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Liljegren MM, Gama JA, Johnsen PJ, Harms K. The recombination initiation functions DprA and RecFOR suppress microindel mutations in Acinetobacter baylyi ADP1. Mol Microbiol 2024. [PMID: 38760330 DOI: 10.1111/mmi.15277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 04/24/2024] [Accepted: 04/26/2024] [Indexed: 05/19/2024]
Abstract
Short-Patch Double Illegitimate Recombination (SPDIR) has been recently identified as a rare mutation mechanism. During SPDIR, ectopic DNA single-strands anneal with genomic DNA at microhomologies and get integrated during DNA replication, presumably acting as primers for Okazaki fragments. The resulting microindel mutations are highly variable in size and sequence. In the soil bacterium Acinetobacter baylyi, SPDIR is tightly controlled by genome maintenance functions including RecA. It is thought that RecA scavenges DNA single-strands and renders them unable to anneal. To further elucidate the role of RecA in this process, we investigate the roles of the upstream functions DprA, RecFOR, and RecBCD, all of which load DNA single-strands with RecA. Here we show that all three functions suppress SPDIR mutations in the wildtype to levels below the detection limit. While SPDIR mutations are slightly elevated in the absence of DprA, they are strongly increased in the absence of both DprA and RecA. This SPDIR-avoiding function of DprA is not related to its role in natural transformation. These results suggest a function for DprA in combination with RecA to avoid potentially harmful microindel mutations, and offer an explanation for the ubiquity of dprA in the genomes of naturally non-transformable bacteria.
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Affiliation(s)
- Mikkel M Liljegren
- Microbial Pharmacology and Population Biology Research Group, Department of Pharmacy, UiT The Arctic University of Norway, Tromsø, Norway
| | - João A Gama
- Microbial Pharmacology and Population Biology Research Group, Department of Pharmacy, UiT The Arctic University of Norway, Tromsø, Norway
- Department of Microbiology, Ramón y Cajal University Hospital, Ramón y Cajal Institute for Health Research (IRYCIS), Madrid, Spain
| | - Pål J Johnsen
- Microbial Pharmacology and Population Biology Research Group, Department of Pharmacy, UiT The Arctic University of Norway, Tromsø, Norway
| | - Klaus Harms
- Microbial Pharmacology and Population Biology Research Group, Department of Pharmacy, UiT The Arctic University of Norway, Tromsø, Norway
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Lorentzen ØM, Haukefer ASB, Johnsen PJ, Frøhlich C. The Biofilm Lifestyle Shapes the Evolution of β-Lactamases. Genome Biol Evol 2024; 16:evae030. [PMID: 38366392 PMCID: PMC10917518 DOI: 10.1093/gbe/evae030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 02/02/2024] [Accepted: 02/08/2024] [Indexed: 02/18/2024] Open
Abstract
The evolutionary relationship between the biofilm lifestyle and antibiotic resistance enzymes remains a subject of limited understanding. Here, we investigate how β-lactamases affect biofilm formation in Vibrio cholerae and how selection for a biofilm lifestyle impacts the evolution of these enzymes. Genetically diverse β-lactamases expressed in V. cholerae displayed a strong inhibitory effect on biofilm production. To understand how natural evolution affects this antagonistic pleiotropy, we randomly mutagenized a β-lactamase and selected for elevated biofilm formation. Our results revealed that biofilm evolution selects for β-lactamase variants able to hydrolyze β-lactams without inhibiting biofilms. Mutational analysis of evolved variants demonstrated that restoration of biofilm development was achieved either independently of enzymatic function or by actively leveraging enzymatic activity. Taken together, the biofilm lifestyle can impose a profound selective pressure on antimicrobial resistance enzymes. Shedding light on such evolutionary interplays is of importance to understand the factors driving antimicrobial resistance.
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Affiliation(s)
- Øyvind M Lorentzen
- Department of Pharmacy, UiT The Arctic University of Norway, Tromsø, Norway
| | | | - Pål J Johnsen
- Department of Pharmacy, UiT The Arctic University of Norway, Tromsø, Norway
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Pöntinen AK, Gladstone RA, Pesonen H, Pesonen M, Cléon F, Parcell BJ, Kallonen T, Simonsen GS, Croucher NJ, McNally A, Parkhill J, Johnsen PJ, Samuelsen Ø, Corander J. Modulation of multidrug-resistant clone success in Escherichia coli populations: a longitudinal, multi-country, genomic and antibiotic usage cohort study. Lancet Microbe 2024; 5:e142-e150. [PMID: 38219757 DOI: 10.1016/s2666-5247(23)00292-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 08/24/2023] [Accepted: 09/01/2023] [Indexed: 01/16/2024]
Abstract
BACKGROUND The effect of antibiotic usage on the success of multidrug-resistant (MDR) clones in a population remains unclear. With this genomics-based molecular epidemiology study, we aimed to investigate the contribution of antibiotic use to Escherichia coli clone success, relative to intra-strain competition for colonisation and infection. METHODS We sequenced all the available E coli bloodstream infection isolates provided by the British Society for Antimicrobial Chemotherapy (BSAC) from 2012 to 2017 (n=718) and combined these with published data from the UK (2001-11; n=1090) and Norway (2002-17; n=3254). Defined daily dose (DDD) data from the European Centre for Disease Prevention and Control (retrieved on Sept 21, 2021) for major antibiotic classes (β-lactam, tetracycline, macrolide, sulfonamide, quinolone, and non-penicillin β-lactam) were used together with sequence typing, resistance profiling, regression analysis, and non-neutral Wright-Fisher simulation-based modelling to enable systematic comparison of resistance levels, clone success, and antibiotic usage between the UK and Norway. FINDINGS Sequence type (ST)73, ST131, ST95, and ST69 accounted for 892 (49·3%) of 1808 isolates in the BSAC collection. In the UK, the proportion of ST69 increased between 2001-10 and 2011-17 (p=0·0004), whereas the proportions of ST73 and ST95 did not vary between periods. ST131 expanded quickly after its emergence in 2003 and its prevalence remained consistent throughout the study period (apart from a brief decrease in 2009-10). The extended-spectrum β-lactamase (ESBL)-carrying, globally disseminated MDR clone ST131-C2 showed overall greater success in the UK (154 [56·8%] of 271 isolates in 2003-17) compared with Norway (51 [18·3%] of 278 isolates in 2002-17; p<0·0001). DDD data indicated higher total use of antimicrobials in the UK, driven mainly by the class of non-penicillin β-lactams, which were used between 2·7-times and 5·1-times more in the UK per annum (ratio mean 3·7 [SD 0·8]). This difference was associated with the higher success of the MDR clone ST131-C2 (pseudo-R2 69·1%). A non-neutral Wright-Fisher model replicated the observed expansion of non-MDR and MDR sequence types under higher DDD regimes. INTERPRETATION Our study indicates that resistance profiles of contemporaneously successful clones can vary substantially, warranting caution in the interpretation of correlations between aggregate measures of resistance and antibiotic usage. Our study further suggests that in countries with low-to-moderate use of antibiotics, such as the UK and Norway, the extent of non-penicillin β-lactam use modulates rather than determines the success of widely disseminated MDR ESBL-carrying E coli clones. Detailed understanding of underlying causal drivers of success is important for improved control of resistant pathogens. FUNDING Trond Mohn Foundation, Marie Skłodowska-Curie Actions, European Research Council, Royal Society, and Wellcome Trust.
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Affiliation(s)
- Anna K Pöntinen
- Department of Biostatistics, Faculty of Medicine, University of Oslo, Oslo, Norway; Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway.
| | - Rebecca A Gladstone
- Department of Biostatistics, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Henri Pesonen
- Department of Biostatistics, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Maiju Pesonen
- Department of Biostatistics, Faculty of Medicine, University of Oslo, Oslo, Norway; Oslo Centre for Biostatistics and Epidemiology, Oslo University Hospital Research Support Services, Oslo, Norway
| | - François Cléon
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | | | - Teemu Kallonen
- Department of Clinical Microbiology, Turku University Hospital, Turku, Finland
| | - Gunnar Skov Simonsen
- Research Group for Host-Microbe Interaction, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway; Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Nicholas J Croucher
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Alan McNally
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Julian Parkhill
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Pål J Johnsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Ørjan Samuelsen
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway; Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Jukka Corander
- Department of Biostatistics, Faculty of Medicine, University of Oslo, Oslo, Norway; Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK; Helsinki Institute of Information Technology, Department of Mathematics and Statistics, University of Helsinki, Helsinki, Finland.
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Arredondo-Alonso S, Blundell-Hunter G, Fu Z, Gladstone RA, Fillol-Salom A, Loraine J, Cloutman-Green E, Johnsen PJ, Samuelsen Ø, Pöntinen AK, Cléon F, Chavez-Bueno S, De la Cruz MA, Ares MA, Vongsouvath M, Chmielarczyk A, Horner C, Klein N, McNally A, Reis JN, Penadés JR, Thomson NR, Corander J, Taylor PW, McCarthy AJ. Evolutionary and functional history of the Escherichia coli K1 capsule. Nat Commun 2023; 14:3294. [PMID: 37322051 PMCID: PMC10272209 DOI: 10.1038/s41467-023-39052-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 05/26/2023] [Indexed: 06/17/2023] Open
Abstract
Escherichia coli is a leading cause of invasive bacterial infections in humans. Capsule polysaccharide has an important role in bacterial pathogenesis, and the K1 capsule has been firmly established as one of the most potent capsule types in E. coli through its association with severe infections. However, little is known about its distribution, evolution and functions across the E. coli phylogeny, which is fundamental to elucidating its role in the expansion of successful lineages. Using systematic surveys of invasive E. coli isolates, we show that the K1-cps locus is present in a quarter of bloodstream infection isolates and has emerged in at least four different extraintestinal pathogenic E. coli (ExPEC) phylogroups independently in the last 500 years. Phenotypic assessment demonstrates that K1 capsule synthesis enhances E. coli survival in human serum independent of genetic background, and that therapeutic targeting of the K1 capsule re-sensitizes E. coli from distinct genetic backgrounds to human serum. Our study highlights that assessing the evolutionary and functional properties of bacterial virulence factors at population levels is important to better monitor and predict the emergence of virulent clones, and to also inform therapies and preventive medicine to effectively control bacterial infections whilst significantly lowering antibiotic usage.
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Affiliation(s)
- Sergio Arredondo-Alonso
- Department of Biostatistics, University of Oslo, 0317, Oslo, Norway
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK
| | | | - Zuyi Fu
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, UK
| | - Rebecca A Gladstone
- Department of Biostatistics, University of Oslo, 0317, Oslo, Norway
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK
| | - Alfred Fillol-Salom
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, UK
| | | | - Elaine Cloutman-Green
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Pål J Johnsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Ørjan Samuelsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Anna K Pöntinen
- Department of Biostatistics, University of Oslo, 0317, Oslo, Norway
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - François Cléon
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Susana Chavez-Bueno
- University of Missouri Kansas City, Kansas City, USA
- Division of Infectious Diseases, Children's Mercy Hospital Kansas City, UMKC School of Medicine, Kansas City, USA
| | - Miguel A De la Cruz
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI Instituto Mexicano del Seguro Social, Mexico City, Mexico
- Facultad de Medicina, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Miguel A Ares
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Manivanh Vongsouvath
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Agnieszka Chmielarczyk
- Faculty of Medicine, Chair of Microbiology, Jagiellonian University Medical College, Czysta str. 18, 31-121, Kraków, Poland
| | - Carolyne Horner
- British Society for Antimicrobial Chemotherapy, Birmingham, UK
| | - Nigel Klein
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Alan McNally
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Joice N Reis
- Laboratory of Pathology and Molecular Biology (LPBM), Gonçalo Moniz Research Institute, Oswaldo Cruz Foundation, Salvador, Brazil
- Faculdade de Farmácia, Universidade Federal da Bahia, Salvador, Brazil
| | - José R Penadés
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, UK
| | - Nicholas R Thomson
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK
- London School of Hygiene and Tropical Medicine, London, UK
| | - Jukka Corander
- Department of Biostatistics, University of Oslo, 0317, Oslo, Norway.
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK.
- Helsinki Institute of Information Technology, Department of Mathematics and Statistics, University of Helsinki, Helsinki, Finland.
| | - Peter W Taylor
- School of Pharmacy, University College London, London, UK.
| | - Alex J McCarthy
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, UK.
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5
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Mäklin T, Thorpe HA, Pöntinen AK, Gladstone RA, Shao Y, Pesonen M, McNally A, Johnsen PJ, Samuelsen Ø, Lawley TD, Honkela A, Corander J. Strong pathogen competition in neonatal gut colonisation. Nat Commun 2022; 13:7417. [PMID: 36456554 PMCID: PMC9715557 DOI: 10.1038/s41467-022-35178-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Accepted: 11/21/2022] [Indexed: 12/02/2022] Open
Abstract
Opportunistic bacterial pathogen species and their strains that colonise the human gut are generally understood to compete against both each other and the commensal species colonising this ecosystem. Currently we are lacking a population-wide quantification of strain-level colonisation dynamics and the relationship of colonisation potential to prevalence in disease, and how ecological factors might be modulating these. Here, using a combination of latest high-resolution metagenomics and strain-level genomic epidemiology methods we performed a characterisation of the competition and colonisation dynamics for a longitudinal cohort of neonatal gut microbiomes. We found strong inter- and intra-species competition dynamics in the gut colonisation process, but also a number of synergistic relationships among several species belonging to genus Klebsiella, which includes the prominent human pathogen Klebsiella pneumoniae. No evidence of preferential colonisation by hospital-adapted pathogen lineages in either vaginal or caesarean section birth groups was detected. Our analysis further enabled unbiased assessment of strain-level colonisation potential of extra-intestinal pathogenic Escherichia coli (ExPEC) in comparison with their propensity to cause bloodstream infections. Our study highlights the importance of systematic surveillance of bacterial gut pathogens, not only from disease but also from carriage state, to better inform therapies and preventive medicine in the future.
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Affiliation(s)
- Tommi Mäklin
- grid.7737.40000 0004 0410 2071Helsinki Institute for Information Technology HIIT, Department of Computer Science, University of Helsinki, Helsinki, Finland
| | - Harry A. Thorpe
- grid.5510.10000 0004 1936 8921Department of Biostatistics, University of Oslo, Oslo, Norway
| | - Anna K. Pöntinen
- grid.5510.10000 0004 1936 8921Department of Biostatistics, University of Oslo, Oslo, Norway ,grid.412244.50000 0004 4689 5540Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Rebecca A. Gladstone
- grid.5510.10000 0004 1936 8921Department of Biostatistics, University of Oslo, Oslo, Norway
| | - Yan Shao
- grid.10306.340000 0004 0606 5382Parasites and Microbes, Wellcome Sanger Institute, Hinxton, Cambridgeshire UK
| | - Maiju Pesonen
- grid.5510.10000 0004 1936 8921Department of Biostatistics, University of Oslo, Oslo, Norway
| | - Alan McNally
- grid.6572.60000 0004 1936 7486Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Pål J. Johnsen
- grid.10919.300000000122595234Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Ørjan Samuelsen
- grid.412244.50000 0004 4689 5540Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway ,grid.10919.300000000122595234Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Trevor D. Lawley
- grid.10306.340000 0004 0606 5382Parasites and Microbes, Wellcome Sanger Institute, Hinxton, Cambridgeshire UK
| | - Antti Honkela
- grid.7737.40000 0004 0410 2071Helsinki Institute for Information Technology HIIT, Department of Computer Science, University of Helsinki, Helsinki, Finland
| | - Jukka Corander
- grid.5510.10000 0004 1936 8921Department of Biostatistics, University of Oslo, Oslo, Norway ,grid.10306.340000 0004 0606 5382Parasites and Microbes, Wellcome Sanger Institute, Hinxton, Cambridgeshire UK ,grid.7737.40000 0004 0410 2071Helsinki Institute for Information Technology HIIT, Department of Mathematics and Statistics, University of Helsinki, Helsinki, Finland
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Guðmundsdóttir JS, Fredheim EGA, Koumans CIM, Hegstad J, Tang PC, Andersson DI, Samuelsen Ø, Johnsen PJ. The chemotherapeutic drug methotrexate selects for antibiotic resistance. EBioMedicine 2021; 74:103742. [PMID: 34902789 PMCID: PMC8671861 DOI: 10.1016/j.ebiom.2021.103742] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 10/27/2021] [Accepted: 11/25/2021] [Indexed: 11/28/2022] Open
Abstract
Background Understanding drivers of antibiotic resistance evolution is fundamental for designing optimal treatment strategies and interventions to reduce the spread of antibiotic resistance. Various cytotoxic drugs used in cancer chemotherapy have antibacterial properties, but how bacterial populations are affected by these selective pressures is unknown. Here we test the hypothesis that the widely used cytotoxic drug methotrexate affects the evolution and selection of antibiotic resistance. Methods First, we determined methotrexate susceptibility (IC90) and selective abilities in a collection of Escherichia coli and Klebsiella pneumoniae strains with and without pre-existing trimethoprim resistance determinants. We constructed fluorescently labelled pairs of E. coli MG1655 differing only in trimethoprim resistance determinants and determined the minimum selective concentrations of methotrexate using flow-cytometry. We further used an experimental evolution approach to investigate the effects of methotrexate on de novo trimethoprim resistance evolution. Findings We show that methotrexate can select for acquired trimethoprim resistance determinants located on the chromosome or a plasmid. Additionally, methotrexate co-selects for genetically linked resistance determinants when present together with trimethoprim resistance on a multi-drug resistance plasmid. These selective effects occur at concentrations 40- to >320-fold below the methotrexate minimal inhibitory concentration. Interpretation Our results strongly suggest a selective role of methotrexate for virtually any antibiotic resistance determinant when present together with trimethoprim resistance on a multi-drug resistance plasmid. The presented results may have significant implications for patient groups strongly depending on effective antibiotic treatment. Funding PJJ was supported by 10.13039/100007465UiT The Arctic University of Norway and the Northern Norway Regional Health Authority (SFP1292–16/HNF1586–21) and JPI-EC-AMR (Project 271,176/H10). DIA was supported by the 10.13039/501100004359Swedish Research Council (grant 2017–01,527). The publication charges for this article have been funded by a grant from the publication fund of UiT The Arctic University of Norway.
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Affiliation(s)
- Jónína S Guðmundsdóttir
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway.
| | - Elizabeth G A Fredheim
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | | | - Joachim Hegstad
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway; Research and Development Division, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Po-Cheng Tang
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Dan I Andersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Ørjan Samuelsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway; Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Pål J Johnsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway.
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Arredondo-Alonso S, Pöntinen AK, Cléon F, Gladstone RA, Schürch AC, Johnsen PJ, Samuelsen Ø, Corander J. A high-throughput multiplexing and selection strategy to complete bacterial genomes. Gigascience 2021; 10:giab079. [PMID: 34891160 PMCID: PMC8673558 DOI: 10.1093/gigascience/giab079] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 09/29/2021] [Accepted: 11/12/2021] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Bacterial whole-genome sequencing based on short-read technologies often results in a draft assembly formed by contiguous sequences. The introduction of long-read sequencing technologies permits those contiguous sequences to be unambiguously bridged into complete genomes. However, the elevated costs associated with long-read sequencing frequently limit the number of bacterial isolates that can be long-read sequenced. Here we evaluated the recently released 96 barcoding kit from Oxford Nanopore Technologies (ONT) to generate complete genomes on a high-throughput basis. In addition, we propose an isolate selection strategy that optimizes a representative selection of isolates for long-read sequencing considering as input large-scale bacterial collections. RESULTS Despite an uneven distribution of long reads per barcode, near-complete chromosomal sequences (assembly contiguity = 0.89) were generated for 96 Escherichia coli isolates with associated short-read sequencing data. The assembly contiguity of the plasmid replicons was even higher (0.98), which indicated the suitability of the multiplexing strategy for studies focused on resolving plasmid sequences. We benchmarked hybrid and ONT-only assemblies and showed that the combination of ONT sequencing data with short-read sequencing data is still highly desirable (i) to perform an unbiased selection of isolates for long-read sequencing, (ii) to achieve an optimal genome accuracy and completeness, and (iii) to include small plasmids underrepresented in the ONT library. CONCLUSIONS The proposed long-read isolate selection ensures the completion of bacterial genomes that span the genome diversity inherent in large collections of bacterial isolates. We show the potential of using this multiplexing approach to close bacterial genomes on a high-throughput basis.
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Affiliation(s)
- Sergio Arredondo-Alonso
- Department of Biostatistics, University of Oslo, 0317, Oslo, Norway
- Parasites and Microbes, Wellcome Sanger Institute, Cambridgeshire CB10 1RQ, UK
| | - Anna K Pöntinen
- Department of Biostatistics, University of Oslo, 0317, Oslo, Norway
| | - François Cléon
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | | | - Anita C Schürch
- Department of Medical Microbiology, UMC Utrecht, 3584 CX, Utrecht, the Netherlands
| | - Pål J Johnsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Ørjan Samuelsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, 9038, Tromsø, Norway
| | - Jukka Corander
- Department of Biostatistics, University of Oslo, 0317, Oslo, Norway
- Parasites and Microbes, Wellcome Sanger Institute, Cambridgeshire CB10 1RQ, UK
- Department of Mathematics and Statistics, Helsinki Institute of Information Technology (HIIT), FI-00014 University of Helsinki, 02130, Espoo, Helsinki, Finland
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Gladstone RA, McNally A, Johnsen PJ, Samuelsen Ø, Corander J. Antimicrobial resistance genes and clonal success in Escherichia coli isolates causing bloodstream infection – Authors’ reply. The Lancet Microbe 2021; 2:e493. [DOI: 10.1016/s2666-5247(21)00176-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 11/30/2022] Open
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Gladstone RA, McNally A, Pöntinen AK, Tonkin-Hill G, Lees JA, Skytén K, Cléon F, Christensen MOK, Haldorsen BC, Bye KK, Gammelsrud KW, Hjetland R, Kümmel A, Larsen HE, Lindemann PC, Löhr IH, Marvik Å, Nilsen E, Noer MT, Simonsen GS, Steinbakk M, Tofteland S, Vattøy M, Bentley SD, Croucher NJ, Parkhill J, Johnsen PJ, Samuelsen Ø, Corander J. Emergence and dissemination of antimicrobial resistance in Escherichia coli causing bloodstream infections in Norway in 2002-17: a nationwide, longitudinal, microbial population genomic study. Lancet Microbe 2021; 2:e331-e341. [PMID: 35544167 PMCID: PMC7614948 DOI: 10.1016/s2666-5247(21)00031-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 02/01/2021] [Accepted: 02/03/2021] [Indexed: 01/23/2023]
Abstract
BACKGROUND The clonal diversity underpinning trends in multidrug resistant Escherichia coli causing bloodstream infections remains uncertain. We aimed to determine the contribution of individual clones to resistance over time, using large-scale genomics-based molecular epidemiology. METHODS This was a longitudinal, E coli population, genomic, cohort study that sampled isolates from 22 512 E coli bloodstream infections included in the Norwegian surveillance programme on resistant microbes (NORM) from 2002 to 2017. 15 of 22 laboratories were able to share their isolates, and the first 22·5% of isolates from each year were requested. We used whole genome sequencing to infer the population structure (PopPUNK), and we investigated the clade composition of the dominant multidrug resistant clonal complex (CC)131 using genetic markers previously reported for sequence type (ST)131, effective population size (BEAST), and presence of determinants of antimicrobial resistance (ARIBA, PointFinder, and ResFinder databases) over time. We compared these features between the 2002-10 and 2011-17 time periods. We also compared our results with those of a longitudinal study from the UK done between 2001 and 2011. FINDINGS Of the 3500 isolates requested from the participating laboratories, 3397 (97·1%) were received, of which 3254 (95·8%) were successfully sequenced and included in the analysis. A significant increase in the number of multidrug resistant CC131 isolates from 71 (5·6%) of 1277 in 2002-10 to 207 (10·5%) of 1977 in 2011-17 (p<0·0001), was the largest clonal expansion. CC131 was the most common clone in extended-spectrum β-lactamase (ESBL)-positive isolates (75 [58·6%] of 128) and fluoroquinolone non-susceptible isolates (148 [39·2%] of 378). Within CC131, clade A increased in prevalence from 2002, whereas the global multidrug resistant clade C2 was not observed until 2007. Multiple de-novo acquisitions of both blaCTX-M ESBL-encoding genes in clades A and C1 and gain of phenotypic fluoroquinolone non-susceptibility across the clade A phylogeny were observed. We estimated that exponential increases in the effective population sizes of clades A, C1, and C2 occurred in the mid-2000s, and in clade B a decade earlier. The rate of increase in the estimated effective population size of clade A (Ne=3147) was nearly ten-times that of C2 (Ne=345), with clade A over-represented in Norwegian CC131 isolates (75 [27·0%] of 278) compared with the UK study (8 [5·4%] of 147 isolates). INTERPRETATION The early and sustained establishment of predominantly antimicrobial susceptible CC131 clade A isolates, relative to multidrug resistant clade C2 isolates, suggests that resistance is not necessary for clonal success. However, even in the low antibiotic use setting of Norway, resistance to important antimicrobial classes has rapidly been selected for in CC131 clade A isolates. This study shows the importance of genomic surveillance in uncovering the complex ecology underlying multidrug resistance dissemination and competition, which have implications for the design of strategies and interventions to control the spread of high-risk multidrug resistant clones. FUNDING Trond Mohn Foundation, European Research Council, Marie Skłodowska-Curie Actions, and the Wellcome Trust.
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Affiliation(s)
| | - Alan McNally
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Anna K Pöntinen
- Department of Biostatistics, University of Oslo, Oslo, Norway
| | | | - John A Lees
- Faculty of Medicine, School of Public Health, Imperial College, London, UK
| | - Kusti Skytén
- Department of Biostatistics, University of Oslo, Oslo, Norway
| | - François Cléon
- Department of Pharmacy, Faculty of Health Sciences UiT The Arctic University of Norway, Tromsø, Norway
| | - Martin O K Christensen
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Bjørg C Haldorsen
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Kristina K Bye
- Laboratory of Microbiology, Department of Medical Biochemistry, Oslo University Hospital Radiumhospitalet, Oslo, Norway
| | - Karianne W Gammelsrud
- Department of Microbiology, Division of Laboratory Medicine, Oslo University Hospital Ullevål, Oslo, Norway
| | - Reidar Hjetland
- Department of Microbiology, Førde General Hospital, Førde Health Trust, Førde, Norway
| | - Angela Kümmel
- Department of Laboratory Medicine, Levanger Hospital, Nord-Trøndelag Hospital Trust, Levanger, Norway
| | - Hege E Larsen
- Department of Microbiology, Nordland Hospital, Bodø, Norway
| | | | - Iren H Löhr
- Department of Medical Microbiology, Stavanger University Hospital, Stavanger, Norway
| | - Åshild Marvik
- Department of Microbiology, Vestfold Hospital, Tønsberg, Norway
| | - Einar Nilsen
- Department of Microbiology, Moere and Romsdal Hospital Trust, Molde, Norway
| | - Marie T Noer
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway; Institute of Medical Microbiology, Oslo University Hospital Rikshospitalet, Oslo, Norway
| | - Gunnar S Simonsen
- Department of Medical Biology, Faculty of Health Sciences UiT The Arctic University of Norway, Tromsø, Norway; Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway; Norwegian Institute of Public Health, Oslo, Norway
| | - Martin Steinbakk
- Centre for Laboratory Medicine, Sections for Microbiology, Østfold Hospital, Kalnes, Norway
| | - Ståle Tofteland
- Department of Medical Microbiology, Sørlandet Hospital, Kristiansand, Norway
| | - Marit Vattøy
- Department of Microbiology, Akershus University Hospital, Lørenskog, Norway
| | | | | | - Julian Parkhill
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Pål J Johnsen
- Department of Pharmacy, Faculty of Health Sciences UiT The Arctic University of Norway, Tromsø, Norway
| | - Ørjan Samuelsen
- Department of Pharmacy, Faculty of Health Sciences UiT The Arctic University of Norway, Tromsø, Norway; Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Jukka Corander
- Department of Biostatistics, University of Oslo, Oslo, Norway; Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK
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10
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Johnsen PJ, Gama JA, Harms K. Bacterial evolution on demand. eLife 2021; 10:68070. [PMID: 33820602 PMCID: PMC8024006 DOI: 10.7554/elife.68070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 03/29/2021] [Indexed: 11/23/2022] Open
Abstract
Bacteria carry antibiotic resistant genes on movable sections of DNA that allow them to select the relevant genes on demand.
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Affiliation(s)
- Pål J Johnsen
- Department of Pharmacy, Faculty of Health Sciences, The Arctic University of Norway, Tromsø, Norway
| | - João A Gama
- Department of Pharmacy, Faculty of Health Sciences, The Arctic University of Norway, Tromsø, Norway
| | - Klaus Harms
- Department of Pharmacy, Faculty of Health Sciences, The Arctic University of Norway, Tromsø, Norway
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11
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Kloos J, Gama JA, Hegstad J, Samuelsen Ø, Johnsen PJ. Piggybacking on Niche Adaptation Improves the Maintenance of Multidrug-Resistance Plasmids. Mol Biol Evol 2021; 38:3188-3201. [PMID: 33760032 PMCID: PMC8321521 DOI: 10.1093/molbev/msab091] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 02/12/2021] [Accepted: 03/23/2021] [Indexed: 12/27/2022] Open
Abstract
The persistence of plasmids in bacterial populations represents a puzzling evolutionary problem with serious clinical implications due to their role in the ongoing antibiotic resistance crisis. Recently, major advancements have been made toward resolving this “plasmid paradox” but mainly in a nonclinical context. Here, we propose an additional explanation for the maintenance of multidrug‐resistance plasmids in clinical Escherichia coli strains. After coevolving two multidrug‐resistance plasmids encoding resistance to last resort carbapenems with an extraintestinal pathogenic E. coli strain, we observed that chromosomal media adaptive mutations in the global regulatory systems CCR (carbon catabolite repression) and ArcAB (aerobic respiration control) pleiotropically improved the maintenance of both plasmids. Mechanistically, a net downregulation of plasmid gene expression reduced the fitness cost. Our results suggest that global chromosomal transcriptional rewiring during bacterial niche adaptation may facilitate plasmid maintenance.
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Affiliation(s)
- Julia Kloos
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - João A Gama
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Joachim Hegstad
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway.,Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Ørjan Samuelsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway.,Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Pål J Johnsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
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12
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Kloos J, Johnsen PJ, Harms K. Tn 1 transposition in the course of natural transformation enables horizontal antibiotic resistance spread in Acinetobacter baylyi. Microbiology (Reading) 2020; 167. [PMID: 33270000 PMCID: PMC8116780 DOI: 10.1099/mic.0.001003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Transposons are genetic elements that change their intracellular genomic position by transposition and are spread horizontally between bacteria when located on plasmids. It was recently discovered that transposition from fully heterologous DNA also occurs in the course of natural transformation. Here, we characterize the molecular details and constraints of this process using the replicative transposon Tn1 and the naturally competent bacterium Acinetobacter baylyi. We find that chromosomal insertion of Tn1 by transposition occurs at low but detectable frequencies and preferably around the A. baylyi terminus of replication. We show that Tn1 transposition is facilitated by transient expression of the transposase and resolvase encoded by the donor DNA. RecA protein is essential for the formation of a circular, double-stranded cytoplasmic intermediate from incoming donor DNA, and RecO is beneficial but not essential in this process. Absence of the recipient RecBCD nuclease stabilizes the double-stranded intermediate. Based on these results, we suggest a mechanistic model for transposition during natural transformation.
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Affiliation(s)
- Julia Kloos
- Microbial Pharmacology and Population Biology Research Group, Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Pål J Johnsen
- Microbial Pharmacology and Population Biology Research Group, Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Klaus Harms
- Microbial Pharmacology and Population Biology Research Group, Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
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13
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Gama JA, Kloos J, Johnsen PJ, Samuelsen Ø. Host dependent maintenance of a bla NDM-1-encoding plasmid in clinical Escherichia coli isolates. Sci Rep 2020; 10:9332. [PMID: 32518312 PMCID: PMC7283256 DOI: 10.1038/s41598-020-66239-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 05/15/2020] [Indexed: 11/09/2022] Open
Abstract
Dissemination of bacterial clones carrying plasmid-mediated resistance genes is a major factor contributing to the increasing prevalence of antibiotic resistance. Understanding the evolution of successful clones and the association to mobile resistance elements are therefore crucial. In this study, we determined the sequence of a 145 kb IncC multi-drug resistance plasmid (pK71-77-1-NDM), harbouring resistance genes to last-resort antibiotics including carbapenems. We show that the plasmid is able to transfer into a range of genetically diverse clinical Escherichia coli strains and that the fitness cost imposed on the host is often low. Moreover, the plasmid is stably maintained under non-selective conditions across different genetic backgrounds. However, we also observed a lower conjugation frequency and higher fitness cost in the E. coli sequence type (ST) 73 background, which could partially explain why this clone is associated with a lower level of antibiotic resistance than other E. coli clones. This is supported by a bioinformatical analysis showing that the ST73 background harbours plasmids less frequently than the other studied E. coli STs. Studying the evolution of antibiotic resistance in a clinical context and in diverse genetic backgrounds improves our understanding of the variability in plasmid-host associations.
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Affiliation(s)
- João Alves Gama
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Julia Kloos
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Pål J Johnsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Ørjan Samuelsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway. .,Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway.
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14
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Podnecky NL, Fredheim EGA, Kloos J, Sørum V, Primicerio R, Roberts AP, Rozen DE, Samuelsen Ø, Johnsen PJ. Conserved collateral antibiotic susceptibility networks in diverse clinical strains of Escherichia coli. Nat Commun 2018; 9:3673. [PMID: 30202004 PMCID: PMC6131505 DOI: 10.1038/s41467-018-06143-y] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 08/16/2018] [Indexed: 01/09/2023] Open
Abstract
There is urgent need to develop novel treatment strategies to reduce antimicrobial resistance. Collateral sensitivity (CS), where resistance to one antimicrobial increases susceptibility to other drugs, might enable selection against resistance during treatment. However, the success of this approach would depend on the conservation of CS networks across genetically diverse bacterial strains. Here, we examine CS conservation across diverse Escherichia coli strains isolated from urinary tract infections. We determine collateral susceptibilities of mutants resistant to relevant antimicrobials against 16 antibiotics. Multivariate statistical analyses show that resistance mechanisms, in particular efflux-related mutations, as well as the relative fitness of resistant strains, are principal contributors to collateral responses. Moreover, collateral responses shift the mutant selection window, suggesting that CS-informed therapies may affect evolutionary trajectories of antimicrobial resistance. Our data allow optimism for CS-informed therapy and further suggest that rapid detection of resistance mechanisms is important to accurately predict collateral responses.
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Affiliation(s)
- Nicole L Podnecky
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway.
| | - Elizabeth G A Fredheim
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Julia Kloos
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Vidar Sørum
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Raul Primicerio
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Adam P Roberts
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
- Research Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Daniel E Rozen
- Institute of Biology, Leiden University, Sylviusweg 72, PO Box 9505, 2300 RA, Leiden, The Netherlands
| | - Ørjan Samuelsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, 9037, Tromsø, Norway
| | - Pål J Johnsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway.
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15
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Ambur OH, Engelstädter J, Johnsen PJ, Miller EL, Rozen DE. Steady at the wheel: conservative sex and the benefits of bacterial transformation. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0528. [PMID: 27619692 PMCID: PMC5031613 DOI: 10.1098/rstb.2015.0528] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2016] [Indexed: 12/25/2022] Open
Abstract
Many bacteria are highly sexual, but the reasons for their promiscuity remain obscure. Did bacterial sex evolve to maximize diversity and facilitate adaptation in a changing world, or does it instead help to retain the bacterial functions that work right now? In other words, is bacterial sex innovative or conservative? Our aim in this review is to integrate experimental, bioinformatic and theoretical studies to critically evaluate these alternatives, with a main focus on natural genetic transformation, the bacterial equivalent of eukaryotic sexual reproduction. First, we provide a general overview of several hypotheses that have been put forward to explain the evolution of transformation. Next, we synthesize a large body of evidence highlighting the numerous passive and active barriers to transformation that have evolved to protect bacteria from foreign DNA, thereby increasing the likelihood that transformation takes place among clonemates. Our critical review of the existing literature provides support for the view that bacterial transformation is maintained as a means of genomic conservation that provides direct benefits to both individual bacterial cells and to transformable bacterial populations. We examine the generality of this view across bacteria and contrast this explanation with the different evolutionary roles proposed to maintain sex in eukaryotes. This article is part of the themed issue 'Weird sex: the underappreciated diversity of sexual reproduction'.
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Affiliation(s)
- Ole Herman Ambur
- Department of Life Sciences and Health, Oslo and Akershus University College of Applied Sciences, 1478 Oslo, Norway
| | - Jan Engelstädter
- School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Pål J Johnsen
- Faculty of Health Sciences, Department of Pharmacy, UiT-The Arctic University of Norway, 9037 Tromsø, Norway
| | - Eric L Miller
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PL, UK
| | - Daniel E Rozen
- Institute of Biology, Leiden University, 2333 BE Leiden, The Netherlands
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16
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Hülter N, Sørum V, Borch-Pedersen K, Liljegren MM, Utnes ALG, Primicerio R, Harms K, Johnsen PJ. Costs and benefits of natural transformation in Acinetobacter baylyi. BMC Microbiol 2017; 17:34. [PMID: 28202049 PMCID: PMC5312590 DOI: 10.1186/s12866-017-0953-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Accepted: 02/10/2017] [Indexed: 11/10/2022] Open
Abstract
Background Natural transformation enables acquisition of adaptive traits and drives genome evolution in prokaryotes. Yet, the selective forces responsible for the evolution and maintenance of natural transformation remain elusive since taken-up DNA has also been hypothesized to provide benefits such as nutrients or templates for DNA repair to individual cells. Results We investigated the immediate effects of DNA uptake and recombination on the naturally competent bacterium Acinetobacter baylyi in both benign and genotoxic conditions. In head-to-head competition experiments between DNA uptake-proficient and -deficient strains, we observed a fitness benefit of DNA uptake independent of UV stress. This benefit was found with both homologous and heterologous DNA and was independent of recombination. Recombination with taken-up DNA reduced survival of transformed cells with increasing levels of UV-stress through interference with nucleotide excision repair, suggesting that DNA strand breaks occur during recombination attempts with taken-up DNA. Consistent with this, we show that absence of RecBCD and RecFOR recombinational DNA repair pathways strongly decrease natural transformation. Conclusions Our data show a physiological benefit of DNA uptake unrelated to recombination. In contrast, recombination during transformation is a strand break inducing process that represents a previously unrecognized cost of natural transformation. Electronic supplementary material The online version of this article (doi:10.1186/s12866-017-0953-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nils Hülter
- Genomic Microbiology, Institute of Microbiology, Christian-Albrechts-University Kiel, Am Botanischen Garten 11, 24118, Kiel, Germany.,Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, P.O. Box 6050 Langnes, Tromsø, Norway
| | - Vidar Sørum
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, P.O. Box 6050 Langnes, Tromsø, Norway
| | - Kristina Borch-Pedersen
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, P.O. Box 8146 Dep, 0033, Oslo, Norway
| | - Mikkel M Liljegren
- Centre for Ecolgical and Evolutionary Synthesis, Faculty of Mathematics and Natural Sciences, University of Oslo, P.O. Box 1066 Blindern, 0316, Oslo, Norway
| | - Ane L G Utnes
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, P.O. Box 6050 Langnes, Tromsø, Norway
| | - Raul Primicerio
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, P.O. Box 6050 Langnes, Tromsø, Norway
| | - Klaus Harms
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, P.O. Box 6050 Langnes, Tromsø, Norway. .,Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350, Copenhagen K, Denmark.
| | - Pål J Johnsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, P.O. Box 6050 Langnes, Tromsø, Norway.
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17
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Di Luca MC, Sørum V, Starikova I, Kloos J, Hülter N, Naseer U, Johnsen PJ, Samuelsen Ø. Low biological cost of carbapenemase-encoding plasmids following transfer from Klebsiella pneumoniae to Escherichia coli. J Antimicrob Chemother 2016; 72:85-89. [PMID: 27591293 DOI: 10.1093/jac/dkw350] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 06/20/2016] [Accepted: 07/27/2016] [Indexed: 02/03/2023] Open
Abstract
OBJECTIVES The objective of this study was to determine the biological cost, stability and sequence of two carbapenemase-encoding plasmids containing blaKPC-2 (pG12-KPC-2) and blaVIM-1 (pG06-VIM-1) isolated from Klebsiella pneumoniae when newly acquired by uropathogenic Escherichia coli clinical isolates of different genetic backgrounds. METHODS The two plasmids were transferred into plasmid-free E. coli clinical isolates by transformation. The fitness effect of newly acquired plasmids on the host cell was assessed in head-to-head competitions with the corresponding isogenic strain. Plasmid stability was estimated by propagating monocultures for ∼312 generations. Plasmid nucleotide sequences were determined using next-generation sequencing technology. Assembly, gap closure, annotation and comparative analyses were performed. RESULTS Both plasmids were stably maintained in three of four E. coli backgrounds and resulted in low to moderate reductions in host fitness ranging from 1.1% to 3.6%. A difference in fitness cost was observed for pG12-KPC-2 between two different genetic backgrounds, while no difference was detected for pG06-VIM-1 between three different genetic backgrounds. In addition, a difference was observed between pG12-KPC-2 and pG06-VIM-1 in the same genetic background. In general, the magnitude of biological cost of plasmid carriage was both host and plasmid dependent. The sequences of the two plasmids showed high backbone similarity to previously circulating plasmids in K. pneumoniae. CONCLUSIONS The low to modest fitness cost of newly acquired and stably maintained carbapenemase-encoding plasmids in E. coli indicates a potential for establishment and further dissemination into other Enterobacteriaceae species. We also show that the fitness cost is both plasmid and host specific.
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Affiliation(s)
- Maria Chiara Di Luca
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Vidar Sørum
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Irina Starikova
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Julia Kloos
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Nils Hülter
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Umaer Naseer
- Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Pål J Johnsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Ørjan Samuelsen
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway .,Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
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18
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Engelstädter J, Harms K, Johnsen PJ. The evolutionary dynamics of integrons in changing environments. ISME J 2016; 10:1296-307. [PMID: 26849314 DOI: 10.1038/ismej.2015.222] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 10/13/2015] [Accepted: 10/16/2015] [Indexed: 11/09/2022]
Abstract
Integrons are genetic elements that are common in bacteria and are hotspots for genome evolution. They facilitate the acquisition and reassembly of gene cassettes encoding a variety of functions, including drug resistance. Despite their importance in clinical settings, the selective forces responsible for the evolution and maintenance of integrons are poorly understood. We present a mathematical model of integron evolution within bacterial populations subject to fluctuating antibiotic exposures. Bacteria carrying a functional integrase that mediates reshuffling of cassette genes and thereby modulates gene expression patterns compete with bacteria without a functional integrase. Our results indicate that for a wide range of parameters, the functional integrase can be stably maintained in the population despite substantial fitness costs. This selective advantage arises because gene-cassette shuffling generates genetic diversity, thus enabling the population to respond rapidly to changing selective pressures. We also show that horizontal gene transfer promotes stable maintenance of the integrase and can also lead to de novo assembly of integrons. Our model generates testable predictions for integron evolution, including loss of functional integrases in stable environments and selection for intermediate gene-shuffling rates in changing environments. Our results highlight the need for experimental studies of integron population biology.
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Affiliation(s)
- Jan Engelstädter
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Klaus Harms
- Faculty of Health Sciences, Department of Pharmacy, UIT - The Arctic University of Norway, Tromsø, Norway.,Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - Pål J Johnsen
- Faculty of Health Sciences, Department of Pharmacy, UIT - The Arctic University of Norway, Tromsø, Norway
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19
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Harms K, Starikova I, Johnsen PJ. Costly Class-1 integrons and the domestication of the the functional integrase. Mob Genet Elements 2014; 3:e24774. [PMID: 23914313 PMCID: PMC3681742 DOI: 10.4161/mge.24774] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 04/15/2013] [Accepted: 04/22/2013] [Indexed: 11/19/2022] Open
Abstract
Class-1 integrons play an important role in the emergence and spread of antimicrobial resistance determinants. In a recent study we showed that host fitness was dramatically reduced following acquisition of these elements. These fitness costs were due to the presence of an active integrase and we suggested that the mechanistic explanation was due to reduced genetic stability through IntI1 mediated recombination events between attI/attC and non-canonical sites in the chromosome. Here we demonstrate that the attI degenerated target sequence is highly prevalent in our model organism Acinetobacter baylyi adding support to the hypothesis that IntI1 is costly due to genomic instability.
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Affiliation(s)
- Klaus Harms
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, Norway
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20
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Levin BR, Baquero F, Johnsen PJ. A model-guided analysis and perspective on the evolution and epidemiology of antibiotic resistance and its future. Curr Opin Microbiol 2014; 19:83-89. [PMID: 25016172 DOI: 10.1016/j.mib.2014.06.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 06/11/2014] [Accepted: 06/11/2014] [Indexed: 01/06/2023]
Abstract
A simple epidemiological model is used as a framework to explore the potential efficacy of measures to control antibiotic resistance in community-based self-limiting human infections. The analysis of the properties of this model predict that resistance can be maintained at manageable levels if: first, the rates at which specific antibiotics are used declines with the frequency of resistance to these drugs; second, resistance rarely emerges during therapy; and third, external sources rarely contribute to the entry of resistant bacteria into the community. We discuss the feasibility and limitations of these measures to control the rates of antibiotic resistance and the potential of advances in diagnostic procedures to facilitate this endeavor.
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Affiliation(s)
- Bruce R Levin
- Department of Biology Emory University, Atlanta, GA, USA.
| | - Fernando Baquero
- Ramón y Cajal Institute for Health Research (IRYCIS), Ramón y Cajal University Hospital, Madrid, Spain
| | - Pål J Johnsen
- Department of Pharmacy, UiT, The Arctic University, Tromsø, Norway
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21
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Fulsundar S, Harms K, Flaten GE, Johnsen PJ, Chopade BA, Nielsen KM. Gene transfer potential of outer membrane vesicles of Acinetobacter baylyi and effects of stress on vesiculation. Appl Environ Microbiol 2014; 80:3469-83. [PMID: 24657872 PMCID: PMC4018862 DOI: 10.1128/aem.04248-13] [Citation(s) in RCA: 157] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 03/19/2014] [Indexed: 11/20/2022] Open
Abstract
Outer membrane vesicles (OMVs) are continually released from a range of bacterial species. Numerous functions of OMVs, including the facilitation of horizontal gene transfer (HGT) processes, have been proposed. In this study, we investigated whether OMVs contribute to the transfer of plasmids between bacterial cells and species using Gram-negative Acinetobacter baylyi as a model system. OMVs were extracted from bacterial cultures and tested for the ability to vector gene transfer into populations of Escherichia coli and A. baylyi, including naturally transformation-deficient mutants of A. baylyi. Anti-double-stranded DNA (anti-dsDNA) antibodies were used to determine the movement of DNA into OMVs. We also determined how stress affected the level of vesiculation and the amount of DNA in vesicles. OMVs were further characterized by measuring particle size distribution (PSD) and zeta potential. Transmission electron microscopy (TEM) and immunogold labeling were performed using anti-fluorescein isothiocyanate (anti-FITC)-conjugated antibodies and anti-dsDNA antibodies to track the movement of FITC-labeled and DNA-containing OMVs. Exposure to OMVs isolated from plasmid-containing donor cells resulted in HGT to A. baylyi and E. coli at transfer frequencies ranging from 10(-6) to 10(-8), with transfer efficiencies of approximately 10(3) and 10(2) per μg of vesicular DNA, respectively. Antibiotic stress was shown to affect the DNA content of OMVs as well as their hydrodynamic diameter and zeta potential. Morphological observations suggest that OMVs from A. baylyi interact with recipient cells in different ways, depending on the recipient species. Interestingly, the PSD measurements suggest that distinct size ranges of OMVs are released from A. baylyi.
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Affiliation(s)
- Shweta Fulsundar
- Institute of Bioinformatics and Biotechnology, University of Pune, Pune, India
- Department of Pharmacy, University of Tromsø, Tromsø, Norway
| | - Klaus Harms
- Department of Pharmacy, University of Tromsø, Tromsø, Norway
| | - Gøril E. Flaten
- Department of Pharmacy, University of Tromsø, Tromsø, Norway
| | - Pål J. Johnsen
- Department of Pharmacy, University of Tromsø, Tromsø, Norway
| | | | - Kaare M. Nielsen
- Department of Pharmacy, University of Tromsø, Tromsø, Norway
- Genøk-Center for Biosafety, Research Park, Tromsø, Norway
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22
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Starikova I, Al-Haroni M, Werner G, Roberts AP, Sørum V, Nielsen KM, Johnsen PJ. Fitness costs of various mobile genetic elements in Enterococcus faecium and Enterococcus faecalis. J Antimicrob Chemother 2013; 68:2755-65. [PMID: 23833178 PMCID: PMC3820106 DOI: 10.1093/jac/dkt270] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Objectives To determine the fitness effects of various mobile genetic elements (MGEs) in Enterococcus faecium and Enterococcus faecalis when newly acquired. We also tested the hypothesis that the biological cost of vancomycin resistance plasmids could be mitigated during continuous growth in the laboratory. Methods Different MGEs, including two conjugative transposons (CTns) of the Tn916 family (18 and 33 kb), a pathogenicity island (PAI) of 200 kb and vancomycin-resistance (vanA) plasmids (80–200 kb) of various origins and classes, were transferred into common ancestral E. faecium and E. faecalis strains by conjugation assays and experimentally evolved (vanA plasmids only). Transconjugants were characterized by PFGE, S1 nuclease assays and Southern blotting hybridization analyses. Single specific primer PCR was performed to determine the target sites for the insertion of the CTns. The fitness costs of various MGEs in E. faecium and E. faecalis were estimated in head-to-head competition experiments, and evolved populations were generated in serial transfer assays. Results The biological cost of a newly acquired PAI and two CTns were both host- and insertion-locus-dependent. Newly acquired vanA plasmids may severely reduce host fitness (25%–27%), but these costs were rapidly mitigated after only 400 generations of continuous growth in the absence of antibiotic selection. Conclusions Newly acquired MGEs may impose an immediate biological cost in E. faecium. However, as demonstrated for vanA plasmids, the initial costs of MGE carriage may be mitigated during growth and beneficial plasmid–host association can rapidly emerge.
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Affiliation(s)
- Irina Starikova
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
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Starikova I, Harms K, Haugen P, Lunde TTM, Primicerio R, Samuelsen Ø, Nielsen KM, Johnsen PJ. A trade-off between the fitness cost of functional integrases and long-term stability of integrons. PLoS Pathog 2012; 8:e1003043. [PMID: 23209414 PMCID: PMC3510236 DOI: 10.1371/journal.ppat.1003043] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 10/05/2012] [Indexed: 11/23/2022] Open
Abstract
Horizontal gene transfer (HGT) plays a major role in bacterial microevolution as evident from the rapid emergence and spread of antimicrobial drug resistance. Few studies have however addressed the population dynamics of newly imported genetic elements after HGT. Here, we show that newly acquired class-1 integrons from Salmonella enterica serovar Typhimurium and Acinetobacter baumannii, free of associated transposable elements, strongly reduce host fitness in Acinetobacter baylyi. Insertional inactivation of the integron intI1 restored fitness, demonstrating that the observed fitness costs were due to the presence of an active integrase. The biological cost of harboring class-1 integrons was rapidly reduced during serial transfers due to intI1 frameshift mutations leading to inactivated integrases. We use a mathematical model to explore the conditions where integrons with functional integrases are maintained and conclude that environmental fluctuations and episodic selection is necessary for the maintenance of functional integrases. Taken together, the presented data suggest a trade-off between the ability to capture gene cassettes and long-term stability of integrons and provide an explanation for the frequent observation of inactive integron-integrases in bacterial populations. Horizontal acquisition of mobile and mobilizable genetic elements plays a major role in the development of antimicrobial drug resistance in bacteria. Despite their causal role in drug treatment failure, there is only limited understanding of how horizontal acquisitions of these elements affect bacterial fitness. A prominent group of such genetic elements are the integrons. These genetic elements harbor an integrase-gene that allows the integron to respond to environmental changes by capture and excision of gene cassettes. Here, we have experimentally determined if horizontal acquisition of an integron affect host fitness. The data demonstrate that the initial costs are substantial. However, inactivation of the integrase gene occurred rapidly by spontaneous mutation alleviating the detrimental effect of the integron on bacterial fitness. The same fitness restoring effects was also shown by targeted inactivation of the integrase gene. The inactivation results in a negative trade-off between host adaptation and loss of the ability to capture new gene cassettes. Importantly, our results explain the frequent observation of inactive integrase genes in integrons found in bacteria of different origins. Finally, we use mathematical modeling to determine the conditions necessary for maintaining functional integrases.
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Affiliation(s)
- Irina Starikova
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
| | - Klaus Harms
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
| | - Pål Haugen
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
| | - Tracy T. M. Lunde
- Reference Centre for Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Raul Primicerio
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
| | - Ørjan Samuelsen
- Reference Centre for Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Kaare M. Nielsen
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
- GenØk, Center for Biosafety, Research Park, Tromsø, Norway
| | - Pål J. Johnsen
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
- * E-mail:
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24
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Domingues S, Harms K, Fricke WF, Johnsen PJ, da Silva GJ, Nielsen KM. Natural transformation facilitates transfer of transposons, integrons and gene cassettes between bacterial species. PLoS Pathog 2012; 8:e1002837. [PMID: 22876180 PMCID: PMC3410848 DOI: 10.1371/journal.ppat.1002837] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 06/19/2012] [Indexed: 12/24/2022] Open
Abstract
We have investigated to what extent natural transformation acting on free DNA substrates can facilitate transfer of mobile elements including transposons, integrons and/or gene cassettes between bacterial species. Naturally transformable cells of Acinetobacter baylyi were exposed to DNA from integron-carrying strains of the genera Acinetobacter, Citrobacter, Enterobacter, Escherichia, Pseudomonas, and Salmonella to determine the nature and frequency of transfer. Exposure to the various DNA sources resulted in acquisition of antibiotic resistance traits as well as entire integrons and transposons, over a 24 h exposure period. DNA incorporation was not solely dependent on integrase functions or the genetic relatedness between species. DNA sequence analyses revealed that several mechanisms facilitated stable integration in the recipient genome depending on the nature of the donor DNA; homologous or heterologous recombination and various types of transposition (Tn21-like and IS26-like). Both donor strains and transformed isolates were extensively characterized by antimicrobial susceptibility testing, integron- and cassette-specific PCRs, DNA sequencing, pulsed field gel electrophoreses (PFGE), Southern blot hybridizations, and by re-transformation assays. Two transformant strains were also genome-sequenced. Our data demonstrate that natural transformation facilitates interspecies transfer of genetic elements, suggesting that the transient presence of DNA in the cytoplasm may be sufficient for genomic integration to occur. Our study provides a plausible explanation for why sequence-conserved transposons, IS elements and integrons can be found disseminated among bacterial species. Moreover, natural transformation of integron harboring populations of competent bacteria revealed that interspecies exchange of gene cassettes can be highly efficient, and independent on genetic relatedness between donor and recipient. In conclusion, natural transformation provides a much broader capacity for horizontal acquisitions of genetic elements and hence, resistance traits from divergent species than previously assumed. Genetic elements, such as transposons and integrons, frequently carry antimicrobial resistance determinants and can be found widely disseminated among pathogenic bacteria. Their distribution pattern suggests dissemination through horizontal gene transfer. The role of natural transformation in horizontal transfer of genetic elements other than those that are self-replicative (plasmids) has remained largely unexplored. We have tested if natural transformation can facilitate transfer of transposons and class 1 integrons between bacterial species. We here provide experimental evidence showing that natural transformation can be a general mechanism for dissemination of genetic elements that by themselves do not encode interspecies transfer functions (e.g. transposons, insertion sequences). We demonstrate that antibiotic resistance determinants present in such genetic elements can spread by natural transformation between species of clinical interest. We show by quantitative data that interspecies exchange of resistance gene cassettes is highly efficient among integron-containing strains and species. Our study also provides a plausible explanation for how sequence-conserved integrons can become distributed among bacterial species.
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Affiliation(s)
- Sara Domingues
- Centre of Pharmaceutical Studies, Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
| | - Klaus Harms
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
| | - W. Florian Fricke
- Institute for Genome Sciences, University of Maryland, School of Medicine, Baltimore, Maryland, United States of America
| | - Pål J. Johnsen
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
| | - Gabriela J. da Silva
- Centre of Pharmaceutical Studies, Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Kaare Magne Nielsen
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
- Genøk-Centre for Biosafety, Tromsø, Norway
- * E-mail:
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25
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Johnsen PJ, Townsend JP, Bøhn T, Simonsen GS, Sundsfjord A, Nielsen KM. Retrospective evidence for a biological cost of vancomycin resistance determinants in the absence of glycopeptide selective pressures. J Antimicrob Chemother 2011; 66:608-10. [PMID: 21217128 PMCID: PMC3037156 DOI: 10.1093/jac/dkq512] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Objectives To estimate the relative fitness differences between glycopeptide-resistant Enterococcus faecium (GREF) and glycopeptide-susceptible E. faecium (GSEF) from yearly surveillance data on the occurrence of GREF in Danish poultry farm environments. Methods A population genetic model was adapted to retrospectively estimate the biological fitness cost of acquired resistance. Maximization of a likelihood function was used to predict the longitudinal persistence of acquired resistance. Results Our analysis suggests strong selection against GREF following the 1995 ban on the glycopeptide growth promoter avoparcin. However, parameterizing the model with two selection coefficients suggesting a reduced negative effect of the acquired resistance on bacterial fitness over time significantly improved the fit of the model. Our analyses suggest that the acquired glycopeptide resistance will persist for >25 years. Conclusions Acquired resistance determinants in commensal E. faecium populations in Danish farm environments are likely to persist for decades, even in the absence of glycopeptide use.
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Affiliation(s)
- P J Johnsen
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, 9037 Tromsø, Norway.
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26
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Sletvold H, Johnsen PJ, Wikmark OG, Simonsen GS, Sundsfjord A, Nielsen KM. Tn1546 is part of a larger plasmid-encoded genetic unit horizontally disseminated among clonal Enterococcus faecium lineages. J Antimicrob Chemother 2010; 65:1894-906. [PMID: 20558469 PMCID: PMC2920175 DOI: 10.1093/jac/dkq219] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES To determine the genetic composition of the first VanA-type plasmid (pIP816) reported, which was isolated from a clinical Enterococcus faecium (BM4147) strain in France in 1986, and to reveal the genetic units responsible for the dissemination of the vanA gene cluster by comparisons with current, published and additionally generated vanA-spanning plasmid sequences obtained from a heterogeneous E. faecium strain collection (n = 28). METHODS Plasmid sequences were produced by shotgun sequencing using ABI dye chemistry and primer walking, and were subsequently annotated. Comparative sequence analysis of the vanA region was done with published plasmids, with a partial vanA plasmid (pVEF4) reported here and to >140 kb of sequence obtained from a collection of vanA-harbouring plasmid fragments. RESULTS Bioinformatic analyses revealed that pIP816 from 1986 and contemporary vanA plasmids shared a conserved genetic fragment of 25 kb, spanning the 10.85 kb vanA cluster encoded by Tn1546, and that the larger unit is present in both clinical and animal complexes of E. faecium. A new group II intron in pVEF4 was characterized. CONCLUSIONS Comparative DNA analyses suggest that Tn1546 disseminates in and between clonal complexes of E. faecium as part of a larger genetic unit, possibly as a composite transposon flanked by IS1216 elements.
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Affiliation(s)
- H Sletvold
- Department of Pharmacy, Faculty of Medicine, University of Tromsø, 9037 Tromsø, Norway
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27
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Abstract
From the perspective of a bacterium, higher eukaryotes are oversexed, unadventurous and reproduce in an inconvenient way. Sex, or recombination following horizontal gene transfer (HGT) events, to be less provocative, is a rare event for a bacterium, but a potentially profound one. Through HGT a bacterium can acquire DNA from distant as well as closely related species and, thereby, instantly obtain genes that encode novel functions or replace its existing genes with better ones. While there is an abundance of retrospective evidence for HGT in bacteria, there has been little consideration of the dynamics of the process. In this issue of Molecular Microbiology Lind et al. explore these dynamics theoretically, and then experimentally by substituting Salmonella Typhimurium ribosomal genes with orthologues from various microbial origins. The authors show that the majority of these newly acquired ribosomal proteins reduce fitness in S. Typhimurium, but within short order (40-250 generations) subsequent evolution will mitigate the fitness costs of the alien alleles. The presented results suggest that that at least the initial phase of adapting to alien genes of this informational core ilk is not by changing them but rather by increasing their level of expression by gene amplification. Lind et al. argue that their results provide an explanation as to why duplicated genes are overrepresented among horizontally transferred genes.
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Affiliation(s)
- Pål J Johnsen
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway.
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28
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Brusetti L, Glad T, Borin S, Myren P, Rizzi A, Johnsen PJ, Carter P, Daffonchio D, Nielsen KM. Low prevalence ofblaTEMgenes in Arctic environments and agricultural soil and rhizosphere. Microbial Ecology in Health and Disease 2009. [DOI: 10.1080/08910600701838244] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Lorenzo Brusetti
- Department of Food Science, Technology and Microbiology (DISTAM), University of Milan, Milan, Italy
| | - Trine Glad
- Department of Pharmacy, Faculty of Medicine, University of Tromsø, Tromsø, Norway
| | - Sara Borin
- Department of Food Science, Technology and Microbiology (DISTAM), University of Milan, Milan, Italy
| | - Petter Myren
- Department of Pharmacy, Faculty of Medicine, University of Tromsø, Tromsø, Norway
- ESR Kenepuru Science Centre, Porirua, New Zealand
| | - Aurora Rizzi
- Department of Food Science, Technology and Microbiology (DISTAM), University of Milan, Milan, Italy
| | - Pål J. Johnsen
- Department of Pharmacy, Faculty of Medicine, University of Tromsø, Tromsø, Norway
| | - Phil Carter
- ESR Kenepuru Science Centre, Porirua, New Zealand
| | - Daniele Daffonchio
- Department of Food Science, Technology and Microbiology (DISTAM), University of Milan, Milan, Italy
| | - Kaare M. Nielsen
- Department of Pharmacy, Faculty of Medicine, University of Tromsø, Tromsø, Norway
- Norwegian Institute of Gene Ecology, Science Park, Tromsø, Norway
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29
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Johnsen PJ, Townsend JP, Bøhn T, Simonsen GS, Sundsfjord A, Nielsen KM. Factors affecting the reversal of antimicrobial-drug resistance. Lancet Infect Dis 2009; 9:357-64. [PMID: 19467475 DOI: 10.1016/s1473-3099(09)70105-7] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The persistence or loss of acquired antimicrobial-drug resistance in bacterial populations previously exposed to drug-selective pressure depends on several biological processes. We review mechanisms promoting or preventing the loss of resistance, including rates of reacquisition, effects of resistance traits on bacterial fitness, linked selection, and segregational stability of resistance determinants. As a case study, we discuss the persistence of glycopeptide-resistant enterococci in Norwegian and Danish poultry farms 12 years after the ban of the animal growth promoter avoparcin. We conclude that complete eradication of antimicrobial resistance in bacterial populations following relaxed drug-selective pressures is not straightforward. Resistance determinants may persist at low, but detectable, levels for many years in the absence of the corresponding drugs.
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Affiliation(s)
- Pål J Johnsen
- Department of Pharmacy, Faculty of Medicine, University of Tromsø, Tromsø, Norway.
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30
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Sletvold H, Johnsen PJ, Hamre I, Simonsen GS, Sundsfjord A, Nielsen KM. Complete sequence of Enterococcus faecium pVEF3 and the detection of an omega-epsilon-zeta toxin-antitoxin module and an ABC transporter. Plasmid 2008; 60:75-85. [PMID: 18511120 DOI: 10.1016/j.plasmid.2008.04.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Revised: 04/11/2008] [Accepted: 04/14/2008] [Indexed: 10/22/2022]
Abstract
Glycopeptide resistant Enterococcus faecium (GREF) persists on Norwegian poultry farms despite the ban on the growth promoter avoparcin. The biological basis for long-term persistence of avoparcin resistance is not fully understood. This study presents the complete DNA sequence of the E. faecium R-plasmid pVEF3 and functional studies of some plasmid-encoded traits (a toxin-antitoxin (TA) system and an ABC transporter) that may be of importance for plasmid persistence. The pVEF3 (63.1 kbp), isolated from an E. faecium strain of poultry origin sampled in Norway in 1999, has 71 coding sequences including the vanA avoparcin/vancomycin resistance encoding gene cluster. pVEF3 encodes the TA system omega-epsilon-zeta, and plasmid stability tests and transcription analysis show that omega-epsilon-zeta is functional in Enterococcus faecalis OGIX, although with decreasing effect over time. The predicted ABC transporter was not found to confer reduced susceptibility to any of the 28 substances tested. The TA system identified in the pVEF-type plasmids may contribute to vanA plasmid persistence on Norwegian poultry farms. However, size and compositional heterogeneity among E. faecium vanA plasmids suggest that additional plasmid maintenance systems in combination with host specific factors and frequent horizontal gene transfer and rearrangement causes the observed plasmid composition and distribution patterns.
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Affiliation(s)
- H Sletvold
- Department of Pharmacy, Faculty of Medicine, University of Tromsø, 9037 Tromsø, Norway.
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Nielsen KM, Johnsen PJ, Bensasson D, Daffonchio D. Release and persistence of extracellular DNA in the environment. ACTA ACUST UNITED AC 2007; 6:37-53. [DOI: 10.1051/ebr:2007031] [Citation(s) in RCA: 366] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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32
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Sletvold H, Johnsen PJ, Simonsen GS, Aasnaes B, Sundsfjord A, Nielsen KM. Comparative DNA analysis of two vanA plasmids from Enterococcus faecium strains isolated from poultry and a poultry farmer in Norway. Antimicrob Agents Chemother 2006; 51:736-9. [PMID: 17116680 PMCID: PMC1797720 DOI: 10.1128/aac.00557-06] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The DNA sequences of two plasmids carrying vanA, pVEF1 (39,626 bp) and pVEF2 (39,714 bp), were determined. Forty-three shared coding sequences were identified, and the only nucleotide difference was an 88-bp indel. A postsegregational killing system was identified. This system possibly explains the persistence of the vanA gene cluster in Norwegian poultry farms.
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Affiliation(s)
- H Sletvold
- Department of Pharmacy, Faculty of Medicine, University of Tromsø, and Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway.
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Sørum M, Johnsen PJ, Aasnes B, Rosvoll T, Kruse H, Sundsfjord A, Simonsen GS. Prevalence, persistence, and molecular characterization of glycopeptide-resistant enterococci in Norwegian poultry and poultry farmers 3 to 8 years after the ban on avoparcin. Appl Environ Microbiol 2006; 72:516-21. [PMID: 16391086 PMCID: PMC1352202 DOI: 10.1128/aem.72.1.516-521.2006] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2005] [Accepted: 10/20/2005] [Indexed: 11/20/2022] Open
Abstract
Environmental reservoirs of glycopeptide-resistant enterococci (GRE) in Norway have been linked to former growth promoting use of the glycopeptide avoparcin in poultry production. We have examined the prevalence of fecal GRE in poultry and poultry farmers 3 to 8 years after the Norwegian avoparcin ban in 1995 and performed molecular analyses of the GRE population. Fecal samples from poultry farmers and their flocks on 29 previously avoparcin-exposed farms were collected on five occasions during the study period (1998 to 2003). All flocks (100%) were GRE positive in 1998. Throughout the study period, 78.5% of the poultry samples were GRE positive. Glycopeptide-resistant Enterococcus faecium (GREF) was isolated from 27.6% of the farmer samples in 1998 and from 27.8% of the samples collected between 1998 and 2003. The prevalence of fecal GRE in poultry declined significantly during the study period, but prevalence in samples from the farmers did not decline. PCR analysis revealed a specific Tn1546-plasmid junction fragment in 93.9% of E. faecium isolates. A putative postsegregation killing (PSK) system linked to Tn1546 was detected in 97.1% of the isolates examined. Multilocus sequence typing of glycopeptide-susceptible (n = 10) and -resistant (n = 10) E. faecium isolates from humans (n = 10) and poultry (n = 10) on two farms displayed 17 different sequence types. The study confirms the continuing persistence of a widespread common plasmid-mediated vanA-pRE25-PSK element within a heterogeneous GRE population on Norwegian poultry farms 8 years after the avoparcin ban. Moreover, it suggests an important role of PSK systems in the maintenance of antimicrobial resistance determinants in reservoirs without apparent antimicrobial selection.
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Affiliation(s)
- M Sørum
- Department of Microbiology and Virology, Faculty of Medicine, University and University Hospital of North Norway, Tromsø, Norway.
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Johnsen PJ, Østerhus JI, Sletvold H, Sørum M, Kruse H, Nielsen K, Simonsen GS, Sundsfjord A. Persistence of animal and human glycopeptide-resistant enterococci on two Norwegian poultry farms formerly exposed to avoparcin is associated with a widespread plasmid-mediated vanA element within a polyclonal enterococcus faecium population. Appl Environ Microbiol 2005; 71:159-68. [PMID: 15640183 PMCID: PMC544227 DOI: 10.1128/aem.71.1.159-168.2005] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2004] [Accepted: 08/23/2004] [Indexed: 11/20/2022] Open
Abstract
The evolutionary processes responsible for the long-term persistence of glycopeptide-resistant Enterococcus faecium (GREF) in nonselective environments were addressed by genetic analyses of E. faecium populations in animals and humans on two Norwegian poultry farms that were previously exposed to avoparcin. A total of 222 fecal GREF (n = 136) and glycopeptide-susceptible (n = 86) E. faecium (GSEF) isolates were obtained from farmers and poultry on three separate occasions in 1998 and 1999. Pulsed-field gel electrophoresis (PFGE) and plasmid DNA analyses discerned 22 GREF and 32 GSEF PFGE types within shifting polyclonal animal and human E. faecium populations and indicated the presence of transferable plasmid-mediated vanA resistance, respectively. Examples of dominant, persistent GREF PFGE types supported the notion that environmentally well-adapted GREF types may counteract the reversal of resistance. PFGE analyses, sequencing of the purK housekeeping gene, and partial typing of vanA-containing Tn1546 suggested a common animal and human reservoir of glycopeptide resistance. Inverse PCR amplification and sequence analyses targeting the right end of the Tn1546-plasmid junction fragment strongly indicated the presence of a common single Tn1546-plasmid-mediated element in 20 of 22 GREF PFGE types. This observation was further strengthened by vanY-vanZ hybridization analyses of plasmid DNAs as well as the finding of a physical linkage between Tn1546 and a putative postsegregation killing system for seven GREF PFGE types. In conclusion, our observations suggest that the molecular unit of persistence of glycopeptide resistance is a common mobile plasmid-mediated vanA-containing element within a polyclonal GREF population that changes over time. In addition, we propose that "plasmid addiction systems" may contribute to the persistence of GREF in nonselective environments.
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Affiliation(s)
- P J Johnsen
- Department of Microbiology and Virology, Faculty of Medicine, University of Tromsø, N-9037 Tromsø, Norway.
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Johnsen PJ, Simonsen GS, Olsvik O, Midtvedt T, Sundsfjord A. Stability, persistence, and evolution of plasmid-encoded VanA glycopeptide resistance in enterococci in the absence of antibiotic selection in vitro and in gnotobiotic mice. Microb Drug Resist 2003; 8:161-70. [PMID: 12363004 DOI: 10.1089/107662902760326869] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Long-term persistence of VanA glycopeptide-resistant enterococci (GRE) has been observed in the absence of antibiotic selection. In the present study, we examined fitness parameters of a glycopeptide-susceptible Enterococcus faecium parent strain and its plasmid-mediated, VanA-resistant derivative before and after 1,000 generations in serial transfer broth cultures with or without antibiotic selection. With the exception of the vanA-containing plasmid, the strains were otherwise isogenic. The stability of the plasmid-encoded vanA resistance determinant was also investigated in vitro and in gnotobiotic mice. Competition experiments revealed that GRE with newly acquired VanA resistance had a 4% reduction in fitness relative to their susceptible parental counterpart. The relative difference in competitive fitness between resistant and susceptible strains was not significantly changed after 1,000 generations. Environmental adaptation was observed in all strains and exceeded the biological cost of resistance. Thus, the evolved VanA-resistant E. faecium populations out-numbered their unevolved ancestral susceptible E. faecium strain in mixed cultures, but remained less competitive than the evolved parent. The glycopeptide resistance determinant was similarly stably maintained during long-term colonization in gnotobiotic mice without antibiotic selection. In vivo vanA plasmid transfer was observed. The results suggest that environmental adaptation, in vivo gene transfer, and plasmid maintenance system(s) favor long-term VanA GRE persistence without antibiotic selection and compensate for the biological costs of possessing the resistance genes.
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Affiliation(s)
- Pål J Johnsen
- Department of Microbiology and Virology, University and University Hospital of Tromsø, Norway.
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