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Michaelis C, Berger TMI, Kuhlmann K, Ghulam R, Petrowitsch L, Besora Vecino M, Gesslbauer B, Pavkov-Keller T, Keller W, Grohmann E. Effect of TraN key residues involved in DNA binding on pIP501 transfer rates in Enterococcus faecalis. Front Mol Biosci 2024; 11:1268647. [PMID: 38380428 PMCID: PMC10877727 DOI: 10.3389/fmolb.2024.1268647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 01/04/2024] [Indexed: 02/22/2024] Open
Abstract
Conjugation is a major mechanism that facilitates the exchange of antibiotic resistance genes among bacteria. The broad-host-range Inc18 plasmid pIP501 harbors 15 genes that encode for a type IV secretion system (T4SS). It is a membrane-spanning multiprotein complex formed between conjugating donor and recipient cells. The penultimate gene of the pIP501 operon encodes for the cytosolic monomeric protein TraN. This acts as a transcriptional regulator by binding upstream of the operon promotor, partially overlapping with the origin of transfer. Additionally, TraN regulates traN and traO expression by binding upstream of the PtraNO promoter. This study investigates the impact of nine TraN amino acids involved in binding to pIP501 DNA through site-directed mutagenesis by exchanging one to three residues by alanine. For three traN variants, complementation of the pIP501∆traN knockout resulted in an increase of the transfer rate by more than 1.5 orders of magnitude compared to complementation of the mutant with native traN. Microscale thermophoresis (MST) was used to assess the binding affinities of three TraN double-substituted variants and one triple-substituted variant to its cognate pIP501 double-stranded DNA. The MST data strongly correlated with the transfer rates obtained by biparental mating assays in Enterococcus faecalis. The TraN variants TraN_R23A-N24A-Q28A, TraN_H82A-R86A, and TraN_G100A-K101A not only exhibited significantly lower DNA binding affinities but also, upon complementation of the pIP501∆traN knockout, resulted in the highest pIP501 transfer rates. This confirms the important role of the TraN residues R23, N24, Q28, H82, R86, G100, and K101 in downregulating pIP501 transfer. Although TraN is not part of the mating pair formation complex, TraE, TraF, TraH, TraJ, TraK, and TraM were coeluted with TraN in a pull-down. Moreover, TraN homologs are present not only in Inc18 plasmids but also in RepA_N and Rep_3 family plasmids, which are frequently found in enterococci, streptococci, and staphylococci. This points to a widespread role of this repressor in conjugative plasmid transfer among Firmicutes.
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Affiliation(s)
- Claudia Michaelis
- Faculty of Life Sciences and Technology, Department of Microbiology, Berliner Hochschule für Technik, Berlin, Germany
| | | | - Kirill Kuhlmann
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Rangina Ghulam
- Faculty of Life Sciences and Technology, Department of Microbiology, Berliner Hochschule für Technik, Berlin, Germany
| | - Lukas Petrowitsch
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | | | - Bernd Gesslbauer
- Institute of Pharmaceutical Sciences, Division of Pharmaceutical Chemistry, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
| | - Tea Pavkov-Keller
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
| | - Walter Keller
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
| | - Elisabeth Grohmann
- Faculty of Life Sciences and Technology, Department of Microbiology, Berliner Hochschule für Technik, Berlin, Germany
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2
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Frederiksen RF, Slettemeås JS, Granstad S, Lagesen K, Pikkemaat MG, Urdahl AM, Simm R. Polyether ionophore resistance in a one health perspective. Front Microbiol 2024; 15:1347490. [PMID: 38351920 PMCID: PMC10863045 DOI: 10.3389/fmicb.2024.1347490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 01/09/2024] [Indexed: 02/16/2024] Open
Abstract
Antimicrobial resistance is a major threat to human health and must be approached from a One Health perspective. Use of antimicrobials in animal husbandry can lead to dissemination and persistence of resistance in human pathogens. Polyether ionophores (PIs) have antimicrobial activities and are among the most extensively used feed additives for major production animals. Recent discoveries of genetically encoded PI resistance mechanisms and co-localization of resistance mechanisms against PIs and antimicrobials used in human medicine on transferrable plasmids, have raised concerns that use of PIs as feed additives bear potential risks for human health. This review summarizes the current knowledge on PI resistance and discusses the potential consequences of PI-usage as feed additives in a One Health perspective.
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Affiliation(s)
| | - Jannice Schau Slettemeås
- Department of Animal Health, Welfare and Food Safety, Norwegian Veterinary Institute, Ås, Norway
| | - Silje Granstad
- Department of Animal Health, Welfare and Food Safety, Norwegian Veterinary Institute, Ås, Norway
| | - Karin Lagesen
- Department of Animal Health, Welfare and Food Safety, Norwegian Veterinary Institute, Ås, Norway
| | - Mariel G. Pikkemaat
- Wageningen Food Safety Research, Wageningen University and Research, Wageningen, Netherlands
| | - Anne Margrete Urdahl
- Department of Animal Health, Welfare and Food Safety, Norwegian Veterinary Institute, Ås, Norway
| | - Roger Simm
- Department of Biosciences, University of Oslo, Oslo, Norway
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3
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Sarosh A, Kwong SM, Jensen SO, Northern F, Walton WG, Eakes TC, Redinbo MR, Firth N, McLaughlin KJ. pSK41/pGO1-family conjugative plasmids of Staphylococcus aureus encode a cryptic repressor of replication. Plasmid 2023; 128:102708. [PMID: 37967733 DOI: 10.1016/j.plasmid.2023.102708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 11/01/2023] [Accepted: 11/09/2023] [Indexed: 11/17/2023]
Abstract
The majority of large multiresistance plasmids of Staphylococcus aureus utilise a RepA_N-type replication initiation protein, the expression of which is regulated by a small antisense RNA (RNAI) that overlaps the rep mRNA leader. The pSK41/pGO1-family of conjugative plasmids additionally possess a small (86 codon) divergently transcribed ORF (orf86) located upstream of the rep locus. The product of pSK41 orf86 was predicted to have a helix-turn-helix motif suggestive of a likely function in transcriptional repression. In this study, we investigated the effect of Orf86 on transcription of thirteen pSK41 backbone promoters. We found that Orf86 only repressed transcription from the rep promoter, and hence now redesignate the product as Cop. Over-expression of Cop in trans reduced the copy number of pSK41 mini-replicons, both in the presence and absence of rnaI. in vitro protein-DNA binding experiments with purified 6 × His-Cop demonstrated specific DNA binding, adjacent to, and partially overlapping the -35 hexamer of the rep promoter. The crystal structure of Cop revealed a dimeric structure similar to other known transcriptional regulators. Cop mRNA was found to result from "read-through" transcription from the strong RNAI promoter that escapes the rnaI terminator. Thus, PrnaI is responsible for transcription of two distinct negative regulators of plasmid copy number; the antisense RNAI that primarily represses Rep translation, and Cop protein that can repress rep transcription. Deletion of cop in a native plasmid did not appear to impact copy number, indicating a cryptic auxiliary role.
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Affiliation(s)
- Alvina Sarosh
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Stephen M Kwong
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Slade O Jensen
- Microbiology and Infectious Diseases, School of Medicine, Western Sydney University, Sydney, New South Wales 2751, Australia; Antibiotic Resistance & Mobile Elements Group, Ingham Institute for Applied Medical Research, Liverpool, New South Wales 2170, Australia
| | - Faith Northern
- Chemistry Department, Vassar College, Poughkeepsie, NY 12604, USA
| | - William G Walton
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Thomas C Eakes
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Matthew R Redinbo
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Biochemistry, Microbiology and Genomics, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Neville Firth
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia.
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4
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Messele YE, Trott DJ, Hasoon MF, Veltman T, McMeniman JP, Kidd SP, Petrovski KR, Low WY. Phylogeny, Virulence, and Antimicrobial Resistance Gene Profiles of Enterococcus faecium Isolated from Australian Feedlot Cattle and Their Significance to Public and Environmental Health. Antibiotics (Basel) 2023; 12:1122. [PMID: 37508218 PMCID: PMC10376260 DOI: 10.3390/antibiotics12071122] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 06/22/2023] [Accepted: 06/27/2023] [Indexed: 07/30/2023] Open
Abstract
The extent of similarity between E. faecium strains found in healthy feedlot beef cattle and those causing extraintestinal infections in humans is not yet fully understood. This study used whole-genome sequencing to analyse the antimicrobial resistance profile of E. faecium isolated from beef cattle (n = 59) at a single feedlot and compared them to previously reported Australian isolates obtained from pig (n = 60) and meat chicken caecal samples (n = 8), as well as human sepsis cases (n = 302). The E. faecium isolated from beef cattle and other food animal sources neither carried vanA/vanB responsible for vancomycin nor possessed gyrA/parC and liaR/liaS gene mutations associated with high-level fluoroquinolone and daptomycin resistance, respectively. A small proportion (7.6%) of human isolates clustered with beef cattle and pig isolates, including a few isolates belonging to the same sequence types ST22 (one beef cattle, one pig, and two human isolates), ST32 (eight beef cattle and one human isolate), and ST327 (two beef cattle and one human isolate), suggesting common origins. This provides further evidence that these clonal lineages may have broader host range but are unrelated to the typical hospital-adapted human strains belonging to clonal complex 17, significant proportions of which contain vanA/vanB and liaR/liaS. Additionally, none of the human isolates belonging to these STs contained resistance genes to WHO critically important antimicrobials. The results confirm that most E. faecium isolated from beef cattle in this study do not pose a significant risk for resistance to critically important antimicrobials and are not associated with current human septic infections.
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Affiliation(s)
- Yohannes E Messele
- The Davies Livestock Research Centre, School of Animal and Veterinary Sciences, University of Adelaide, Adelaide, SA 5371, Australia
| | - Darren J Trott
- The Australian Centre for Antimicrobial Resistance Ecology, University of Adelaide, Adelaide, SA 5005, Australia
| | - Mauida F Hasoon
- The Australian Centre for Antimicrobial Resistance Ecology, University of Adelaide, Adelaide, SA 5005, Australia
| | - Tania Veltman
- The Australian Centre for Antimicrobial Resistance Ecology, University of Adelaide, Adelaide, SA 5005, Australia
| | - Joe P McMeniman
- Meat & Livestock Australia, Level 1, 40 Mount Street, North Sydney, NSW 2060, Australia
| | - Stephen P Kidd
- The Australian Centre for Antimicrobial Resistance Ecology, University of Adelaide, Adelaide, SA 5005, Australia
- Research Centre for Infectious Disease, School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Kiro R Petrovski
- The Davies Livestock Research Centre, School of Animal and Veterinary Sciences, University of Adelaide, Adelaide, SA 5371, Australia
- The Australian Centre for Antimicrobial Resistance Ecology, University of Adelaide, Adelaide, SA 5005, Australia
| | - Wai Y Low
- The Davies Livestock Research Centre, School of Animal and Veterinary Sciences, University of Adelaide, Adelaide, SA 5371, Australia
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Halgasova N, Javorova R, Bocanova L, Krajcikova D, Bauer JA, Bukovska G. Characterization of a newly discovered putative DNA replication initiator from Paenibacillus polymyxa phage phiBP. Microbiol Res 2023; 274:127437. [PMID: 37327604 DOI: 10.1016/j.micres.2023.127437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/08/2023] [Accepted: 06/10/2023] [Indexed: 06/18/2023]
Abstract
The bacteriophage phiBP contains a newly discovered putative replisome organizer, a helicase loader, and a beta clamp, which together may serve to replicate its DNA. Bioinformatics analysis of the phiBP replisome organizer sequence showed that it belongs to a recently identified family of putative initiator proteins. We prepared and isolated a wild type-like recombinant protein, gpRO-HC, and a mutant protein gpRO-HCK8A, containing a lysine to alanine substitution at position 8. gpRO-HC had low ATPase activity regardless of the presence of DNA, while the ATPase activity of the mutant was significantly higher. gpRO-HC bound to both single- and double-stranded DNA substrates. Different methods showed that gpRO-HC forms higher oligomers containing about 12 subunits. This work provides the first information about another group of phage initiator proteins, which trigger DNA replication in phages infecting low GC Gram-positive bacteria.
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Affiliation(s)
- Nora Halgasova
- Department of Genomics and Biotechnology, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
| | - Rachel Javorova
- Department of Genomics and Biotechnology, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
| | - Lucia Bocanova
- Department of Genomics and Biotechnology, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
| | - Daniela Krajcikova
- Department of Microbial Genetics, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
| | - Jacob A Bauer
- Department of Biochemistry and Protein Structure, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
| | - Gabriela Bukovska
- Department of Genomics and Biotechnology, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
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6
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Al-Trad EI, Chew CH, Che Hamzah AM, Suhaili Z, Rahman NIA, Ismail S, Puah SM, Chua KH, Kwong SM, Yeo CC. The Plasmidomic Landscape of Clinical Methicillin-Resistant Staphylococcus aureus Isolates from Malaysia. Antibiotics (Basel) 2023; 12:antibiotics12040733. [PMID: 37107095 PMCID: PMC10135026 DOI: 10.3390/antibiotics12040733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 03/31/2023] [Accepted: 04/07/2023] [Indexed: 04/29/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a priority nosocomial pathogen with plasmids playing a crucial role in its genetic adaptability, particularly in the acquisition and spread of antimicrobial resistance. In this study, the genome sequences of 79 MSRA clinical isolates from Terengganu, Malaysia, (obtained between 2016 and 2020) along with an additional 15 Malaysian MRSA genomes from GenBank were analyzed for their plasmid content. The majority (90%, 85/94) of the Malaysian MRSA isolates harbored 1-4 plasmids each. In total, 189 plasmid sequences were identified ranging in size from 2.3 kb to ca. 58 kb, spanning all seven distinctive plasmid replication initiator (replicase) types. Resistance genes (either to antimicrobials, heavy metals, and/or biocides) were found in 74% (140/189) of these plasmids. Small plasmids (<5 kb) were predominant (63.5%, 120/189) with a RepL replicase plasmid harboring the ermC gene that confers resistance to macrolides, lincosamides, and streptogramin B (MLSB) identified in 63 MRSA isolates. A low carriage of conjugative plasmids was observed (n = 2), but the majority (64.5%, 122/189) of the non-conjugative plasmids have mobilizable potential. The results obtained enabled us to gain a rare view of the plasmidomic landscape of Malaysian MRSA isolates and reinforces their importance in the evolution of this pathogen.
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Affiliation(s)
- Esra'a I Al-Trad
- Centre for Research in Infectious Diseases and Biotechnology (CeRIDB), Faculty of Medicine, Universiti Sultan Zainal Abidin, Kuala Terengganu 20400, Malaysia
| | - Ching Hoong Chew
- Faculty of Health Sciences, Universiti Sultan Zainal Abidin, Kuala Nerus 21300, Malaysia
| | | | - Zarizal Suhaili
- Faculty of Bioresources and Food Industry, Universiti Sultan Zainal Abidin, Besut 22200, Malaysia
| | - Nor Iza A Rahman
- Centre for Research in Infectious Diseases and Biotechnology (CeRIDB), Faculty of Medicine, Universiti Sultan Zainal Abidin, Kuala Terengganu 20400, Malaysia
| | - Salwani Ismail
- Centre for Research in Infectious Diseases and Biotechnology (CeRIDB), Faculty of Medicine, Universiti Sultan Zainal Abidin, Kuala Terengganu 20400, Malaysia
| | - Suat Moi Puah
- Department of Biomedical Science, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Kek Heng Chua
- Department of Biomedical Science, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Stephen M Kwong
- Infectious Diseases & Microbiology, School of Medicine, Western Sydney University, Campbelltown 2560, Australia
| | - Chew Chieng Yeo
- Centre for Research in Infectious Diseases and Biotechnology (CeRIDB), Faculty of Medicine, Universiti Sultan Zainal Abidin, Kuala Terengganu 20400, Malaysia
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7
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Comparative Genomic Analysis of a Multidrug-Resistant Staphylococcus hominis ShoR14 Clinical Isolate from Terengganu, Malaysia, Led to the Discovery of Novel Mobile Genetic Elements. Pathogens 2022; 11:pathogens11121406. [PMID: 36558739 PMCID: PMC9782665 DOI: 10.3390/pathogens11121406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 11/20/2022] [Accepted: 11/21/2022] [Indexed: 11/24/2022] Open
Abstract
Staphylococcus hominis is a coagulase-negative Staphylococcus (CoNS) commensal capable of causing serious systemic infections in humans. The emergence of multidrug-resistant S. hominis strains is of concern but little is known about the characteristics of this organism, particularly from Malaysia. Here, we present the comparative genome analysis of S. hominis ShoR14, a multidrug-resistant, methicillin-resistant blood isolate from Terengganu, Malaysia. Genomic DNA of S. hominis ShoR14 was sequenced on the Illumina platform and assembled using Unicycler v0.4.8. ShoR14 belonged to sequence type (ST) 1 which is the most prevalent ST of the S. hominis subsp. hominis. Comparative genomic analysis with closely related strains in the database with complete genome sequences, led to the discovery of a novel variant of the staphylococcal chromosome cassette mec (SCCmec) type VIII element harboring the mecA methicillin-resistance gene in ShoR14 and its possible carriage of a SCCfus element that encodes the fusidic acid resistance gene (fusC). Up to seven possible ShoR14 plasmid contigs were identified, three of which harbored resistance genes for tetracycline (tetK), chloramphenicol (catA7), macrolides, lincosamides, and streptogramin B (ermC). Additionally, we report the discovery of a novel mercury-resistant transposon, Tn7456, other genomic islands, and prophages which make up the S. hominis mobilome.
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8
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Val-Calvo J, Miguel-Arribas A, Abia D, Wu LJ, Meijer WJJ. pLS20 is the archetype of a new family of conjugative plasmids harboured by Bacillus species. NAR Genom Bioinform 2021; 3:lqab096. [PMID: 34729475 PMCID: PMC8557374 DOI: 10.1093/nargab/lqab096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 09/03/2021] [Accepted: 10/04/2021] [Indexed: 12/12/2022] Open
Abstract
Conjugation plays important roles in genome plasticity, adaptation and evolution but is also the major horizontal gene-transfer route responsible for spreading toxin, virulence and antibiotic resistance genes. A better understanding of the conjugation process is required for developing drugs and strategies to impede the conjugation-mediated spread of these genes. So far, only a limited number of conjugative elements have been studied. For most of them, it is not known whether they represent a group of conjugative elements, nor about their distribution patterns. Here we show that pLS20 from the Gram-positive bacterium Bacillus subtilis is the prototype conjugative plasmid of a family of at least 35 members that can be divided into four clades, and which are harboured by different Bacillus species found in different global locations and environmental niches. Analyses of their phylogenetic relationship and their conjugation operons have expanded our understanding of a family of conjugative plasmids of Gram-positive origin.
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Affiliation(s)
- Jorge Val-Calvo
- Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), C. Nicolás Cabrera 1, Universidad Autónoma de Madrid, Canto Blanco, 28049, Madrid, Spain
| | - Andrés Miguel-Arribas
- Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), C. Nicolás Cabrera 1, Universidad Autónoma de Madrid, Canto Blanco, 28049, Madrid, Spain
| | - David Abia
- Bioinformatics Facility, Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), C. Nicolás Cabrera 1, Universidad Autónoma de Madrid, Canto Blanco, 28049, Madrid, Spain
| | - Ling Juan Wu
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4AX, UK
| | - Wilfried J J Meijer
- Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), C. Nicolás Cabrera 1, Universidad Autónoma de Madrid, Canto Blanco, 28049, Madrid, Spain
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9
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Guimarães VA, Le Scornet A, Khemici V, Hausmann S, Armitano J, Prados J, Jousselin A, Manzano C, Linder P, Redder P. RNase J1 and J2 Are Host-Encoded Factors for Plasmid Replication. Front Microbiol 2021; 12:586886. [PMID: 34017314 PMCID: PMC8129170 DOI: 10.3389/fmicb.2021.586886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 04/06/2021] [Indexed: 11/13/2022] Open
Abstract
Plasmids need to ensure their transmission to both daughter-cells when their host divides, but should at the same time avoid overtaxing their hosts by directing excessive host-resources toward production of plasmid factors. Naturally occurring plasmids have therefore evolved regulatory mechanisms to restrict their copy-number in response to the volume of the cytoplasm. In many plasmid families, copy-number control is mediated by a small plasmid-specified RNA, which is continuously produced and rapidly degraded, to ensure that its concentration is proportional to the current plasmid copy-number. We show here that pSA564 from the RepA_N-family is regulated by a small antisense RNA (RNA1), which, when over-expressed in trans, blocks plasmid replication and cures the bacterial host. The 5' untranslated region (5'UTR) of the plasmid replication initiation gene (repA) potentially forms two mutually exclusive secondary structures, ON and OFF, where the latter both sequesters the repA ribosome binding site and acts as a rho-independent transcriptional terminator. Duplex formation between RNA1 and the 5'UTR shifts the equilibrium to favor the putative OFF-structure, enabling a single small RNA to down-regulate repA expression at both transcriptional and translational levels. We further examine which sequence elements on the antisense RNA and on its 5'UTR target are needed for this regulation. Finally, we identify the host-encoded exoribonucleases RNase J1 and J2 as the enzymes responsible for rapidly degrading the replication-inhibiting section of RNA1. This region accumulates and blocks RepA expression in the absence of either RNase J1 or J2, which are therefore essential host factors for pSA564 replication in Staphylococcus aureus.
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Affiliation(s)
- Vanessa Andrade Guimarães
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Alexandre Le Scornet
- Laboratoire de Microbiologie et Génétique Moléculaires, Centre de Biologie Integrative, Paul Sabatier University, Toulouse, France
| | - Vanessa Khemici
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Stéphane Hausmann
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Joshua Armitano
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Julien Prados
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Ambre Jousselin
- Laboratoire de Microbiologie et Génétique Moléculaires, Centre de Biologie Integrative, Paul Sabatier University, Toulouse, France
| | - Caroline Manzano
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Patrick Linder
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Peter Redder
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Laboratoire de Microbiologie et Génétique Moléculaires, Centre de Biologie Integrative, Paul Sabatier University, Toulouse, France
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10
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Barth ZK, Silvas TV, Angermeyer A, Seed KD. Genome replication dynamics of a bacteriophage and its satellite reveal strategies for parasitism and viral restriction. Nucleic Acids Res 2020; 48:249-263. [PMID: 31667508 PMCID: PMC7145576 DOI: 10.1093/nar/gkz1005] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 09/14/2019] [Accepted: 10/17/2019] [Indexed: 12/13/2022] Open
Abstract
Phage-inducible chromosomal island-like elements (PLEs) are bacteriophage satellites found in Vibrio cholerae. PLEs parasitize the lytic phage ICP1, excising from the bacterial chromosome, replicating, and mobilizing to new host cells following cell lysis. PLEs protect their host cell populations by completely restricting the production of ICP1 progeny. Previously, it was found that ICP1 replication was reduced during PLE(+) infection. Despite robust replication of the PLE genome, relatively few transducing units are produced. We investigated if PLE DNA replication itself is antagonistic to ICP1 replication. Here we identify key constituents of PLE replication and assess their role in interference of ICP1. PLE encodes a RepA_N initiation factor that is sufficient to drive replication from the PLE origin of replication during ICP1 infection. In contrast to previously characterized bacteriophage satellites, expression of the PLE initiation factor was not sufficient for PLE replication in the absence of phage. Replication of PLE was necessary for interference of ICP1 DNA replication, but replication of a minimalized PLE replicon was not sufficient for ICP1 DNA replication interference. Despite restoration of ICP1 DNA replication, non-replicating PLE remained broadly inhibitory against ICP1. These results suggest that PLE DNA replication is one of multiple mechanisms contributing to ICP1 restriction.
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Affiliation(s)
- Zachary K Barth
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Tania V Silvas
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Angus Angermeyer
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Kimberley D Seed
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA.,Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
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11
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Evolution of a 72-Kilobase Cointegrant, Conjugative Multiresistance Plasmid in Community-Associated Methicillin-Resistant Staphylococcus aureus Isolates from the Early 1990s. Antimicrob Agents Chemother 2019; 63:AAC.01560-19. [PMID: 31501140 DOI: 10.1128/aac.01560-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 09/03/2019] [Indexed: 12/13/2022] Open
Abstract
Horizontal transfer of plasmids encoding antimicrobial resistance and virulence determinants has been instrumental in Staphylococcus aureus evolution, including the emergence of community-associated methicillin-resistant S. aureus (CA-MRSA). In the early 1990s, the first CA-MRSA strain isolated in Western Australia (WA), WA-5, encoded cadmium, tetracycline, and penicillin resistance genes on plasmid pWBG753 (∼30 kb). WA-5 and pWBG753 appeared only briefly in WA; however, fusidic acid resistance plasmids related to pWBG753 were also present in the first European CA-MRSA isolates at the time. Here, we characterize a 72-kb conjugative plasmid, pWBG731, present in multiresistant WA-5-like clones from the same period. pWBG731 was a cointegrant formed from pWBG753 and a pWBG749 family conjugative plasmid. pWBG731 carried mupirocin, trimethoprim, cadmium, and penicillin resistance genes. The stepwise evolution of pWBG731 likely occurred through the combined actions of IS257, IS257-dependent miniature inverted-repeat transposable elements (MITEs), and the BinL resolution system of the β-lactamase transposon Tn552 An evolutionarily intermediate ∼42-kb nonconjugative plasmid, pWBG715, possessed the same resistance genes as pWBG731 but retained an integrated copy of the small tetracycline resistance plasmid pT181. IS257 likely facilitated the replacement of pT181 with conjugation genes on pWBG731, thus enabling autonomous transfer. Like conjugative plasmid pWBG749, pWBG731 also mobilized nonconjugative plasmids carrying oriT mimics. It seems likely that pWBG731 represents the product of multiple recombination events between the WA-5 pWBG753 plasmid and other mobile genetic elements present in indigenous community-associated methicillin-sensitive S. aureus (CA-MSSA) isolates. The molecular evolution of pWBG731 saliently illustrates how diverse mobile genetic elements can together facilitate rapid accrual and horizontal dissemination of multiresistance in S. aureus CA-MRSA.
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A Novel, Widespread qacA Allele Results in Reduced Chlorhexidine Susceptibility in Staphylococcus epidermidis. Antimicrob Agents Chemother 2019; 63:AAC.02607-18. [PMID: 30988144 DOI: 10.1128/aac.02607-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 03/13/2019] [Indexed: 12/12/2022] Open
Abstract
Chlorhexidine gluconate (CHG) is a topical antiseptic widely used in health care settings. In Staphylococcus spp., the pump QacA effluxes CHG, while the closely related QacB cannot due to a single amino acid substitution. We characterized 1,050 cutaneous Staphylococcus isolates obtained from 173 pediatric oncology patients enrolled in a multicenter CHG bathing trial. CHG susceptibility testing revealed that 63 (6%) of these isolates had elevated CHG MICs (≥4 μg/ml). Screening of all 1,050 isolates for the qacA/B gene (the same qac gene with A or B allele) by restriction fragment length polymorphism (RFLP) yielded 56 isolates with a novel qacA/B RFLP pattern, qacA/B273 The CHG MIC was significantly higher for qacA/B273 -positive isolates (MIC50, 4 μg/ml; MIC range, 0.5 to 4 μg/ml) than for other qac groups: qacA-positive isolates (n = 559; MIC50, 1 μg/ml; MIC range, 0.5 to 4 μg/ml), qacB-positive isolates (n = 17; MIC50, 1 μg/ml; MIC range, 0.25 to 2 μg/ml), and qacA/B-negative isolates (n = 418, MIC50, 1 μg/ml; MIC range, 0.125 to 2 μg/ml) (P = 0.001). A high proportion of the qacA/B273 -positive isolates also displayed methicillin resistance (96.4%) compared to the other qac groups (24.9 to 61.7%) (P = 0.001). Whole-genome sequencing revealed that qacA/B273 -positive isolates encoded a variant of QacA with 2 amino acid substitutions. This new allele, named qacA4, was carried on the novel plasmid pAQZ1. The qacA4-carrying isolates belonged to the highly resistant Staphylococcus epidermidis sequence type 2 clone. By searching available sequence data sets, we identified 39 additional qacA4-carrying S. epidermidis strains from 5 countries. Curing an isolate of qacA4 resulted in a 4-fold decrease in the CHG MIC, confirming the role of qacA4 in the elevated CHG MIC. Our results highlight the importance of further studying qacA4 and its functional role in clinical staphylococci.
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Abstract
The study of the genetics of enterococci has focused heavily on mobile genetic elements present in these organisms, the complex regulatory circuits used to control their mobility, and the antibiotic resistance genes they frequently carry. Recently, more focus has been placed on the regulation of genes involved in the virulence of the opportunistic pathogenic species Enterococcus faecalis and Enterococcus faecium. Little information is available concerning fundamental aspects of DNA replication, partition, and division; this article begins with a brief overview of what little is known about these issues, primarily by comparison with better-studied model organisms. A variety of transcriptional and posttranscriptional mechanisms of regulation of gene expression are then discussed, including a section on the genetics and regulation of vancomycin resistance in enterococci. The article then provides extensive coverage of the pheromone-responsive conjugation plasmids, including sections on regulation of the pheromone response, the conjugative apparatus, and replication and stable inheritance. The article then focuses on conjugative transposons, now referred to as integrated, conjugative elements, or ICEs, and concludes with several smaller sections covering emerging areas of interest concerning the enterococcal mobilome, including nonpheromone plasmids of particular interest, toxin-antitoxin systems, pathogenicity islands, bacteriophages, and genome defense.
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Abstract
Strains of Staphylococcus aureus, and to a lesser extent other staphylococcal species, are a significant cause of morbidity and mortality. An important factor in the notoriety of these organisms stems from their frequent resistance to many antimicrobial agents used for chemotherapy. This review catalogues the variety of mobile genetic elements that have been identified in staphylococci, with a primary focus on those associated with the recruitment and spread of antimicrobial resistance genes. These include plasmids, transposable elements such as insertion sequences and transposons, and integrative elements including ICE and SCC elements. In concert, these diverse entities facilitate the intra- and inter-cellular gene mobility that enables horizontal genetic exchange, and have also been found to play additional roles in modulating gene expression and genome rearrangement.
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Partridge SR, Kwong SM, Firth N, Jensen SO. Mobile Genetic Elements Associated with Antimicrobial Resistance. Clin Microbiol Rev 2018; 31:e00088-17. [PMID: 30068738 PMCID: PMC6148190 DOI: 10.1128/cmr.00088-17] [Citation(s) in RCA: 1101] [Impact Index Per Article: 183.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Strains of bacteria resistant to antibiotics, particularly those that are multiresistant, are an increasing major health care problem around the world. It is now abundantly clear that both Gram-negative and Gram-positive bacteria are able to meet the evolutionary challenge of combating antimicrobial chemotherapy, often by acquiring preexisting resistance determinants from the bacterial gene pool. This is achieved through the concerted activities of mobile genetic elements able to move within or between DNA molecules, which include insertion sequences, transposons, and gene cassettes/integrons, and those that are able to transfer between bacterial cells, such as plasmids and integrative conjugative elements. Together these elements play a central role in facilitating horizontal genetic exchange and therefore promote the acquisition and spread of resistance genes. This review aims to outline the characteristics of the major types of mobile genetic elements involved in acquisition and spread of antibiotic resistance in both Gram-negative and Gram-positive bacteria, focusing on the so-called ESKAPEE group of organisms (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp., and Escherichia coli), which have become the most problematic hospital pathogens.
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Affiliation(s)
- Sally R Partridge
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, The University of Sydney and Westmead Hospital, Westmead, New South Wales, Australia
| | - Stephen M Kwong
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Neville Firth
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Slade O Jensen
- Microbiology and Infectious Diseases, School of Medicine, Western Sydney University, Sydney, New South Wales, Australia
- Antibiotic Resistance & Mobile Elements Group, Ingham Institute for Applied Medical Research, Sydney, New South Wales, Australia
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16
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Wang P, Zhu Y, Shang H, Deng Y, Sun M. A minireplicon of plasmid pBMB26 represents a new typical replicon in the megaplasmids of Bacillus cereus group. J Basic Microbiol 2017; 58:263-272. [PMID: 29243837 DOI: 10.1002/jobm.201700525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/02/2017] [Accepted: 11/19/2017] [Indexed: 11/11/2022]
Abstract
A new minireplicon (rep26 minireplicon) from pBMB26, the 188 kb indigenous plasmid related to spore-crystal association (SCA) phenotype in Bacillus thuringiensis strain YBT-020, was characterized. A 12 kb EcoRI fragment, which encoded 10 putative open reading frames (ORFs), was capable of supporting replication when cloned in a replication probe vector. Deletion and frame shift mutation analysis showed that a 4.1 kb region encompassing two putative ORFs (orf21 and orf22) was essential for the plasmid replication in B. thuringiensis. Gene orf21 encoding a 49.8 kDa protein (named Rep26) with a helix-turn-helix motif showed no homology with known replication proteins and gene orf22 encoding a protein of 82.6 kDa showed homology to bacterial PcrA helicase. The replication origin of rep26 minireplicon was proved to be located in the coding region of orf21. Plasmid stability experiments indicated that the recombinant plasmid containing rep26 minireplicon has excellent segregational stability. BLASTP analysis revealed that amino acid sequences of ORF21 and ORF22 were well conserved among Bacillus cereus group strains. The rep26 minireplicon was widely distributed and could be defined as a new typical replicon in the megaplasmids of B. cereus group.
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Affiliation(s)
- Pengxia Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Yiguang Zhu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Hui Shang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Yun Deng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Ming Sun
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
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Kwong SM, Ramsay JP, Jensen SO, Firth N. Replication of Staphylococcal Resistance Plasmids. Front Microbiol 2017; 8:2279. [PMID: 29218034 PMCID: PMC5703833 DOI: 10.3389/fmicb.2017.02279] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 11/06/2017] [Indexed: 11/16/2022] Open
Abstract
The currently widespread and increasing prevalence of resistant bacterial pathogens is a significant medical problem. In clinical strains of staphylococci, the genetic determinants that confer resistance to antimicrobial agents are often located on mobile elements, such as plasmids. Many of these resistance plasmids are capable of horizontal transmission to other bacteria in their surroundings, allowing extraordinarily rapid adaptation of bacterial populations. Once the resistance plasmids have been spread, they are often perpetually maintained in the new host, even in the absence of selective pressure. Plasmid persistence is accomplished by plasmid-encoded genetic systems that ensure efficient replication and segregational stability during cell division. Staphylococcal plasmids utilize proteins of evolutionarily diverse families to initiate replication from the plasmid origin of replication. Several distinctive plasmid copy number control mechanisms have been studied in detail and these appear conserved within plasmid classes. The initiators utilize various strategies and serve a multifunctional role in (i) recognition and processing of the cognate replication origin to an initiation active form and (ii) recruitment of host-encoded replication proteins that facilitate replisome assembly. Understanding the detailed molecular mechanisms that underpin plasmid replication may lead to novel approaches that could be used to reverse or slow the development of resistance.
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Affiliation(s)
- Stephen M Kwong
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia
| | - Joshua P Ramsay
- School of Biomedical Sciences, Curtin University, Perth, WA, Australia
| | - Slade O Jensen
- Antimicrobial Resistance and Mobile Elements Group, Ingham Institute for Applied Medical Research, Sydney, NSW, Australia
| | - Neville Firth
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia
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Luo G, Li B, Li LG, Zhang T, Angelidaki I. Antibiotic Resistance Genes and Correlations with Microbial Community and Metal Resistance Genes in Full-Scale Biogas Reactors As Revealed by Metagenomic Analysis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:4069-4080. [PMID: 28272884 DOI: 10.1021/acs.est.6b05100] [Citation(s) in RCA: 120] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Digested residues from biogas plants are often used as biofertilizers for agricultural crops cultivation. The antibiotic resistance genes (ARGs) in digested residues pose a high risk to public health due to their potential spread to the disease-causing microorganisms and thus reduce the susceptibility of disease-causing microorganisms to antibiotics in medical treatment. A high-throughput sequencing (HTS)-based metagenomic approach was used in the present study to investigate the variations of ARGs in full-scale biogas reactors and the correlations of ARGs with microbial communities and metal resistance genes (MRGs). The total abundance of ARGs in all the samples varied from 7 × 10-3 to 1.08 × 10-1 copy of ARG/copy of 16S-rRNA gene, and the samples obtained from thermophilic biogas reactors had a lower total abundance of ARGs, indicating the superiority of thermophilic anaerobic digestion for ARGs removal. ARGs in all the samples were composed of 175 ARG subtypes; however, only 7 ARG subtypes were shared by all the samples. Principal component analysis and canonical correspondence analysis clustered the samples into three groups (samples from manure-based mesophilic reactors, manure-based thermophilic reactors, and sludge-based mesophilic reactors), and substrate, temperature, and hydraulic retention time (HRT) as well as volatile fatty acids (VFAs) were identified as crucial environmental variables affecting the ARGs compositions. Procrustes analysis revealed microbial community composition was the determinant of ARGs composition in biogas reactors, and there was also a significant correlation between ARGs composition and MRGs composition. Network analysis further revealed the co-occurrence of ARGs with specific microorganisms and MRGs.
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Affiliation(s)
- Gang Luo
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University , 200433, Shanghai, China
| | - Bing Li
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Graduate School at Shenzhen, Tsinghua University , Shenzhen, Guangdong 518055, China
| | - Li-Guan Li
- Environmental Biotechnology Laboratory, The University of Hong Kong , Hong Kong SAR, China
| | - Tong Zhang
- Environmental Biotechnology Laboratory, The University of Hong Kong , Hong Kong SAR, China
| | - Irini Angelidaki
- Department of Environmental Engineering, Technical University of Denmark , DK-2800, Kongens Lyngby, Denmark
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Coluzzi C, Guédon G, Devignes MD, Ambroset C, Loux V, Lacroix T, Payot S, Leblond-Bourget N. A Glimpse into the World of Integrative and Mobilizable Elements in Streptococci Reveals an Unexpected Diversity and Novel Families of Mobilization Proteins. Front Microbiol 2017; 8:443. [PMID: 28373865 PMCID: PMC5357655 DOI: 10.3389/fmicb.2017.00443] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 03/03/2017] [Indexed: 12/22/2022] Open
Abstract
Recent analyses of bacterial genomes have shown that integrated elements that transfer by conjugation play an essential role in horizontal gene transfer. Among these elements, the integrative and mobilizable elements (IMEs) are known to encode their own excision and integration machinery, and to carry all the sequences or genes necessary to hijack the mating pore of a conjugative element for their own transfer. However, knowledge of their prevalence and diversity is still severely lacking. In this work, an extensive analysis of 124 genomes from 27 species of Streptococcus reveals 144 IMEs. These IMEs encode either tyrosine or serine integrases. The identification of IME boundaries shows that 141 are specifically integrated in 17 target sites. The IME-encoded relaxases belong to nine superfamilies, among which four are previously unknown in any mobilizable or conjugative element. A total of 118 IMEs are found to encode a non-canonical relaxase related to rolling circle replication initiators (belonging to the four novel families or to MobT). Surprisingly, among these, 83 encode a TcpA protein (i.e., a non-canonical coupling protein (CP) that is more closely related to FtsK than VirD4) that was not previously known to be encoded by mobilizable elements. Phylogenetic analyses reveal not only many integration/excision module replacements but also losses, acquisitions or replacements of TcpA genes between IMEs. This glimpse into the still poorly known world of IMEs reveals that mobilizable elements have a very high prevalence. Their diversity is even greater than expected, with most encoding a CP and/or a non-canonical relaxase.
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Affiliation(s)
- Charles Coluzzi
- UMR1128 DynAMic, Institut National de la Recherche Agronomique, Université de Lorraine, Vandœuvre-lès-Nancy, France
| | - Gérard Guédon
- UMR1128 DynAMic, Institut National de la Recherche Agronomique, Université de Lorraine, Vandœuvre-lès-Nancy, France
| | - Marie-Dominique Devignes
- UMR7503 Laboratoire Lorrain de Recherche en Informatique et ses Applications, Centre National de la Recherche Scientifique, Université de Lorraine, Vandœuvre-lès-Nancy, France
| | - Chloé Ambroset
- UMR1128 DynAMic, Institut National de la Recherche Agronomique, Université de Lorraine, Vandœuvre-lès-Nancy, France
| | - Valentin Loux
- UR1404 Mathématiques et Informatique Appliquées du Génome à l'Environnement, Institut National de la Recherche Agronomique, Université Paris-Saclay, Jouy-en-Josas, France
| | - Thomas Lacroix
- UR1404 Mathématiques et Informatique Appliquées du Génome à l'Environnement, Institut National de la Recherche Agronomique, Université Paris-Saclay, Jouy-en-Josas, France
| | - Sophie Payot
- UMR1128 DynAMic, Institut National de la Recherche Agronomique, Université de Lorraine, Vandœuvre-lès-Nancy, France
| | - Nathalie Leblond-Bourget
- UMR1128 DynAMic, Institut National de la Recherche Agronomique, Université de Lorraine, Vandœuvre-lès-Nancy, France
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Kurushima J, Ike Y, Tomita H. Partial Diversity Generates Effector Immunity Specificity of the Bac41-Like Bacteriocins of Enterococcus faecalis Clinical Strains. J Bacteriol 2016; 198:2379-90. [PMID: 27353651 PMCID: PMC4984558 DOI: 10.1128/jb.00348-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Accepted: 06/22/2016] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED Bacteriocin 41 (Bac41) is the plasmid-encoded bacteriocin produced by the opportunistic pathogen Enterococcus faecalis Its genetic determinant consists of bacL1 (effector), bacL2 (regulator), bacA (effector), and bacI (immunity). The secreted effectors BacL1 and BacA coordinate to induce the lytic cell death of E. faecalis Meanwhile, the immunity factor BacI provides self-resistance to the Bac41 producer, E. faecalis, against the action of BacL1 and BacA. In this study, we demonstrated that more than half of the 327 clinical strains of E. faecalis screened had functional Bac41 genes. Analysis of the genetic structure of the Bac41 genes in the DNA sequences of the E. faecalis strains revealed that the Bac41-like genes consist of a relatively conserved region and a variable region located downstream from bacA Based on similarities in the variable region, the Bac41-like genes could be classified into type I, type IIa, and type IIb. Interestingly, the distinct Bac41 types had specific immunity factors for self-resistance, BacI1 or BacI2, and did not show cross-immunity to the other type of effector. We also demonstrated experimentally that the specificity of the immunity was determined by the combination of the C-terminal region of BacA and the presence of the unique BacI1 or BacI2 factor. These observations suggested that Bac41-like bacteriocin genes are extensively disseminated among E. faecalis strains in the clinical environment and can be grouped into at least three types. It was also indicated that the partial diversity results in specificity of self-resistance which may offer these strains a competitive advantage. IMPORTANCE Bacteriocins are antibacterial effectors produced by bacteria. In general, a bacteriocin-coding gene is accompanied by a cognate immunity gene that confers self-resistance on the bacteriocin-producing bacterium itself. We demonstrated that one of the bacteriocins, Bac41, is disseminated among E. faecalis clinical strains and the Bac41 subtypes with partial diversity. The Bac41-like bacteriocins were found to be classified into type I, type IIa, and type IIb by variation of the cognate immunity factors. The antibacterial activity of the respective effectors was specifically inhibited by the immunity factor from the same type of Bac41 but not the other types. This specificity of effector-immunity pairs suggests that bacteriocin genes might have evolved to change the immunity specificity to acquire an advantage in interbacterial competition.
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Affiliation(s)
- Jun Kurushima
- Department of Bacteriology, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Yasuyoshi Ike
- Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Haruyoshi Tomita
- Department of Bacteriology, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan Laboratory of Bacterial Drug Resistance, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
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Dynamic Filament Formation by a Divergent Bacterial Actin-Like ParM Protein. PLoS One 2016; 11:e0156944. [PMID: 27310470 PMCID: PMC4911067 DOI: 10.1371/journal.pone.0156944] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Accepted: 05/23/2016] [Indexed: 01/24/2023] Open
Abstract
Actin-like proteins (Alps) are a diverse family of proteins whose genes are abundant in the chromosomes and mobile genetic elements of many bacteria. The low-copy-number staphylococcal multiresistance plasmid pSK41 encodes ParM, an Alp involved in efficient plasmid partitioning. pSK41 ParM has previously been shown to form filaments in vitro that are structurally dissimilar to those formed by other bacterial Alps. The mechanistic implications of these differences are not known. In order to gain insights into the properties and behavior of the pSK41 ParM Alp in vivo, we reconstituted the parMRC system in the ectopic rod-shaped host, E. coli, which is larger and more genetically amenable than the native host, Staphylococcus aureus. Fluorescence microscopy showed a functional fusion protein, ParM-YFP, formed straight filaments in vivo when expressed in isolation. Strikingly, however, in the presence of ParR and parC, ParM-YFP adopted a dramatically different structure, instead forming axial curved filaments. Time-lapse imaging and selective photobleaching experiments revealed that, in the presence of all components of the parMRC system, ParM-YFP filaments were dynamic in nature. Finally, molecular dissection of the parMRC operon revealed that all components of the system are essential for the generation of dynamic filaments.
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The Plasmidome of Firmicutes: Impact on the Emergence and the Spread of Resistance to Antimicrobials. Microbiol Spectr 2016; 3:PLAS-0039-2014. [PMID: 26104702 DOI: 10.1128/microbiolspec.plas-0039-2014] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The phylum Firmicutes is one of the most abundant groups of prokaryotes in the microbiota of humans and animals and includes genera of outstanding relevance in biomedicine, health care, and industry. Antimicrobial drug resistance is now considered a global health security challenge of the 21st century, and this heterogeneous group of microorganisms represents a significant part of this public health issue.The presence of the same resistant genes in unrelated bacterial genera indicates a complex history of genetic interactions. Plasmids have largely contributed to the spread of resistance genes among Staphylococcus, Enterococcus, and Streptococcus species, also influencing the selection and ecological variation of specific populations. However, this information is fragmented and often omits species outside these genera. To date, the antimicrobial resistance problem has been analyzed under a "single centric" perspective ("gene tracking" or "vehicle centric" in "single host-single pathogen" systems) that has greatly delayed the understanding of gene and plasmid dynamics and their role in the evolution of bacterial communities.This work analyzes the dynamics of antimicrobial resistance genes using gene exchange networks; the role of plasmids in the emergence, dissemination, and maintenance of genes encoding resistance to antimicrobials (antibiotics, heavy metals, and biocides); and their influence on the genomic diversity of the main Gram-positive opportunistic pathogens under the light of evolutionary ecology. A revision of the approaches to categorize plasmids in this group of microorganisms is given using the 1,326 fully sequenced plasmids of Gram-positive bacteria available in the GenBank database at the time the article was written.
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Kaminska PS, Yernazarova A, Drewnowska JM, Zambrowski G, Swiecicka I. The worldwide distribution of genetically and phylogenetically diverse Bacillus cereus isolates harbouring Bacillus anthracis-like plasmids. ENVIRONMENTAL MICROBIOLOGY REPORTS 2015; 7:738-745. [PMID: 26033739 DOI: 10.1111/1758-2229.12305] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Accepted: 05/28/2015] [Indexed: 06/04/2023]
Abstract
Bacillus cereus is a close relative of B. anthracis, the causative agent of anthrax whose pathogenic determinants are located on pXO1 and pXO2 plasmids. Bacillus anthracis-like plasmids have been also noted among B. cereus, however, genetic features of B. cereus harbouring these elements remain largely undescribed, especially from the global perspective. Herein, we present the genetic polymorphism, population structure and phylogeny of B. cereus with pXO1-/pXO2-like plasmids originating from Argentina, Kazakhstan, Kenya and Poland. The plasmids were found in about 17% of the isolates, but their frequencies and expression of replicons differed within and between populations. In the multi-locus sequence typing, the bacteria exhibited high genetic polymorphism reflected by 116 sequencing types, including 84 singletons and 10 clonal complexes, which mainly consisted of isolates of the same origin. The phylogenetic analysis of pXO1-/pXO2-like positive B. cereus isolates revealed six independent clades; in certain clades individual populations predominated. Generally, B. cereus with pXO1-/pXO2-like plasmids did not indicate the genetic relationship with B. anthracis, and cannot be classified into an evolutionary independent anthrax line within the B. cereus group. Our report is of a crucial importance for discovering the genetic specificity and evolution of B. cereus bacilli.
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Affiliation(s)
- Paulina Sylwia Kaminska
- Department of Microbiology, Institute of Biology, University of Bialystok, Bialystok, 1J Konstanty Ciolkowski Street, Bialystok, 15-245, Poland
| | - Aliya Yernazarova
- Department of Biotechnology, al-Farabi Kazakh National University, 71 Al Farabi Ave, Almaty, 050121, Kazakhstan
| | - Justyna Malgorzata Drewnowska
- Department of Microbiology, Institute of Biology, University of Bialystok, Bialystok, 1J Konstanty Ciolkowski Street, Bialystok, 15-245, Poland
| | - Grzegorz Zambrowski
- Department of Microbiology, Institute of Biology, University of Bialystok, Bialystok, 1J Konstanty Ciolkowski Street, Bialystok, 15-245, Poland
| | - Izabela Swiecicka
- Department of Microbiology, Institute of Biology, University of Bialystok, Bialystok, 1J Konstanty Ciolkowski Street, Bialystok, 15-245, Poland
- Laboratory of Applied Microbiology, Institute of Biology, University of Bialystok, Bialystok, 1J Konstanty Ciolkowski Street, Bialystok, 15-245, Poland
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Mikalsen T, Pedersen T, Willems R, Coque TM, Werner G, Sadowy E, van Schaik W, Jensen LB, Sundsfjord A, Hegstad K. Investigating the mobilome in clinically important lineages of Enterococcus faecium and Enterococcus faecalis. BMC Genomics 2015; 16:282. [PMID: 25885771 PMCID: PMC4438569 DOI: 10.1186/s12864-015-1407-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 02/27/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The success of Enterococcus faecium and E. faecalis evolving as multi-resistant nosocomial pathogens is associated with their ability to acquire and share adaptive traits, including antimicrobial resistance genes encoded by mobile genetic elements (MGEs). Here, we investigate this mobilome in successful hospital associated genetic lineages, E. faecium sequence type (ST)17 (n=10) and ST78 (n=10), E. faecalis ST6 (n=10) and ST40 (n=10) by DNA microarray analyses. RESULTS The hybridization patterns of 272 representative targets including plasmid backbones (n=85), transposable elements (n=85), resistance determinants (n=67), prophages (n=29) and clustered regularly interspaced short palindromic repeats (CRISPR)-cas sequences (n=6) separated the strains according to species, and for E. faecalis also according to STs. RCR-, Rep_3-, RepA_N- and Inc18-family plasmids were highly prevalent and with the exception of Rep_3, evenly distributed between the species. There was a considerable difference in the replicon profile, with rep 17/pRUM , rep 2/pRE25 , rep 14/EFNP1 and rep 20/pLG1 dominating in E. faecium and rep 9/pCF10 , rep 2/pRE25 and rep 7 in E. faecalis strains. We observed an overall high correlation between the presence and absence of genes coding for resistance towards antibiotics, metals, biocides and their corresponding MGEs as well as their phenotypic antimicrobial susceptibility pattern. Although most IS families were represented in both E. faecalis and E. faecium, specific IS elements within these families were distributed in only one species. The prevalence of IS256-, IS3-, ISL3-, IS200/IS605-, IS110-, IS982- and IS4-transposases was significantly higher in E. faecium than E. faecalis, and that of IS110-, IS982- and IS1182-transposases in E. faecalis ST6 compared to ST40. Notably, the transposases of IS981, ISEfm1 and IS1678 that have only been reported in few enterococcal isolates were well represented in the E. faecium strains. E. faecalis ST40 strains harboured possible functional CRISPR-Cas systems, and still resistance and prophage sequences were generally well represented. CONCLUSIONS The targeted MGEs were highly prevalent among the selected STs, underlining their potential importance in the evolution of hospital-adapted lineages of enterococci. Although the propensity of inter-species horizontal gene transfer (HGT) must be emphasized, the considerable species-specificity of these MGEs indicates a separate vertical evolution of MGEs within each species, and for E. faecalis within each ST.
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Affiliation(s)
- Theresa Mikalsen
- Research group for Host-microbe Interactions, Department of Medical Biology, Faculty of Health Science, UiT - The Arctic University of Norway, Tromsø, Norway.
| | - Torunn Pedersen
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway.
| | - Rob Willems
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Teresa M Coque
- Servicio de Microbiologia, Hospital Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain. .,Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBER-ESP), Madrid, Spain.
| | - Guido Werner
- Division of Nosocomial Pathogens and Antibiotic Resistance, Robert Koch Institute, Wernigerode Branch, Wernigerode, Germany.
| | - Ewa Sadowy
- Department of Molecular Microbiology, National Medicines Institute, ul, Chełmska 30/34, 00-725, Warsaw, Poland.
| | - Willem van Schaik
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Lars Bogø Jensen
- Division of Food Microbiologyt, National Food Institute, Danish Technical University, Copenhagen V, Denmark.
| | - Arnfinn Sundsfjord
- Research group for Host-microbe Interactions, Department of Medical Biology, Faculty of Health Science, 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.
| | - Kristin Hegstad
- Research group for Host-microbe Interactions, Department of Medical Biology, Faculty of Health Science, 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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Zischka M, Künne CT, Blom J, Wobser D, Sakιnç T, Schmidt-Hohagen K, Dabrowski PW, Nitsche A, Hübner J, Hain T, Chakraborty T, Linke B, Goesmann A, Voget S, Daniel R, Schomburg D, Hauck R, Hafez HM, Tielen P, Jahn D, Solheim M, Sadowy E, Larsen J, Jensen LB, Ruiz-Garbajosa P, Quiñones Pérez D, Mikalsen T, Bender J, Steglich M, Nübel U, Witte W, Werner G. Comprehensive molecular, genomic and phenotypic analysis of a major clone of Enterococcus faecalis MLST ST40. BMC Genomics 2015; 16:175. [PMID: 25887115 PMCID: PMC4374294 DOI: 10.1186/s12864-015-1367-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 02/20/2015] [Indexed: 11/28/2022] Open
Abstract
Background Enterococcus faecalis is a multifaceted microorganism known to act as a beneficial intestinal commensal bacterium. It is also a dreaded nosocomial pathogen causing life-threatening infections in hospitalised patients. Isolates of a distinct MLST type ST40 represent the most frequent strain type of this species, distributed worldwide and originating from various sources (animal, human, environmental) and different conditions (colonisation/infection). Since enterococci are known to be highly recombinogenic we determined to analyse the microevolution and niche adaptation of this highly distributed clonal type. Results We compared a set of 42 ST40 isolates by assessing key molecular determinants, performing whole genome sequencing (WGS) and a number of phenotypic assays including resistance profiling, formation of biofilm and utilisation of carbon sources. We generated the first circular closed reference genome of an E. faecalis isolate D32 of animal origin and compared it with the genomes of other reference strains. D32 was used as a template for detailed WGS comparisons of high-quality draft genomes of 14 ST40 isolates. Genomic and phylogenetic analyses suggest a high level of similarity regarding the core genome, also demonstrated by similar carbon utilisation patterns. Distribution of known and putative virulence-associated genes did not differentiate between ST40 strains from a commensal and clinical background or an animal or human source. Further analyses of mobile genetic elements (MGE) revealed genomic diversity owed to: (1) a modularly structured pathogenicity island; (2) a site-specifically integrated and previously unknown genomic island of 138 kb in two strains putatively involved in exopolysaccharide synthesis; and (3) isolate-specific plasmid and phage patterns. Moreover, we used different cell-biological and animal experiments to compare the isolate D32 with a closely related ST40 endocarditis isolate whose draft genome sequence was also generated. D32 generally showed a greater capacity of adherence to human cell lines and an increased pathogenic potential in various animal models in combination with an even faster growth in vivo (not in vitro). Conclusion Molecular, genomic and phenotypic analysis of representative isolates of a major clone of E. faecalis MLST ST40 revealed new insights into the microbiology of a commensal bacterium which can turn into a conditional pathogen. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1367-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Melanie Zischka
- Division of Nosocomial Pathogens and Antibiotic Resistances, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Burgstr. 37, D-38855, Wernigerode, Germany. .,Present address: Institute for Pathology, Hannover Medical School (MHH), Hannover, Germany.
| | - Carsten T Künne
- Functional Genomics of Bacterial Pathogens, Institute for Medical Microbiology, Justus Liebig University Giessen and German Center for Infection Research (DZIF), Partner site Giessen-Marburg-Langen, Campus Giessen, Giessen, Germany. .,Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.
| | - Jochen Blom
- Center for Biotechnology (CeBiTec)/University of Bielefeld, Bielefeld, Germany. .,Institute for Bioinformatics and Systems Biology, Justus Liebig University Giessen, Giessen, Germany.
| | - Dominique Wobser
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg, Germany.
| | - Türkân Sakιnç
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg, Germany.
| | - Kerstin Schmidt-Hohagen
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Braunschweig, Germany.
| | - P Wojtek Dabrowski
- Robert Koch Institute, ZBS 1 Highly Pathogenic Viruses, Centre for Biological Threats and Special Pathogens, Berlin, Germany.
| | - Andreas Nitsche
- Robert Koch Institute, ZBS 1 Highly Pathogenic Viruses, Centre for Biological Threats and Special Pathogens, Berlin, Germany.
| | - Johannes Hübner
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg, Germany. .,Division of Pediatric Infectious Diseases, Hauner Children's Hospital, Ludwig-Maximilians University Munich, Munich, Germany.
| | - Torsten Hain
- Functional Genomics of Bacterial Pathogens, Institute for Medical Microbiology, Justus Liebig University Giessen and German Center for Infection Research (DZIF), Partner site Giessen-Marburg-Langen, Campus Giessen, Giessen, Germany.
| | - Trinad Chakraborty
- Functional Genomics of Bacterial Pathogens, Institute for Medical Microbiology, Justus Liebig University Giessen and German Center for Infection Research (DZIF), Partner site Giessen-Marburg-Langen, Campus Giessen, Giessen, Germany.
| | - Burkhard Linke
- Center for Biotechnology (CeBiTec)/University of Bielefeld, Bielefeld, Germany. .,Institute for Bioinformatics and Systems Biology, Justus Liebig University Giessen, Giessen, Germany.
| | - Alexander Goesmann
- Center for Biotechnology (CeBiTec)/University of Bielefeld, Bielefeld, Germany. .,Institute for Bioinformatics and Systems Biology, Justus Liebig University Giessen, Giessen, Germany.
| | - Sonja Voget
- Goettingen Genomics Laboratory, Georg August University, Goettingen, Germany.
| | - Rolf Daniel
- Goettingen Genomics Laboratory, Georg August University, Goettingen, Germany.
| | - Dietmar Schomburg
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Braunschweig, Germany.
| | - Rüdiger Hauck
- Department of Veterinary Medicine, Institute for Poultry Diseases, Free University Berlin, Berlin, Germany.
| | - Hafez M Hafez
- Department of Veterinary Medicine, Institute for Poultry Diseases, Free University Berlin, Berlin, Germany.
| | - Petra Tielen
- Institute for Microbiology, Technische Universität Braunschweig, Braunschweig, Germany.
| | - Dieter Jahn
- Institute for Microbiology, Technische Universität Braunschweig, Braunschweig, Germany.
| | - Margrete Solheim
- Laboratory of Microbial Gene Technology and Food Microbiology, The Norwegian University of Life Sciences, Ås, Norway.
| | - Ewa Sadowy
- National Medicines Institute, Warsaw, Poland.
| | | | - Lars B Jensen
- Division of Microbiology, National Food Institute, Danish Technical University, Copenhagen, Denmark.
| | | | - Dianelys Quiñones Pérez
- Instituto de Medicina Tropical Pedro Kourí, Servicio de Bacteriología-Micología, La Habana, Cuba.
| | - Theresa Mikalsen
- Department of Medical Biology, Faculty of Health Sciences, Research Group for Host Microbe Interactions, University of Tromsø, Tromsø, Norway.
| | - Jennifer Bender
- Division of Nosocomial Pathogens and Antibiotic Resistances, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Burgstr. 37, D-38855, Wernigerode, Germany.
| | - Matthias Steglich
- Division of Nosocomial Pathogens and Antibiotic Resistances, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Burgstr. 37, D-38855, Wernigerode, Germany.
| | - Ulrich Nübel
- Division of Nosocomial Pathogens and Antibiotic Resistances, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Burgstr. 37, D-38855, Wernigerode, Germany. .,Leibniz-Institut DSMZ - Deutsche Sammlung von Mikrorganismen und Zellkulturen GmbH, Braunschweig, Germany.
| | - Wolfgang Witte
- Division of Nosocomial Pathogens and Antibiotic Resistances, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Burgstr. 37, D-38855, Wernigerode, Germany.
| | - Guido Werner
- Division of Nosocomial Pathogens and Antibiotic Resistances, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Burgstr. 37, D-38855, Wernigerode, Germany.
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Structural and sequence requirements for the antisense RNA regulating replication of staphylococcal multiresistance plasmid pSK41. Plasmid 2015; 78:17-25. [PMID: 25634580 DOI: 10.1016/j.plasmid.2015.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 01/16/2015] [Accepted: 01/20/2015] [Indexed: 11/22/2022]
Abstract
pSK41 is a prototypical 46-kb conjugative multiresistance plasmid of Staphylococcus aureus. The pSK41 replication initiation protein (Rep) is rate-limiting for plasmid replication, and its expression is negatively regulated by a small, non-coding antisense transcript, RNAI, that is complementary to the rep mRNA leader region. In this study, enzymatic probing was used to verify the predicted secondary structures of RNAI and its target RNA. We demonstrated that two stem-loop structures of RNAI, SLRNAI-II and SLRNAI-III, were important for inhibition. A putative U-turn motif detected in the loop of SLrep-I (5'-UUGG-3') was analysed for its significance to RNAI-mediated inhibition in vivo and Northern blotting suggested that rep mRNA was processed. Taken together, these observations support our previously proposed model but also raise new questions about the replication control mechanism.
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27
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Mechanism of staphylococcal multiresistance plasmid replication origin assembly by the RepA protein. Proc Natl Acad Sci U S A 2014; 111:9121-6. [PMID: 24927575 DOI: 10.1073/pnas.1406065111] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The staphylococcal multiresistance plasmids are key contributors to the alarming rise in bacterial multidrug resistance. A conserved replication initiator, RepA, encoded on these plasmids is essential for their propagation. RepA proteins consist of flexibly linked N-terminal (NTD) and C-terminal (CTD) domains. Despite their essential role in replication, the molecular basis for RepA function is unknown. Here we describe a complete structural and functional dissection of RepA proteins. Unexpectedly, both the RepA NTD and CTD show similarity to the corresponding domains of the bacterial primosome protein, DnaD. Although the RepA and DnaD NTD both contain winged helix-turn-helices, the DnaD NTD self-assembles into large scaffolds whereas the tetrameric RepA NTD binds DNA iterons using a newly described DNA binding mode. Strikingly, structural and atomic force microscopy data reveal that the NTD tetramer mediates DNA bridging, suggesting a molecular mechanism for origin handcuffing. Finally, data show that the RepA CTD interacts with the host DnaG primase, which binds the replicative helicase. Thus, these combined data reveal the molecular mechanism by which RepA mediates the specific replicon assembly of staphylococcal multiresistant plasmids.
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28
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Chen Z, Lin J, Ma C, Zhao S, She Q, Liang Y. Characterization of pMC11, a plasmid with dual origins of replication isolated from Lactobacillus casei MCJ and construction of shuttle vectors with each replicon. Appl Microbiol Biotechnol 2014; 98:5977-89. [PMID: 24652065 DOI: 10.1007/s00253-014-5649-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 02/24/2014] [Accepted: 02/26/2014] [Indexed: 01/15/2023]
Abstract
Many lactic acid bacteria carry different plasmids, particularly those that replicate via a theta mechanism. Here we describe Lactobacillus casei MCJ(CCTCC AB20130356), a new isolate that contains pMC11, carrying two distinct theta-type replicons. Each replicon contained an iteron in the origin of replication (oriV1 or oriV2) and a gene coding for the replicase (RepA_1 or RepB_1), both of which are essential for plasmid replication. Escherichia coli/Lactobacillus shuttle vectors were constructed with each replicon, yielding pEL5.7 and pEL5.6 that are based on oriV2 and oriV1 replicons, respectively. These plasmids showed distinct properties: pEL5.7 was capable of replicating in L. casei MCJΔ1 and Lactobacillus delbrueckii subsp. lactic LBCH-1 but failed to do so in two other tested lactobacilli strains whereas pEL5.6 replicated in three different strains, including L. casei MCJΔ1, L. casei NJ, Lactobacillus paracasei LPC-37 and L. delbrueckii subsp. lactic LBCH-1. Plasmid stability was studied: pEL5.6 and pEL5.7 were very stably maintained in L. casei, as the loss rate was lower than 1 % per generation. pEL5.7 was also stable in L. delbrueckii subsp. lactic LBCH-1 with the loss rate estimated to be 3 %. These vectors were employed to express a green fluorescent protein (GFP) using the promoter of S-layer protein SlpA from Lactobacillus acidophilus. And a growth-phase regulated expression of GFP was observed in different strains. In conclusion, these shuttle vectors provide efficient genetic tools for DNA cloning and heterologous gene expression in lactobacilli.
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Affiliation(s)
- Zhengjun Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
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Zheng J, Peng D, Ruan L, Sun M. Evolution and dynamics of megaplasmids with genome sizes larger than 100 kb in the Bacillus cereus group. BMC Evol Biol 2013; 13:262. [PMID: 24295128 PMCID: PMC4219350 DOI: 10.1186/1471-2148-13-262] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Accepted: 11/25/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Plasmids play a crucial role in the evolution of bacterial genomes by mediating horizontal gene transfer. However, the origin and evolution of most plasmids remains unclear, especially for megaplasmids. Strains of the Bacillus cereus group contain up to 13 plasmids with genome sizes ranging from 2 kb to 600 kb, and thus can be used to study plasmid dynamics and evolution. RESULTS This work studied the origin and evolution of 31 B. cereus group megaplasmids (>100 kb) focusing on the most conserved regions on plasmids, minireplicons. Sixty-five putative minireplicons were identified and classified to six types on the basis of proteins that are essential for replication. Twenty-nine of the 31 megaplasmids contained two or more minireplicons. Phylogenetic analysis of the protein sequences showed that different minireplicons on the same megaplasmid have different evolutionary histories. Therefore, we speculated that these megaplasmids are the results of fusion of smaller plasmids. All plasmids of a bacterial strain must be compatible. In megaplasmids of the B. cereus group, individual minireplicons of different megaplasmids in the same strain belong to different types or subtypes. Thus, the subtypes of each minireplicon they contain may determine the incompatibilities of megaplasmids. A broader analysis of all 1285 bacterial plasmids with putative known minireplicons whose complete genome sequences were available from GenBank revealed that 34% (443 plasmids) of the plasmids have two or more minireplicons. This indicates that plasmid fusion events are general among bacterial plasmids. CONCLUSIONS Megaplasmids of B. cereus group are fusion of smaller plasmids, and the fusion of plasmids likely occurs frequently in the B. cereus group and in other bacterial taxa. Plasmid fusion may be one of the major mechanisms for formation of novel megaplasmids in the evolution of bacteria.
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Affiliation(s)
- Jinshui Zheng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
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30
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Phage ϕC2 mediates transduction of Tn6215, encoding erythromycin resistance, between Clostridium difficile strains. mBio 2013; 4:e00840-13. [PMID: 24255122 PMCID: PMC3870246 DOI: 10.1128/mbio.00840-13] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
In this work, we show that Clostridium difficile phage ϕC2 transduces erm(B), which confers erythromycin resistance, from a donor to a recipient strain at a frequency of 10−6 per PFU. The transductants were lysogenic for ϕC2 and contained the erm(B) gene in a novel transposon, Tn6215. This element is 13,008 bp in length and contains 17 putative open reading frames (ORFs). It could also be transferred at a lower frequency by filter mating. Clostridium difficile is a major human pathogen that causes diarrhea that can be persistent and difficult to resolve using antibiotics. C. difficile is potentially zoonotic and has been detected in animals, food, and environmental samples. C. difficile genomes contain large portions of horizontally acquired genetic elements. The conjugative elements have been reasonably well studied, but transduction has not yet been demonstrated. Here, we show for the first time transduction as a mechanism for the transfer of a novel genetic element in C. difficile. Transduction may also be a useful tool for the genetic manipulation of C. difficile.
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Wardal E, Gawryszewska I, Hryniewicz W, Sadowy E. Abundance and diversity of plasmid-associated genes among clinical isolates of Enterococcus faecalis. Plasmid 2013; 70:329-42. [PMID: 23906674 DOI: 10.1016/j.plasmid.2013.07.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Revised: 07/18/2013] [Accepted: 07/21/2013] [Indexed: 11/18/2022]
Abstract
Enterococcus faecalis, a normal compound of the human intestinal microbiome, plays an important role in hospital-acquired infections. Plasmids make a significant contribution to the acquisition of the novel traits such as antimicrobial resistance and virulence by this pathogen. The study investigated the plasmid content and the diversity of plasmid-associated genes in a group of 152 hospital isolates of E. faecalis. The majority of plasmids visualized by pulsed-field gel electrophoresis of S1 nuclease-digested DNA fell into the range of 50-100 kb. PCR-based screening allowed detection of genes of the rep1(pIP501), rep2(pRE25), rep4(pMBB1), rep6(pS86), rep7(pT181), rep8(pAM373), rep9(pAD1/pTEF2/pCF10), rep10(pIM13) and rep13(pC194) families in 29 different combinations. The par and ω-ε-ζ plasmid stabilization systems were ubiquitous (45 isolates, 29.6% and 88 isolates, 57.9%, respectively), while the axe-txe system was not found. The asa1 gene homologues encoding aggregation substance characteristic for the pAD1 and related group of pheromone-responsive plasmids were present in 106 isolates. A variety of sequence variants, including novel ones, of genes associated with pheromone-responsive plasmids, such as rep8(pAM373), rep9(pAD1/pTEF2/pCF10), par, and asa1 were observed. In conclusion, there is a big and only partially characterized pool of diverse plasmids in clinical E. faecalis.
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Affiliation(s)
- Ewa Wardal
- National Medicines Institute, ul. Chełmska 30/34, 00-725 Warsaw, Poland.
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Freitas AR, Novais C, Tedim AP, Francia MV, Baquero F, Peixe L, Coque TM. Microevolutionary events involving narrow host plasmids influences local fixation of vancomycin-resistance in Enterococcus populations. PLoS One 2013; 8:e60589. [PMID: 23555993 PMCID: PMC3612099 DOI: 10.1371/journal.pone.0060589] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 02/28/2013] [Indexed: 12/28/2022] Open
Abstract
Vancomycin-resistance in enterococci (VRE) is associated with isolates within ST18, ST17, ST78 Enterococcus faecium (Efm) and ST6 Enterococcus faecalis (Efs) human adapted lineages. Despite of its global spread, vancomycin resistance rates in enterococcal populations greatly vary temporally and geographically. Portugal is one of the European countries where Tn1546 (vanA) is consistently found in a variety of environments. A comprehensive multi-hierarchical analysis of VRE isolates (75 Efm and 29 Efs) from Portuguese hospitals and aquatic surroundings (1996–2008) was performed to clarify the local dynamics of VRE. Clonal relatedness was established by PFGE and MLST while plasmid characterization comprised the analysis of known relaxases, rep initiator proteins and toxin-antitoxin systems (TA) by PCR-based typing schemes, RFLP comparison, hybridization and sequencing. Tn1546 variants were characterized by PCR overlapping/sequencing. Intra- and inter-hospital dissemination of Efm ST18, ST132 and ST280 and Efs ST6 clones, carrying rolling-circle (pEFNP1/pRI1) and theta-replicating (pCIZ2-like, Inc18, pHTβ-like, two pRUM-variants, pLG1-like, and pheromone-responsive) plasmids was documented. Tn1546 variants, mostly containing ISEf1 or IS1216, were located on plasmids (30–150 kb) with a high degree of mosaicism and heterogeneous RFLP patterns that seem to have resulted from the interplay between broad host Inc18 plasmids (pIP501, pRE25, pEF1), and narrow host RepA_N plasmids (pRUM, pAD1-like). TAs of Inc18 (ω-ε-ζ) and pRUM (Axe-Txe) plasmids were infrequently detected. Some plasmid chimeras were persistently recovered over years from different clonal lineages. This work represents the first multi-hierarchical analysis of VRE, revealing a frequent recombinatorial diversification of a limited number of interacting clonal backgrounds, plasmids and transposons at local scale. These interactions provide a continuous process of parapatric clonalization driving a full exploration of the local adaptive landscape, which might assure long-term maintenance of resistant clones and eventually fixation of Tn1546 in particular geographic areas.
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Affiliation(s)
- Ana R. Freitas
- REQUIMTE, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
- Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Carla Novais
- REQUIMTE, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Ana P. Tedim
- Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- CIBER en Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
- Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - María Victoria Francia
- Servicio de Microbiologia, Hospital Universitario Marqués de Valdecilla e Instituto de Formación e Investigación Marqués de Valdecilla (IFIMAV), Santander, Spain
| | - Fernando Baquero
- Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- CIBER en Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
- Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Luísa Peixe
- REQUIMTE, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Teresa M. Coque
- Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- CIBER en Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
- Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- * E-mail:
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Werner G, Coque TM, Franz CMAP, Grohmann E, Hegstad K, Jensen L, van Schaik W, Weaver K. Antibiotic resistant enterococci-tales of a drug resistance gene trafficker. Int J Med Microbiol 2013; 303:360-79. [PMID: 23602510 DOI: 10.1016/j.ijmm.2013.03.001] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Enterococci have been recognized as important hospital-acquired pathogens in recent years, and isolates of E. faecalis and E. faecium are the third- to fourth-most prevalent nosocomial pathogen worldwide. Acquired resistances, especially against penicilin/ampicillin, aminoglycosides (high-level) and glycopeptides are therapeutically important and reported in increasing numbers. On the other hand, isolates of E. faecalis and E. faecium are commensals of the intestines of humans, many vertebrate and invertebrate animals and may also constitute an active part of the plant flora. Certain enterococcal isolates are used as starter cultures or supplements in food fermentation and food preservation. Due to their preferred intestinal habitat, their wide occurrence, robustness and ease of cultivation, enterococci are used as indicators for fecal pollution assessing hygiene standards for fresh- and bathing water and they serve as important key indicator bacteria for various veterinary and human resistance surveillance systems. Enterococci are widely prevalent and genetically capable of acquiring, conserving and disseminating genetic traits including resistance determinants among enterococci and related Gram-positive bacteria. In the present review we aimed at summarizing recent advances in the current understanding of the population biology of enterococci, the role mobile genetic elements including plasmids play in shaping the population structure and spreading resistance. We explain how these elements could be classified and discuss mechanisms of plasmid transfer and regulation and the role and cross-talk of enterococcal isolates from food and food animals to humans.
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Affiliation(s)
- Guido Werner
- National Reference Centre for Stapyhlococci and Enterococci, Division of Nosocomial Pathogens and Antibiotic Resistances, Robert Koch Institute, Wernigerode Branch, Burgstr. 37, 38855 Wernigerode, Germany.
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Modular evolution of TnGBSs, a new family of integrative and conjugative elements associating insertion sequence transposition, plasmid replication, and conjugation for their spreading. J Bacteriol 2013; 195:1979-90. [PMID: 23435978 DOI: 10.1128/jb.01745-12] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Integrative and conjugative elements (ICEs) have a major impact on gene flow and genome dynamics in bacteria. The ICEs TnGBS1 and TnGBS2, first identified in Streptococcus agalactiae, use a DDE transposase, unlike most characterized ICEs, which depend on a phage-like integrase for their mobility. Here we identified 56 additional TnGBS-related ICEs by systematic genome analysis. Interestingly, all except one are inserted in streptococcal genomes. Sequence comparison of the proteins conserved among these ICEs defined two subtypes related to TnGBS1 or TnGBS2. We showed that both types encode different conjugation modules: a type IV secretion system, a VirD4 coupling protein, and a relaxase and its cognate oriT site, shared with distinct lineages of conjugative elements of Firmicutes. Phylogenetic analysis suggested that TnGBSs evolved from two conjugative elements of different origins by the successive recruitment of a transposition module derived from insertion sequences (ISs). Furthermore, TnGBSs share replication modules with different plasmids. Mutational analyses and conjugation experiments showed that TnGBS1 and TnGBS2 combine replication and transposition upstream promoters for their transfer and stabilization. Despite an evolutionarily successful horizontal dissemination within the genus Streptococcus, these ICEs have a restricted host range. However, we reveal that for TnGBS1 and TnGBS2, this host restriction is not due to a transfer incompatibility linked to the conjugation machineries but most likely to their ability for transient maintenance through replication after their transfer.
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Liu MA, Kwong SM, Jensen SO, Brzoska AJ, Firth N. Biology of the staphylococcal conjugative multiresistance plasmid pSK41. Plasmid 2013; 70:42-51. [PMID: 23415796 DOI: 10.1016/j.plasmid.2013.02.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2012] [Revised: 02/01/2013] [Accepted: 02/03/2013] [Indexed: 11/27/2022]
Abstract
Plasmid pSK41 is a large, low-copy-number, conjugative plasmid from Staphylococcus aureus that is representative of a family of staphylococcal plasmids that confer multiple resistances to a wide range of antimicrobial agents. The plasmid consists of a conserved plasmid backbone containing the genes for plasmid housekeeping functions, which is punctuated by copies of IS257 that flank a Tn4001-hybrid structure and cointegrated plasmids that harbour resistance genes. This review summarises the current understanding of the biology of pSK41, focussing on the systems responsible for its replication, maintenance and transmission, and their regulation.
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Affiliation(s)
- Michael A Liu
- School of Biological Sciences, University of Sydney, NSW 2006, Australia
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Abstract
The complete and annotated genome sequence of Enterococcus faecalis D32, a commensal strain isolated from a Danish pig, suggests putative adaptation to the porcine host and absence of distinct virulence-associated traits.
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Rosvoll TC, Lindstad BL, Lunde TM, Hegstad K, Aasnæs B, Hammerum AM, Lester CH, Simonsen GS, Sundsfjord A, Pedersen T. Increased high-level gentamicin resistance in invasiveEnterococcus faeciumis associated withaac(6′)Ie-aph(2″)Ia-encoding transferable megaplasmids hosted by major hospital-adapted lineages. ACTA ACUST UNITED AC 2012; 66:166-76. [DOI: 10.1111/j.1574-695x.2012.00997.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 04/23/2012] [Accepted: 05/24/2012] [Indexed: 12/22/2022]
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Liu MA, Kwong SM, Pon CK, Skurray RA, Firth N. Genetic requirements for replication initiation of the staphylococcal multiresistance plasmid pSK41. MICROBIOLOGY-SGM 2012; 158:1456-1467. [PMID: 22442303 DOI: 10.1099/mic.0.057620-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Replication of staphylococcal multiresistance plasmid pSK41 is initiated by binding of the replication initiator protein (Rep) to the Rep boxes, a series of four direct repeats located centrally within the rep gene. A Staphylococcus aureus strain was engineered to provide Rep in trans, allowing localization of the pSK41 origin of replication (oriV) to a 185 bp segment, which included the Rep boxes and a series of downstream direct repeats. Deletion analysis of individual Rep boxes revealed that all four Rep boxes are required for maximum origin activity, with the deletion of one or more Rep boxes having a significant effect on the proficiency of replication. However, a hierarchy of importance was identified among the Rep boxes, which appears to be mediated by the minor sequence variations that exist between them. DNA binding studies with truncated Rep proteins have enabled the DNA binding domain to be localized to the N-terminal 134 amino acids of the protein.
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Affiliation(s)
- Michael A Liu
- School of Biological Sciences, University of Sydney, NSW 2006, Australia
| | - Stephen M Kwong
- School of Biological Sciences, University of Sydney, NSW 2006, Australia
| | - Cindy K Pon
- School of Biological Sciences, University of Sydney, NSW 2006, Australia
| | - Ronald A Skurray
- School of Biological Sciences, University of Sydney, NSW 2006, Australia
| | - Neville Firth
- School of Biological Sciences, University of Sydney, NSW 2006, Australia
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Insights into the completely annotated genome of Lactobacillus buchneri CD034, a strain isolated from stable grass silage. J Biotechnol 2012; 161:153-66. [PMID: 22465289 DOI: 10.1016/j.jbiotec.2012.03.007] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 03/05/2012] [Accepted: 03/08/2012] [Indexed: 12/26/2022]
Abstract
Lactobacillus buchneri belongs to the group of heterofermentative lactic acid bacteria and is a common member of the silage microbiome. Here we report the completely annotated genomic sequence of L. buchneri CD034, a strain isolated from stable grass silage. The whole genome of L. buchneri CD034 was sequenced on the Roche Genome Sequencer FLX platform. It was found to consist of four replicons, a circular chromosome, and three plasmids. The circular chromosome was predicted to encode 2319 proteins and contains a genomic island and two prophages which significantly differ in G+C-content from the remaining chromosome. It possesses all genes for enzymes of a complete phosphoketolase pathway, whereas two enzymes necessary for glycolysis are lacking. This confirms the classification of L. buchneri CD034 as an obligate heterofermentative lactic acid bacterium. A set of genes considered to be involved in the lactate degradation pathway and genes putatively involved in the breakdown of plant cell wall polymers were identified. Moreover, several genes encoding putative S-layer proteins and two CRISPR systems, belonging to the subclasses I-E and II-A, are located on the chromosome. The largest plasmid pCD034-3 was predicted to encode 57 genes, including a putative polysaccharide synthesis gene cluster, whereas the functions of the two smaller plasmids, pCD034-1 and pCD034-2, remain cryptic. Phylogenetic analysis based on sequence comparison of the conserved marker gene rpoA reveals that L. buchneri CD034 is more closely related to Lactobacillus hilgardii strains than to Lactobacillus brevis and Lactobacillus plantarum strains. Comparison of the L. buchneri CD034 core genome to other fully sequenced and closely related members of the genus Lactobacillus disclosed a high degree of conservation between L. buchneri CD034 and the recently sequenced L. buchneri strain NRRL B-30929 and a more distant relationship to L. buchneri ATCC 11577 and L. brevis ssp. gravesensis ATCC 27305, which cluster together with L. hilgardii type strain ATCC 8290. L. buchneri CD034 genome information will certainly provide the basis for further postgenome studies with the objective to optimize application of the strain in silage production.
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Major families of multiresistant plasmids from geographically and epidemiologically diverse staphylococci. G3-GENES GENOMES GENETICS 2011; 1:581-91. [PMID: 22384369 PMCID: PMC3276174 DOI: 10.1534/g3.111.000760] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 10/12/2011] [Indexed: 01/25/2023]
Abstract
Staphylococci are increasingly aggressive human pathogens suggesting that active evolution is spreading novel virulence and resistance phenotypes. Large staphylococcal plasmids commonly carry antibiotic resistances and virulence loci, but relatively few have been completely sequenced. We determined the plasmid content of 280 staphylococci isolated in diverse geographical regions from the 1940s to the 2000s and found that 79% of strains carried at least one large plasmid >20 kb and that 75% of these large plasmids were 20–30 kb. Using restriction fragment length polymorphism (RFLP) analysis, we grouped 43% of all large plasmids into three major families, showing remarkably conserved intercontinental spread of multiresistant staphylococcal plasmids over seven decades. In total, we sequenced 93 complete and 57 partial staphylococcal plasmids ranging in size from 1.3 kb to 64.9 kb, tripling the number of complete sequences for staphylococcal plasmids >20 kb in the NCBI RefSeq database. These plasmids typically carried multiple antimicrobial and metal resistances and virulence genes, transposases and recombinases. Remarkably, plasmids within each of the three main families were >98% identical, apart from insertions and deletions, despite being isolated from strains decades apart and on different continents. This suggests enormous selective pressure has optimized the content of certain plasmids despite their large size and complex organization.
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Laverde Gomez JA, Hendrickx APA, Willems RJ, Top J, Sava I, Huebner J, Witte W, Werner G. Intra- and interspecies genomic transfer of the Enterococcus faecalis pathogenicity island. PLoS One 2011; 6:e16720. [PMID: 21559082 PMCID: PMC3084688 DOI: 10.1371/journal.pone.0016720] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 12/23/2010] [Indexed: 12/11/2022] Open
Abstract
Enterococci are the third leading cause of hospital associated infections and have gained increased importance due to their fast adaptation to the clinical environment by acquisition of antibiotic resistance and pathogenicity traits. Enterococcus faecalis harbours a pathogenicity island (PAI) of 153 kb containing several virulence factors including the enterococcal surface protein (esp). Until now only internal fragments of the PAI or larger chromosomal regions containing it have been transferred. Here we demonstrate precise excision, circularization and horizontal transfer of the entire PAI element from the chromosome of E. faecalis strain UW3114. This PAI (ca. 200 kb) contained some deletions and insertions as compared to the PAI of the reference strain MMH594, transferred precisely and integrated site-specifically into the chromosome of E. faecalis (intergenic region) and Enterococcus faecium (tRNAlys). The internal PAI structure was maintained after transfer. We assessed phenotypic changes accompanying acquisition of the PAI and expression of some of its determinants. The esp gene is expressed on the surface of donor and both transconjugants. Biofilm formation and cytolytic activity were enhanced in E. faecalis transconjugants after acquisition of the PAI. No differences in pathogenicity of E. faecalis were detected using a mouse bacteraemia and a mouse peritonitis models (tail vein and intraperitoneal injection). A 66 kb conjugative pheromone-responsive plasmid encoding erm(B) (pLG2) that was transferred in parallel with the PAI was sequenced. pLG2 is a pheromone responsive plasmid that probably promotes the PAI horizontal transfer, encodes antibiotic resistance features and contains complete replication and conjugation modules of enterococcal origin in a mosaic-like composition. The E. faecalis PAI can undergo precise intra- and interspecies transfer probably with the help of conjugative elements like conjugative resistance plasmids, supporting the role of horizontal gene transfer and antibiotic selective pressure in the successful establishment of certain enterococci as nosocomial pathogens.
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Hegstad K, Mikalsen T, Coque TM, Werner G, Sundsfjord A. Mobile genetic elements and their contribution to the emergence of antimicrobial resistant Enterococcus faecalis and Enterococcus faecium. Clin Microbiol Infect 2011; 16:541-54. [PMID: 20569265 DOI: 10.1111/j.1469-0691.2010.03226.x] [Citation(s) in RCA: 234] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mobile genetic elements (MGEs) including plasmids and transposons are pivotal in the dissemination and persistence of antimicrobial resistance in Enterococcus faecalis and Enterococcus faecium. Enterococcal MGEs have also been shown to be able to transfer resistance determinants to more pathogenic bacteria such as Staphylococcus aureus. Despite their importance, we have a limited knowledge about the prevalence, distribution and genetic content of specific MGEs in enterococcal populations. Molecular epidemiological studies of enterococcal MGEs have been hampered by the lack of standardized molecular typing methods and relevant genome information. This review focuses on recent developments in the detection of MGEs and their contribution to the spread of antimicrobial resistance in clinically relevant enterococci.
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Affiliation(s)
- K Hegstad
- Reference Centre for Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North-Norway.
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Werner G, Freitas AR, Coque TM, Sollid JE, Lester C, Hammerum AM, Garcia-Migura L, Jensen LB, Francia MV, Witte W, Willems RJ, Sundsfjord A. Host range of enterococcal vanA plasmids among Gram-positive intestinal bacteria. J Antimicrob Chemother 2010; 66:273-82. [PMID: 21131318 DOI: 10.1093/jac/dkq455] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES The most prevalent type of acquired glycopeptide resistance is encoded by the vanA transposon Tn1546 located mainly on transferable plasmids in Enterococcus faecium. The limited occurrence in other species could be due to the lack of inter-species transferability and/or stability of Tn1546-containing plasmids in other species. We investigated the in vitro transferability of 14 pre-characterized vanA-containing plasmids hosted by E. faecium (n = 9), Enterococcus faecalis (n = 4) and Enterococcus raffinosus (n = 1) into several enterococcal, lactobacterial, lactococcal and bifidobacterial recipients. METHODS A filter-mating protocol was harmonized using procedures of seven partner laboratories. Donor strains were mated with three E. faecium recipients, three E. faecalis recipients, a Lactobacillus acidophilus recipient, a Lactococcus lactis recipient and two Bifidobacterium recipients. Transfer rates were calculated per donor and recipient. Transconjugants were confirmed by determining their phenotypic and genotypic properties. Stability of plasmids in the new host was assessed in long-term growth experiments. RESULTS In total, 282 enterococcal matings and 73 inter-genus matings were performed and evaluated. In summary, intra-species transfer was far more frequent than inter-species transfer, if that was detectable at all. All recipients of the same species behaved similarly. Inter-genus transfer was shown for broad host range control plasmids (pIP501/pAMβ1) only. Acquired resistance plasmids remained stable in the new host. CONCLUSIONS Intra-species transfer of enterococcal vanA plasmids was far more frequent than transfer across species or genus barriers and may thus explain the preferred prevalence of vanA-containing plasmids among E. faecium. A reservoir of vanA plasmids in non-enterococcal intestinal colonizers does not seem to be reasonable.
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Complete nucleotide sequence and determination of the replication region of the sporulation inhibiting plasmid p576 from Bacillus pumilus NRS576. Res Microbiol 2010; 161:772-82. [PMID: 20863889 DOI: 10.1016/j.resmic.2010.07.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Accepted: 07/27/2010] [Indexed: 01/08/2023]
Abstract
Large plasmids, presumably replicating via the theta mechanism, have been identified in numerous gram-positive bacteria. However, their characterization is rather poor and predominantly limited to those harbored by some (opportunistic) pathogenic bacteria. Here we determined the DNA sequence of the 43.3 kb plasmid p576 from Bacillus pumilus strain NRS576, the first B. pumilus theta-replicating plasmid sequenced. Plasmid p576 has a modular structure, but surprisingly, it does not seem to encode a Rep protein found on most theta-replicating plasmids. However, a ∼1 kb region was identified showing homology with the Rep-independent replication region of Bacillus subtilis plasmid pLS20, and we demonstrated that this region is sufficient for autonomous replication. The plasmid contains various large direct repeat sequences. A likely function could be attributed to at least 15 putative p576 genes. Some of these are predicted to be involved in stable maintenance of the plasmid; others are likely to encode proteins involved in conjugation. p576 also carries a rap-phr cassette whose possible function is discussed.
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Global spread of the hyl(Efm) colonization-virulence gene in megaplasmids of the Enterococcus faecium CC17 polyclonal subcluster. Antimicrob Agents Chemother 2010; 54:2660-5. [PMID: 20385861 DOI: 10.1128/aac.00134-10] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Enterococcus faecium has increasingly been reported as a nosocomial pathogen since the early 1990s, presumptively associated with the expansion of a human-associated Enterococcus faecium polyclonal subcluster known as clonal complex 17 (CC17) that has progressively acquired different antibiotic resistance (ampicillin and vancomycin) and virulence (esp(Efm), hyl(Efm), and fms) traits. We analyzed the presence and the location of a putative glycoside hydrolase hyl(Efm) gene among E. faecium strains obtained from hospitalized patients (255 patients; outbreak, bacteremic, and/or disseminated isolates from 23 countries and five continents; 1986 to 2009) and from nonclinical origins (isolates obtained from healthy humans [25 isolates], poultry [30], swine [90], and the environment [55]; 1999 to 2007). Clonal relatedness was established by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Plasmid analysis included determination of content and size (S1-PFGE), transferability (filter mating), screening of Rep initiator proteins (PCR), and location of vanA, vanB, ermB, and hyl(Efm) genes (S1/I-CeuI hybridization). Most E. faecium isolates contained large plasmids (>150 kb) and showed variable contents of van, hyl(Efm), or esp(Efm). The hyl(Efm) gene was associated with megaplasmids (170 to 375 kb) of worldwide spread (ST16, ST17, and ST18) or locally predominant (ST192, ST203, ST280, and ST412) ampicillin-resistant CC17 clones collected in the five continents since the early 1990s. All but one hyl(Efm)-positive isolate belonged to the CC17 polyclonal subcluster. The presence of hyl(Efm) megaplasmids among CC17 from Europe, Australia, Asia, and Africa since at least the mid-1990s was documented. This study further demonstrates the pandemic expansion of particular CC17 clones before acquisition of vancomycin resistance and putative virulence traits and describes the presence of megaplasmids in most of the contemporary E. faecium isolates with different origins.
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46
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Complete nucleotide sequence and comparative analysis of pPR9, a 41.7-kilobase conjugative staphylococcal multiresistance plasmid conferring high-level mupirocin resistance. Antimicrob Agents Chemother 2010; 54:2252-7. [PMID: 20211895 DOI: 10.1128/aac.01074-09] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have sequenced the conjugative plasmid pPR9, which carries the ileS2 gene, which had contributed to the dissemination of high-level mupirocin resistance at our institution. The plasmid backbone shows extensive genetic conservation with plasmids belonging to the pSK41/pGO1 family, but comparative analyses have revealed key differences that provide important insights into the evolution of these medically important plasmids and high-level mupirocin resistance in staphylococci and highlight the role of insertion sequence IS257 in these processes.
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47
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Sequence analysis of plasmid pIR52-1 from Lactobacillus helveticus R0052 and investigation of its origin of replication. Plasmid 2010; 63:108-17. [DOI: 10.1016/j.plasmid.2009.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2009] [Revised: 12/19/2009] [Accepted: 12/21/2009] [Indexed: 11/20/2022]
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Jensen LB, Garcia-Migura L, Valenzuela AJS, Løhr M, Hasman H, Aarestrup FM. A classification system for plasmids from enterococci and other Gram-positive bacteria. J Microbiol Methods 2009; 80:25-43. [PMID: 19879906 DOI: 10.1016/j.mimet.2009.10.012] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 10/19/2009] [Accepted: 10/20/2009] [Indexed: 11/18/2022]
Abstract
A classification system for plasmids isolated from enterococci and other Gram-positive bacteria was developed based on 111 published plasmid sequences from enterococci and other Gram-positive bacteria; mostly staphylococci. Based on PCR amplification of conserved areas of the replication initiating genes (rep), alignment of these sequences and using a cutoff value of 80% identity on both protein and DNA level, 19 replicon families (rep-families) were defined together with several unique sequences. The prevalence of these rep-families was tested on 79 enterococcal isolates from a collection of isolates of animal and human origin. Difference in prevalence of the designed rep-families were detected with rep(9) being most prevalent in Enterococcus faecalis and rep(2) in Enterococcus faecium. In 33% of the tested E. faecium and 32% of the tested E. faecalis no positive amplicons were detected. Furthermore, conjugation experiments were performed obtaining 30 transconjugants when selecting for antimicrobial resistance. Among them 19 gave no positive amplicons indicating presence of rep-families not tested for in this experimental setup.
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Affiliation(s)
- L B Jensen
- National Food Institute, DTU, Division of Microbiology and Risk Assessment, Bülowsvej 27, DK-1790 Copenhagen V, Denmark.
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Weaver KE, Reddy SG, Brinkman CL, Patel S, Bayles KW, Endres JL. Identification and characterization of a family of toxin-antitoxin systems related to the Enterococcus faecalis plasmid pAD1 par addiction module. MICROBIOLOGY-SGM 2009; 155:2930-2940. [PMID: 19542006 DOI: 10.1099/mic.0.030932-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The par locus of the Enterococcus faecalis plasmid pAD1 is an RNA-regulated addiction module encoding the peptide toxin Fst. Homology searches revealed that Fst belongs to a family of at least nine related peptides encoded on the chromosomes and plasmids of six different Gram-positive bacterial species. Comparison of an alignment of these peptides with the results of a saturation mutagenesis analysis indicated regions of the peptides important for biological function. Examination of the genetic context of the fst genes revealed that all of these peptides are encoded within par-like loci with conserved features similar to pAD1 par. All four Ent. faecalis family members were demonstrated to produce the expected toxin-encoding and regulatory RNA products. The locus from the Ent. faecalis plasmid pAMS1 was demonstrated to function as an addiction module and Fst was shown to be toxic to Staphylococcus aureus, suggesting that a plasmid-encoded module in that species is performing the same function. Thus, the pAD1-encoded par locus appears to be the prototype of a family of related loci found in several Gram-positive species.
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Affiliation(s)
- Keith E Weaver
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
| | - Shirisha G Reddy
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
| | - Cassandra L Brinkman
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
| | - Smita Patel
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
| | - Kenneth W Bayles
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Jennifer L Endres
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
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Fisher K, Phillips C. The ecology, epidemiology and virulence of Enterococcus. MICROBIOLOGY-SGM 2009; 155:1749-1757. [PMID: 19383684 DOI: 10.1099/mic.0.026385-0] [Citation(s) in RCA: 661] [Impact Index Per Article: 44.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Enterococci are Gram-positive, catalase-negative, non-spore-forming, facultative anaerobic bacteria, which usually inhabit the alimentary tract of humans in addition to being isolated from environmental and animal sources. They are able to survive a range of stresses and hostile environments, including those of extreme temperature (5-65 degrees C), pH (4.5-10.0) and high NaCl concentration, enabling them to colonize a wide range of niches. Virulence factors of enterococci include the extracellular protein Esp and aggregation substances (Agg), both of which aid in colonization of the host. The nosocomial pathogenicity of enterococci has emerged in recent years, as well as increasing resistance to glycopeptide antibiotics. Understanding the ecology, epidemiology and virulence of Enterococcus species is important for limiting urinary tract infections, hepatobiliary sepsis, endocarditis, surgical wound infection, bacteraemia and neonatal sepsis, and also stemming the further development of antibiotic resistance.
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Affiliation(s)
- Katie Fisher
- University of Northampton, School of Health, Park Campus, Boughton Green Road, Northampton NN2 7AL, UK
| | - Carol Phillips
- University of Northampton, School of Health, Park Campus, Boughton Green Road, Northampton NN2 7AL, UK
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