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Hussain H, Nubgan A, Rodríguez C, Imwattana K, Knight DR, Parthala V, Mullany P, Goh S. Removal of mobile genetic elements from the genome of Clostridioides difficile and the implications for the organism's biology. Front Microbiol 2024; 15:1416665. [PMID: 38966395 PMCID: PMC11222575 DOI: 10.3389/fmicb.2024.1416665] [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: 04/12/2024] [Accepted: 06/04/2024] [Indexed: 07/06/2024] Open
Abstract
Clostridioides difficile is an emerging pathogen of One Health significance. Its highly variable genome contains mobile genetic elements (MGEs) such as transposons and prophages that influence its biology. Systematic deletion of each genetic element is required to determine their precise role in C. difficile biology and contribution to the wider mobilome. Here, Tn5397 (21 kb) and ϕ027 (56 kb) were deleted from C. difficile 630 and R20291, respectively, using allele replacement facilitated by CRISPR-Cas9. The 630 Tn5397 deletant transferred PaLoc at the same frequency (1 × 10-7) as 630 harboring Tn5397, indicating that Tn5397 alone did not mediate conjugative transfer of PaLoc. The R20291 ϕ027 deletant was sensitive to ϕ027 infection, and contained two unexpected features, a 2.7 kb remnant of the mutagenesis plasmid, and a putative catalase gene adjacent to the deleted prophage was also deleted. Growth kinetics of R20291 ϕ027 deletant was similar to wild type (WT) in rich medium but marginally reduced compared with WT in minimal medium. This work indicates the commonly used pMTL8000 plasmid series works well for CRISPR-Cas9-mediated gene deletion, resulting in the largest deleted locus (56.8 kb) described in C. difficile. Removal of MGEs was achieved by targeting conjugative/integrative regions to promote excision and permanent loss. The deletants created will be useful strains for investigating Tn5397 or ϕ027 prophage contribution to host virulence, fitness, and physiology, and a platform for other mutagenesis studies aimed at functional gene analysis without native transposon or phage interference in C. difficile 630 and R20291.
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Affiliation(s)
- Haitham Hussain
- Department of Microbial Diseases, Eastman Dental Institute, University College London, London, United Kingdom
| | - Amer Nubgan
- Department of Clinical, Pharmaceutical and Biological Sciences, University of Hertfordshire, Hatfield, United Kingdom
| | - César Rodríguez
- Facultad de Microbiología and Centro de Investigación en Enfermedades Tropicales (CIET), Universidad de Costa Rica, San José, Costa Rica
| | - Korakrit Imwattana
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Salaya, Thailand
| | - Daniel R. Knight
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
- Department of Microbiology, PathWest Laboratory Medicine WA, Queen Elizabeth II Medical Centre, Nedlands, WA, Australia
| | - Valerija Parthala
- Department of Clinical, Pharmaceutical and Biological Sciences, University of Hertfordshire, Hatfield, United Kingdom
| | - Peter Mullany
- Department of Microbial Diseases, Eastman Dental Institute, University College London, London, United Kingdom
| | - Shan Goh
- Department of Clinical, Pharmaceutical and Biological Sciences, University of Hertfordshire, Hatfield, United Kingdom
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Spigaglia P, Mastrantonio P, Barbanti F. Antibiotic Resistances of Clostridioides difficile. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1435:169-198. [PMID: 38175476 DOI: 10.1007/978-3-031-42108-2_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
The rapid evolution of antibiotic resistance in Clostridioides difficile and the consequent effects on prevention and treatment of C. difficile infections (CDIs) are a matter of concern for public health. Antibiotic resistance plays an important role in driving C. difficile epidemiology. Emergence of new types is often associated with the emergence of new resistances, and most of the epidemic C. difficile clinical isolates is currently resistant to multiple antibiotics. In particular, it is to worth to note the recent identification of strains with reduced susceptibility to the first-line antibiotics for CDI treatment and/or for relapsing infections. Antibiotic resistance in C. difficile has a multifactorial nature. Acquisition of genetic elements and alterations of the antibiotic target sites, as well as other factors, such as variations in the metabolic pathways or biofilm production, contribute to the survival of this pathogen in the presence of antibiotics. Different transfer mechanisms facilitate the spread of mobile elements among C. difficile strains and between C. difficile and other species. Furthermore, data indicate that both genetic elements and alterations in the antibiotic targets can be maintained in C. difficile regardless of the burden imposed on fitness, and therefore resistances may persist in C. difficile population in absence of antibiotic selective pressure.
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Affiliation(s)
- Patrizia Spigaglia
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy.
| | - Paola Mastrantonio
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Fabrizio Barbanti
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
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3
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Yushkova E, Moskalev A. Transposable elements and their role in aging. Ageing Res Rev 2023; 86:101881. [PMID: 36773759 DOI: 10.1016/j.arr.2023.101881] [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: 11/17/2022] [Revised: 01/16/2023] [Accepted: 02/07/2023] [Indexed: 02/12/2023]
Abstract
Transposable elements (TEs) are an important part of eukaryotic genomes. The role of somatic transposition in aging, carcinogenesis, and other age-related diseases has been determined. This review discusses the fundamental properties of TEs and their complex interactions with cellular processes, which are crucial for understanding the diverse effects of their activity on the genetics and epigenetics of the organism. The interactions of TEs with recombination, replication, repair, and chromosomal regulation; the ability of TEs to maintain a balance between their own activity and repression, the involvement of TEs in the creation of new or alternative genes, the expression of coding/non-coding RNA, and the role in DNA damage and modification of regulatory networks are reviewed. The contribution of the derepressed TEs to age-dependent effects in individual cells/tissues in different organisms was assessed. Conflicting information about TE activity under stress as well as theories of aging mechanisms related to TEs is discussed. On the one hand, transposition activity in response to stressors can lead to organisms acquiring adaptive innovations of great importance for evolution at the population level. On the other hand, the TE expression can cause decreased longevity and stress tolerance at the individual level. The specific features of TE effects on aging processes in germline and soma and the ways of their regulation in cells are highlighted. Recent results considering somatic mutations in normal human and animal tissues are indicated, with the emphasis on their possible functional consequences. In the context of aging, the correlation between somatic TE activation and age-related changes in the number of proteins required for heterochromatin maintenance and longevity regulation was analyzed. One of the original features of this review is a discussion of not only effects based on the TEs insertions and the associated consequences for the germline cell dynamics and somatic genome, but also the differences between transposon- and retrotransposon-mediated structural genome changes and possible phenotypic characteristics associated with aging and various age-related pathologies. Based on the analysis of published data, a hypothesis about the influence of the species-specific features of number, composition, and distribution of TEs on aging dynamics of different animal genomes was formulated.
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Affiliation(s)
- Elena Yushkova
- Laboratory of Geroprotective and Radioprotective Technologies, Institute of Biology, Komi Science Center, Ural Branch, Russian Academy of Sciences, 28 Kommunisticheskaya st., 167982 Syktyvkar, Russian Federation
| | - Alexey Moskalev
- Laboratory of Geroprotective and Radioprotective Technologies, Institute of Biology, Komi Science Center, Ural Branch, Russian Academy of Sciences, 28 Kommunisticheskaya st., 167982 Syktyvkar, Russian Federation; Laboratory of Genetics and Epigenetics of Aging, Russian Clinical Research Center for Gerontology, Pirogov Russian National Research Medical University, Moscow 129226, Russian Federation; Longaevus Technologies, London, UK.
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BELITSKY BORISR. VanG- and D-Ala-D-Ser-dependent peptidoglycan synthesis and vancomycin resistance in Clostridioides difficile. Mol Microbiol 2022; 118:526-540. [PMID: 36065735 PMCID: PMC9671823 DOI: 10.1111/mmi.14980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 08/30/2022] [Accepted: 09/02/2022] [Indexed: 11/29/2022]
Abstract
A Clostridioides difficile strain deficient in the ddl gene is unable to synthesize the dipeptide D-Ala-D-Ala, an essential component of peptidoglycan and the target of vancomycin. We isolated spontaneous suppressors of a ∆ddl mutation that allowed cell growth in the absence of D-Ala-D-Ala. The mutations caused constitutive or partly constitutive expression of the vancomycin-inducible vanG operon responsible for the synthesis of D-Ala-D-Ser, which can replace D-Ala-D-Ala in peptidoglycan. The mutations mapped to the vanS or vanR genes, which regulate expression of the vanG operon. The constitutive level of vanG expression was about 10-fold above that obtained by vancomycin induction. The incorporation of D-Ala-D-Ser into peptidoglycan due to high expression of the vanG operon conferred only low-level resistance to vancomycin, but VanG was found to synthesize D-Ala-D-Ala in addition to D-Ala-D-Ser. However, the same, low resistance to vancomycin was also observed in cells completely unable to synthesize D-Ala-D-Ala and grown in the presence of D-Ala-D-Ser. D-Ala-D-Ala presence was required for efficient vancomycin induction of the vanG operon showing that vancomycin is not by itself able to activate VanS. D-Ala-D-Ser, similar to D-Ala-D-Ala, served as an anti-activator of DdlR, the positive regulator of the ddl gene, thereby coupling vanG and ddl expression.
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Affiliation(s)
- BORIS R. BELITSKY
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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Lao J, Lacroix T, Guédon G, Coluzzi C, Payot S, Leblond-Bourget N, Chiapello H. ICEscreen: a tool to detect Firmicute ICEs and IMEs, isolated or enclosed in composite structures. NAR Genom Bioinform 2022; 4:lqac079. [PMID: 36285285 PMCID: PMC9585547 DOI: 10.1093/nargab/lqac079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 10/03/2022] [Accepted: 10/06/2022] [Indexed: 11/23/2022] Open
Abstract
Mobile Genetic Elements (MGEs) are integrated in bacterial genomes and key elements that drive prokaryote genome evolution. Among them are Integrative and Conjugative Elements (ICEs) and Integrative Mobilizable Elements (IMEs) which are important for bacterial fitness since they frequently carry genes participating in important bacterial adaptation phenotypes such as antibiotic resistance, virulence or specialized metabolic pathways. Although ICEs and IMEs are widespread, they are as yet almost never annotated in public bacterial genomes. To address the need of dedicated strategies for the annotation of these elements, we developed ICEscreen, a tool that introduces two new features to detect ICEs and IMEs in Firmicute genomes. First, ICEscreen uses an efficient strategy to detect Signature Proteins of ICEs and IMEs based on a database dedicated to Firmicutes and composed of manually curated proteins and Hidden Markov Models (HMM) profiles. Second, ICEscreen includes a new original algorithm that detects composite structures of ICEs and IMEs that are frequent in genomes of Firmicutes but are currently not resolved by any other tool. We benchmarked ICEscreen on experimentally supported elements and on a public dataset of 246 manually annotated elements including the genomes of 40 Firmicutes and demonstrate its efficiency to detect ICEs and IMEs.
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Affiliation(s)
| | | | - Gérard Guédon
- Université de Lorraine, INRAE, DynAMic, F-54000 Nancy, France
| | - Charles Coluzzi
- Université Paris-Saclay, INRAE, MaIAGE, F-78350 Jouy-en-Josas, France,Université de Lorraine, INRAE, DynAMic, F-54000 Nancy, France
| | - Sophie Payot
- Université de Lorraine, INRAE, DynAMic, F-54000 Nancy, France
| | | | - Hélène Chiapello
- To whom correspondence should be addressed. Tel: +33 1 34652884; Fax: +33 1 34652217;
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Redding LE, Tu V, Abbas A, Alvarez M, Zackular JP, Gu C, Bushman FD, Kelly DJ, Barnhart D, Lee JJ, Bittinger KL. Genetic and phenotypic characteristics of Clostridium (Clostridioides) difficile from canine, bovine, and pediatric populations. Anaerobe 2022; 74:102539. [PMID: 35217150 PMCID: PMC9359814 DOI: 10.1016/j.anaerobe.2022.102539] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 02/02/2022] [Accepted: 02/17/2022] [Indexed: 12/15/2022]
Abstract
Objectives: Carriage of Clostridioides difficile by different species of animals has led to speculation that animals could represent a reservoir of this pathogen for human infections. The objective of this study was to compare C. difficile isolates from humans, dogs, and cattle from a restricted geographic area. Methods: C. difficile isolates from 36 dogs and 15 dairy calves underwent whole genome sequencing, and phenotypic assays assessing growth and virulence were performed. Genomes of animal-derived isolates were compared to 29 genomes of isolates from a pediatric population as well as 44 reference genomes. Results: Growth rates and relative cytotoxicity of isolates were significantly higher and lower, respectively, in bovine-derived isolates compared to pediatric- and canine-derived isolates. Analysis of core genes showed clustering by host species, though in a few cases, human strains co-clustered with canine or bovine strains, suggesting possible interspecies transmission. Geographic differences (e.g., farm, litter) were small compared to differences between species. In an analysis of accessory genes, the total number of genes in each genome varied between host species, with 6.7% of functional orthologs differentially present/absent between host species and bovine-derived strains having the lowest number of genes. Canine-derived isolates were most likely to be non-toxigenic and more likely to carry phages. A targeted study of episomes identified in local pediatric strains showed sharing of a methicillin-resistance plasmid with dogs, and historic sharing of a wide range of episomes across hosts. Bovine-derived isolates harbored the widest variety of antibiotic-resistance genes, followed by canine Conclusions: While C. difficile isolates mostly clustered by host species, occasional co-clustering of canine and pediatric-derived isolates suggests the possibility of interspecies transmission. The presence of a pool of resistance genes in animal-derived isolates with the potential to appear in humans given sufficient pressure from antibiotic use warrants concern.
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Affiliation(s)
- L E Redding
- Department of Clinical Studies-New Bolton Center, University of Pennsylvania, School of Veterinary Medicine, Kennett Square, PA, 19348, USA.
| | - V Tu
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, PA, 19104, USA
| | - A Abbas
- Division of Protective Immunity, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - M Alvarez
- Division of Protective Immunity, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - J P Zackular
- Division of Protective Immunity, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - C Gu
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - F D Bushman
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - D J Kelly
- Department of Clinical Studies-New Bolton Center, University of Pennsylvania, School of Veterinary Medicine, Kennett Square, PA, 19348, USA
| | - D Barnhart
- Department of Clinical Studies-New Bolton Center, University of Pennsylvania, School of Veterinary Medicine, Kennett Square, PA, 19348, USA
| | - J J Lee
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, PA, 19104, USA
| | - K L Bittinger
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, PA, 19104, USA
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VirB4- and VirD4-Like ATPases, Components of a Putative Type 4C Secretion System in Clostridioides difficile. J Bacteriol 2021; 203:e0035921. [PMID: 34424036 DOI: 10.1128/jb.00359-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The type 4 secretion system (T4SS) represents a bacterial nanomachine capable of trans-cell wall transportation of proteins and DNA and has attracted intense interest due to its roles in the pathogenesis of infectious diseases. In the current investigation, we uncovered three distinct gene clusters in Clostridioides difficile strain 630 encoding proteins structurally related to components of the VirB4/D4 type 4C secretion system from Streptococcus suis strain 05ZYH33 and located within sequences of conjugative transposons (CTn). Phylogenic analysis revealed that VirB4- and VirD4-like proteins of the CTn4 locus, on the one hand, and those of the CTn2 and CTn5 loci, on the other hand, fit into separate clades, suggesting specific roles of identified secretion system variants in the physiology of C. difficile. Our further study on VirB4- and VirD4-like products encoded by CTn4 revealed that both proteins possess Mg2+-dependent ATPase activity, form oligomers (most likely hexamers) in aqueous solutions, and rely on potassium but not sodium ions for the highest catalytic rate. VirD4 binds nonspecifically to DNA and RNA. The DNA-binding activity of VirD4 strongly decreased with the W241A variant. Mutations in the nucleotide sequences encoding presumable Walker A and Walker B motifs decreased the stability of the oligomers and significantly but not completely attenuated the enzymatic activity of VirB4. In VirD4, substitutions of amino acid residues in the peptides reminiscent of Walker structural motifs neither attenuated the enzymatic activity of the protein nor influenced the oligomerization state of the ATPase. IMPORTANCE C. difficile is a Gram-positive, anaerobic, spore-forming bacterium that causes life-threatening colitis in humans. Major virulence factors of the microorganism include the toxins TcdA, TcdB, and CDT. However, other bacterial products, including a type 4C secretion system, have been hypothesized to contribute to the pathogenesis of the infection and are considered possible virulence factors of C. difficile. In the current paper, we describe the structural organization of putative T4SS machinery in C. difficile and characterize its VirB4- and VirD4-like components. Our studies, in addition to its significance for basic science, can potentially aid the development of antivirulence drugs suitable for the treatment of C. difficile infection.
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Durand R, Huguet KT, Rivard N, Carraro N, Rodrigue S, Burrus V. Crucial role of Salmonella genomic island 1 master activator in the parasitism of IncC plasmids. Nucleic Acids Res 2021; 49:7807-7824. [PMID: 33834206 PMCID: PMC8373056 DOI: 10.1093/nar/gkab204] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 03/09/2021] [Accepted: 03/15/2021] [Indexed: 12/26/2022] Open
Abstract
IncC conjugative plasmids and the multiple variants of Salmonella Genomic Island 1 (SGI1) are two functionally interacting families of mobile genetic elements commonly associated with multidrug resistance in the Gammaproteobacteria. SGI1 and its siblings are specifically mobilised in trans by IncC conjugative plasmids. Conjugative transfer of IncC plasmids is activated by the plasmid-encoded master activator AcaCD. SGI1 carries five AcaCD-responsive promoters that drive the expression of genes involved in its excision, replication, and mobilisation. SGI1 encodes an AcaCD homologue, the transcriptional activator complex SgaCD (also known as FlhDCSGI1) that seems to recognise and activate the same SGI1 promoters. Here, we investigated the relevance of SgaCD in SGI1's lifecycle. Mating assays revealed the requirement for SgaCD and its IncC-encoded counterpart AcaCD in the mobilisation of SGI1. An integrative approach combining ChIP-exo, Cappable-seq, and RNA-seq confirmed that SgaCD activates each of the 18 AcaCD-responsive promoters driving the expression of the plasmid transfer functions. A comprehensive analysis of the activity of the complete set of AcaCD-responsive promoters of SGI1 and the helper IncC plasmid was performed through reporter assays. qPCR and flow cytometry assays revealed that SgaCD is essential to elicit the excision and replication of SGI1 and destabilise the helper IncC plasmid.
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Affiliation(s)
- Romain Durand
- Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
| | - Kévin T Huguet
- Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
| | - Nicolas Rivard
- Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
| | - Nicolas Carraro
- Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
| | - Sébastien Rodrigue
- Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
| | - Vincent Burrus
- Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
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Riedel T, Neumann-Schaal M, Wittmann J, Schober I, Hofmann JD, Lu CW, Dannheim A, Zimmermann O, Lochner M, Groß U, Overmann J. Characterization of Clostridioides difficile DSM 101085 with A-B-CDT+ Phenotype from a Late Recurrent Colonization. Genome Biol Evol 2021; 12:566-577. [PMID: 32302381 PMCID: PMC7250501 DOI: 10.1093/gbe/evaa072] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/10/2020] [Indexed: 12/29/2022] Open
Abstract
During the last decades, hypervirulent strains of Clostridioides difficile with frequent disease recurrence and increased mortality appeared. Clostridioides difficile DSM 101085 was isolated from a patient who suffered from several recurrent infections and colonizations, likely contributing to a fatal outcome. Analysis of the toxin repertoire revealed the presence of a complete binary toxin locus and an atypical pathogenicity locus consisting of only a tcdA pseudogene and a disrupted tcdC gene sequence. The pathogenicity locus shows upstream a transposon and has been subject to homologous recombination or lateral gene transfer events. Matching the results of the genome analysis, neither TcdA nor TcdB production but the expression of cdtA and cdtB was detected. This highlights a potential role of the binary toxin C. difficile toxin in this recurrent colonization and possibly further in a host-dependent virulence. Compared with the C. difficile metabolic model strains DSM 28645 (630Δerm) and DSM 27147 (R20291), strain DSM 101085 showed a specific metabolic profile, featuring changes in the threonine degradation pathways and alterations in the central carbon metabolism. Moreover, products originating from Stickland pathways processing leucine, aromatic amino acids, and methionine were more abundant in strain DSM 101085, indicating a more efficient use of these substrates. The particular characteristics of strain C. difficile DSM 101085 may represent an adaptation to a low-protein diet in a patient with recurrent infections.
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Affiliation(s)
- Thomas Riedel
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.,German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Braunschweig, Germany
| | - Meina Neumann-Schaal
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.,Department of Bioinformatics and Biochemistry and Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Germany
| | - Johannes Wittmann
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Isabel Schober
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Julia Danielle Hofmann
- Department of Bioinformatics and Biochemistry and Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Germany
| | - Chia-Wen Lu
- Institute of Infection Immunology, TWINCORE, Centre for Experimental and Clinical Infection Research, a Joint Venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
| | - Antonia Dannheim
- Department of Bioinformatics and Biochemistry and Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Germany
| | - Ortrud Zimmermann
- Institute of Medical Microbiology, University Medical Center Göttingen, Germany
| | - Matthias Lochner
- Institute of Infection Immunology, TWINCORE, Centre for Experimental and Clinical Infection Research, a Joint Venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
| | - Uwe Groß
- Institute of Medical Microbiology, University Medical Center Göttingen, Germany.,Göttingen International Health Network, Göttingen, Germany
| | - Jörg Overmann
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.,German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Braunschweig, Germany.,Institute of Microbiology, Technical University of Braunschweig, Germany
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Kartalidis P, Skoulakis A, Tsilipounidaki K, Florou Z, Petinaki E, Fthenakis GC. Clostridioides difficile as a Dynamic Vehicle for the Dissemination of Antimicrobial-Resistance Determinants: Review and In Silico Analysis. Microorganisms 2021; 9:microorganisms9071383. [PMID: 34202117 PMCID: PMC8307371 DOI: 10.3390/microorganisms9071383] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/21/2021] [Accepted: 06/22/2021] [Indexed: 01/11/2023] Open
Abstract
The present paper is divided into two parts. The first part focuses on the role of Clostridioides difficile in the accumulation of genes associated with antimicrobial resistance and then the transmission of them to other pathogenic bacteria occupying the same human intestinal niche. The second part describes an in silico analysis of the genomes of C. difficile available in GenBank, with regard to the presence of mobile genetic elements and antimicrobial resistance genes. The diversity of the C. difficile genome is discussed, and the current status of resistance of the organisms to various antimicrobial agents is reviewed. The role of transposons associated with antimicrobial resistance is appraised; the importance of plasmids associated with antimicrobial resistance is discussed, and the significance of bacteriophages as a potential shuttle for antimicrobial resistance genes is presented. In the in silico study, 1101 C. difficile genomes were found to harbor mobile genetic elements; Tn6009, Tn6105, CTn7 and Tn6192, Tn6194 and IS256 were the ones more frequently identified. The genes most commonly harbored therein were: ermB, blaCDD, vanT, vanR, vanG and vanS. Tn6194 was likely associated with resistance to erythromycin, Tn6192 and CTn7 with resistance to the β-lactams and vancomycin, IS256 with resistance to aminoglycoside and Tn6105 to vancomycin.
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Affiliation(s)
- Philip Kartalidis
- Department of Clinical and Laboratory Research, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41110 Larissa, Greece; (P.K.); (A.S.); (K.T.); (Z.F.); (E.P.)
| | - Anargyros Skoulakis
- Department of Clinical and Laboratory Research, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41110 Larissa, Greece; (P.K.); (A.S.); (K.T.); (Z.F.); (E.P.)
| | - Katerina Tsilipounidaki
- Department of Clinical and Laboratory Research, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41110 Larissa, Greece; (P.K.); (A.S.); (K.T.); (Z.F.); (E.P.)
| | - Zoi Florou
- Department of Clinical and Laboratory Research, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41110 Larissa, Greece; (P.K.); (A.S.); (K.T.); (Z.F.); (E.P.)
| | - Efthymia Petinaki
- Department of Clinical and Laboratory Research, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41110 Larissa, Greece; (P.K.); (A.S.); (K.T.); (Z.F.); (E.P.)
| | - George C. Fthenakis
- Veterinary Faculty, University of Thessaly, 43100 Karditsa, Greece
- Correspondence:
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Soutourina O, Dubois T, Monot M, Shelyakin PV, Saujet L, Boudry P, Gelfand MS, Dupuy B, Martin-Verstraete I. Genome-Wide Transcription Start Site Mapping and Promoter Assignments to a Sigma Factor in the Human Enteropathogen Clostridioides difficile. Front Microbiol 2020; 11:1939. [PMID: 32903654 PMCID: PMC7438776 DOI: 10.3389/fmicb.2020.01939] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/23/2020] [Indexed: 12/12/2022] Open
Abstract
The emerging human enteropathogen Clostridioides difficile is the main cause of diarrhea associated with antibiotherapy. Regulatory pathways underlying the adaptive responses remain understudied and the global view of C. difficile promoter structure is still missing. In the genome of C. difficile 630, 22 genes encoding sigma factors are present suggesting a complex pattern of transcription in this bacterium. We present here the first transcriptional map of the C. difficile genome resulting from the identification of transcriptional start sites (TSS), promoter motifs and operon structures. By 5′-end RNA-seq approach, we mapped more than 1000 TSS upstream of genes. In addition to these primary TSS, this analysis revealed complex structure of transcriptional units such as alternative and internal promoters, potential RNA processing events and 5′ untranslated regions. By following an in silico iterative strategy that used as an input previously published consensus sequences and transcriptomic analysis, we identified candidate promoters upstream of most of protein-coding and non-coding RNAs genes. This strategy also led to refine consensus sequences of promoters recognized by major sigma factors of C. difficile. Detailed analysis focuses on the transcription in the pathogenicity locus and regulatory genes, as well as regulons of transition phase and sporulation sigma factors as important components of C. difficile regulatory network governing toxin gene expression and spore formation. Among the still uncharacterized regulons of the major sigma factors of C. difficile, we defined the SigL regulon by combining transcriptome and in silico analyses. We showed that the SigL regulon is largely involved in amino-acid degradation, a metabolism crucial for C. difficile gut colonization. Finally, we combined our TSS mapping, in silico identification of promoters and RNA-seq data to improve gene annotation and to suggest operon organization in C. difficile. These data will considerably improve our knowledge of global regulatory circuits controlling gene expression in C. difficile and will serve as a useful rich resource for scientific community both for the detailed analysis of specific genes and systems biology studies.
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Affiliation(s)
- Olga Soutourina
- Laboratoire Pathogenèses des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, Paris, France.,Institut Universitaire de France, Paris, France.,Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Thomas Dubois
- Laboratoire Pathogenèses des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, Paris, France
| | - Marc Monot
- Laboratoire Pathogenèses des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, Paris, France
| | | | - Laure Saujet
- Laboratoire Pathogenèses des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, Paris, France
| | - Pierre Boudry
- Laboratoire Pathogenèses des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, Paris, France
| | - Mikhail S Gelfand
- Institute for Information Transmission Problems, Moscow, Russia.,Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Bruno Dupuy
- Laboratoire Pathogenèses des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, Paris, France
| | - Isabelle Martin-Verstraete
- Laboratoire Pathogenèses des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, Paris, France.,Institut Universitaire de France, Paris, France
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12
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Hornung BVH, Kuijper EJ, Smits WK. An in silico survey of Clostridioides difficile extrachromosomal elements . Microb Genom 2020; 5. [PMID: 31526450 PMCID: PMC6807378 DOI: 10.1099/mgen.0.000296] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Gram-positive enteropathogen Clostridioides difficile (Clostridium difficile) is the major cause of healthcare-associated diarrhoea and is also an important cause of community-acquired infectious diarrhoea. Considering the burden of the disease, many studies have employed whole-genome sequencing of bacterial isolates to identify factors that contribute to virulence and pathogenesis. Though extrachromosomal elements (ECEs) such as plasmids are important for these processes in other bacteria, the few characterized plasmids of C. difficile have no relevant functions assigned and no systematic identification of plasmids has been carried out to date. Here, we perform an in silico analysis of publicly available sequence data to show that ~13 % of all C. difficile strains contain ECEs, with 1–6 elements per strain. Our approach identifies known plasmids (e.g. pCD6, pCD630 and cloning plasmids) and six novel putative plasmid families. Our study shows that plasmids are abundant and may encode functions that are relevant for C. difficile physiology. The newly identified plasmids may also form the basis for the construction of novel cloning plasmids for C. difficile that are compatible with existing tools.
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Affiliation(s)
- Bastian V H Hornung
- Department of Medical Microbiology, Leiden University Medical Center, PO Box 9600, 2300RC, Leiden, The Netherlands
| | - Ed J Kuijper
- Netherlands Centre for One Health, The Netherlands.,Department of Medical Microbiology, Leiden University Medical Center, PO Box 9600, 2300RC, Leiden, The Netherlands
| | - Wiep Klaas Smits
- Netherlands Centre for One Health, The Netherlands.,Department of Medical Microbiology, Leiden University Medical Center, PO Box 9600, 2300RC, Leiden, The Netherlands.,Centre for Microbial Cell Biology, Leiden, The Netherlands
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13
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Wu Y, Yang L, Li WG, Zhang WZ, Liu ZJ, Lu JX. Microevolution within ST11 group Clostridioides difficile isolates through mobile genetic elements based on complete genome sequencing. BMC Genomics 2019; 20:796. [PMID: 31666016 PMCID: PMC6822371 DOI: 10.1186/s12864-019-6184-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 10/15/2019] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Clade 5 Clostridioides difficile diverges significantly from the other clades and is therefore, attracting increasing attention due its great heterogeneity. In this study, we used third-generation sequencing techniques to sequence the complete whole genomes of three ST11 C. difficile isolates, RT078 and another two new ribotypes (RTs), obtained from three independent hospitalized elderly patients undergoing antibiotics treatment. Mobile genetic elements (MGEs), antibiotic-resistance, drug resistance genes, and virulent-related genes were analyzed and compared within these three isolates. RESULTS Isolates 10,010 and 12,038 carried a distinct deletion in tcdA compared with isolate 21,062. Furthermore, all three isolates had identical deletions and point-mutations in tcdC, which was once thought to be a unique characteristic of RT078. Isolate 21,062 (RT078) had a unique plasmid, different numbers of transposons and genetic organization, and harboring special CRISPR spacers. All three isolates retained high-level sensitivity to 11 drugs and isolate 21,062 (RT078) carried distinct drug-resistance genes and loss of numerous flagellum-related genes. CONCLUSIONS We concluded that capillary electrophoresis based PCR-ribotyping is important for confirming RT078. Furthermore, RT078 isolates displayed specific MGEs, indicating an independent evolutionary process. In the further study, we could testify these findings with more RT078 isolates of divergent origins.
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Affiliation(s)
- Yuan Wu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China. .,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
| | - Lin Yang
- BGI-Shen zhen, main building, Beishan industry zone, Yan tian District, Shenzhen, China
| | - Wen-Ge Li
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Wen Zhu Zhang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Zheng Jie Liu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jin-Xing Lu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China. .,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
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14
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Clostridium difficile clade 3 (RT023) have a modified cell surface and contain a large transposable island with novel cargo. Sci Rep 2019; 9:15330. [PMID: 31653906 PMCID: PMC6814731 DOI: 10.1038/s41598-019-51628-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 10/02/2019] [Indexed: 12/16/2022] Open
Abstract
The major global pathogen Clostridium difficile (recently renamed Clostridioides difficile) has large genetic diversity including multiple mobile genetic elements. In this study, whole genome sequencing of 86 strains from the poorly characterised clade 3, predominantly PCR ribotype (RT)023, of C. difficile revealed distinctive surface architecture characteristics and a large mobile genetic island. These strains have a unique sortase substrate phenotype compared with well-characterised strains of C. difficile, and loss of the phage protection protein CwpV. A large genetic insertion (023_CTnT) comprised of three smaller elements (023_CTn1-3) is present in 80/86 strains analysed in this study, with genes common among other bacterial strains in the gut microbiome. Novel cargo regions of 023_CTnT include genes encoding a sortase, putative sortase substrates, lantibiotic ABC transporters and a putative siderophore biosynthetic cluster. We demonstrate the excision of 023_CTnT and sub-elements 023_CTn2 and 023_CTn3 from the genome of RT023 reference strain CD305 and the transfer of 023_CTn3 to a non-toxigenic C. difficile strain, which may have implications for the use of non-toxigenic C. difficile strains as live attenuated vaccines. Finally, we show that the genes within the island are expressed in a regulated manner in C. difficile RT023 strains conferring a distinct "niche adaptation".
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15
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Gumkowski JD, Martinie RJ, Corrigan PS, Pan J, Bauerle MR, Almarei M, Booker SJ, Silakov A, Krebs C, Boal AK. Analysis of RNA Methylation by Phylogenetically Diverse Cfr Radical S-Adenosylmethionine Enzymes Reveals an Iron-Binding Accessory Domain in a Clostridial Enzyme. Biochemistry 2019; 58:3169-3184. [PMID: 31246421 DOI: 10.1021/acs.biochem.9b00197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cfr is a radical S-adenosylmethionine (SAM) RNA methylase linked to multidrug antibiotic resistance in bacterial pathogens. It catalyzes a chemically challenging C-C bond-forming reaction to methylate C8 of A2503 (Escherichia coli numbering) of 23S rRNA during ribosome assembly. The cfr gene has been identified as a mobile genetic element in diverse bacteria and in the genome of select Bacillales and Clostridiales species. Despite the importance of Cfr, few representatives have been purified and characterized in vitro. Here we show that Cfr homologues from Bacillus amyloliquefaciens, Enterococcus faecalis, Paenibacillus lautus, and Clostridioides difficile act as C8 adenine RNA methylases in biochemical assays. C. difficile Cfr contains an additional Cys-rich C-terminal domain that binds a mononuclear Fe2+ ion in a rubredoxin-type Cys4 motif. The C-terminal domain can be truncated with minimal impact on C. difficile Cfr activity, but the rate of turnover is decreased upon disruption of the Fe2+-binding site by Zn2+ substitution or ligand mutation. These findings indicate an important purpose for the observed C-terminal iron in the native fusion protein. Bioinformatic analysis of the C. difficile Cfr Cys-rich domain shows that it is widespread (∼1400 homologues) as a stand-alone gene in pathogenic or commensal Bacilli and Clostridia, with >10% encoded adjacent to a predicted radical SAM RNA methylase. Although the domain is not essential for in vitro C. difficile Cfr activity, the genomic co-occurrence and high abundance in the human microbiome suggest a possible functional role for a specialized rubredoxin in certain radical SAM RNA methylases that are relevant to human health.
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Affiliation(s)
- James D Gumkowski
- Department of Chemistry , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Ryan J Martinie
- Department of Chemistry , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Patrick S Corrigan
- Department of Chemistry , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Juan Pan
- Department of Chemistry , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Matthew R Bauerle
- Department of Chemistry , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Mohamed Almarei
- Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Squire J Booker
- Department of Chemistry , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States.,Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States.,Howard Hughes Medical Institute , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Alexey Silakov
- Department of Chemistry , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Carsten Krebs
- Department of Chemistry , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States.,Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Amie K Boal
- Department of Chemistry , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States.,Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
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16
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Williamson CHD, Stone NE, Nunnally AE, Hornstra HM, Wagner DM, Roe CC, Vazquez AJ, Nandurkar N, Vinocur J, Terriquez J, Gillece J, Travis J, Lemmer D, Keim P, Sahl JW. A global to local genomics analysis of Clostridioides difficile ST1/RT027 identifies cryptic transmission events in a northern Arizona healthcare network. Microb Genom 2019; 5:e000271. [PMID: 31107202 PMCID: PMC6700662 DOI: 10.1099/mgen.0.000271] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 04/04/2019] [Indexed: 12/15/2022] Open
Abstract
Clostridioides difficile is a ubiquitous, diarrhoeagenic pathogen often associated with healthcare-acquired infections that can cause a range of symptoms from mild, self-limiting disease to toxic megacolon and death. Since the early 2000s, a large proportion of C. difficile cases have been attributed to the ribotype 027 (RT027) lineage, which is associated with sequence type 1 (ST1) in the C. difficile multilocus sequence typing scheme. The spread of ST1 has been attributed, in part, to resistance to fluoroquinolones used to treat unrelated infections, which creates conditions ideal for C. difficile colonization and proliferation. In this study, we analysed 27 isolates from a healthcare network in northern Arizona, USA, and 1352 publicly available ST1 genomes to place locally sampled isolates into a global context. Whole genome, single nucleotide polymorphism analysis demonstrated that at least six separate introductions of ST1 were observed in healthcare facilities in northern Arizona over an 18-month sampling period. A reconstruction of transmission networks identified potential nosocomial transmission of isolates, which were only identified via whole genome sequence analysis. Antibiotic resistance heterogeneity was observed among ST1 genomes, including variability in resistance profiles among locally sampled ST1 isolates. To investigate why ST1 genomes are so common globally and in northern Arizona, we compared all high-quality C. difficile genomes and identified that ST1 genomes have gained and lost a number of genomic regions compared to all other C. difficile genomes; analyses of other toxigenic C. difficile sequence types demonstrate that this loss may be anomalous and could be related to niche specialization. These results suggest that a combination of antimicrobial resistance and gain and loss of specific genes may explain the prominent association of this sequence type with C. difficile infection cases worldwide. The degree of genetic variability in ST1 suggests that classifying all ST1 genomes into a quinolone-resistant hypervirulent clone category may not be appropriate. Whole genome sequencing of clinical C. difficile isolates provides a high-resolution surveillance strategy for monitoring persistence and transmission of C. difficile and for assessing the performance of infection prevention and control strategies.
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Affiliation(s)
| | - Nathan E. Stone
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Amalee E. Nunnally
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Heidie M. Hornstra
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - David M. Wagner
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Chandler C. Roe
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Adam J. Vazquez
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Nivedita Nandurkar
- Northern Arizona Healthcare, Flagstaff Medical Center, Flagstaff, AZ 86001, USA
| | - Jacob Vinocur
- Northern Arizona Healthcare, Flagstaff Medical Center, Flagstaff, AZ 86001, USA
| | - Joel Terriquez
- Northern Arizona Healthcare, Flagstaff Medical Center, Flagstaff, AZ 86001, USA
| | - John Gillece
- Translational Genomics Research Institute, Flagstaff, AZ 86001, USA
| | - Jason Travis
- Translational Genomics Research Institute, Flagstaff, AZ 86001, USA
| | - Darrin Lemmer
- Translational Genomics Research Institute, Flagstaff, AZ 86001, USA
| | - Paul Keim
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Jason W. Sahl
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA
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17
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Soler N, Robert E, Chauvot de Beauchêne I, Monteiro P, Libante V, Maigret B, Staub J, Ritchie DW, Guédon G, Payot S, Devignes MD, Leblond-Bourget N. Characterization of a relaxase belonging to the MOB T family, a widespread family in Firmicutes mediating the transfer of ICEs. Mob DNA 2019; 10:18. [PMID: 31073337 PMCID: PMC6499999 DOI: 10.1186/s13100-019-0160-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 04/11/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Conjugative spread of antibiotic resistance and virulence genes in bacteria constitutes an important threat to public health. Beyond the well-known conjugative plasmids, recent genome analyses have shown that integrative and conjugative elements (ICEs) are the most widespread conjugative elements, even if their transfer mechanism has been little studied until now. The initiator of conjugation is the relaxase, a protein catalyzing a site-specific nick on the origin of transfer (oriT) of the ICE. Besides canonical relaxases, recent studies revealed non-canonical ones, such as relaxases of the MOBT family that are related to rolling-circle replication proteins of the Rep_trans family. MOBT relaxases are encoded by ICEs of the ICESt3/ICEBs1/Tn916 superfamily, a superfamily widespread in Firmicutes, and frequently conferring antibiotic resistance. RESULTS Here, we present the first biochemical and structural characterization of a MOBT relaxase: the RelSt3 relaxase encoded by ICESt3 from Streptococcus thermophilus. We identified the oriT region of ICESt3 and demonstrated that RelSt3 is required for its conjugative transfer. The purified RelSt3 protein is a stable dimer that provides a Mn2+-dependent single-stranded endonuclease activity. Sequence comparisons of MOBT relaxases led to the identification of MOBT conserved motifs. These motifs, together with the construction of a 3D model of the relaxase domain of RelSt3, allowed us to determine conserved residues of the RelSt3 active site. The involvement of these residues in DNA nicking activity was demonstrated by targeted mutagenesis. CONCLUSIONS All together, this work argues in favor of MOBT being a full family of non-canonical relaxases. The biochemical and structural characterization of a MOBT member provides new insights on the molecular mechanism of conjugative transfer mediated by ICEs in Gram-positive bacteria. This could be a first step towards conceiving rational strategies to control gene transfer in these bacteria.
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Affiliation(s)
- Nicolas Soler
- Université de Lorraine, Inra, UMR1128 DynAMic, F-54000 Nancy, France
| | - Emilie Robert
- Université de Lorraine, Inra, UMR1128 DynAMic, F-54000 Nancy, France
| | | | - Philippe Monteiro
- Université de Lorraine, Inra, UMR1128 DynAMic, F-54000 Nancy, France
| | - Virginie Libante
- Université de Lorraine, Inra, UMR1128 DynAMic, F-54000 Nancy, France
| | - Bernard Maigret
- Université de Lorraine, CNRS, Inria, LORIA, F-54000 Nancy, France
| | - Johan Staub
- Université de Lorraine, Inra, UMR1128 DynAMic, F-54000 Nancy, France
| | - David W. Ritchie
- Université de Lorraine, CNRS, Inria, LORIA, F-54000 Nancy, France
| | - Gérard Guédon
- Université de Lorraine, Inra, UMR1128 DynAMic, F-54000 Nancy, France
| | - Sophie Payot
- Université de Lorraine, Inra, UMR1128 DynAMic, F-54000 Nancy, France
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18
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Independent Microevolution Mediated by Mobile Genetic Elements of Individual Clostridium difficile Isolates from Clade 4 Revealed by Whole-Genome Sequencing. mSystems 2019; 4:mSystems00252-18. [PMID: 30944881 PMCID: PMC6435816 DOI: 10.1128/msystems.00252-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 01/18/2019] [Indexed: 12/15/2022] Open
Abstract
Mobile genetic elements play a key role in the continuing evolution of Clostridium difficile, resulting in the emergence of new phenotypes for individual isolates. On the basis of whole-genome sequencing analysis, we comprehensively explored transposons, CRISPR, prophage, and genetic sites for drug resistance within clade 4 C. difficile isolates with different sequence types. Great diversity in MGEs and a high rate of multidrug resistance were found within this clade, including new transposons, Tn4453a/b with aac(6′) aph(2′′) instead of catD, and a relatively high rate of prophage-carried CRISPR arrays. These findings provide important new insights into the mechanism of genome remodeling within clade 4 and offer a new method for typing and tracing the origins of closely related isolates. Horizontal gene transfer of mobile genetic elements (MGEs) accounts for the mosaic genome of Clostridium difficile, leading to acquisition of new phenotypes, including drug resistance and reconstruction of the genomes. MGEs were analyzed according to the whole-genome sequences of 37 C. difficile isolates with a variety of sequence types (STs) within clade 4 from China. Great diversity was found in each transposon even within isolates with the same ST. Two novel transposons were identified in isolates ZR9 and ZR18, of which approximately one third to half of the genes showed heterogenous origins compared with the usual intestinal bacterial genes. Most importantly, catD, known to be harbored by Tn4453a/b, was replaced by aac(6′) aph(2′′) in isolates 2, 7, and 28. This phenomenon illustrated the frequent occurrence of gene exchanges between C. difficile and other enterobacteria with individual heterogeneity. Numerous prophages and CRISPR arrays were identified in C. difficile isolates of clade 4. Approximately 20% of spacers were located in prophage-carried CRISPR arrays, providing a new method for typing and tracing the origins of closely related isolates, as well as in-depth studies of the mechanism underlying genome remodeling. The rates of drug resistance were obviously higher than those reported previously around the world, although all isolates retained high sensitivity to vancomycin and metronidazole. The increasing number of C. difficile isolates resistant to all antibiotics tested here suggests the ease with which resistance is acquired in vivo. This study gives insights into the genetic mechanism of microevolution within clade 4. IMPORTANCE Mobile genetic elements play a key role in the continuing evolution of Clostridium difficile, resulting in the emergence of new phenotypes for individual isolates. On the basis of whole-genome sequencing analysis, we comprehensively explored transposons, CRISPR, prophage, and genetic sites for drug resistance within clade 4 C. difficile isolates with different sequence types. Great diversity in MGEs and a high rate of multidrug resistance were found within this clade, including new transposons, Tn4453a/b with aac(6′) aph(2′′) instead of catD, and a relatively high rate of prophage-carried CRISPR arrays. These findings provide important new insights into the mechanism of genome remodeling within clade 4 and offer a new method for typing and tracing the origins of closely related isolates.
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19
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Isidro J, Menezes J, Serrano M, Borges V, Paixão P, Mimoso M, Martins F, Toscano C, Santos A, Henriques AO, Oleastro M. Genomic Study of a Clostridium difficile Multidrug Resistant Outbreak-Related Clone Reveals Novel Determinants of Resistance. Front Microbiol 2018; 9:2994. [PMID: 30574133 PMCID: PMC6291485 DOI: 10.3389/fmicb.2018.02994] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 11/20/2018] [Indexed: 12/15/2022] Open
Abstract
Background:Clostridium difficile infection (CDI) is prevalent in healthcare settings. The emergence of hypervirulent and antibiotic resistant strains has led to an increase in CDI incidence and frequent outbreaks. While the main virulence factors are the TcdA and TcdB toxins, antibiotic resistance is thought to play a key role in the infection by and dissemination of C. difficile. Methods: A CDI outbreak involving 12 patients was detected in a tertiary care hospital, in Lisbon, which extended from January to July, with a peak in February, in 2016. The C. difficile isolates, obtained from anaerobic culture of stool samples, were subjected to antimicrobial susceptibility testing with Etest®strips against 11 antibiotics, determination of toxin genes profile, PCR-ribotyping, multilocus variable-number tandem-repeat analysis (MLVA) and whole genome sequencing (WGS). Results: Of the 12 CDI cases detected, 11 isolates from 11 patients were characterized. All isolates were tcdA-/tcdB+ and belonged to ribotype 017, and showed high level resistance to clindamycin, erythromycin, gentamicin, imipenem, moxifloxacin, rifampicin and tetracycline. The isolates belonged to four genetically related MLVA types, with six isolates forming a clonal cluster. Three outbreak isolates, each from a different MLVA type, were selected for WGS. Bioinformatics analysis showed the presence of several antibiotic resistance determinants, including the Thr82Ile substitution in gyrA, conferring moxifloxacin resistance, the substitutions His502Asn and Arg505Lys in rpoB for rifampicin resistance, the tetM gene, associated with tetracycline resistance, and two genes encoding putative aminoglycoside-modifying enzymes, aadE and aac(6′)-aph(2″). Furthermore, a not previously described 61.3 kb putative mobile element was identified, presenting a mosaic structure and containing the genes ermG, mefA/msrD and vat, associated with macrolide, lincosamide and streptogramins resistance. A substitution found in a class B penicillin-binding protein, Cys721Ser, is thought to contribute to imipenem resistance. Conclusion: We describe an epidemic, tcdA-/tcdB+, multidrug resistant clone of C. difficile from ribotype 017 associated with a hospital outbreak, providing further evidence that the lack of TcdA does not impair the infectious potential of these strains. We identified several determinants of antimicrobial resistance, including new ones located in mobile elements, highlighting the importance of horizontal gene transfer in the pathogenicity and epidemiological success of C. difficile.
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Affiliation(s)
- Joana Isidro
- Departamento de Doenças Infecciosas, Instituto Nacional de Saúde Doutor Ricardo Jorge, Lisbon, Portugal.,Departamento de Genética Humana, Unidade de Tecnologia e Inovação, Instituto Nacional de Saúde Doutor Ricardo Jorge, Lisbon, Portugal
| | - Juliana Menezes
- Departamento de Doenças Infecciosas, Instituto Nacional de Saúde Doutor Ricardo Jorge, Lisbon, Portugal
| | - Mónica Serrano
- Instituto de Tecnologia Química e Biológica António Xavier, Oeiras, Portugal
| | - Vítor Borges
- Departamento de Doenças Infecciosas, Instituto Nacional de Saúde Doutor Ricardo Jorge, Lisbon, Portugal
| | - Pedro Paixão
- Centro Hospitalar Lisboa Ocidental, Lisbon, Portugal
| | | | | | | | - Andrea Santos
- Departamento de Doenças Infecciosas, Instituto Nacional de Saúde Doutor Ricardo Jorge, Lisbon, Portugal
| | - Adriano O Henriques
- Instituto de Tecnologia Química e Biológica António Xavier, Oeiras, Portugal
| | - Mónica Oleastro
- Departamento de Doenças Infecciosas, Instituto Nacional de Saúde Doutor Ricardo Jorge, Lisbon, Portugal
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Khodadoost L, Hussain H, Mullany P. Plasmids can transfer to Clostridium difficile CD37 and 630Δerm both by a DNase resistant conjugation-like mechanism and a DNase sensitive mechanism. FEMS Microbiol Lett 2018; 364:4329271. [PMID: 29029255 DOI: 10.1093/femsle/fnx208] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 09/29/2017] [Indexed: 11/13/2022] Open
Abstract
Broad host range conjugative plasmids that replicate in Escherichia coli have been widely used to mobilise smaller replicons, bearing their cognate origin of transfer (oriT) into a variety of organisms that are less tractable genetically, such as Clostridium (Clostridioides) difficile. In this work we demonstrated that the oriT region of pMTL9301 (derived from RK2) is not required for transfer between E. coli and C. difficile strains 630Δerm and CD37 and that this oriT-independent transfer is abolished in the presence of DNase when CD37 is the recipient. Transfer to the 630Δerm strain is DNase resistant even without an obvious oriT, when E. coli CA434 is used as a donor and is sensitive to DNase when E. coli HB101 is the donor.
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Affiliation(s)
- Ladan Khodadoost
- Department of Microbial Diseases, University College London, 256 Gray's Inn Road, London WC1X 8LD, United Kingdom
| | - Haitham Hussain
- Department of Microbial Diseases, University College London, 256 Gray's Inn Road, London WC1X 8LD, United Kingdom
| | - Peter Mullany
- Department of Microbial Diseases, University College London, 256 Gray's Inn Road, London WC1X 8LD, United Kingdom
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Kambarev S, Pecorari F, Corvec S. Novel Tn916-like elements confer aminoglycoside/macrolide co-resistance in clinical isolates of Streptococcus gallolyticus ssp. gallolyticus. J Antimicrob Chemother 2018; 73:1201-1205. [DOI: 10.1093/jac/dky016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 01/03/2018] [Indexed: 01/21/2023] Open
Affiliation(s)
- Stanimir Kambarev
- CRCINA, Inserm, CNRS, Université d’Angers, Université de Nantes, Nantes, France
| | - Frédéric Pecorari
- CRCINA, Inserm, CNRS, Université d’Angers, Université de Nantes, Nantes, France
| | - Stéphane Corvec
- Service de Bactériologie – Hygiène hospitalière, CHU de Nantes, Nantes, France
- CRCINA, Inserm 1232, Université de Nantes, Nantes, France
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Smits WK, Weese JS, Roberts AP, Harmanus C, Hornung B. A helicase-containing module defines a family of pCD630-like plasmids in Clostridium difficile. Anaerobe 2018; 49:78-84. [DOI: 10.1016/j.anaerobe.2017.12.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 12/07/2017] [Accepted: 12/11/2017] [Indexed: 12/18/2022]
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Gu H, Yang Y, Wang M, Chen S, Wang H, Li S, Ma Y, Wang J. Novel Cysteine Desulfidase CdsB Involved in Releasing Cysteine Repression of Toxin Synthesis in Clostridium difficile. Front Cell Infect Microbiol 2018; 7:531. [PMID: 29376034 PMCID: PMC5767170 DOI: 10.3389/fcimb.2017.00531] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Accepted: 12/18/2017] [Indexed: 01/05/2023] Open
Abstract
Clostridium difficile, a major cause of nosocomial diarrhea and pseudomembranous colitis, still poses serious health-care challenges. The expression of its two main virulence factors, TcdA and TcdB, is reportedly repressed by cysteine, but molecular mechanism remains unclear. The cysteine desulfidase CdsB affects the virulence and infection progresses of some bacteria. The C. difficile strain 630 genome encodes a homolog of CdsB, and in the present study, we analyzed its role in C. difficile 630Δerm by constructing an isogenic ClosTron-based cdsB mutant. When C. difficile was cultured in TY broth supplemented with cysteine, the cdsB gene was rapidly induced during the exponential growth phase. The inactivation of cdsB not only affected the resistance of C. difficile to cysteine, but also altered the expression levels of intracellular cysteine-degrading enzymes and the production of hydrogen sulfide. This suggests that C. difficile CdsB is a major inducible cysteine-degrading enzyme. The inactivation of the cdsB gene in C. difficile also removed the cysteine-dependent repression of toxin production, but failed to remove the Na2S-dependent repression, which supports that the cysteine-dependent repression of toxin production is probably attributable to the accumulation of cysteine by-products. We also mapped a δ54 (SigL)-dependent promoter upstream from the cdsB gene, and cdsB expression was not induced in response to cysteine in the cdsR::ermB or sigL::ermB strain. Using a reporter gene fusion analysis, we identified the necessary promoter sequence for cysteine-dependent cdsB expression. Taken together, these results indicate that CdsB is a key inducible cysteine desulfidase in C. difficile which is regulated by δ54 and CdsR in response to cysteine and that cysteine-dependent regulation of toxin production is closely associated with cysteine degradation.
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Affiliation(s)
- Huawei Gu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Yingyin Yang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Meng Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Shuyi Chen
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Haiying Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Shan Li
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Yi Ma
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Jufang Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
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Johanesen P, Lyras D. Methods for Determining Transfer of Mobile Genetic Elements in Clostridium difficile. Methods Mol Biol 2018; 1476:199-213. [PMID: 27507343 DOI: 10.1007/978-1-4939-6361-4_15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Horizontal gene transfer by mobile genetic elements plays an important role in the evolution of bacteria, allowing them to rapidly acquire new traits, including antibiotic resistance. Mobile genetic elements such as conjugative and mobilizable transposons make up a considerable part of the C. difficile genome. While sequence analysis has identified a large number of these elements, experimental analysis is required to demonstrate mobility and function. This chapter describes the experimental methods utilized for determining function and transfer of mobile genetic elements in C. difficile including detection of the circular transfer intermediate and the analysis and confirmation of mobile genetic element transfer to recipient cells.
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Affiliation(s)
- Priscilla Johanesen
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Victoria, 3800, Australia
| | - Dena Lyras
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Victoria, 3800, Australia.
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Antibiotic Resistances of Clostridium difficile. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1050:137-159. [PMID: 29383668 DOI: 10.1007/978-3-319-72799-8_9] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The rapid evolution of antibiotic resistance in Clostridium difficile and the consequent effects on prevention and treatment of C. difficile infections (CDIs) are matter of concern for public health. Antibiotic resistance plays an important role in driving C. difficile epidemiology. Emergence of new types is often associated with the emergence of new resistances and most of epidemic C. difficile clinical isolates is currently resistant to multiple antibiotics. In particular, it is to worth to note the recent identification of strains with reduced susceptibility to the first-line antibiotics for CDI treatment and/or for relapsing infections. Antibiotic resistance in C. difficile has a multifactorial nature. Acquisition of genetic elements and alterations of the antibiotic target sites, as well as other factors, such as variations in the metabolic pathways and biofilm production, contribute to the survival of this pathogen in the presence of antibiotics. Different transfer mechanisms facilitate the spread of mobile elements among C. difficile strains and between C. difficile and other species. Furthermore, recent data indicate that both genetic elements and alterations in the antibiotic targets can be maintained in C. difficile regardless of the burden imposed on fitness, and therefore resistances may persist in C. difficile population in absence of antibiotic selective pressure.
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The Obscure World of Integrative and Mobilizable Elements, Highly Widespread Elements that Pirate Bacterial Conjugative Systems. Genes (Basel) 2017; 8:genes8110337. [PMID: 29165361 PMCID: PMC5704250 DOI: 10.3390/genes8110337] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 11/15/2017] [Accepted: 11/15/2017] [Indexed: 12/22/2022] Open
Abstract
Conjugation is a key mechanism of bacterial evolution that involves mobile genetic elements. Recent findings indicated that the main actors of conjugative transfer are not the well-known conjugative or mobilizable plasmids but are the integrated elements. This paper reviews current knowledge on “integrative and mobilizable elements” (IMEs) that have recently been shown to be highly diverse and highly widespread but are still rarely described. IMEs encode their own excision and integration and use the conjugation machinery of unrelated co-resident conjugative element for their own transfer. Recent studies revealed a much more complex and much more diverse lifecycle than initially thought. Besides their main transmission as integrated elements, IMEs probably use plasmid-like strategies to ensure their maintenance after excision. Their interaction with conjugative elements reveals not only harmless hitchhikers but also hunters that use conjugative elements as target for their integration or harmful parasites that subvert the conjugative apparatus of incoming elements to invade cells that harbor them. IMEs carry genes conferring various functions, such as resistance to antibiotics, that can enhance the fitness of their hosts and that contribute to their maintenance in bacterial populations. Taken as a whole, IMEs are probably major contributors to bacterial evolution.
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27
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van Eijk E, Paschalis V, Green M, Friggen AH, Larson MA, Spriggs K, Briggs GS, Soultanas P, Smits WK. Primase is required for helicase activity and helicase alters the specificity of primase in the enteropathogen Clostridium difficile. Open Biol 2017; 6:rsob.160272. [PMID: 28003473 PMCID: PMC5204125 DOI: 10.1098/rsob.160272] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 11/22/2016] [Indexed: 12/16/2022] Open
Abstract
DNA replication is an essential and conserved process in all domains of life and may serve as a target for the development of new antimicrobials. However, such developments are hindered by subtle mechanistic differences and limited understanding of DNA replication in pathogenic microorganisms. Clostridium difficile is the main cause of healthcare-associated diarrhoea and its DNA replication machinery is virtually uncharacterized. We identify and characterize the mechanistic details of the putative replicative helicase (CD3657), helicase-loader ATPase (CD3654) and primase (CD1454) of C. difficile, and reconstitute helicase and primase activities in vitro. We demonstrate a direct and ATP-dependent interaction between the helicase loader and the helicase. Furthermore, we find that helicase activity is dependent on the presence of primase in vitro. The inherent trinucleotide specificity of primase is determined by a single lysine residue and is similar to the primase of the extreme thermophile Aquifex aeolicus. However, the presence of helicase allows more efficient de novo synthesis of RNA primers from non-preferred trinucleotides. Thus, loader–helicase–primase interactions, which crucially mediate helicase loading and activation during DNA replication in all organisms, differ critically in C. difficile from that of the well-studied Gram-positive Bacillus subtilis model.
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Affiliation(s)
- Erika van Eijk
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Vasileios Paschalis
- School of Chemistry, Center for Biomolecular Sciences, University of Nottingham, UK
| | - Matthew Green
- School of Chemistry, Center for Biomolecular Sciences, University of Nottingham, UK
| | - Annemieke H Friggen
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Marilynn A Larson
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198-5900, USA.,National Strategic Research Institute, Omaha, NE 68105, USA
| | | | - Geoffrey S Briggs
- School of Chemistry, Center for Biomolecular Sciences, University of Nottingham, UK
| | - Panos Soultanas
- School of Chemistry, Center for Biomolecular Sciences, University of Nottingham, UK
| | - Wiep Klaas Smits
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands
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Update on Antimicrobial Resistance in Clostridium difficile: Resistance Mechanisms and Antimicrobial Susceptibility Testing. J Clin Microbiol 2017; 55:1998-2008. [PMID: 28404671 DOI: 10.1128/jcm.02250-16] [Citation(s) in RCA: 161] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Oral antibiotics such as metronidazole, vancomycin and fidaxomicin are therapies of choice for Clostridium difficile infection. Several important mechanisms for C. difficile antibiotic resistance have been described, including the acquisition of antibiotic resistance genes via the transfer of mobile genetic elements, selective pressure in vivo resulting in gene mutations, altered expression of redox-active proteins, iron metabolism, and DNA repair, as well as via biofilm formation. This update summarizes new information published since 2010 on phenotypic and genotypic resistance mechanisms in C. difficile and addresses susceptibility test methods and other strategies to counter antibiotic resistance of C. difficile.
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Elliott B, Androga GO, Knight DR, Riley TV. Clostridium difficile infection: Evolution, phylogeny and molecular epidemiology. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2017; 49:1-11. [PMID: 28012982 DOI: 10.1016/j.meegid.2016.12.018] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Revised: 12/19/2016] [Accepted: 12/19/2016] [Indexed: 02/07/2023]
Abstract
Over the recent decades, Clostridium difficile infection (CDI) has emerged as a global public health threat. Despite growing attention, C. difficile remains a poorly understood pathogen, however, the exquisite sensitivity offered by next generation sequencing (NGS) technology has enabled analysis of the genome of C. difficile, giving us access to massive genomic data on factors such as virulence, evolution, and genetic relatedness within C. difficile groups. NGS has also demonstrated excellence in investigations of outbreaks and disease transmission, in both small and large-scale applications. This review summarizes the molecular epidemiology, evolution, and phylogeny of C. difficile, one of the most important pathogens worldwide in the current antibiotic resistance era.
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Affiliation(s)
- Briony Elliott
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia
| | - Grace O Androga
- School of Pathology and Laboratory Medicine, The University of Western Australia, Crawley, Australia
| | - Daniel R Knight
- School of Pathology and Laboratory Medicine, The University of Western Australia, Crawley, Australia
| | - Thomas V Riley
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia; School of Pathology and Laboratory Medicine, The University of Western Australia, Crawley, Australia; School of Veterinary and Life Sciences, Murdoch University, Murdoch, Australia; Department of Microbiology, PathWest Laboratory Medicine, Perth, Australia.
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30
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Aljarallah KM. Conventional and alternative treatment approaches for Clostridium difficile infection. Int J Health Sci (Qassim) 2017; 11:1-10. [PMID: 28293151 PMCID: PMC5327666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Clostridium difficile-associated disease continues to be one of the leading health concerns worldwide. C. difficile is considered as a causative agent of nosocomial diarrhea that causes serious infection, which may result in death. The incidences of C. difficile infection (CDI) in developed countries have become increasingly high which may be attributed to the emergence of newer epidemic strains, extensive use of antibiotics, and limited alternative therapies. The available treatment options against CDI are expensive and promote resistance. Therefore, there is urgent need for new approaches to meet these challenges. This review discusses the current understanding of CDI, the existing clinical treatment strategies and future potential options as antidifficile agents based on the available published works.
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Affiliation(s)
- Khalid M. Aljarallah
- Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Majmaah University, Majmaah, KSA,Address for correspondence: Dr. Khalid M. Aljarallah, Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Majmaah University, Majmaah, KSA. E-mail:
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31
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Zhang W, Cheng Y, Du P, Zhang Y, Jia H, Li X, Wang J, Han N, Qiang Y, Chen C, Lu J. Genomic study of the Type IVC secretion system in Clostridium difficile: understanding C. difficile evolution via horizontal gene transfer. Genome 2017; 60:8-16. [DOI: 10.1139/gen-2016-0053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Clostridium difficile, the etiological agent of Clostridium difficile infection (CDI), is a gram-positive, spore-forming bacillus that is responsible for ∼20% of antibiotic-related cases of diarrhea and nearly all cases of pseudomembranous colitis. Previous data have shown that a substantial proportion (11%) of the C. difficile genome consists of mobile genetic elements, including seven conjugative transposons. However, the mechanism underlying the formation of a mosaic genome in C. difficile is unknown. The type-IV secretion system (T4SS) is the only secretion system known to transfer DNA segments among bacteria. We searched genome databases to identify a candidate T4SS in C. difficile that could transfer DNA among different C. difficile strains. All T4SS gene clusters in C. difficile are located within genomic islands (GIs), which have variable lengths and structures and are all conjugative transposons. During the horizontal-transfer process of T4SS GIs within the C. difficile population, the excision sites were altered, resulting in different short-tandem repeat sequences among the T4SS GIs, as well as different chromosomal insertion sites and additional regions in the GIs.
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Affiliation(s)
- Wen Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou 310003, China
| | - Ying Cheng
- Key Laboratory of Surveillance and Early-warning on Infectious Disease, Division of Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Pengcheng Du
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
- Beijing Key Laboratory of Emerging Infectious Diseases, Beijing 100011, China
| | - Yuanyuan Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
- Beijing Key Laboratory of Emerging Infectious Diseases, Beijing 100011, China
| | - Hongbing Jia
- Department of clinical laboratory, China–Japan Friendship Hospital, Beijing 100029, China
| | - Xianping Li
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou 310003, China
| | - Jing Wang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou 310003, China
| | - Na Han
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou 310003, China
| | - Yujun Qiang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou 310003, China
| | - Chen Chen
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
- Beijing Key Laboratory of Emerging Infectious Diseases, Beijing 100011, China
| | - Jinxing Lu
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou 310003, China
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32
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Wright LD, Grossman AD. Autonomous Replication of the Conjugative Transposon Tn916. J Bacteriol 2016; 198:3355-3366. [PMID: 27698087 PMCID: PMC5116939 DOI: 10.1128/jb.00639-16] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 09/29/2016] [Indexed: 01/14/2023] Open
Abstract
Integrative and conjugative elements (ICEs), also known as conjugative transposons, are self-transferable elements that are widely distributed among bacterial phyla and are important drivers of horizontal gene transfer. Many ICEs carry genes that confer antibiotic resistances to their host cells and are involved in the dissemination of these resistance genes. ICEs reside in host chromosomes but under certain conditions can excise to form a plasmid that is typically the substrate for transfer. A few ICEs are known to undergo autonomous replication following activation. However, it is not clear if autonomous replication is a general property of many ICEs. We found that Tn916, the first conjugative transposon identified, replicates autonomously via a rolling-circle mechanism. Replication of Tn916 was dependent on the relaxase encoded by orf20 of Tn916 The origin of transfer of Tn916, oriT(916), also functioned as an origin of replication. Using immunoprecipitation and mass spectrometry, we found that the relaxase (Orf20) and the two putative helicase processivity factors (Orf22 and Orf23) encoded by Tn916 likely interact in a complex and that the Tn916 relaxase contains a previously unidentified conserved helix-turn-helix domain in its N-terminal region that is required for relaxase function and replication. Lastly, we identified a functional single-strand origin of replication (sso) in Tn916 that we predict primes second-strand synthesis during rolling-circle replication. Together these results add to the emerging data that show that several ICEs replicate via a conserved, rolling-circle mechanism. IMPORTANCE Integrative and conjugative elements (ICEs) drive horizontal gene transfer and the spread of antibiotic resistances in bacteria. ICEs reside integrated in a host genome but can excise to create a plasmid that is the substrate for transfer to other cells. Here we show that Tn916, an ICE with broad host range, undergoes autonomous rolling-circle replication when in the plasmid form. We found that the origin of transfer functions as a double-stranded origin of replication and identified a single-stranded origin of replication. It was long thought that ICEs do not undergo autonomous replication. Our work adds to the evidence that ICEs replicate autonomously as part of their normal life cycle and indicates that diverse ICEs use the same replicative mechanism.
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Affiliation(s)
- Laurel D Wright
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Alan D Grossman
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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33
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Hargreaves KR, Thanki AM, Jose BR, Oggioni MR, Clokie MRJ. Use of single molecule sequencing for comparative genomics of an environmental and a clinical isolate of Clostridium difficile ribotype 078. BMC Genomics 2016; 17:1020. [PMID: 27964731 PMCID: PMC5154133 DOI: 10.1186/s12864-016-3346-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 11/25/2016] [Indexed: 01/20/2023] Open
Abstract
Background How the pathogen Clostridium difficile might survive, evolve and be transferred between reservoirs within the natural environment is poorly understood. Some ribotypes are found both in clinical and environmental settings. Whether these strains are distinct from each another and evolve in the specific environments is not established. The possession of a highly mobile genome has contributed to the genetic diversity and ongoing evolution of C. difficile. Interpretations of genetic diversity have been limited by fragmented assemblies resulting from short-read length sequencing approaches and by a limited understanding of epigenetic regulation of diversity. To address this, single molecule real time (SMRT) sequencing was used in this study as it produces high quality genome sequences, with resolution of repeat regions (including those found in mobile elements) and can generate data to determine methylation modifications across the sequence (the methylome). Results Chromosomal rearrangements and ribosomal operon duplications were observed in both genomes. The rearrangements occurred at insertion sites within two mobile genetic elements (MGEs), Tn6164 and Tn6293, present only in the M120 and CD105HS27 genomes, respectively. The gene content of these two transposons differ considerably which could impact upon horizontal gene transfer; differences include CDSs encoding methylases and a conjugative prophage only in Tn6164. To investigate mechanisms which could affect MGE transfer, the methylome, restriction modification (RM) and the CRISPR/Cas systems were characterised for each strain. Notably, the environmental isolate, CD105HS27, does not share a consensus motif for m4C methylation, but has one additional spacer when compared to the clinical isolate M120. Conclusions These findings show key differences between the two strains in terms of their genetic capacity for MGE transfer. The carriage of horizontally transferred genes appear to have genome wide effects based on two different methylation patterns. The CRISPR/Cas system appears active although perhaps slow to evolve. Data suggests that both mechanisms are functional and impact upon horizontal gene transfer and genome evolution within C. difficile. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3346-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Katherine R Hargreaves
- Department Infection, Immunity and Inflammation, University of Leicester, Leicester, UK. .,Department Microbiology, The Ohio State University, Columbus, OH, USA.
| | - Anisha M Thanki
- Department Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Bethany R Jose
- Department Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | | | - Martha R J Clokie
- Department Infection, Immunity and Inflammation, University of Leicester, Leicester, UK.
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34
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Drouin A, Giguère S, Déraspe M, Marchand M, Tyers M, Loo VG, Bourgault AM, Laviolette F, Corbeil J. Predictive computational phenotyping and biomarker discovery using reference-free genome comparisons. BMC Genomics 2016; 17:754. [PMID: 27671088 PMCID: PMC5037627 DOI: 10.1186/s12864-016-2889-6] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Accepted: 07/06/2016] [Indexed: 12/14/2022] Open
Abstract
Background The identification of genomic biomarkers is a key step towards improving diagnostic tests and therapies. We present a reference-free method for this task that relies on a k-mer representation of genomes and a machine learning algorithm that produces intelligible models. The method is computationally scalable and well-suited for whole genome sequencing studies. Results The method was validated by generating models that predict the antibiotic resistance of C. difficile, M. tuberculosis, P. aeruginosa, and S. pneumoniae for 17 antibiotics. The obtained models are accurate, faithful to the biological pathways targeted by the antibiotics, and they provide insight into the process of resistance acquisition. Moreover, a theoretical analysis of the method revealed tight statistical guarantees on the accuracy of the obtained models, supporting its relevance for genomic biomarker discovery. Conclusions Our method allows the generation of accurate and interpretable predictive models of phenotypes, which rely on a small set of genomic variations. The method is not limited to predicting antibiotic resistance in bacteria and is applicable to a variety of organisms and phenotypes. Kover, an efficient implementation of our method, is open-source and should guide biological efforts to understand a plethora of phenotypes (http://github.com/aldro61/kover/). Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2889-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alexandre Drouin
- Department of Computer Science and Software Engineering, Université Laval, Québec, Canada.
| | - Sébastien Giguère
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Maxime Déraspe
- Department of Molecular Medicine, Université Laval, Québec, Canada
| | - Mario Marchand
- Department of Computer Science and Software Engineering, Université Laval, Québec, Canada.,Big Data Research Centre, Université Laval, Québec, Canada
| | - Michael Tyers
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Vivian G Loo
- Division of Infectious Diseases, Departments of Medicine and Microbiology, McGill University Health Centre, Montréal, Canada.,Department of Medicine, McGill University, Montréal, Canada
| | - Anne-Marie Bourgault
- Division of Infectious Diseases, Departments of Medicine and Microbiology, McGill University Health Centre, Montréal, Canada.,Department of Medicine, McGill University, Montréal, Canada
| | - François Laviolette
- Department of Computer Science and Software Engineering, Université Laval, Québec, Canada.,Big Data Research Centre, Université Laval, Québec, Canada
| | - Jacques Corbeil
- Department of Molecular Medicine, Université Laval, Québec, Canada.,Big Data Research Centre, Université Laval, Québec, Canada
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A Phenotypically Silent vanB2 Operon Carried on a Tn1549-Like Element in Clostridium difficile. mSphere 2016; 1:mSphere00177-16. [PMID: 27536735 PMCID: PMC4980698 DOI: 10.1128/msphere.00177-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Accepted: 07/22/2016] [Indexed: 11/20/2022] Open
Abstract
In the last decade, Clostridium difficile infection (CDI) has reached an epidemic state with increasing incidence and severity in both health care and community settings. Vancomycin is an important first-line therapy for CDI, and the emergence of resistance would have significant clinical consequences. In this study, we describe for the first time a vanB2 vancomycin resistance operon in C. difficile, isolated from an Australian veal calf at slaughter. The operon was carried on an ~42-kb element showing significant homology and synteny to Tn1549, a conjugative transposon linked with the emergence and global dissemination of vancomycin-resistant enterococci (VRE). Notably, the C. difficile strain did not show any reduced susceptibility to vancomycin in vitro (MIC, 1 mg/liter), possibly as a result of an aberrant vanRB gene. As observed for other anaerobic species of the animal gut microbiota, C. difficile may be a reservoir of clinically important vancomycin resistance genes. IMPORTANCE In an era when the development of new antimicrobial drugs is slow, vancomycin remains the preferred antimicrobial therapy for Clostridium difficile infection (CDI), the most important health care-related infection in the world today. The emergence of resistance to vancomycin would have significant consequences in relation to treating patients with CDI. In this paper, we describe for the first time a complete set of vancomycin resistance genes in C. difficile. The genes were very similar to genes found in vancomycin-resistant enterococci (VRE) that were associated with the emergence and global dissemination of this organism. Fortunately, the C. difficile strain did not show any reduced susceptibility to vancomycin in vitro (MIC, 1 mg/liter), possibly because of a small difference in one gene. However, this observation signals that we may be very close to seeing a fully vancomycin-resistant strain of C. difficile.
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36
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Spigaglia P. Recent advances in the understanding of antibiotic resistance in Clostridium difficile infection. Ther Adv Infect Dis 2016; 3:23-42. [PMID: 26862400 DOI: 10.1177/2049936115622891] [Citation(s) in RCA: 145] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Clostridium difficile epidemiology has changed in recent years, with the emergence of highly virulent types associated with severe infections, high rates of recurrences and mortality. Antibiotic resistance plays an important role in driving these epidemiological changes and the emergence of new types. While clindamycin resistance was driving historical endemic types, new types are associated with resistance to fluoroquinolones. Furthermore, resistance to multiple antibiotics is a common feature of the newly emergent strains and, in general, of many epidemic isolates. A reduced susceptibility to antibiotics used for C. difficile infection (CDI) treatment, in particular to metronidazole, has recently been described in several studies. Furthermore, an increased number of strains show resistance to rifamycins, used for the treatment of relapsing CDI. Several mechanisms of resistance have been identified in C. difficile, including acquisition of genetic elements and alterations of the antibiotic target sites. The C. difficile genome contains a plethora of mobile genetic elements, many of them involved in antibiotic resistance. Transfer of genetic elements among C. difficile strains or between C. difficile and other bacterial species can occur through different mechanisms that facilitate their spread. Investigations of the fitness cost in C. difficile indicate that both genetic elements and mutations in the molecular targets of antibiotics can be maintained regardless of the burden imposed on fitness, suggesting that resistances may persist in the C. difficile population also in absence of antibiotic selective pressure. The rapid evolution of antibiotic resistance and its composite nature complicate strategies in the treatment and prevention of CDI. The rapid identification of new phenotypic and genotypic traits, the implementation of effective antimicrobial stewardship and infection control programs, and the development of alternative therapies are needed to prevent and contain the spread of resistance and to ensure an efficacious therapy for CDI.
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37
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Johanesen PA, Mackin KE, Hutton ML, Awad MM, Larcombe S, Amy JM, Lyras D. Disruption of the Gut Microbiome: Clostridium difficile Infection and the Threat of Antibiotic Resistance. Genes (Basel) 2015; 6:1347-60. [PMID: 26703737 PMCID: PMC4690045 DOI: 10.3390/genes6041347] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 12/09/2015] [Accepted: 12/10/2015] [Indexed: 12/15/2022] Open
Abstract
Clostridium difficile is well recognized as the leading cause of antibiotic-associated diarrhea, having a significant impact in both health-care and community settings. Central to predisposition to C. difficile infection is disruption of the gut microbiome by antibiotics. Being a Gram-positive anaerobe, C. difficile is intrinsically resistant to a number of antibiotics. Mobile elements encoding antibiotic resistance determinants have also been characterized in this pathogen. While resistance to antibiotics currently used to treat C. difficile infection has not yet been detected, it may be only a matter of time before this occurs, as has been seen with other bacterial pathogens. This review will discuss C. difficile disease pathogenesis, the impact of antibiotic use on inducing disease susceptibility, and the role of antibiotic resistance and mobile elements in C. difficile epidemiology.
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Affiliation(s)
- Priscilla A Johanesen
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton 3800, Australia.
| | - Kate E Mackin
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton 3800, Australia.
| | - Melanie L Hutton
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton 3800, Australia.
| | - Milena M Awad
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton 3800, Australia.
| | - Sarah Larcombe
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton 3800, Australia.
| | - Jacob M Amy
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton 3800, Australia.
| | - Dena Lyras
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton 3800, Australia.
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38
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Abstract
Clostridium difficile infection (CDI) is the leading cause of antimicrobial and health care-associated diarrhea in humans, presenting a significant burden to global health care systems. In the last 2 decades, PCR- and sequence-based techniques, particularly whole-genome sequencing (WGS), have significantly furthered our knowledge of the genetic diversity, evolution, epidemiology, and pathogenicity of this once enigmatic pathogen. C. difficile is taxonomically distinct from many other well-known clostridia, with a diverse population structure comprising hundreds of strain types spread across at least 6 phylogenetic clades. The C. difficile species is defined by a large diverse pangenome with extreme levels of evolutionary plasticity that has been shaped over long time periods by gene flux and recombination, often between divergent lineages. These evolutionary events are in response to environmental and anthropogenic activities and have led to the rapid emergence and worldwide dissemination of virulent clonal lineages. Moreover, genome analysis of large clinically relevant data sets has improved our understanding of CDI outbreaks, transmission, and recurrence. The epidemiology of CDI has changed dramatically over the last 15 years, and CDI may have a foodborne or zoonotic etiology. The WGS era promises to continue to redefine our view of this significant pathogen.
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Neugebauer T, Bordeleau E, Burrus V, Brzezinski R. DNA Data Visualization (DDV): Software for Generating Web-Based Interfaces Supporting Navigation and Analysis of DNA Sequence Data of Entire Genomes. PLoS One 2015; 10:e0143615. [PMID: 26636979 PMCID: PMC4670077 DOI: 10.1371/journal.pone.0143615] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 11/06/2015] [Indexed: 11/18/2022] Open
Abstract
Data visualization methods are necessary during the exploration and analysis activities of an increasingly data-intensive scientific process. There are few existing visualization methods for raw nucleotide sequences of a whole genome or chromosome. Software for data visualization should allow the researchers to create accessible data visualization interfaces that can be exported and shared with others on the web. Herein, novel software developed for generating DNA data visualization interfaces is described. The software converts DNA data sets into images that are further processed as multi-scale images to be accessed through a web-based interface that supports zooming, panning and sequence fragment selection. Nucleotide composition frequencies and GC skew of a selected sequence segment can be obtained through the interface. The software was used to generate DNA data visualization of human and bacterial chromosomes. Examples of visually detectable features such as short and long direct repeats, long terminal repeats, mobile genetic elements, heterochromatic segments in microbial and human chromosomes, are presented. The software and its source code are available for download and further development. The visualization interfaces generated with the software allow for the immediate identification and observation of several types of sequence patterns in genomes of various sizes and origins. The visualization interfaces generated with the software are readily accessible through a web browser. This software is a useful research and teaching tool for genetics and structural genomics.
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Affiliation(s)
| | - Eric Bordeleau
- Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Vincent Burrus
- Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Ryszard Brzezinski
- Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
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40
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Tracing the Spread of Clostridium difficile Ribotype 027 in Germany Based on Bacterial Genome Sequences. PLoS One 2015; 10:e0139811. [PMID: 26444881 PMCID: PMC4596877 DOI: 10.1371/journal.pone.0139811] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 09/16/2015] [Indexed: 12/18/2022] Open
Abstract
We applied whole-genome sequencing to reconstruct the spatial and temporal dynamics underpinning the expansion of Clostridium difficile ribotype 027 in Germany. Based on re-sequencing of genomes from 57 clinical C. difficile isolates, which had been collected from hospitalized patients at 36 locations throughout Germany between 1990 and 2012, we demonstrate that C. difficile genomes have accumulated sequence variation sufficiently fast to document the pathogen's spread at a regional scale. We detected both previously described lineages of fluoroquinolone-resistant C. difficile ribotype 027, FQR1 and FQR2. Using Bayesian phylogeographic analyses, we show that fluoroquinolone-resistant C. difficile 027 was imported into Germany at least four times, that it had been widely disseminated across multiple federal states even before the first outbreak was noted in 2007, and that it has continued to spread since.
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41
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Gil F, Pizarro-Guajardo M, Álvarez R, Garavaglia M, Paredes-Sabja D. Clostridium difficile recurrent infection: possible implication of TA systems. Future Microbiol 2015; 10:1649-57. [DOI: 10.2217/fmb.15.94] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Clostridium difficile is an important nosocomial pathogen associated with antibiotic treatments. C. difficile's ability to survive antimicrobial therapy and transition from inert colonization to active infection is one of the most perplexing aspects of C. difficile infections and suggests that additional mechanisms are involved in persistence. In this regard, novel mechanisms linked with pathogenesis and persistence of C. difficile such as toxin–antitoxin systems might significantly contribute to biofilm formation and persistent infection. This review will focus on advances of toxin–antitoxin systems in C. difficile and their putative roles will be discussed.
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Affiliation(s)
- Fernando Gil
- Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, República 217, Santiago, Chile
| | - Marjorie Pizarro-Guajardo
- Gut Microbiota & Clostridia Research Group, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, República 217, Santiago, Chile
| | - Ricardo Álvarez
- Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, República 217, Santiago, Chile
| | - Marco Garavaglia
- Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Daniel Paredes-Sabja
- Gut Microbiota & Clostridia Research Group, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, República 217, Santiago, Chile
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Hargreaves KR, Otieno JR, Thanki A, Blades MJ, Millard AD, Browne HP, Lawley TD, Clokie MRJ. As Clear as Mud? Determining the Diversity and Prevalence of Prophages in the Draft Genomes of Estuarine Isolates of Clostridium difficile. Genome Biol Evol 2015; 7:1842-55. [PMID: 26019165 PMCID: PMC4524475 DOI: 10.1093/gbe/evv094] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The bacterium Clostridium difficile is a significant cause of nosocomial infections worldwide. The pathogenic success of this organism can be attributed to its flexible genome which is characterized by the exchange of mobile genetic elements, and by ongoing genome evolution. Despite its pathogenic status, C. difficile can also be carried asymptomatically, and has been isolated from natural environments such as water and sediments where multiple strain types (ribotypes) are found in close proximity. These include ribotypes which are associated with disease, as well as those that are less commonly isolated from patients. Little is known about the genomic content of strains in such reservoirs in the natural environment. In this study, draft genomes have been generated for 13 C. difficile isolates from estuarine sediments including clinically relevant and environmental associated types. To identify the genetic diversity within this strain collection, whole-genome comparisons were performed using the assemblies. The strains are highly genetically diverse with regards to the C. difficile “mobilome,” which includes transposons and prophage elements. We identified a novel transposon-like element in two R078 isolates. Multiple, related and unrelated, prophages were detected in isolates across ribotype groups, including two novel prophage elements and those related to the transducing phage φC2. The susceptibility of these isolates to lytic phage infection was tested using a panel of characterized phages found from the same locality. In conclusion, estuarine sediments are a source of genetically diverse C. difficile strains with a complex network of prophages, which could contribute to the emergence of new strains in clinics.
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Affiliation(s)
- Katherine R Hargreaves
- Department of Infection, Immunity and Inflammation, University of Leicester, United Kingdom Department of Ecology and Evolutionary Biology, University of Arizona
| | - James R Otieno
- Department of Infection, Immunity and Inflammation, University of Leicester, United Kingdom KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Anisha Thanki
- Department of Infection, Immunity and Inflammation, University of Leicester, United Kingdom
| | - Matthew J Blades
- Bioinformatics and Biostatistics Analysis Support Hub (BBASH), Core Biotechnology Services, University of Leicester, United Kingdom
| | - Andrew D Millard
- Microbiology & Infection, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Hilary P Browne
- Microbial Pathogenesis Laboratory, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Trevor D Lawley
- Microbial Pathogenesis Laboratory, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Martha R J Clokie
- Department of Infection, Immunity and Inflammation, University of Leicester, United Kingdom
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43
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Piotrowska M, Popowska M. Insight into the mobilome of Aeromonas strains. Front Microbiol 2015; 6:494. [PMID: 26074893 PMCID: PMC4444841 DOI: 10.3389/fmicb.2015.00494] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 05/05/2015] [Indexed: 11/13/2022] Open
Abstract
The mobilome is a pool of genes located within mobile genetic elements (MGE), such as plasmids, IS elements, transposons, genomic/pathogenicity islands, and integron-associated gene cassettes. These genes are often referred to as “flexible” and may encode virulence factors, toxic compounds as well as resistance to antibiotics. The phenomenon of MGE transfer between bacteria, known as horizontal gene transfer (HGT), is well documented. The genes present on MGE are subject to continuous processes of evolution and environmental changes, largely induced or significantly accelerated by man. For bacteria, the only chance of survival in an environment contaminated with toxic chemicals, heavy metals and antibiotics is the acquisition of genes providing the ability to survive in such conditions. The process of acquiring and spreading antibiotic resistance genes (ARG) is of particular significance, as it is important for the health of humans and animals. Therefore, it is important to thoroughly study the mobilome of Aeromonas spp. that is widely distributed in various environments, causing many diseases in fishes and humans. This review discusses the recently published information on MGE prevalent in Aeromonas spp. with special emphasis on plasmids belonging to different incompatibility groups, i.e., IncA/C, IncU, IncQ, IncF, IncI, and ColE-type. The vast majority of plasmids carry a number of different transposons (Tn3, Tn21, Tn1213, Tn1721, Tn4401), the 1st, 2nd, or 3rd class of integrons, IS elements (e.g., IS26, ISPa12, ISPa13, ISKpn8, ISKpn6) and encode determinants such as antibiotic and mercury resistance genes, as well as virulence factors. Although the actual role of Aeromonas spp. as a human pathogen remains controversial, species of this genus may pose a serious risk to human health. This is due to the considerable potential of their mobilome, particularly in terms of antibiotic resistance and the possibility of the horizontal transfer of resistance genes.
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Affiliation(s)
- Marta Piotrowska
- Department of Applied Microbiology, Institute of Microbiology, Faculty of Biology, University of Warsaw Warsaw, Poland
| | - Magdalena Popowska
- Department of Applied Microbiology, Institute of Microbiology, Faculty of Biology, University of Warsaw Warsaw, Poland
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44
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Amy J, Johanesen P, Lyras D. Extrachromosomal and integrated genetic elements in Clostridium difficile. Plasmid 2015; 80:97-110. [PMID: 25929174 DOI: 10.1016/j.plasmid.2015.04.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 04/21/2015] [Accepted: 04/22/2015] [Indexed: 12/21/2022]
Abstract
Clostridium difficile is a major nosocomial pathogen, causing gastrointestinal disease in patients undergoing antibiotic therapy. This bacterium contains many extrachromosomal and integrated genetic elements, with recent genomic work giving new insights into their variability and distribution. This review summarises research conducted in this area over the last 30 years and includes a discussion on the functional contributions of these elements to host cell phenotypes, as well as encompassing recent genome sequencing studies that have contributed to our understanding of their evolution and dissemination. Importantly, we also include a review of antibiotic resistance determinants associated with mobile genetic elements since antibiotic use and the spread of antibiotic resistance are currently of significant global clinical importance.
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Affiliation(s)
- Jacob Amy
- Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Priscilla Johanesen
- Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Dena Lyras
- Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia.
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45
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Abstract
Clostridium difficile is a spore-forming anaerobic gram-positive organism that is the leading cause of antibiotic-associated nosocomial infectious diarrhea in the Western world. This article describes the evolving epidemiology of C difficile infection (CDI) in the twenty-first century, evaluates the importance of vaccines against the disease, and defines the roles of both innate and adaptive host immune responses in CDI. The effects of passive immunotherapy and active vaccination against CDI in both humans and animals are also discussed.
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Affiliation(s)
- Chandrabali Ghose
- Aaron Diamond AIDS Research Center, 455 First Avenue, 7th Floor, New York, NY 10016, USA.
| | - Ciarán P Kelly
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
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46
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van Eijk E, Anvar SY, Browne HP, Leung WY, Frank J, Schmitz AM, Roberts AP, Smits WK. Complete genome sequence of the Clostridium difficile laboratory strain 630Δerm reveals differences from strain 630, including translocation of the mobile element CTn5. BMC Genomics 2015; 16:31. [PMID: 25636331 PMCID: PMC4320837 DOI: 10.1186/s12864-015-1252-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 01/16/2015] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Clostridium difficile strain 630Δerm is a spontaneous erythromycin sensitive derivative of the reference strain 630 obtained by serial passaging in antibiotic-free media. It is widely used as a defined and tractable C. difficile strain. Though largely similar to the ancestral strain, it demonstrates phenotypic differences that might be the result of underlying genetic changes. Here, we performed a de novo assembly based on single-molecule real-time sequencing and an analysis of major methylation patterns. RESULTS In addition to single nucleotide polymorphisms and various indels, we found that the mobile element CTn5 is present in the gene encoding the methyltransferase rumA rather than adhesin CD1844 where it is located in the reference strain. CONCLUSIONS Together, the genetic features identified in this study may help to explain at least part of the phenotypic differences. The annotated genome sequence of this lab strain, including the first analysis of major methylation patterns, will be a valuable resource for genetic research on C. difficile.
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Affiliation(s)
- Erika van Eijk
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, the Netherlands.
| | - Seyed Yahya Anvar
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands. .,Leiden Genome Technology Center, Human and Clinical Genetics, Leiden University Medical Center, Leiden, the Netherlands.
| | | | - Wai Yi Leung
- Sequence Analysis Support Core, Leiden University Medical Center, Leiden, the Netherlands.
| | - Jeroen Frank
- Leiden Genome Technology Center, Human and Clinical Genetics, Leiden University Medical Center, Leiden, the Netherlands.
| | - Arnoud M Schmitz
- Leiden Genome Technology Center, Human and Clinical Genetics, Leiden University Medical Center, Leiden, the Netherlands.
| | - Adam P Roberts
- Department of Microbial Diseases, UCL Eastman Dental Institute, London, UK.
| | - Wiep Klaas Smits
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, the Netherlands.
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47
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Mullany P, Allan E, Roberts AP. Mobile genetic elements in Clostridium difficile and their role in genome function. Res Microbiol 2015; 166:361-7. [PMID: 25576774 PMCID: PMC4430133 DOI: 10.1016/j.resmic.2014.12.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 12/10/2014] [Accepted: 12/13/2014] [Indexed: 11/25/2022]
Abstract
Approximately 11% the Clostridium difficile genome is made up of mobile genetic elements which have a profound effect on the biology of the organism. This includes transfer of antibiotic resistance and other factors that allow the organism to survive challenging environments, modulation of toxin gene expression, transfer of the toxin genes themselves and the conversion of non-toxigenic strains to toxin producers. Mobile genetic elements have also been adapted by investigators to probe the biology of the organism and the various ways in which these have been used are reviewed.
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Affiliation(s)
- Peter Mullany
- Department of Microbial Diseases, UCL Eastman Dental Institute, University College London, 256 Gray's Inn Road, London WC1X 8LD, UK.
| | - Elaine Allan
- Department of Microbial Diseases, UCL Eastman Dental Institute, University College London, 256 Gray's Inn Road, London WC1X 8LD, UK.
| | - Adam P Roberts
- Department of Microbial Diseases, UCL Eastman Dental Institute, University College London, 256 Gray's Inn Road, London WC1X 8LD, UK.
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48
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Barra-Carrasco J, Paredes-Sabja D. Clostridium difficile spores: a major threat to the hospital environment. Future Microbiol 2014; 9:475-86. [PMID: 24810347 DOI: 10.2217/fmb.14.2] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Clostridium difficile is a Gram-positive, anaerobic spore former and is an important nosocomial and community-acquired pathogenic bacterium. C. difficile infections (CDI) are a leading cause of infections worldwide with elevated rates of morbidity. Despite the fact that two major virulence factors, the enterotoxin TcdA and the cytotoxin TcdB, are essential in the development of CDI, C. difficile spores are the main vehicle of infection, and persistence and transmission of CDI and are thought to play an essential role in episodes of CDI recurrence and horizontal transmission. Recent research has unmasked several properties of C. difficile's unique strategy to form highly transmissible spores and to persist in the colonic environment. Therefore, the aim of this article is to summarize recent advances in the biological properties of C. difficile spores, which might be clinically relevant to improve the management of CDI in hospital environments.
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Affiliation(s)
- Jonathan Barra-Carrasco
- Laboratorio de Mecanismos de Patogénesis Bacteriana, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, República 217, Santiago, Chile
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Mandal J, Akhter MZ, Kabir MS, Ahsan S. Development of a multiplex polymerase chain reaction protocol for the simultaneous detection of Salmonella enterica serovar Typhi and Class 1 integron. ASIAN PACIFIC JOURNAL OF TROPICAL DISEASE 2014. [DOI: 10.1016/s2222-1808(14)60732-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Bellanger X, Payot S, Leblond-Bourget N, Guédon G. Conjugative and mobilizable genomic islands in bacteria: evolution and diversity. FEMS Microbiol Rev 2014; 38:720-60. [DOI: 10.1111/1574-6976.12058] [Citation(s) in RCA: 223] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 11/15/2013] [Accepted: 12/19/2013] [Indexed: 11/28/2022] Open
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