433428 DOI: 10.1099/mic.0.001362] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Accepted: 07/03/2023] [Indexed: 07/29/2023]
Abstract
Plasmids, extrachromosomal DNA molecules commonly found in bacterial and archaeal cells, play an important role in bacterial genetics and evolution. Our understanding of plasmid biology has been furthered greatly by the development of mathematical models, and there are many questions about plasmids that models would be useful in answering. In this review, we present an introductory, yet comprehensive, overview of the biology of plasmids suitable for modellers unfamiliar with plasmids who want to get up to speed and to begin working on plasmid-related models. In addition to reviewing the diversity of plasmids and the genes they carry, their key physiological functions, and interactions between plasmid and host, we also highlight selected plasmid topics that may be of particular interest to modellers and areas where there is a particular need for theoretical development. The world of plasmids holds a great variety of subjects that will interest mathematical biologists, and introducing new modellers to the subject will help to expand the existing body of plasmid theory.
Collapse
Affiliation(s)
- Ian Dewan
- Research Group Stochastic Evolutionary Dynamics, Department of Theoretical Biology, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Hildegard Uecker
- Research Group Stochastic Evolutionary Dynamics, Department of Theoretical Biology, Max Planck Institute for Evolutionary Biology, Plön, Germany
| |
Collapse
|
7
|
Zhou S, Yang Z, Zhang S, Gao Y, Tang Z, Duan Y, Zhang Y, Wang Y. Metagenomic insights into the distribution, mobility, and hosts of extracellular antibiotic resistance genes in activated sludge under starvation stress. WATER RESEARCH 2023; 236:119953. [PMID: 37060877 DOI: 10.1016/j.watres.2023.119953] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 04/06/2023] [Accepted: 04/07/2023] [Indexed: 06/19/2023]
Abstract
Extracellular antibiotic resistance genes (eARGs) are important emerging environmental pollutants in wastewater treatment plants (WWTPs). Nutritional substrate deficiency (i.e., starvation) frequently occurs in WWTPs owing to annual maintenance, water quality fluctuation, and sludge storage; and it can greatly alter the antibiotic resistance and extracellular DNA content of bacteria. However, the fate and corresponding transmission risk of eARGs in activated sludge under starvation stress remain largely unknown. Herein, we used metagenomic sequencing to explore the effects of starvation scenarios (carbon, nitrogen, and/or phosphorus deficiency) and environmental conditions (alternating anaerobic-aerobic, anaerobic, anoxic, and aerobic) on the distribution, mobility, and hosts of eARGs in activated sludge. The results showed that 30 days of starvation reduced the absolute abundances of eARGs by 40.9%-88.2%, but high-risk dual and multidrug resistance genes persisted. Starvation, particularly the simultaneous lack of carbon, nitrogen, and phosphorus under aerobic conditions, effectively alleviated eARGs by reducing the abundance of extracellular mobile genetic elements (eMGEs). Starvation also altered the profile of bacterial hosts of eARGs and the bacterial community composition, the latter of which had an indirect positive effect on eARGs via changing eMGEs. Our findings shed light on the response patterns and mechanisms of eARGs in activated sludge under starvation conditions and highlight starvation as a potential strategy to mitigate the risk of previously neglected eARGs in WWTPs.
Collapse
Affiliation(s)
- Shuai Zhou
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, China; Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, School of Civil Engineering, University of South China, Hengyang 421001, China
| | - Zhengqing Yang
- Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, School of Civil Engineering, University of South China, Hengyang 421001, China
| | - Siqi Zhang
- Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, School of Civil Engineering, University of South China, Hengyang 421001, China
| | - Yuanyuan Gao
- Hunan Province Key Laboratory of Rare Metal Minerals Exploitation and Geological Disposal of Wastes, University of South China, Hengyang 421001, China
| | - Zhenping Tang
- Hunan Province Key Laboratory of Rare Metal Minerals Exploitation and Geological Disposal of Wastes, University of South China, Hengyang 421001, China
| | - Yi Duan
- Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, School of Civil Engineering, University of South China, Hengyang 421001, China
| | - Yalei Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, China
| | - Yayi Wang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, China.
| |
Collapse
|
8
|
Rebelo JS, Domingues CPF, Nogueira T, Dionisio F. Plasmids Increase the Competitive Ability of Plasmid-Bearing Cells Even When Transconjugants Are Poor Donors, as Shown by Computer Simulations. Microorganisms 2023; 11:1238. [PMID: 37317212 DOI: 10.3390/microorganisms11051238] [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: 04/03/2023] [Revised: 04/26/2023] [Accepted: 05/03/2023] [Indexed: 06/16/2023] Open
Abstract
Bacterial cells often suffer a fitness cost after conjugative plasmids' entry because these cells replicate slower than plasmid-free cells. Compensatory mutations may appear after tens of or a few hundred generations, reducing or eliminating this cost. A previous work based on a mathematical model and computer simulations has shown that plasmid-bearing cells already adapted to the plasmid may gain a fitness advantage when plasmids transfer into neighboring plasmid-free cells because these cells are still unadapted to the plasmid. These slow-growing transconjugants use fewer resources, which can benefit donor cells. However, opportunities for compensatory mutations in transconjugants increase if these cells become numerous (through replication or conjugation). Moreover, transconjugants also gain an advantage when transferring the plasmid, but the original donors may be too distant from conjugation events to gain an advantage. To understand which consequence prevails, we performed further computer simulations allowing versus banning transfer from transconjugants. The advantage to donors is higher if transconjugants do not transfer plasmids, mainly when donors are rare and when the plasmid transfer rate (from donors) is high. These results show that conjugative plasmids are efficient biological weapons even if the transconjugant cells are poor plasmid donors. After some time, conjugative plasmids gain other host-benefit genes, such as virulence and drug-resistance.
Collapse
Affiliation(s)
- João S Rebelo
- cE3c-Centre for Ecology, Evolution and Environmental Changes & CHANGE, Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Célia P F Domingues
- cE3c-Centre for Ecology, Evolution and Environmental Changes & CHANGE, Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
- INIAV-National Institute for Agrarian and Veterinary Research, 2780-157 Oeiras, Portugal
| | - Teresa Nogueira
- cE3c-Centre for Ecology, Evolution and Environmental Changes & CHANGE, Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
- INIAV-National Institute for Agrarian and Veterinary Research, 2780-157 Oeiras, Portugal
| | - Francisco Dionisio
- cE3c-Centre for Ecology, Evolution and Environmental Changes & CHANGE, Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| |
Collapse
|
9
|
Rebelo JS, Domingues CPF, Dionisio F. Plasmid Costs Explain Plasmid Maintenance, Irrespective of the Nature of Compensatory Mutations. Antibiotics (Basel) 2023; 12:841. [PMID: 37237742 PMCID: PMC10215365 DOI: 10.3390/antibiotics12050841] [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: 04/08/2023] [Revised: 04/27/2023] [Accepted: 04/28/2023] [Indexed: 05/28/2023] Open
Abstract
Conjugative plasmids often carry virulence and antibiotic-resistant genes. Therefore, understanding the behavior of these extra-chromosomal DNA elements gives insights into their spread. Bacteria frequently replicate slower after plasmids' entry, an observation inconsistent with the plasmids' ubiquity in nature. Several hypotheses explain the maintenance of plasmids among bacterial communities. However, the numerous combinations of bacterial species and strains, plasmids, and environments claim a robust elucidatory mechanism of plasmid maintenance. Previous works have shown that donor cells already adapted to the plasmid may use the plasmid as a 'weapon' to compete with non-adapted plasmid-free cells. Computer simulations corroborated this hypothesis with a wide range of parameters. Here we show that donor cells benefit from harboring conjugative plasmids even if compensatory mutations in transconjugant cells occur in the plasmid, not on chromosomes. The advantage's leading causes are as follows: mutations take time to appear, many plasmids remain costly, and re-transfer of mutated plasmids usually occurs in sites distant to the original donors, implying little competition between these cells. Research in previous decades cautioned against uncritical acceptance of the hypothesis that resistance cost helps to preserve antibiotics' effectiveness. This work gives a new twist to this conclusion by showing that costs help antibiotic-resistant bacteria to compete with plasmid-free cells even if compensatory mutations appear in plasmids.
Collapse
Affiliation(s)
- João S. Rebelo
- cE3c—Centre for Ecology, Evolution and Environmental Changes & CHANGE, Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal; (J.S.R.); (C.P.F.D.)
| | - Célia P. F. Domingues
- cE3c—Centre for Ecology, Evolution and Environmental Changes & CHANGE, Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal; (J.S.R.); (C.P.F.D.)
- INIAV—National Institute for Agrarian and Veterinary Research, 2780-157 Oeiras, Portugal
| | - Francisco Dionisio
- cE3c—Centre for Ecology, Evolution and Environmental Changes & CHANGE, Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal; (J.S.R.); (C.P.F.D.)
| |
Collapse
|
10
|
Soil Component: A Potential Factor Affecting the Occurrence and Spread of Antibiotic Resistance Genes. Antibiotics (Basel) 2023; 12:antibiotics12020333. [PMID: 36830244 PMCID: PMC9952537 DOI: 10.3390/antibiotics12020333] [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: 12/30/2022] [Revised: 01/21/2023] [Accepted: 02/01/2023] [Indexed: 02/09/2023] Open
Abstract
In recent years, antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) in soil have become research hotspots in the fields of public health and environmental ecosystems, but the effects of soil types and soil components on the occurrence and spread of ARGs still lack systematic sorting and in-depth research. Firstly, investigational information about ARB and ARGs contamination of soil was described. Then, existing laboratory studies about the influence of the soil component on ARGs were summarized in the following aspects: the influence of soil types on the occurrence of ARGs during natural or human activities and the control of exogenously added soil components on ARGs from the macro perspectives, the effects of soil components on the HGT of ARGs in a pure bacterial system from the micro perspectives. Following that, the similarities in pathways by which soil components affect HGT were identified, and the potential mechanisms were discussed from the perspectives of intracellular responses, plasmid activity, quorum sensing, etc. In the future, related research on multi-component systems, multi-omics methods, and microbial communities should be carried out in order to further our understanding of the occurrence and spread of ARGs in soil.
Collapse
|
11
|
Neethu CS, Saravanakumar C, Purvaja R, Robin RS, Ramesh R. Arsenic resistance and horizontal gene transfer are associated with carbon and nitrogen enrichment in bacteria. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 311:119937. [PMID: 35977641 DOI: 10.1016/j.envpol.2022.119937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/14/2022] [Accepted: 08/07/2022] [Indexed: 06/15/2023]
Abstract
Coastal waters are confluences receiving large amounts of point and non-point sources of pollution. An attempt was made to explore microbial community interactions in response to carbon, nitrogen and metal pollution. Additionally, experiments were designed to analyze the influence of these factors on horizontal gene transfer (HGT). Shift in bacterial diversity dynamics by arsenic stress and nutrient addition in coastal waters was explored by metagenomics of microcosm setups. Phylogenetic analysis revealed equal distribution of Gammaproteobacteria (29%) and Betaproteobacteria (28%) in control microcosm. This proportional diversity from control switched to unique distribution of Gammaproteobacteria (44.5%)> Flavobacteria (17.7%)> Bacteriodia (11.92%)> Betaproteobacteria (11.52%) in microcosm supplemented with carbon, nitrogen and metal (C + N + M). Among metal-stressed systems, alpha diversity analysis indicated highest diversity of genera in C + N + M followed by N + M > C+M> metal alone. Arsenic and ampicillin sensitive E. coli XL1 blue and environmental strains (Vibrio tubiashii W85 and E. coli W101) were tested for efficiency of uptake of plasmid (P) pUCminusMCS (arsBRampR) under varying stress conditions. Transformation experiments revealed that combined effect of carbon, nitrogen and metal on horizontal gene transfer (HGT) was significantly higher (p < 0.01) than individual factors. The effect of carbon on HGT was proved to be superior to nitrogen under metal stressed conditions. Presence of arsenic in experimental setups (P + M, P + N + M and P + C + M) enhanced the HGT compared to non-metal counterparts supplemented with carbon or nitrogen. Arsenic resistant bacterial isolates (n = 200) were tested for the ability to utilize various carbon and nitrogen substrates and distinct positive correlation (p < 0.001) was found between arsenic resistance and utilization of urea and nitrate. However, evident positive correlation was not found between carbon sources and arsenic resistance. Our findings suggest that carbon and nitrogen pollution in aquatic habitats under arsenic stress determine the microbial community dynamics and critically influence uptake of genetic material from the surrounding environment.
Collapse
Affiliation(s)
- C S Neethu
- National Centre for Sustainable Coastal Management (NCSCM), Ministry of Environment, Forest and Climate Change (MoEFCC), Chennai 600025, India
| | - C Saravanakumar
- National Centre for Sustainable Coastal Management (NCSCM), Ministry of Environment, Forest and Climate Change (MoEFCC), Chennai 600025, India
| | - R Purvaja
- National Centre for Sustainable Coastal Management (NCSCM), Ministry of Environment, Forest and Climate Change (MoEFCC), Chennai 600025, India
| | - R S Robin
- National Centre for Sustainable Coastal Management (NCSCM), Ministry of Environment, Forest and Climate Change (MoEFCC), Chennai 600025, India
| | - R Ramesh
- National Centre for Sustainable Coastal Management (NCSCM), Ministry of Environment, Forest and Climate Change (MoEFCC), Chennai 600025, India.
| |
Collapse
|
12
|
Orevi T, Sørensen SJ, Kashtan N. Droplet size and surface hydrophobicity enhance bacterial plasmid transfer rates in microscopic surface wetness. ISME COMMUNICATIONS 2022; 2:72. [PMID: 37938682 PMCID: PMC9723546 DOI: 10.1038/s43705-022-00159-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 07/25/2022] [Accepted: 08/02/2022] [Indexed: 11/09/2023]
Abstract
Conjugal plasmids constitute a major engine for horizontal gene transfer in bacteria, and are key drivers of the spread of antibiotic resistance, virulence, and metabolic functions. Bacteria in terrestrial habitats often inhabit surfaces that are not constantly water-saturated, where microscopic surface wetness (MSW), comprised of thin liquid films and microdroplets, permanently or intermittently occurs. How physical properties of microdroplets, and of the surfaces they reside on, affect plasmid transfer rates is not well understood. Here, building on microscopy-based microdroplet experiments, we examined the relation between droplet properties (size and spread) and plasmid transfer rates at single-cell and individual droplet resolution, using Pseudomonas putida as a model species. We show that transfer rates increase with droplet size, due to higher densities of cells on the surface in larger droplets, resulting from lower ratio between the area of the liquid-solid interface and droplet volumes. We further show that surface hydrophobicity promotes transfer rates via the same mechanism. Our results provide new insights into how physical properties of surfaces and MSW affect plasmid transfer rates, and more generally, microbial interactions mediated by cell-to-cell contact, with important implications for our understanding of the ecology and evolution of bacteria in unsaturated environments.
Collapse
Affiliation(s)
- Tomer Orevi
- Department of Plant Pathology and Microbiology, Institute of Environmental Sciences, Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University, Rehovot, 76100, Israel
| | - Søren J Sørensen
- Department of Biology, University of Copenhagen, DK 2100, Copenhagen, Denmark
| | - Nadav Kashtan
- Department of Plant Pathology and Microbiology, Institute of Environmental Sciences, Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University, Rehovot, 76100, Israel.
| |
Collapse
|
13
|
Gibert M, Jiménez CJ, Comas J, Zechner EL, Madrid C, Balsalobre C. In Situ Monitoring and Quantitative Determination of R27 Plasmid Conjugation. LIFE (BASEL, SWITZERLAND) 2022; 12:life12081212. [PMID: 36013391 PMCID: PMC9410318 DOI: 10.3390/life12081212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/06/2022] [Accepted: 08/07/2022] [Indexed: 11/16/2022]
Abstract
Horizontal gene transfer (HGT) by plasmid conjugation is a major driving force in the spread of antibiotic resistance among Enterobacteriaceae. Most of the conjugation studies are based on calculation of conjugation ratios (number of transconjugants/number of donors) after viable counting of transconjugant and donor cells. The development of robust, fast and reliable techniques for in situ monitoring and quantification of conjugation ratios might accelerate progress in understanding the impact of this cellular process in the HGT. The IncHI1 plasmids, involved in multiresistance phenotypes of relevant pathogens such as Salmonella and E. coli, are distinguished by the thermosensitivity of their conjugative transfer. Conjugation mediated by IncHI1 plasmids is more efficient at temperatures lower than 30 °C, suggesting that the transfer process takes place during the environmental transit of the bacteria. In this report, we described a methodology to monitor in situ the conjugation process during agar surface matings of the IncHI1 plasmid R27 and its derepressed derivative drR27 at different temperatures. A three-color-labeling strategy was used to visualize the spatial distribution of transconjugants within the heterogeneous environment by epifluorescence and confocal microscopy. Moreover, the fluorescent labelling was also used to quantify conjugation frequencies in liquid media by flow cytometry.
Collapse
Affiliation(s)
- Marta Gibert
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Avda, Diagonal 643, 08028 Barcelona, Spain
| | - Carlos J. Jiménez
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Avda, Diagonal 643, 08028 Barcelona, Spain
| | - Jaume Comas
- Laboratori de Citometria/Genòmica CCiT, Parc Científic de Barcelona, Baldiri Reixac 10, 08024 Barcelona, Spain
| | - Ellen L. Zechner
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, A-8010 Graz, Austria
| | - Cristina Madrid
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Avda, Diagonal 643, 08028 Barcelona, Spain
- Correspondence: (C.M.); (C.B.); Tel.: +34-934-039-382 (C.M.); +34-934-034-622 (C.B.)
| | - Carlos Balsalobre
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Avda, Diagonal 643, 08028 Barcelona, Spain
- Correspondence: (C.M.); (C.B.); Tel.: +34-934-039-382 (C.M.); +34-934-034-622 (C.B.)
| |
Collapse
|
14
|
Sun R, Yu P, Zuo P, Alvarez PJ. Bacterial Concentrations and Water Turbulence Influence the Importance of Conjugation Versus Phage-Mediated Antibiotic Resistance Gene Transfer in Suspended Growth Systems. ACS ENVIRONMENTAL AU 2022; 2:156-165. [PMID: 37101581 PMCID: PMC10114721 DOI: 10.1021/acsenvironau.1c00027] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Despite the abundance of phage-borne antibiotic resistance genes (ARGs) in the environment, the frequency of ARG propagation via phage-mediated transduction (relative to via conjugation) is poorly understood. We investigated the influence of bacterial concentration and water turbulence level [quantified as Reynold's number (Re)] in suspended growth systems on the frequency of ARG transfer by two mechanisms: delivery by a lysogenic phage (phage λ carrying gentamycin-resistance gene, genR) and conjugation mediated by the self-transmissible plasmid RP4. Using Escherichia coli (E. coli) as the recipient, phage delivery had a comparable frequency (1.2 ± 0.9 × 10-6) to that of conjugation (1.1 ± 0.9 × 10-6) in suspensions with low cell concentration (104 CFU/mL) and moderate turbulence (Re = 5 × 104). Turbulence affected cell (or phage)-to-cell contact rates and detachment (due to shear force), and thus, it affected the relative importance of conjugation versus phage delivery. At 107 CFU/mL, no significant difference was observed between the frequencies of ARG transfer by the two mechanisms under quiescent water conditions (2.8 ± 0.3 × 10-5 for conjugation vs 2.2 ± 0.5 × 10-5 for phage delivery, p = 0.19) or when Re reached 5 × 105 (3.4 ± 1.5 × 10-5 for conjugation vs 2.9 ± 1.0 × 10-5 for phage delivery, p = 0.52). Transcriptomic analysis of genes related to conjugation and phage delivery and simulation of cell (or phage)-to-cell collisions at different Re values corroborate that the importance of phage delivery relative to conjugation increases under either quiescent or turbulent conditions. This finding challenges the prevailing view that conjugation is the dominant ARG transfer mechanism and underscores the need to consider and mitigate potential ARG dissemination via transduction.
Collapse
Affiliation(s)
- Ruonan Sun
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
| | - Pingfeng Yu
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
| | - Pengxiao Zuo
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
| | - Pedro J.J. Alvarez
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
| |
Collapse
|
15
|
Genome-Wide Association Study Reveals Host Factors Affecting Conjugation in Escherichia coli. Microorganisms 2022; 10:microorganisms10030608. [PMID: 35336183 PMCID: PMC8954029 DOI: 10.3390/microorganisms10030608] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/08/2022] [Accepted: 03/10/2022] [Indexed: 02/04/2023] Open
Abstract
The emergence and dissemination of antibiotic resistance threaten the treatment of common bacterial infections. Resistance genes are often encoded on conjugative elements, which can be horizontally transferred to diverse bacteria. In order to delay conjugative transfer of resistance genes, more information is needed on the genetic determinants promoting conjugation. Here, we focus on which bacterial host factors in the donor assist transfer of conjugative plasmids. We introduced the broad-host-range plasmid pKJK10 into a diverse collection of 113 Escherichia coli strains and measured by flow cytometry how effectively each strain transfers its plasmid to a fixed E. coli recipient. Differences in conjugation efficiency of up to 2.7 and 3.8 orders of magnitude were observed after mating for 24 h and 48 h, respectively. These differences were linked to the underlying donor strain genetic variants in genome-wide association studies, thereby identifying candidate genes involved in conjugation. We confirmed the role of fliF, fliK, kefB and ucpA in the donor ability of conjugative elements by validating defects in the conjugation efficiency of the corresponding lab strain single-gene deletion mutants. Based on the known cellular functions of these genes, we suggest that the motility and the energy supply, the intracellular pH or salinity of the donor affect the efficiency of plasmid transfer. Overall, this work advances the search for targets for the development of conjugation inhibitors, which can be administered alongside antibiotics to more effectively treat bacterial infections.
Collapse
|
16
|
Domingues CPF, Rebelo JS, Monteiro F, Nogueira T, Dionisio F. Harmful behaviour through plasmid transfer: a successful evolutionary strategy of bacteria harbouring conjugative plasmids. Philos Trans R Soc Lond B Biol Sci 2022; 377:20200473. [PMID: 34839709 PMCID: PMC8628071 DOI: 10.1098/rstb.2020.0473] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Conjugative plasmids are extrachromosomal mobile genetic elements pervasive among bacteria. Plasmids' acquisition often lowers cells' growth rate, so their ubiquity has been a matter of debate. Chromosomes occasionally mutate, rendering plasmids cost-free. However, these compensatory mutations typically take hundreds of generations to appear after plasmid arrival. By then, it could be too late to compete with fast-growing plasmid-free cells successfully. Moreover, arriving plasmids would have to wait hundreds of generations for compensatory mutations to appear in the chromosome of their new host. We hypothesize that plasmid-donor cells may use the plasmid as a 'weapon' to compete with plasmid-free cells, particularly in structured environments. Cells already adapted to plasmids may increase their inclusive fitness through plasmid transfer to impose a cost to nearby plasmid-free cells and increase the replication opportunities of nearby relatives. A mathematical model suggests conditions under which the proposed hypothesis works, and computer simulations tested the long-term plasmid maintenance. Our hypothesis explains the maintenance of conjugative plasmids not coding for beneficial genes. This article is part of the theme issue 'The secret lives of microbial mobile genetic elements'.
Collapse
Affiliation(s)
- Célia P. F. Domingues
- Evolutionary Ecology of Microorganisms Group, cE3c – Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal,INIAV - Instituto Nacional de Investigação Agrária e Veterinária, I.P., Oeiras and Vairão, Portugal
| | - João S. Rebelo
- Evolutionary Ecology of Microorganisms Group, cE3c – Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - Francisca Monteiro
- Evolutionary Ecology of Microorganisms Group, cE3c – Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - Teresa Nogueira
- Evolutionary Ecology of Microorganisms Group, cE3c – Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal,INIAV - Instituto Nacional de Investigação Agrária e Veterinária, I.P., Oeiras and Vairão, Portugal
| | - Francisco Dionisio
- Evolutionary Ecology of Microorganisms Group, cE3c – Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| |
Collapse
|
17
|
Wen X, Xu J, Xiang G, Cao Z, Yan Q, Mi J, Ma B, Zou Y, Zhang N, Liao X, Wang Y, Wu Y. Multiple driving factors contribute to the variations of typical antibiotic resistance genes in different parts of soil-lettuce system. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 225:112815. [PMID: 34562788 DOI: 10.1016/j.ecoenv.2021.112815] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/03/2021] [Accepted: 09/19/2021] [Indexed: 06/13/2023]
Abstract
The application of manure compost may cause the transmission of antibiotic resistance genes (ARGs) in agroecological environment, which poses a global threat to public health. However, the driving factors for the transmission of ARGs from animal manure to agroecological systems remains poorly understood. Here, we explored the spatiotemporal variation in ARG abundance and bacterial community composition as well as relative driving factors in a soil-lettuce system amended with swine manure compost. The results showed that ARGs abundance had different variation trends in soil, lettuce phylloplane and endophyere after the application of swine manure compost. The temporal variations of total ARGs abundance had no significant different in soil and lettuce phylloplane, while lettuce endosphere enriched half of ARGs to the highest level at harvest. There was a significant linear correlation between ARGs and integrase genes (IGs). In contrast to the ARGs variation trend, the alpha diversity of soil and phylloplane bacteria showed increasing trends over planting time, and endosphere bacteria remained stable. Correlation analysis showed no identical ARG-related genera in the three parts, but the shared Proteobacteria, Pseudomonas, Halomonas and Chelativorans, from manure compost dominated ARG profile in the soil-lettuce system. Moreover, redundancy analysis and structural equation modelling showed the variations of ARGs may have resulted from the combination of multiple driving factors in soil-lettuce system. ARGs in soil were more affected by the IGs, antibiotic and heavy metals, and bacterial community structure and IGs were the major influencing factors of ARG profiles in the lettuce. The study provided insight into the multiple driving factors contribute to the variations of typical ARGs in different parts of soil-lettuce system, which was conducive to the risk assessment of ARGs in agroecosystem and the development of effective prevention and control measures for ARGs spread in the environment.
Collapse
Affiliation(s)
- Xin Wen
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Jiaojiao Xu
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Guangfeng Xiang
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Zhen Cao
- WENS Foodstuff Group Co., Ltd., Yunfu, Xinxing 527400, China
| | - Qiufan Yan
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Jiandui Mi
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou 510642, China; National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, China; Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Maoming 525000, China; Guangdong Engineering Technology Research Center of Harmless Treatment and Resource Utilization of Livestock Waste, Yunfu, Xinxing 527400, China
| | - Baohua Ma
- Foshan Customs Comprehensive Technology Center, Foshan 528200, China
| | - Yongde Zou
- Foshan Customs Comprehensive Technology Center, Foshan 528200, China
| | - Na Zhang
- Foshan Customs Comprehensive Technology Center, Foshan 528200, China
| | - Xindi Liao
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou 510642, China; National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, China; Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Maoming 525000, China; Guangdong Engineering Technology Research Center of Harmless Treatment and Resource Utilization of Livestock Waste, Yunfu, Xinxing 527400, China
| | - Yan Wang
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou 510642, China; National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, China; Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Maoming 525000, China; Guangdong Engineering Technology Research Center of Harmless Treatment and Resource Utilization of Livestock Waste, Yunfu, Xinxing 527400, China.
| | - Yinbao Wu
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou 510642, China; National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, China; Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Maoming 525000, China; Guangdong Engineering Technology Research Center of Harmless Treatment and Resource Utilization of Livestock Waste, Yunfu, Xinxing 527400, China.
| |
Collapse
|
18
|
Duxbury SJN, Alderliesten JB, Zwart MP, Stegeman A, Fischer EAJ, de Visser JAGM. Chicken gut microbiome members limit the spread of an antimicrobial resistance plasmid in Escherichia coli. Proc Biol Sci 2021; 288:20212027. [PMID: 34727719 PMCID: PMC8564601 DOI: 10.1098/rspb.2021.2027] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 10/12/2021] [Indexed: 12/17/2022] Open
Abstract
Plasmid-mediated antimicrobial resistance is a major contributor to the spread of resistance genes within bacterial communities. Successful plasmid spread depends upon a balance between plasmid fitness effects on the host and rates of horizontal transmission. While these key parameters are readily quantified in vitro, the influence of interactions with other microbiome members is largely unknown. Here, we investigated the influence of three genera of lactic acid bacteria (LAB) derived from the chicken gastrointestinal microbiome on the spread of an epidemic narrow-range ESBL resistance plasmid, IncI1 carrying blaCTX-M-1, in mixed cultures of isogenic Escherichia coli strains. Secreted products of LAB decreased E. coli growth rates in a genus-specific manner but did not affect plasmid transfer rates. Importantly, we quantified plasmid transfer rates by controlling for density-dependent mating opportunities. Parametrization of a mathematical model with our in vitro estimates illustrated that small fitness costs of plasmid carriage may tip the balance towards plasmid loss under growth conditions in the gastrointestinal tract. This work shows that microbial interactions can influence plasmid success and provides an experimental-theoretical framework for further study of plasmid transfer in a microbiome context.
Collapse
Affiliation(s)
| | - Jesse B. Alderliesten
- Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Mark P. Zwart
- Department of Microbial Ecology, The Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
| | - Arjan Stegeman
- Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Egil A. J. Fischer
- Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | | |
Collapse
|
19
|
Sheppard RJ, Barraclough TG, Jansen VAA. The Evolution of Plasmid Transfer Rate in Bacteria and Its Effect on Plasmid Persistence. Am Nat 2021; 198:473-488. [PMID: 34559608 DOI: 10.1086/716063] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractPlasmids are extrachromosomal segments of DNA that can transfer genes between bacterial cells. Many plasmid genes benefit bacteria but cause harm to human health by granting antibiotic resistance to pathogens. Transfer rate is a key parameter for predicting plasmid dynamics, but observed rates are highly variable, and the effects of selective forces on their evolution are unclear. We apply evolutionary analysis to plasmid conjugation models to investigate selective pressures affecting plasmid transfer rate, emphasizing host versus plasmid control, the costs of plasmid transfer, and the role of recipient cells. Our analyses show that plasmid-determined transfer rates can be predicted with three parameters (host growth rate, plasmid loss rate, and the cost of plasmid transfer on growth) under some conditions. We also show that low-frequency genetic variation in transfer rate can accumulate, facilitating rapid adaptation to changing conditions. Furthermore, reduced transfer rates due to host control have limited effects on plasmid prevalence until low enough to prevent plasmid persistence. These results provide a framework to predict plasmid transfer rate evolution in different environments and demonstrate the limited impact of host mechanisms to control the costs incurred when plasmids are present.
Collapse
|
20
|
Properties affecting transfer and expression of degradative plasmids for the purpose of bioremediation. Biodegradation 2021; 32:361-375. [PMID: 34046775 DOI: 10.1007/s10532-021-09950-1] [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: 02/16/2021] [Accepted: 05/15/2021] [Indexed: 10/21/2022]
Abstract
Plasmids, circular DNA that exist and replicate outside of the host chromosome, have been important in the spread of non-essential genes as well as the rapid evolution of prokaryotes. Recent advances in environmental engineering have aimed to utilize the mobility of plasmids carrying degradative genes to disseminate them into the environment for cost-effective and environmentally friendly remediation of harmful contaminants. Here, we review the knowledge surrounding plasmid transfer and the conditions needed for successful transfer and expression of degradative plasmids. Both abiotic and biotic factors have a great impact on the success of degradative plasmid transfer and expression of the degradative genes of interest. Properties such as ecological growth strategies of bacteria may also contribute to plasmid transfer and may be an important consideration for bioremediation applications. Finally, the methods for detection of conjugation events have greatly improved and the application of these tools can help improve our understanding of conjugation in complex communities. However, it remains clear that more methods for in situ detection of plasmid transfer are needed to help detangle the complexities of conjugation in natural environments to better promote a framework for precision bioremediation.
Collapse
|
21
|
Kottara A, Hall JPJ, Brockhurst MA. The proficiency of the original host species determines community-level plasmid dynamics. FEMS Microbiol Ecol 2021; 97:6134752. [PMID: 33580956 DOI: 10.1093/femsec/fiab026] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 02/11/2021] [Indexed: 11/13/2022] Open
Abstract
Plasmids are common in natural bacterial communities, facilitating bacterial evolution via horizontal gene transfer. Bacterial species vary in their proficiency to host plasmids: whereas plasmids are stably maintained in some species regardless of selection for plasmid-encoded genes, in other species, even beneficial plasmids are rapidly lost. It is, however, unclear how this variation in host proficiency affects plasmid persistence in communities. Here, we test this using multispecies bacterial soil communities comprising species varying in their proficiency to host a large conjugative mercury resistance plasmid, pQBR103. The plasmid reached higher community-level abundance where beneficial and when introduced to the community in a more proficient host species. Proficient plasmid host species were also better able to disseminate the plasmid to a wider diversity of host species. These findings suggest that the dynamics of plasmids in natural bacterial communities depend not only upon the plasmid's attributes and the selective environment but also upon the proficiency of their host species.
Collapse
Affiliation(s)
- Anastasia Kottara
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - James P J Hall
- Department of Evolution, Ecology and Behaviour, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L69 7ZB, UK
| | - Michael A Brockhurst
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| |
Collapse
|
22
|
Zwanzig M. The ecology of plasmid-coded antibiotic resistance: a basic framework for experimental research and modeling. Comput Struct Biotechnol J 2020; 19:586-599. [PMID: 33510864 PMCID: PMC7807137 DOI: 10.1016/j.csbj.2020.12.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 12/16/2020] [Accepted: 12/20/2020] [Indexed: 12/27/2022] Open
Abstract
Many antibiotic resistance genes are associated with plasmids. The ecological success of these mobile genetic elements within microbial communities depends on varying mechanisms to secure their own propagation, not only on environmental selection. Among the most important are the cost of plasmids and their ability to be transferred to new hosts through mechanisms such as conjugation. These are regulated by dynamic control systems of the conjugation machinery and genetic adaptations that plasmid-host pairs can acquire in coevolution. However, in complex communities, these processes and mechanisms are subject to a variety of interactions with other bacterial species and other plasmid types. This article summarizes basic plasmid properties and ecological principles particularly important for understanding the persistence of plasmid-coded antibiotic resistance in aquatic environments. Through selected examples, it further introduces to the features of different types of simulation models such as systems of ordinary differential equations and individual-based models, which are considered to be important tools to understand these complex systems. This ecological perspective aims to improve the way we study and understand the dynamics, diversity and persistence of plasmids and associated antibiotic resistance genes.
Collapse
Affiliation(s)
- Martin Zwanzig
- Faculty of Environmental Sciences, Technische Universität Dresden, Pienner Str. 8, D-01737 Tharandt, Germany
| |
Collapse
|
23
|
The Conjugation Window in an Escherichia coli K-12 Strain with an IncFII Plasmid. Appl Environ Microbiol 2020; 86:AEM.00948-20. [PMID: 32591383 DOI: 10.1128/aem.00948-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 06/18/2020] [Indexed: 12/26/2022] Open
Abstract
Many studies have examined the role that conjugation plays in disseminating antibiotic resistance genes in bacteria. However, relatively little research has quantitively examined and modeled the dynamics of conjugation under growing and nongrowing conditions beyond a couple of hours. We therefore examined growing and nongrowing cultures of Escherichia coli over a 24-h period to understand the dynamics of bacterial conjugation in the presence and absence of antibiotics with pUUH239.2, an IncFII plasmid containing multiantibiotic- and metal-resistant genes. Our data indicate that conjugation occurs after E. coli cells divide and before they have transitioned to a nongrowing phase. The result is that there is only a small window of opportunity for E. coli to conjugate with pUUH239.2 under both growing and nongrowing conditions. Only a very small percentage of the donor cells likely are capable of even undergoing conjugation, and not all transconjugants can become donor cells due to molecular regulatory controls and not being in the correct growth phase. Once a growing culture enters stationary phase, the number of capable donor cells decreases rapidly and conjugation slows to produce a plateau. Published models did not provide accurate descriptions of conjugation under nongrowing conditions. We present here a modified modeling approach that accurately describes observed conjugation behavior under growing and nongrowing conditions.IMPORTANCE There has been growing interest in horizontal gene transfer of antibiotic resistance plasmids as the antibiotic resistance crisis has worsened over the years. Most studies examining conjugation of bacterial plasmids focus on growing cultures of bacteria for short periods, but in the environment, most bacteria grow episodically and at much lower rates than in the laboratory. We examined conjugation of an IncFII antibiotic resistance plasmid in E. coli under growing and nongrowing conditions to understand the dynamics of conjugation under which the plasmid is transferred. We found that conjugation occurs in a narrow time frame when E. coli is transitioning from a growing to nongrowing phase and that the conjugation plateau develops because of a lack of capable donor cells in growing cultures. From an environmental aspect, our results suggest that episodic growth in nutrient-depleted environments could result in more conjugation than sustained growth in a nutrient rich environment.
Collapse
|
24
|
Heß S, Hiltunen T, Berendonk TU, Kneis D. High variability of plasmid uptake rates in Escherichia coli isolated from sewage and river sediments. PLoS One 2020; 15:e0232130. [PMID: 32353032 PMCID: PMC7192377 DOI: 10.1371/journal.pone.0232130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 04/07/2020] [Indexed: 12/05/2022] Open
Abstract
The horizontal transfer of plasmids is a key mechanism behind the spread of antibiotic resistance in bacteria. So far, transfer rate constants were measured for a variety of plasmids, donors and recipients. The employed strains typically had a long history in laboratories. Existing data are, therefore, not necessarily representative for real-world environments. Moreover, information on the inter-strain variability of plasmid transfer rates is scarce. Using a high-throughput approach, we studied the uptake of RP4 by various Escherichia coli recipients using Serratia marcescens as the donor. The recipient strains were isolated from human-borne sewage and river sediments. The rate constants of plasmid transfer generally followed a log-normal distribution with considerable variance. The rate constants for good and poor recipients (95 and 5% quantile) differed by more than three orders of magnitude. Specifically, the inter-strain variability of the rate constant was large in comparison to alterations induced by low-level antibiotic exposure. We did not find evidence for diverging efficiencies of plasmid uptake between E. coli recipients of different origin. On average, strains isolated from river bottom sediments were equally efficient in the acquisition of RP4 as isolates extracted from sewage. We conclude that E. coli strains persisting in the aquatic environment and those of direct human origin share a similar intrinsic potential for the conjugative uptake of certain plasmids. In view of the large inter-strain variability, we propose to work towards probabilistic modeling of the environmental spread of antibiotic resistance.
Collapse
Affiliation(s)
- Stefanie Heß
- Department of Microbiology, University of Helsinki, Helsinki, Finland
- * E-mail: (SH); (DK)
| | - Teppo Hiltunen
- Department of Microbiology, University of Helsinki, Helsinki, Finland
- Department of Biology, University of Turku, Turku, Finland
| | | | - David Kneis
- Institute of Hydrobiology, TU Dresden, Dresden, Germany
- Helmholtz-Centre for Environmental Research, Magdeburg, Germany
- * E-mail: (SH); (DK)
| |
Collapse
|
25
|
Werner J, Nour E, Bunk B, Spröer C, Smalla K, Springael D, Öztürk B. PromA Plasmids Are Instrumental in the Dissemination of Linuron Catabolic Genes Between Different Genera. Front Microbiol 2020; 11:149. [PMID: 32132980 PMCID: PMC7039861 DOI: 10.3389/fmicb.2020.00149] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/22/2020] [Indexed: 01/31/2023] Open
Abstract
PromA plasmids are broad host range (BHR) plasmids, which are often cryptic and hence have an uncertain ecological role. We present three novel PromA γ plasmids which carry genes associated with degradation of the phenylurea herbicide linuron, two of which originated from unrelated Hydrogenophaga hosts isolated from different environments (pPBL-H3-2 and pBPS33-2), and one (pEN1) which was exogenously captured from an on-farm biopurification system (BPS). Hydrogenophaga sp. plasmid pBPS33-2 carries all three necessary gene clusters (hylA, dca, ccd) determining the three main steps for conversion of linuron to Krebs cycle intermediates, while pEN1 only determines the initial linuron hydrolysis step. Hydrogenophaga sp. plasmid pPBL-H3-2 exists as two variants, both containing ccd but with the hylA and dca gene modules interchanged between each other at exactly the same location. Linuron catabolic gene clusters that determine the same step were identical on all plasmids, encompassed in differently arranged constellations and characterized by the presence of multiple IS1071 elements. In all plasmids except pEN1, the insertion spot of the catabolic genes in the PromA γ plasmids was the same. Highly similar PromA plasmids carrying the linuron degrading gene cargo at the same insertion spot were previously identified in linuron degrading Variovorax sp. Interestingly, in both Hydrogenophaga populations not every PromA plasmid copy carries catabolic genes. The results indicate that PromA plasmids are important vehicles of linuron catabolic gene dissemination, rather than being cryptic and only important for the mobilization of other plasmids.
Collapse
Affiliation(s)
- Johannes Werner
- Department of Biological Oceanography, Leibniz Institute for Baltic Sea Research, Rostock, Germany
| | - Eman Nour
- Institute for Epidemiology and Pathogen Diagnostics, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants (JKI), Braunschweig, Germany
- Faculty of Organic Agriculture, Heliopolis University for Sustainable Development, Cairo, Egypt
| | - Boyke Bunk
- Bioinformatics Department, Leibniz Institute DSMZ, German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Cathrin Spröer
- Central Services, Leibniz Institute DSMZ, German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Kornelia Smalla
- Institute for Epidemiology and Pathogen Diagnostics, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants (JKI), Braunschweig, Germany
| | - Dirk Springael
- Division of Soil and Water Management, KU Leuven, Leuven, Belgium
| | - Başak Öztürk
- Division of Soil and Water Management, KU Leuven, Leuven, Belgium
- Junior Research Group Microbial Biotechnology, Leibniz Institute DSMZ, German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| |
Collapse
|
26
|
Lazdins A, Maurya AP, Miller CE, Kamruzzaman M, Liu S, Stephens ER, Lloyd GS, Haratianfar M, Chamberlain M, Haines AS, Kreft JU, Webber MA, Iredell J, Thomas CM. Potentiation of curing by a broad-host-range self-transmissible vector for displacing resistance plasmids to tackle AMR. PLoS One 2020; 15:e0225202. [PMID: 31940351 PMCID: PMC6961859 DOI: 10.1371/journal.pone.0225202] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 10/29/2019] [Indexed: 12/21/2022] Open
Abstract
Plasmids are potent vehicles for spread of antibiotic resistance genes in bacterial populations and often persist in the absence of selection due to efficient maintenance mechanisms. We previously constructed non-conjugative high copy number plasmid vectors that efficiently displace stable plasmids from enteric bacteria in a laboratory context by blocking their replication and neutralising their addiction systems. Here we assess a low copy number broad-host-range self-transmissible IncP-1 plasmid as a vector for such curing cassettes to displace IncF and IncK plasmids. The wild type plasmid carrying the curing cassette displaces target plasmids poorly but derivatives with deletions near the IncP-1 replication origin that elevate copy number about two-fold are efficient. Verification of this in mini IncP-1 plasmids showed that elevated copy number was not sufficient and that the parB gene, korB, that is central to its partitioning and gene control system, also needs to be included. The resulting vector can displace target plasmids from a laboratory population without selection and demonstrated activity in a mouse model although spread is less efficient and requires additional selection pressure.
Collapse
Affiliation(s)
- Alessandro Lazdins
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, England, United Kingdom
| | - Anand Prakash Maurya
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, England, United Kingdom
| | - Claire E. Miller
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, England, United Kingdom
| | - Muhammad Kamruzzaman
- University of Sydney, Centre for Infectious Disease & Microbiology, Westmead Institute of Medical Research, Westmead, New South Wales, Australia
| | - Shuting Liu
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, England, United Kingdom
| | - Elton R. Stephens
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, England, United Kingdom
| | - Georgina S. Lloyd
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, England, United Kingdom
| | - Mona Haratianfar
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, England, United Kingdom
| | - Melissa Chamberlain
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, England, United Kingdom
| | - Anthony S. Haines
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, England, United Kingdom
| | - Jan-Ulrich Kreft
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, England, United Kingdom
| | - Mark. A. Webber
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, England, United Kingdom
| | - Jonathan Iredell
- University of Sydney, Centre for Infectious Disease & Microbiology, Westmead Institute of Medical Research, Westmead, New South Wales, Australia
| | - Christopher M. Thomas
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, England, United Kingdom
| |
Collapse
|
27
|
Kohyama Y, Suzuki S. Conjugative Gene Transfer between Nourished and Starved Cells of Photobacterium damselae ssp. damselae and Escherichia coli. Microbes Environ 2019; 34:388-392. [PMID: 31631079 PMCID: PMC6934395 DOI: 10.1264/jsme2.me19099] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Horizontal gene transfer (HGT) between bacteria with different habitats and nutritional requirements is important for the spread of antibiotic resistance genes (ARG). The objective of the present study was to clarify the effects of organic matter on HGT between nourished and starved bacteria. We demonstrated that conjugation ability is affected by the nutritional conditions of the cell and environment. A filter mating HGT experiment was performed using Photobacterium damselae ssp. damselae, strain 04Ya311, a marine-origin bacterium possessing the multidrug-resistance plasmid pAQU1, as the donor, and Escherichia coli as the recipient. The donor and recipient were both prepared as nutrient-rich cultured and starved cells. Filter mating was performed on agar plates with and without organic nutrients. The transcription of the plasmid-borne genes tet(M) and traI was quantitated under eutrophic and oligotrophic conditions. The donor P. damselae transferred the plasmid to E. coli at a transfer rate of 10−4 under oligotrophic and eutrophic conditions. However, when the donor was starved, HGT was not detected under oligotrophic conditions. The addition of organic matter to starved cells restored conjugative HGT even after 6 d of starvation. The transcription of traI was not detected in starved cells, but was restored upon the addition of organic matter. The HGT rate appears to be affected by the transcription of plasmid-associated genes. The present results suggest that the HGT rate is low in starved donors under oligotrophic conditions, but is restored by the addition of organic matter.
Collapse
Affiliation(s)
| | - Satoru Suzuki
- Center for Marine Environmental Studies, Ehime University
| |
Collapse
|
28
|
Stalder T, Press MO, Sullivan S, Liachko I, Top EM. Linking the resistome and plasmidome to the microbiome. THE ISME JOURNAL 2019; 13:2437-2446. [PMID: 31147603 PMCID: PMC6776055 DOI: 10.1038/s41396-019-0446-4] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 05/02/2019] [Accepted: 05/10/2019] [Indexed: 01/08/2023]
Abstract
The rapid spread of antibiotic resistance among bacterial pathogens is a serious human health threat. While a range of environments have been identified as reservoirs of antibiotic resistance genes (ARGs), we lack understanding of the origins of these ARGs and their spread from environment to clinic. This is partly due to our inability to identify the natural bacterial hosts of ARGs and the mobile genetic elements that mediate this spread, such as plasmids and integrons. Here we demonstrate that the in vivo proximity-ligation method Hi-C can reconstruct a known plasmid-host association from a wastewater community, and identify the in situ host range of ARGs, plasmids, and integrons by physically linking them to their host chromosomes. Hi-C detected both previously known and novel associations between ARGs, mobile genetic elements and host genomes, thus validating this method. We showed that IncQ plasmids and class 1 integrons had the broadest host range in this wastewater, and identified bacteria belonging to Moraxellaceae, Bacteroides, and Prevotella, and especially Aeromonadaceae as the most likely reservoirs of ARGs in this community. A better identification of the natural carriers of ARGs will aid the development of strategies to limit resistance spread to pathogens.
Collapse
Affiliation(s)
- Thibault Stalder
- Department of Biological Sciences, University of Idaho, Moscow, ID, 83844, USA.
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, ID, 83844, USA.
| | | | | | | | - Eva M Top
- Department of Biological Sciences, University of Idaho, Moscow, ID, 83844, USA.
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, ID, 83844, USA.
| |
Collapse
|
29
|
|
30
|
Roe K. Stopping Untreatable Pathogen Infections Using Peptide Ligands to Sabotage Pathogenic Cell Surface Proteins. Mol Biotechnol 2019; 61:602-609. [PMID: 31161299 DOI: 10.1007/s12033-019-00189-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Specifically targeted peptide ligands can sabotage pathogenic cell surface proteins and stop increasingly untreatable pathogen infections. Different approaches might be used to sabotage pathogenic cell surface proteins to stop infections. A conjugation treatment uses carefully selected genetically modified plasmids prepared in advance to activate a secondary immune system response neutralizing pathogens with a new, much larger cascade of antibodies. Non-conjugation treatment introduces genetically modified cells into the center of localized pathogen infections to produce peptide ligands; and another non-conjugation treatment introduces only the peptide ligands into the center of localized pathogen infections to sabotage pathogenic cell surface proteins used to specifically infect mammalian cells. Extensive and meticulous plasmid transfer experiments by two separate groups firmly support the feasibility of extremely rapid and thorough plasmid transfer necessary for the conjugation treatment. A third independent group introduced genetically modified bacteria into mammals, including several human volunteers, with safe and effective experimental results, which also firmly supports the feasibility of the first non-conjugation treatment. These three approaches offer several profound advantages compared to treatments using new antibiotics.
Collapse
|
31
|
Fan XT, Li H, Chen QL, Zhang YS, Ye J, Zhu YG, Su JQ. Fate of Antibiotic Resistant Pseudomonas putida and Broad Host Range Plasmid in Natural Soil Microcosms. Front Microbiol 2019; 10:194. [PMID: 30881351 PMCID: PMC6407330 DOI: 10.3389/fmicb.2019.00194] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 01/23/2019] [Indexed: 12/03/2022] Open
Abstract
Plasmid conjugation is one of the dominant mechanisms of horizontal gene transfer, playing a noticeable role in the rapid spread of antibiotic resistance genes (ARGs). Broad host range plasmids are known to transfer to diverse bacteria in extracted soil bacterial communities when evaluated by filter mating incubation. However, the persistence and dissemination of broad range plasmid in natural soil has not been well studied. In this study, Pseudomonas putida with a conjugative antibiotic resistance plasmid RP4 was inoculated into a soil microcosm, the fate and persistence of P. putida and RP4 were monitored by quantitative PCR. The concentrations of P. putida and RP4 both rapidly decreased within 15-day incubation. P. putida then decayed at a significantly lower rate during subsequent incubation, however, no further decay of RP4 was observed, resulting in an elevated RP4/P. putida ratio (up to 10) after 75-day incubation, which implied potential transfer of RP4 to soil microbiota. We further sorted RP4 recipient bacteria from the soil microcosms by fluorescence-activated cell sorting. Spread of RP4 increased during 75-day microcosm operation and was estimated at around 10-4 transconjugants per recipient at the end of incubation. Analysis of 16S rRNA gene sequences of transconjugants showed that host bacteria of RP4 were affiliated to more than 15 phyla, with increased diversity and shift in the composition of host bacteria. Proteobacteria was the most dominant phylum in the transconjugant pools. Transient transfer of RP4 to some host bacteria was observed. These results emphasize the prolonged persistence of P. putida and RP4 in natural soil microcosms, and highlight the potential risks of increased spread potential of plasmid and broader range of host bacteria in disseminating ARGs in soil.
Collapse
Affiliation(s)
- Xiao-Ting Fan
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Hu Li
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China
| | - Qing-Lin Chen
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China
| | - Yu-Sen Zhang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jun Ye
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China
| | - Yong-Guan Zhu
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.,University of Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Jian-Qiang Su
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China
| |
Collapse
|
32
|
A high-throughput approach to the culture-based estimation of plasmid transfer rates. Plasmid 2019; 101:28-34. [DOI: 10.1016/j.plasmid.2018.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 12/13/2018] [Accepted: 12/13/2018] [Indexed: 12/14/2022]
|
33
|
Petrovich ML, Rosenthal AF, Griffin JS, Wells GF. Spatially resolved abundances of antibiotic resistance genes and intI1 in wastewater treatment biofilms. Biotechnol Bioeng 2018; 116:543-554. [PMID: 30512194 DOI: 10.1002/bit.26887] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 11/15/2018] [Accepted: 11/29/2018] [Indexed: 12/12/2022]
Abstract
Attached growth bioprocesses that use biofilms to remove organic matter or nutrients from wastewater are known to harbor antibiotic resistance genes (ARGs). Biofilms in these processes are spatially heterogeneous, but little is known about depth stratification of ARGs in complex, mixed culture biofilms. To address this knowledge gap, we used an experimental approach combining cryosectioning and quantitative polymerase chain reaction to quantify the spatial distribution of three ARGs (sul1, ermB, and qnrS) and the class 1 integron-integrase gene intI1 in biofilms from a lab-scale rotating annular reactor fed with synthetic wastewater. We also used high throughput 16S ribosomal RNA (rRNA) gene sequencing to characterize community structure with depth in biofilms. The ARG sul1 and the integron-integrase gene intI1 were found in higher abundances in upper layers of biofilm near the fluid-biofilm interface than in lower layers and exhibited significant correlations between the distance from substratum and gene abundances. The genes ermB and qnrS were present in comparatively low relative abundances. Microbial community structure varied significantly by date of sampling and distance from the substratum. These findings highlight the genetic and taxonomic heterogeneity with distance from substratum in wastewater treatment biofilms and show that sul1 and intI1 are particularly abundant near fluid-biofilm interfaces where cells are most likely to detach and flow into downstream portions of treatment systems and can ultimately be released into the environment through effluent.
Collapse
Affiliation(s)
- Morgan L Petrovich
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois
| | - Alex F Rosenthal
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois
| | - James S Griffin
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois
| | - George F Wells
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois
| |
Collapse
|
34
|
Li B, Qiu Y, Zhang J, Huang X, Shi H, Yin H. Real-Time Study of Rapid Spread of Antibiotic Resistance Plasmid in Biofilm Using Microfluidics. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:11132-11141. [PMID: 30179497 DOI: 10.1021/acs.est.8b03281] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Gene transfer in biofilms is known to play an important role in antibiotic resistance dissemination. However, the process remains poorly understood. In this study, microfluidics with time-lapse imaging was used for real-time monitoring of plasmid-mediated horizontal gene transfer (HGT) in biofilms. Pseudomonas putida KT2440 harboring an antibiotic resistance plasmid RP4 was chosen as the donor while Escherichia coli and activated sludge bacteria were used as the recipient cells. Dynamic features of the transfer process, including the transfer rate, cell growth rate and kinetic changes of the transfer frequency, were determined. It was found that the routes for gene transfer strongly depend on the structure and composition of a biofilm. While intraspecies HGT is essential to initiate a transfer event, the secondary retransfer from transconjugants to the same species is more efficient and can cause cascading gene spread in single-strain biofilms. For the activated sludge biofilm, only small and scattered colonies formed and vertical gene transfer appears to be the dominant route after initial intraspecies transfer. Furthermore, more than 46% of genera in the activated sludge were permissive to plasmid RP4, many of which are associated with human pathogens. These phenomena imply early prevention and interruptions to biofilm structure could provide an effect way to inhibit rapid antibiotic resistance gene spread and reduce the likelihood of catastrophic events associated with antibiotic resistance.
Collapse
Affiliation(s)
- Bing Li
- School of Energy and Environmental Engineering , University of Science and Technology Beijing , Beijing , 100083 , China
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment , Tsinghua University , Beijing 100084 , P. R. China
- Division of Biomedical Engineering, School of Engineering, University of Glasgow , Glasgow , G12 8LT , U.K
| | - Yong Qiu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment , Tsinghua University , Beijing 100084 , P. R. China
| | - Jing Zhang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment , Tsinghua University , Beijing 100084 , P. R. China
| | - Xia Huang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment , Tsinghua University , Beijing 100084 , P. R. China
| | - Hanchang Shi
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment , Tsinghua University , Beijing 100084 , P. R. China
| | - Huabing Yin
- Division of Biomedical Engineering, School of Engineering, University of Glasgow , Glasgow , G12 8LT , U.K
| |
Collapse
|
35
|
Cell-to-cell bacterial interactions promoted by drier conditions on soil surfaces. Proc Natl Acad Sci U S A 2018; 115:9791-9796. [PMID: 30209211 DOI: 10.1073/pnas.1808274115] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacterial cell-to-cell interactions are in the core of evolutionary and ecological processes in soil and other environments. Under most conditions, natural soils are unsaturated where the fragmented aqueous habitats and thin liquid films confine bacterial cells within small volumes and close proximity for prolonged periods. We report effects of a range of hydration conditions on bacterial cell-level interactions that are marked by plasmid transfer between donor and recipient cells within populations of the soil bacterium Pseudomonas putida Using hydration-controlled sand microcosms, we demonstrate that the frequency of cell-to-cell contacts under prescribed hydration increases with lowering water potential values (i.e., under drier conditions where the aqueous phase shrinks and fragments). These observations were supported using a mechanistic individual-based model for linking macroscopic soil water potential to microscopic distribution of liquid phase and explicit bacterial cell interactions in a simplified porous medium. Model results are in good agreement with observations and inspire confidence in the underlying mechanisms. The study highlights important physical factors that control short-range bacterial cell interactions in soil and on surfaces, specifically, the central role of the aqueous phase in mediating bacterial interactions and conditions that promote genetic information transfer in support of soil microbial diversity.
Collapse
|
36
|
Hall JPJ, Brockhurst MA, Harrison E. Sampling the mobile gene pool: innovation via horizontal gene transfer in bacteria. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0424. [PMID: 29061896 DOI: 10.1098/rstb.2016.0424] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2017] [Indexed: 12/26/2022] Open
Abstract
In biological systems, evolutionary innovations can spread not only from parent to offspring (i.e. vertical transmission), but also 'horizontally' between individuals, who may or may not be related. Nowhere is this more apparent than in bacteria, where novel ecological traits can spread rapidly within and between species through horizontal gene transfer (HGT). This important evolutionary process is predominantly a by-product of the infectious spread of mobile genetic elements (MGEs). We will discuss the ecological conditions that favour the spread of traits by HGT, the evolutionary and social consequences of sharing traits, and how HGT is shaped by inherent conflicts between bacteria and MGEs.This article is part of the themed issue 'Process and pattern in innovations from cells to societies'.
Collapse
Affiliation(s)
- James P J Hall
- Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Michael A Brockhurst
- Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Ellie Harrison
- P3 Institute, Department of Animal and Plant Sciences, Arthur Willis Environment Centre, University of Sheffield, 1 Maxfield Avenue, Sheffield S10 1AE, UK
| |
Collapse
|
37
|
Lopatkin AJ, Meredith HR, Srimani JK, Pfeiffer C, Durrett R, You L. Persistence and reversal of plasmid-mediated antibiotic resistance. Nat Commun 2017; 8:1689. [PMID: 29162798 PMCID: PMC5698434 DOI: 10.1038/s41467-017-01532-1] [Citation(s) in RCA: 195] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 09/22/2017] [Indexed: 02/07/2023] Open
Abstract
In the absence of antibiotic-mediated selection, sensitive bacteria are expected to displace their resistant counterparts if resistance genes are costly. However, many resistance genes persist for long periods in the absence of antibiotics. Horizontal gene transfer (primarily conjugation) could explain this persistence, but it has been suggested that very high conjugation rates would be required. Here, we show that common conjugal plasmids, even when costly, are indeed transferred at sufficiently high rates to be maintained in the absence of antibiotics in Escherichia coli. The notion is applicable to nine plasmids from six major incompatibility groups and mixed populations carrying multiple plasmids. These results suggest that reducing antibiotic use alone is likely insufficient for reversing resistance. Therefore, combining conjugation inhibition and promoting plasmid loss would be an effective strategy to limit conjugation-assisted persistence of antibiotic resistance. It is unclear whether the transfer of plasmids carrying antibiotic resistance genes can explain their persistence when antibiotics are not present. Here, Lopatkin et al. show that conjugal plasmids, even when costly, are indeed transferred at sufficiently high rates to be maintained in the absence of antibiotics.
Collapse
Affiliation(s)
- Allison J Lopatkin
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Hannah R Meredith
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Jaydeep K Srimani
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Connor Pfeiffer
- Department of Biology, Duke University, Durham, NC, 27708, USA
| | - Rick Durrett
- Department of Mathematics, Duke University, Durham, NC, 27708, USA
| | - Lingchong You
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA. .,Center for Genomic and Computational Biology, Duke University, Durham, NC, 27708, USA. .,Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA.
| |
Collapse
|
38
|
Gumpert H, Kubicek-Sutherland JZ, Porse A, Karami N, Munck C, Linkevicius M, Adlerberth I, Wold AE, Andersson DI, Sommer MOA. Transfer and Persistence of a Multi-Drug Resistance Plasmid in situ of the Infant Gut Microbiota in the Absence of Antibiotic Treatment. Front Microbiol 2017; 8:1852. [PMID: 29018426 PMCID: PMC5622998 DOI: 10.3389/fmicb.2017.01852] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/11/2017] [Indexed: 12/18/2022] Open
Abstract
The microbial ecosystem residing in the human gut is believed to play an important role in horizontal exchange of virulence and antibiotic resistance genes that threatens human health. While the diversity of gut-microorganisms and their genetic content has been studied extensively, high-resolution insight into the plasticity, and selective forces shaping individual genomes is scarce. In a longitudinal study, we followed the dynamics of co-existing Escherichia coli lineages in an infant not receiving antibiotics. Using whole genome sequencing, we observed large genomic deletions, bacteriophage infections, as well as the loss and acquisition of plasmids in these lineages during their colonization of the human gut. In particular, we captured the exchange of multidrug resistance genes, and identified a clinically relevant conjugative plasmid mediating the transfer. This resistant transconjugant lineage was maintained for months, demonstrating that antibiotic resistance genes can disseminate and persist in the gut microbiome; even in absence of antibiotic selection. Furthermore, through in vivo competition assays, we suggest that the resistant transconjugant can persist through a fitness advantage in the mouse gut in spite of a fitness cost in vitro. Our findings highlight the dynamic nature of the human gut microbiota and provide the first genomic description of antibiotic resistance gene transfer between bacteria in the unperturbed human gut. These results exemplify that conjugative plasmids, harboring resistance determinants, can transfer and persists in the gut in the absence of antibiotic treatment.
Collapse
Affiliation(s)
- Heidi Gumpert
- Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark.,Department of Clinical Microbiology, Hvidovre Hospital, University of Copenhagen, Hvidovre, Denmark
| | | | - Andreas Porse
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Nahid Karami
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Christian Munck
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Marius Linkevicius
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Ingegerd Adlerberth
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Agnes E Wold
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Dan I Andersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Morten O A Sommer
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| |
Collapse
|
39
|
Hall JPJ, Brockhurst MA, Dytham C, Harrison E. The evolution of plasmid stability: Are infectious transmission and compensatory evolution competing evolutionary trajectories? Plasmid 2017; 91:90-95. [PMID: 28461121 DOI: 10.1016/j.plasmid.2017.04.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 04/27/2017] [Accepted: 04/27/2017] [Indexed: 11/16/2022]
Abstract
Conjugative plasmids are widespread and play an important role in bacterial evolution by accelerating adaptation through horizontal gene transfer. However, explaining the long-term stability of plasmids remains challenging because segregational loss and the costs of plasmid carriage should drive the loss of plasmids though purifying selection. Theoretical and experimental studies suggest two key evolutionary routes to plasmid stability: First, the evolution of high conjugation rates would allow plasmids to survive through horizontal transmission as infectious agents, and second, compensatory evolution to ameliorate the cost of plasmid carriage can weaken purifying selection against plasmids. How these two evolutionary strategies for plasmid stability interact is unclear. Here, we summarise the literature on the evolution of plasmid stability and then use individual based modelling to investigate the evolutionary interplay between the evolution of plasmid conjugation rate and cost amelioration. We find that, individually, both strategies promote plasmid stability, and that they act together to increase the likelihood of plasmid survival. However, due to the inherent costs of increasing conjugation rate, particularly where conjugation is unlikely to be successful, our model predicts that amelioration is the more likely long-term solution to evolving stable bacteria-plasmid associations. Our model therefore suggests that bacteria-plasmid relationships should evolve towards lower plasmid costs that may forestall the evolution of highly conjugative, 'infectious' plasmids.
Collapse
Affiliation(s)
- James P J Hall
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Michael A Brockhurst
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Calvin Dytham
- Department of Biology, University of York, York YO10 5DD, UK
| | - Ellie Harrison
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK.
| |
Collapse
|
40
|
Werisch M, Berger U, Berendonk TU. Conjugative plasmids enable the maintenance of low cost non-transmissible plasmids. Plasmid 2017; 91:96-104. [PMID: 28461122 DOI: 10.1016/j.plasmid.2017.04.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 04/27/2017] [Accepted: 04/27/2017] [Indexed: 11/27/2022]
Abstract
Some plasmids can be transferred by conjugation to other bacterial hosts. But almost half of the plasmids are non-transmissible. These plasmid types can only be transmitted to the daughter cells of their host after bacterial fission. Previous studies suggest that non-transmissible plasmids become extinct in the absence of selection of their encoded traits, as plasmid-free bacteria are more competitive. Here, we aim to identify mechanisms that enable non-transmissible plasmids to persist, even if they are not beneficial. For this purpose, an individual-based model for plasmid population dynamics was set up and carefully tested for structural consistency and plausibility. Our results demonstrate that non-transmissible plasmids can be stably maintained in a population, even if they impose a substantial burden on their host cells growth. A prerequisite is the co-occurrence of an incompatible and costly conjugative plasmid type, which indirectly facilitates the preservation of the non-transmissible type. We suggest that this constellation might be considered as a potential mechanism maintaining plasmids and associated antibiotic resistances. It should be investigated in upcoming laboratory experiments.
Collapse
Affiliation(s)
- Martin Werisch
- Technische Universität Dresden, Department of Forest Sciences, Institute of Forest Growth and Forest Computer Sciences, Tharandt 01735, Germany.
| | - Uta Berger
- Technische Universität Dresden, Department of Forest Sciences, Institute of Forest Growth and Forest Computer Sciences, Tharandt 01735, Germany
| | - Thomas U Berendonk
- Technische Universität Dresden, Department of Hydro Sciences, Institute of Hydrobiology, Dresden 01217, Germany
| |
Collapse
|
41
|
Gibert M, Paytubi S, Beltrán S, Juárez A, Balsalobre C, Madrid C. Growth phase-dependent control of R27 conjugation is mediated by the interplay between the plasmid-encoded regulatory circuit TrhR/TrhY-HtdA and the cAMP regulon. Environ Microbiol 2016; 18:5277-5287. [PMID: 27768816 DOI: 10.1111/1462-2920.13579] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 10/14/2016] [Indexed: 01/06/2023]
Abstract
Plasmids of the incompatibility group HI1 (IncHI1) have been isolated from several Gram-negative pathogens and are associated with the spread of multidrug resistance. Their conjugation is tightly regulated and it is inhibited at temperatures higher than 30°C, indicating that conjugation occurs outside warm-blooded hosts. Using R27, the prototype of IncHI1 plasmids, we report that plasmid transfer efficiency in E. coli strongly depends on the physiological state of the donor cells. Conjugation frequency is high when cells are actively growing, dropping sharply when cells enter the stationary phase of growth. Accordingly, our transcriptomic assays show significant downregulation of numerous R27 genes during the stationary phase, including several tra (transfer) genes. Growth phase-dependent regulation of tra genes transcription is independent of H-NS, a silencer of horizontal gene transfer, and ppGpp and RpoS, regulators of the stationary phase, but highly dependent on the plasmid-encoded regulatory circuit TrhR/TrhY-HtdA. The metabolic sensor cAMP, whose synthesis is chromosomally encoded, is also involved in the growth phase regulation of R27 conjugation by modulating htdA expression. Our data suggest that the involvement of regulators encoded by both chromosome and plasmid are required for efficient physiological control of IncHI1 plasmid conjugation.
Collapse
Affiliation(s)
- Marta Gibert
- Departament de Microbiologia, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| | - Sonia Paytubi
- Departament de Microbiologia, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| | - Sergi Beltrán
- Centre Nacional d'Anàlisi Genòmica (CNAG), Parc Científic de Barcelona, Baldiri Reixac 4, Barcelona, 08028, Spain
| | - Antonio Juárez
- Departament de Microbiologia, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain.,Institut de Bioenginyeria de Catalunya (IBEC), Parc Científic de Barcelona, Baldiri Reixac 10, Barcelona, 08028, Spain
| | - Carlos Balsalobre
- Departament de Microbiologia, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| | - Cristina Madrid
- Departament de Microbiologia, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| |
Collapse
|
42
|
Berthold T, Centler F, Hübschmann T, Remer R, Thullner M, Harms H, Wick LY. Mycelia as a focal point for horizontal gene transfer among soil bacteria. Sci Rep 2016; 6:36390. [PMID: 27811990 PMCID: PMC5095653 DOI: 10.1038/srep36390] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 10/12/2016] [Indexed: 11/09/2022] Open
Abstract
Horizontal gene transfer (HGT) is a main mechanism of bacterial evolution endowing bacteria with new genetic traits. The transfer of mobile genetic elements such as plasmids (conjugation) requires the close proximity of cells. HGT between genetically distinct bacteria largely depends on cell movement in water films, which are typically discontinuous in natural systems like soil. Using laboratory microcosms, a bacterial reporter system and flow cytometry, we here investigated if and to which degree mycelial networks facilitate contact of and HGT between spatially separated bacteria. Our study shows that the network structures of mycelia promote bacterial HGT by providing continuous liquid films in which bacterial migration and contacts are favoured. This finding was confirmed by individual-based simulations, revealing that the tendency of migrating bacteria to concentrate in the liquid film around hyphae is a key factor for improved HGT along mycelial networks. Given their ubiquity, we propose that hyphae can act as focal point for HGT and genetic adaptation in soil.
Collapse
Affiliation(s)
- Tom Berthold
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Microbiology, Permoserstraße 15, 04318, Leipzig, Germany
| | - Florian Centler
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Microbiology, Permoserstraße 15, 04318, Leipzig, Germany
| | - Thomas Hübschmann
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Microbiology, Permoserstraße 15, 04318, Leipzig, Germany
| | - Rita Remer
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Microbiology, Permoserstraße 15, 04318, Leipzig, Germany
| | - Martin Thullner
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Microbiology, Permoserstraße 15, 04318, Leipzig, Germany
| | - Hauke Harms
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Microbiology, Permoserstraße 15, 04318, Leipzig, Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5E, 04103 Leipzig, Germany
| | - Lukas Y. Wick
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Microbiology, Permoserstraße 15, 04318, Leipzig, Germany
| |
Collapse
|
43
|
Abstract
Biofilms dominate microbial life, and their importance for human health and the environment can no longer be dismissed. Nevertheless many of the processes governing this form of microbial growth are still poorly understood. This includes the horizontal exchange of genetic information, which is a major driver in bacterial evolution and rapid adaptation, exemplified by the alarming spread of multi-drug resistance among pathogens mediated by plasmids. Biofilms are often considered hot spot for horizontal gene transfer, yet several studies have shown that plasmid transfer is limited to the outer layers. On the basis of results from decades of research we analyse this paradox and discuss the mechanisms by which biofilm growth can promote the initial transfer of some plasmids, but also limit further plasmid invasion into the population or community. If we want to adequately promote or combat horizontal gene spread in biofilms, we need to gain better insight into the physicochemical and biological mechanisms that control this process.
Collapse
Affiliation(s)
- Thibault Stalder
- Department of Biological Sciences, University of Idaho, Moscow, ID, USA.,Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, ID, USA
| | - Eva Top
- Department of Biological Sciences, University of Idaho, Moscow, ID, USA.,Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, ID, USA
| |
Collapse
|
44
|
Source-sink plasmid transfer dynamics maintain gene mobility in soil bacterial communities. Proc Natl Acad Sci U S A 2016; 113:8260-5. [PMID: 27385827 DOI: 10.1073/pnas.1600974113] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Horizontal gene transfer is a fundamental process in bacterial evolution that can accelerate adaptation via the sharing of genes between lineages. Conjugative plasmids are the principal genetic elements mediating the horizontal transfer of genes, both within and between bacterial species. In some species, plasmids are unstable and likely to be lost through purifying selection, but when alternative hosts are available, interspecific plasmid transfer could counteract this and maintain access to plasmid-borne genes. To investigate the evolutionary importance of alternative hosts to plasmid population dynamics in an ecologically relevant environment, we established simple soil microcosm communities comprising two species of common soil bacteria, Pseudomonas fluorescens and Pseudomonas putida, and a mercury resistance (Hg(R)) plasmid, pQBR57, both with and without positive selection [i.e., addition of Hg(II)]. In single-species populations, plasmid stability varied between species: although pQBR57 survived both with and without positive selection in P. fluorescens, it was lost or replaced by nontransferable Hg(R) captured to the chromosome in P. putida A simple mathematical model suggests these differences were likely due to pQBR57's lower intraspecific conjugation rate in P. putida By contrast, in two-species communities, both models and experiments show that interspecific conjugation from P. fluorescens allowed pQBR57 to persist in P. putida via source-sink transfer dynamics. Moreover, the replacement of pQBR57 by nontransferable chromosomal Hg(R) in P. putida was slowed in coculture. Interspecific transfer allows plasmid survival in host species unable to sustain the plasmid in monoculture, promoting community-wide access to the plasmid-borne accessory gene pool and thus potentiating future evolvability.
Collapse
|
45
|
Abstract
Conjugative transfer is the most important means of spreading antibiotic resistance and virulence factors among bacteria. The key vehicles of this horizontal gene transfer are a group of mobile genetic elements, termed conjugative plasmids. Conjugative plasmids contain as minimum instrumentation an origin of transfer (oriT), DNA-processing factors (a relaxase and accessory proteins), as well as proteins that constitute the trans-envelope transport channel, the so-called mating pair formation (Mpf) proteins. All these protein factors are encoded by one or more transfer (tra) operons that together form the DNA transport machinery, the Gram-positive type IV secretion system. However, multicellular Gram-positive bacteria belonging to the streptomycetes appear to have evolved another mechanism for conjugative plasmid spread reminiscent of the machinery involved in bacterial cell division and sporulation, which transports double-stranded DNA from donor to recipient cells. Here, we focus on the protein key players involved in the plasmid spread through the two different modes and present a new secondary structure homology-based classification system for type IV secretion protein families. Moreover, we discuss the relevance of conjugative plasmid transfer in the environment and summarize novel techniques to visualize and quantify conjugative transfer in situ.
Collapse
|
46
|
Li X, Wang Y, Brown CJ, Yao F, Jiang Y, Top EM, Li H. Diversification of broad host range plasmids correlates with the presence of antibiotic resistance genes. FEMS Microbiol Ecol 2015; 92:fiv151. [PMID: 26635412 DOI: 10.1093/femsec/fiv151] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/26/2015] [Indexed: 11/13/2022] Open
Abstract
The IncP-1ε subgroup is a recently identified phylogenetic clade within IncP-1 plasmids, which plays an important role in the spread of antibiotic resistance and degradation of xenobiotic pollutants. Here, four IncP-1ε plasmids were exogenously captured from a petroleum-contaminated habitat in China and compared phylogenetically and genomically with previously reported IncP-1ε and other IncP-1 plasmids. The IncP-1ε plasmids can be clearly subdivided into two subclades, designated as ε-I and ε-II, based on phylogenetic analysis of backbone proteins TraI and TrfA. This was further supported by comparison of concatenated backbone genes. Moreover, the two subclades differed in the transposon types, phenotypes and insertion locations of the accessory elements. The accessory genes on ε-I plasmids were inserted between parA and traC, and harbored ISPa17 and Tn402-like transposon modules, typically carrying antibiotic resistance genes. In contrast, the accessory elements on ε-II plasmids were typically located between trfA and oriV, and contained IS1071, which was commonly inserted within the Tn501-like transposon, typically harboring a cluster of genes encoding mercury resistance and/or catabolic pathways. Our study is one of the first to compare IncP-1 plasmid genomes from China, expands the available collection of IncP-1ε plasmids and enhances our understanding of their diversity, biogeography and evolutionary history.
Collapse
Affiliation(s)
- Xiaobin Li
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yafei Wang
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China
| | - Celeste J Brown
- Department of Biological Sciences, Institute for Bioinformatics and Evolutionary Studies (IBEST), University of Idaho, Moscow, ID 83844-3051, USA
| | - Fei Yao
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yong Jiang
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China
| | - Eva M Top
- Department of Biological Sciences, Institute for Bioinformatics and Evolutionary Studies (IBEST), University of Idaho, Moscow, ID 83844-3051, USA
| | - Hui Li
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China
| |
Collapse
|
47
|
Qiu Z, Shen Z, Qian D, Jin M, Yang D, Wang J, Zhang B, Yang Z, Chen Z, Wang X, Ding C, Wang D, Li JW. Effects of nano-TiO2on antibiotic resistance transfer mediated by RP4 plasmid. Nanotoxicology 2015; 9:895-904. [DOI: 10.3109/17435390.2014.991429] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
|
48
|
Hall JPJ, Harrison E, Lilley AK, Paterson S, Spiers AJ, Brockhurst MA. Environmentally co-occurring mercury resistance plasmids are genetically and phenotypically diverse and confer variable context-dependent fitness effects. Environ Microbiol 2015; 17:5008-22. [PMID: 25969927 PMCID: PMC4989453 DOI: 10.1111/1462-2920.12901] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 04/20/2015] [Accepted: 05/05/2015] [Indexed: 01/26/2023]
Abstract
Plasmids are important mobile elements that can facilitate genetic exchange and local adaptation within microbial communities. We compared the sequences of four co‐occurring pQBR family environmental mercury resistance plasmids and measured their effects on competitive fitness of a Pseudomonas fluorescens
SBW25 host, which was isolated at the same field site. Fitness effects of carriage differed between plasmids and were strongly context dependent, varying with medium, plasmid status of competitor and levels of environmental mercury. The plasmids also varied widely in their rates of conjugation and segregational loss. We found that few of the plasmid‐borne accessory genes could be ascribed functions, although we identified a putative chemotaxis operon, a type IV pilus‐encoding cluster and a region encoding putative arylsulfatase enzymes, which were conserved across geographically distant isolates. One plasmid, pQBR55, conferred the ability to catabolize sucrose. Transposons, including the mercury resistance Tn5042, appeared to have been acquired by different pQBR plasmids by recombination, indicating an important role for horizontal gene transfer in the recent evolution of pQBR plasmids. Our findings demonstrate extensive genetic and phenotypic diversity among co‐occurring members of a plasmid community and suggest a role for environmental heterogeneity in the maintenance of plasmid diversity.
Collapse
Affiliation(s)
- James P J Hall
- Department of Biology, Wentworth Way, University of York, York, UK
| | - Ellie Harrison
- Department of Biology, Wentworth Way, University of York, York, UK
| | - Andrew K Lilley
- Pharmaceutical Science Research Division, King's College London, London, UK
| | - Steve Paterson
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Andrew J Spiers
- The SIMBIOS Centre, School of Science, Engineering and Technology, Abertay University, Dundee, UK
| | | |
Collapse
|
49
|
Li X, Top EM, Wang Y, Brown CJ, Yao F, Yang S, Jiang Y, Li H. The broad-host-range plasmid pSFA231 isolated from petroleum-contaminated sediment represents a new member of the PromA plasmid family. Front Microbiol 2015; 5:777. [PMID: 25628616 PMCID: PMC4290620 DOI: 10.3389/fmicb.2014.00777] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 12/18/2014] [Indexed: 11/13/2022] Open
Abstract
A self-transmissible broad-host-range (BHR) plasmid pSFA231 was isolated from petroleum-contaminated sediment in Shen-fu wastewater irrigation zone, China, using the triparental mating exogenous plasmid capture method. Based on its complete sequence the plasmid has a size of 41.5 kb and codes for 50 putative open reading frames (orfs), 29 of which represent genes involved in replication, partitioning and transfer functions of the plasmid. Phylogenetic analysis grouped pSFA231 into the newly defined PromA plasmid family, which currently includes five members. Further comparative genomic analysis shows that pSFA231 shares the common backbone regions with the other PromA plasmids, i.e., genes involved in replication, maintenance and control, and conjugative transfer. Nevertheless, phylogenetic divergence was found in specific gene products. We propose to divide the PromA group into two subgroups, PromA-α (pMRAD02, pSB102) and PromA-β (pMOL98, pIPO2T, pSFA231, pTer331), based on the splits network analysis of the RepA protein. Interestingly, a cluster of hypothetical orfs located between parA and traA of pSFA231 shows high similarity with the corresponding regions on pMOL98, pIPO2T, and pTer331, suggesting these hypothetical orfs may represent “essential” plasmid backbone genes for the PromA-β subgroup. Alternatively, they may also be accessory genes that were first acquired and then stayed as the plasmid diverged. Our study increases the available collection of complete genome sequences of BHR plasmids, and since pSFA231 is the only characterized PromA plasmid from China, our findings also enhance our understanding of the genetic diversity of this plasmid group in different parts of the world.
Collapse
Affiliation(s)
- Xiaobin Li
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences Shenyang, China ; College of Resources and Environment, University of Chinese Academy of Sciences Beijing, China
| | - Eva M Top
- Department of Biological Sciences, Institute for Bioinformatics and Evolutionary Studies, University of Idaho Moscow, ID, USA
| | - Yafei Wang
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences Shenyang, China
| | - Celeste J Brown
- Department of Biological Sciences, Institute for Bioinformatics and Evolutionary Studies, University of Idaho Moscow, ID, USA
| | - Fei Yao
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences Shenyang, China ; College of Resources and Environment, University of Chinese Academy of Sciences Beijing, China
| | - Shan Yang
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences Shenyang, China
| | - Yong Jiang
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences Shenyang, China
| | - Hui Li
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences Shenyang, China
| |
Collapse
|
50
|
Freese PD, Korolev KS, Jiménez JI, Chen IA. Genetic drift suppresses bacterial conjugation in spatially structured populations. Biophys J 2014; 106:944-54. [PMID: 24559997 DOI: 10.1016/j.bpj.2014.01.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 01/02/2014] [Accepted: 01/10/2014] [Indexed: 11/24/2022] Open
Abstract
Conjugation is the primary mechanism of horizontal gene transfer that spreads antibiotic resistance among bacteria. Although conjugation normally occurs in surface-associated growth (e.g., biofilms), it has been traditionally studied in well-mixed liquid cultures lacking spatial structure, which is known to affect many evolutionary and ecological processes. Here we visualize spatial patterns of gene transfer mediated by F plasmid conjugation in a colony of Escherichia coli growing on solid agar, and we develop a quantitative understanding by spatial extension of traditional mass-action models. We found that spatial structure suppresses conjugation in surface-associated growth because strong genetic drift leads to spatial isolation of donor and recipient cells, restricting conjugation to rare boundaries between donor and recipient strains. These results suggest that ecological strategies, such as enforcement of spatial structure and enhancement of genetic drift, could complement molecular strategies in slowing the spread of antibiotic resistance genes.
Collapse
Affiliation(s)
- Peter D Freese
- FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts
| | - Kirill S Korolev
- FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts; Department of Physics, Harvard University, Cambridge, Massachusetts; Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts; Department of Physics and Program in Bioinformatics, Boston University, Boston, Massachusetts
| | - José I Jiménez
- FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts; Faculty of Health and Medical Sciences, University of Surrey, United Kingdom
| | - Irene A Chen
- FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts; Department of Chemistry and Biochemistry, Program in Biomolecular Sciences and Engineering, University of California at Santa Barbara, Santa Barbara, California.
| |
Collapse
|