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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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Saunier M, Fortier LC, Soutourina O. RNA-based regulation in bacteria-phage interactions. Anaerobe 2024; 87:102851. [PMID: 38583547 DOI: 10.1016/j.anaerobe.2024.102851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 03/24/2024] [Accepted: 04/02/2024] [Indexed: 04/09/2024]
Abstract
Interactions of bacteria with their viruses named bacteriophages or phages shape the bacterial genome evolution and contribute to the diversity of phages. RNAs have emerged as key components of several anti-phage defense systems in bacteria including CRISPR-Cas, toxin-antitoxin and abortive infection. Frequent association with mobile genetic elements and interplay between different anti-phage defense systems are largely discussed. Newly discovered defense systems such as retrons and CBASS include RNA components. RNAs also perform their well-recognized regulatory roles in crossroad of phage-bacteria regulatory networks. Both regulatory and defensive function can be sometimes attributed to the same RNA molecules including CRISPR RNAs. This review presents the recent advances on the role of RNAs in the bacteria-phage interactions with a particular focus on clostridial species including an important human pathogen, Clostridioides difficile.
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Affiliation(s)
- Marion Saunier
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France; Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Louis-Charles Fortier
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Olga Soutourina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France; Institut Universitaire de France (IUF), Paris, France.
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3
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Iwanicki A, Roskwitalska M, Frankowska N, Wultańska D, Kabała M, Pituch H, Obuchowski M, Hinc K. Insight into the Mechanism of Lysogeny Control of phiCDKH01 Bacteriophage Infecting Clinical Isolate of Clostridioides difficile. Int J Mol Sci 2024; 25:5662. [PMID: 38891850 PMCID: PMC11172241 DOI: 10.3390/ijms25115662] [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: 04/26/2024] [Revised: 05/20/2024] [Accepted: 05/21/2024] [Indexed: 06/21/2024] Open
Abstract
Clostridioides difficile is a causative agent of antibiotic-associated diarrhea as well as pseudomembranous colitis. So far, all known bacteriophages infecting these bacteria are temperate, which means that instead of prompt lysis of host cells, they can integrate into the host genome or replicate episomally. While C. difficile phages are capable of spontaneous induction and entering the lytic pathway, very little is known about the regulation of their maintenance in the state of lysogeny. In this study, we investigated the properties of a putative major repressor of the recently characterized C. difficile phiCDKH01 bacteriophage. A candidate protein belongs to the XRE family and controls the transcription of genes encoding putative phage antirepressors, known to be involved in the regulation of lytic development. Hence, the putative major phage repressor is likely to be responsible for maintenance of the lysogeny.
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Affiliation(s)
- Adam Iwanicki
- Division of Molecular Bacteriology, Medical University of Gdańsk, 80-211 Gdańsk, Poland; (A.I.); (M.R.); (N.F.); (M.O.)
| | - Małgorzata Roskwitalska
- Division of Molecular Bacteriology, Medical University of Gdańsk, 80-211 Gdańsk, Poland; (A.I.); (M.R.); (N.F.); (M.O.)
| | - Natalia Frankowska
- Division of Molecular Bacteriology, Medical University of Gdańsk, 80-211 Gdańsk, Poland; (A.I.); (M.R.); (N.F.); (M.O.)
- Intercollegiate Faculty of Biotechnology, University of Gdańsk, 80-307 Gdańsk, Poland
| | - Dorota Wultańska
- Department of Medical Microbiology, Medical University of Warsaw, 02-004 Warsaw, Poland; (D.W.); (H.P.)
| | - Monika Kabała
- Department of Medical Microbiology, Medical University of Silesia, 40-055 Katowice, Poland;
| | - Hanna Pituch
- Department of Medical Microbiology, Medical University of Warsaw, 02-004 Warsaw, Poland; (D.W.); (H.P.)
| | - Michał Obuchowski
- Division of Molecular Bacteriology, Medical University of Gdańsk, 80-211 Gdańsk, Poland; (A.I.); (M.R.); (N.F.); (M.O.)
| | - Krzysztof Hinc
- Division of Molecular Bacteriology, Medical University of Gdańsk, 80-211 Gdańsk, Poland; (A.I.); (M.R.); (N.F.); (M.O.)
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Gong JJ, Huang IH, Su MSW, Xie SX, Liu WY, Huang CR, Hung YP, Wu SR, Tsai PJ, Ko WC, Chen JW. Phage transcriptional regulator X (PtrX)-mediated augmentation of toxin production and virulence in Clostridioides difficile strain R20291. Microbiol Res 2024; 280:127576. [PMID: 38183754 DOI: 10.1016/j.micres.2023.127576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/24/2023] [Accepted: 12/13/2023] [Indexed: 01/08/2024]
Abstract
Clostridioides difficile is a Gram-positive, anaerobic, and spore-forming bacterial member of the human gut microbiome. The primary virulence factors of C. difficile are toxin A and toxin B. These toxins damage the cell cytoskeleton and cause various diseases, from diarrhea to severe pseudomembranous colitis. Evidence suggests that bacteriophages can regulate the expression of the pathogenicity locus (PaLoc) genes of C. difficile. We previously demonstrated that the genome of the C. difficile RT027 strain NCKUH-21 contains a prophage-like DNA sequence, which was found to be markedly similar to that of the φCD38-2 phage. In the present study, we investigated the mechanisms underlying the φNCKUH-21-mediated regulation of the pathogenicity and the PaLoc genes expression in the lysogenized C. difficile strain R20291. The carriage of φNCKUH-21 in R20291 cells substantially enhanced toxin production, bacterial motility, biofilm formation, and spore germination in vitro. Subsequent mouse studies revealed that the lysogenized R20291 strain caused a more severe infection than the wild-type strain. We screened three φNCKUH-21 genes encoding DNA-binding proteins to check their effects on PaLoc genes expression. The overexpression of NCKUH-21_03890, annotated as a transcriptional regulator (phage transcriptional regulator X, PtrX), considerably enhanced toxin production, biofilm formation, and bacterial motility of R20291. Transcriptome analysis further confirmed that the overexpression of ptrX led to the upregulation of the expression of toxin genes, flagellar genes, and csrA. In the ptrX-overexpressing R20291 strain, PtrX influenced the expression of flagellar genes and the sigma factor gene sigD, possibly through an increased flagellar phase ON configuration ratio.
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Affiliation(s)
- Jun-Jia Gong
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - I-Hsiu Huang
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, Tulsa, OK 74107, USA
| | - Marcia Shu-Wei Su
- Department of Biotechnology and Laboratory Science in Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Si-Xuan Xie
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Wei-Yong Liu
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Cheng-Rung Huang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yuan-Pin Hung
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Shang-Rung Wu
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Institute of Oral Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Pei-Jane Tsai
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University, Tainan, Taiwan; Department of Pathology, National Cheng Kung University Hospital, Tainan, Taiwan; Center for Clinical Medicine Research, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Wen-Chien Ko
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jenn-Wei Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
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Liu Z, Tang K, Zhou Y, Liu T, Guo Y, Wu D, Wang X. Active prophages in coral-associated Halomonas capable of lateral transduction. THE ISME JOURNAL 2024; 18:wrae085. [PMID: 38739683 PMCID: PMC11131426 DOI: 10.1093/ismejo/wrae085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 04/19/2024] [Accepted: 05/11/2024] [Indexed: 05/16/2024]
Abstract
Temperate phages can interact with bacterial hosts through lytic and lysogenic cycles via different mechanisms. Lysogeny has been identified as the major form of bacteria-phage interaction in the coral-associated microbiome. However, the lysogenic-to-lytic switch of temperate phages in ecologically important coral-associated bacteria and its ecological impact have not been extensively investigated. By studying the prophages in coral-associated Halomonas meridiana, we found that two prophages, Phm1 and Phm3, are inducible by the DNA-damaging agent mitomycin C and that Phm3 is spontaneously activated under normal cultivation conditions. Furthermore, Phm3 undergoes an atypical lytic pathway that can amplify and package adjacent host DNA, potentially resulting in lateral transduction. The induction of Phm3 triggered a process of cell lysis accompanied by the formation of outer membrane vesicles (OMVs) and Phm3 attached to OMVs. This unique cell-lysis process was controlled by a four-gene lytic module within Phm3. Further analysis of the Tara Ocean dataset revealed that Phm3 represents a new group of temperate phages that are widely distributed and transcriptionally active in the ocean. Therefore, the combination of lateral transduction mediated by temperate phages and OMV transmission offers a versatile strategy for host-phage coevolution in marine ecosystems.
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Affiliation(s)
- Ziyao Liu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
- University of Chinese Academy of Sciences, No.1, Yanqihu East Road, Huairou District, Beijing 101408, China
| | - Kaihao Tang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
- University of Chinese Academy of Sciences, No.1, Yanqihu East Road, Huairou District, Beijing 101408, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No.1119, Haibin Road, Nansha District, Guangzhou 511458, China
| | - Yiqing Zhou
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
| | - Tianlang Liu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
- University of Chinese Academy of Sciences, No.1, Yanqihu East Road, Huairou District, Beijing 101408, China
| | - Yunxue Guo
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
- University of Chinese Academy of Sciences, No.1, Yanqihu East Road, Huairou District, Beijing 101408, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No.1119, Haibin Road, Nansha District, Guangzhou 511458, China
| | - Duoting Wu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
| | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
- University of Chinese Academy of Sciences, No.1, Yanqihu East Road, Huairou District, Beijing 101408, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No.1119, Haibin Road, Nansha District, Guangzhou 511458, China
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Muzyukina P, Shkaruta A, Guzman NM, Andreani J, Borges AL, Bondy-Denomy J, Maikova A, Semenova E, Severinov K, Soutourina O. Identification of an anti-CRISPR protein that inhibits the CRISPR-Cas type I-B system in Clostridioides difficile. mSphere 2023; 8:e0040123. [PMID: 38009936 PMCID: PMC10732046 DOI: 10.1128/msphere.00401-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 10/10/2023] [Indexed: 11/29/2023] Open
Abstract
IMPORTANCE Clostridioides difficile is the widespread anaerobic spore-forming bacterium that is a major cause of potentially lethal nosocomial infections associated with antibiotic therapy worldwide. Due to the increase in severe forms associated with a strong inflammatory response and higher recurrence rates, a current imperative is to develop synergistic and alternative treatments for C. difficile infections. In particular, phage therapy is regarded as a potential substitute for existing antimicrobial treatments. However, it faces challenges because C. difficile has highly active CRISPR-Cas immunity, which may be a specific adaptation to phage-rich and highly crowded gut environment. To overcome this defense, C. difficile phages must employ anti-CRISPR mechanisms. Here, we present the first anti-CRISPR protein that inhibits the CRISPR-Cas defense system in this pathogen. Our work offers insights into the interactions between C. difficile and its phages, paving the way for future CRISPR-based applications and development of effective phage therapy strategies combined with the engineering of virulent C. difficile infecting phages.
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Affiliation(s)
- Polina Muzyukina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
- Center for Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Anton Shkaruta
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
- Center for Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Noemi M. Guzman
- Center for Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Jessica Andreani
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Adair L. Borges
- Department of Microbiology and Immunology, University of California, San Francisco, California, USA
| | - Joseph Bondy-Denomy
- Department of Microbiology and Immunology, University of California, San Francisco, California, USA
| | - Anna Maikova
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
- Center for Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Ekaterina Semenova
- Waksman Institute, Rutgers, State University of New Jersey, Piscataway, New Jersey, USA
| | - Konstantin Severinov
- Waksman Institute, Rutgers, State University of New Jersey, Piscataway, New Jersey, USA
- Institute of Molecular Genetics, Kurchatov National Research Center, Moscow, Russia
| | - Olga Soutourina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
- Institut Universitaire de France (IUF), Paris, France
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Dicks LMT. Biofilm Formation of Clostridioides difficile, Toxin Production and Alternatives to Conventional Antibiotics in the Treatment of CDI. Microorganisms 2023; 11:2161. [PMID: 37764005 PMCID: PMC10534356 DOI: 10.3390/microorganisms11092161] [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: 06/29/2023] [Revised: 08/16/2023] [Accepted: 08/24/2023] [Indexed: 09/29/2023] Open
Abstract
Clostridioides difficile is considered a nosocomial pathogen that flares up in patients exposed to antibiotic treatment. However, four out of ten patients diagnosed with C. difficile infection (CDI) acquired the infection from non-hospitalized individuals, many of whom have not been treated with antibiotics. Treatment of recurrent CDI (rCDI) with antibiotics, especially vancomycin (VAN) and metronidazole (MNZ), increases the risk of experiencing a relapse by as much as 70%. Fidaxomicin, on the other hand, proved more effective than VAN and MNZ by preventing the initial transcription of RNA toxin genes. Alternative forms of treatment include quorum quenching (QQ) that blocks toxin synthesis, binding of small anion molecules such as tolevamer to toxins, monoclonal antibodies, such as bezlotoxumab and actoxumab, bacteriophage therapy, probiotics, and fecal microbial transplants (FMTs). This review summarizes factors that affect the colonization of C. difficile and the pathogenicity of toxins TcdA and TcdB. The different approaches experimented with in the destruction of C. difficile and treatment of CDI are evaluated.
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Affiliation(s)
- Leon M T Dicks
- Department of Microbiology, Stellenbosch University, Stellenbosch 7600, South Africa
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Raeisi H, Noori M, Azimirad M, Mohebbi SR, Asadzadeh Aghdaei H, Yadegar A, Zali MR. Emerging applications of phage therapy and fecal virome transplantation for treatment of Clostridioides difficile infection: challenges and perspectives. Gut Pathog 2023; 15:21. [PMID: 37161478 PMCID: PMC10169144 DOI: 10.1186/s13099-023-00550-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 05/02/2023] [Indexed: 05/11/2023] Open
Abstract
Clostridioides difficile, which causes life-threatening diarrheal disease, is considered an urgent threat to healthcare setting worldwide. The current standards of care solely rely on conventional antibiotic treatment, however, there is a risk of promoting recurrent C. difficile infection (rCDI) because of the emergence of antibiotic-resistant strains. Globally, the alarming spread of antibiotic-resistant strains of C. difficile has resulted in a quest for alternative therapeutics. The use of fecal microbiota transplantation (FMT), which involves direct infusion of fecal suspension from a healthy donor into a diseased recipient, has been approved as a highly efficient therapeutic option for patients with rCDI. Bacteriophages or phages are a group of viruses that can infect and destroy bacterial hosts, and are recognized as the dominant viral component of the human gut microbiome. Accumulating data has demonstrated that phages play a vital role in microbial balance of the human gut microbiome. Recently, phage therapy and fecal virome transplantation (FVT) have been introduced as promising alternatives for the treatment of C. difficile -related infections, in particular drug-resistant CDI. Herein, we review the latest updates on C. difficile- specific phages, and phage-mediated treatments, and highlight the current and future prospects of phage therapy in the management of CDI.
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Affiliation(s)
- Hamideh Raeisi
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Maryam Noori
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Masoumeh Azimirad
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Seyed Reza Mohebbi
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hamid Asadzadeh Aghdaei
- Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abbas Yadegar
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Mohammad Reza Zali
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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9
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Dong Q, Lin H, Allen MM, Garneau JR, Sia JK, Smith RC, Haro F, McMillen T, Pope RL, Metcalfe C, Burgo V, Woodson C, Dylla N, Kohout C, Sundararajan A, Snitkin ES, Young VB, Fortier LC, Kamboj M, Pamer EG. Virulence and genomic diversity among clinical isolates of ST1 (BI/NAP1/027) Clostridioides difficile. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.12.523823. [PMID: 36711955 PMCID: PMC9882218 DOI: 10.1101/2023.01.12.523823] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Clostridioides difficile (C. difficile) , a leading cause of nosocomial infection, produces toxins that damage the colonic epithelium and results in colitis that varies from mild to fulminant. Variation in disease severity is poorly understood and has been attributed to host factors (age, immune competence and intestinal microbiome composition) and/or virulence differences between C. difficile strains, with some, such as the epidemic BI/NAP1/027 (MLST1) strain, being associated with greater virulence. We tested 23 MLST1(ST1) C. difficile clinical isolates for virulence in antibiotic-treated C57BL/6 mice. All isolates encoded a complete Tcd pathogenicity locus and achieved similar colonization densities in mice. Disease severity varied, however, with 5 isolates causing lethal infections, 16 isolates causing a range of moderate infections and 2 isolates resulting in no detectable disease. The avirulent ST1 isolates did not cause disease in highly susceptible Myd88 -/- or germ-free mice. Genomic analysis of the avirulent isolates revealed a 69 base-pair deletion in the N-terminus of the cdtR gene, which encodes a response regulator for binary toxin (CDT) expression. Genetic deletion of the 69 base-pair cdtR sequence in the highly virulent ST1 R20291 C. difficile strain rendered it avirulent and reduced toxin gene transcription in cecal contents. Our study demonstrates that a natural deletion within cdtR attenuates virulence in the epidemic ST1 C. difficile strain without reducing colonization and persistence in the gut. Distinguishing strains on the basis of cdtR may enhance the specificity of diagnostic tests for C. difficile colitis.
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Affiliation(s)
- Qiwen Dong
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Huaiying Lin
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Marie-Maude Allen
- Department of Microbiology and Infectious Diseases, Universite de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Julian R. Garneau
- Department of Microbiology and Infectious Diseases, Universite de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Jonathan K. Sia
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York City, New York, USA
| | - Rita C. Smith
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Fidel Haro
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Tracy McMillen
- Infection Control, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Rosemary L. Pope
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
- Committee on Immunology, University of Chicago, Chicago, Illinois, USA
| | - Carolyn Metcalfe
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Victoria Burgo
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Che Woodson
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Nicholas Dylla
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Claire Kohout
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | | | - Evan S Snitkin
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Vincent B. Young
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Louis-Charles Fortier
- Department of Microbiology and Infectious Diseases, Universite de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Mini Kamboj
- Infection Control, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Eric G. Pamer
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
- Committee on Immunology, University of Chicago, Chicago, Illinois, USA
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10
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Nale JY, Thanki AM, Rashid SJ, Shan J, Vinner GK, Dowah ASA, Cheng JKJ, Sicheritz-Pontén T, Clokie MRJ. Diversity, Dynamics and Therapeutic Application of Clostridioides difficile Bacteriophages. Viruses 2022; 14:v14122772. [PMID: 36560776 PMCID: PMC9784644 DOI: 10.3390/v14122772] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 12/08/2022] [Accepted: 12/08/2022] [Indexed: 12/15/2022] Open
Abstract
Clostridioides difficile causes antibiotic-induced diarrhoea and pseudomembranous colitis in humans and animals. Current conventional treatment relies solely on antibiotics, but C. difficile infection (CDI) cases remain persistently high with concomitant increased recurrence often due to the emergence of antibiotic-resistant strains. Antibiotics used in treatment also induce gut microbial imbalance; therefore, novel therapeutics with improved target specificity are being investigated. Bacteriophages (phages) kill bacteria with precision, hence are alternative therapeutics for the targeted eradication of the pathogen. Here, we review current progress in C. difficile phage research. We discuss tested strategies of isolating C. difficile phages directly, and via enrichment methods from various sample types and through antibiotic induction to mediate prophage release. We also summarise phenotypic phage data that reveal their morphological, genetic diversity, and various ways they impact their host physiology and pathogenicity during infection and lysogeny. Furthermore, we describe the therapeutic development of phages through efficacy testing in different in vitro, ex vivo and in vivo infection models. We also discuss genetic modification of phages to prevent horizontal gene transfer and improve lysis efficacy and formulation to enhance stability and delivery of the phages. The goal of this review is to provide a more in-depth understanding of C. difficile phages and theoretical and practical knowledge on pre-clinical, therapeutic evaluation of the safety and effectiveness of phage therapy for CDI.
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Affiliation(s)
- Janet Y. Nale
- Centre for Epidemiology and Planetary Health, Department of Veterinary and Animal Science, Scotland’s Rural College, Inverness IV2 5NA, UK
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Anisha M. Thanki
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Srwa J. Rashid
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Jinyu Shan
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Gurinder K. Vinner
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Ahmed S. A. Dowah
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
- School of Pharmacy, University of Lincoln, Lincoln LN6 7TS, UK
| | | | - Thomas Sicheritz-Pontén
- Center for Evolutionary Hologenomics, The Globe Institute, University of Copenhagen, 1353 Copenhagen, Denmark
- Centre of Excellence for Omics-Driven Computational Biodiscovery, AIMST University, Bedong 08100, Kedah, Malaysia
| | - Martha R. J. Clokie
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
- Correspondence:
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11
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The Life Cycle Transitions of Temperate Phages: Regulating Factors and Potential Ecological Implications. Viruses 2022; 14:v14091904. [PMID: 36146712 PMCID: PMC9502458 DOI: 10.3390/v14091904] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/25/2022] [Accepted: 08/25/2022] [Indexed: 11/17/2022] Open
Abstract
Phages are viruses that infect bacteria. They affect various microbe-mediated processes that drive biogeochemical cycling on a global scale. Their influence depends on whether the infection is lysogenic or lytic. Temperate phages have the potential to execute both infection types and thus frequently switch their infection modes in nature, potentially causing substantial impacts on the host-phage community and relevant biogeochemical cycling. Understanding the regulating factors and outcomes of temperate phage life cycle transition is thus fundamental for evaluating their ecological impacts. This review thus systematically summarizes the effects of various factors affecting temperate phage life cycle decisions in both culturable phage-host systems and natural environments. The review further elucidates the ecological implications of the life cycle transition of temperate phages with an emphasis on phage/host fitness, host-phage dynamics, microbe diversity and evolution, and biogeochemical cycles.
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12
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Interactions between Jumbo Phage SA1 and Staphylococcus: A Global Transcriptomic Analysis. Microorganisms 2022; 10:microorganisms10081590. [PMID: 36014008 PMCID: PMC9414953 DOI: 10.3390/microorganisms10081590] [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: 07/01/2022] [Revised: 07/30/2022] [Accepted: 08/02/2022] [Indexed: 01/21/2023] Open
Abstract
Staphylococcus aureus (S. aureus) is an important zoonotic pathogen that poses a serious health concern to humans and cattle worldwide. Although it has been proven that lytic phages may successfully kill S. aureus, the interaction between the host and the phage has yet to be thoroughly investigated, which will likely limit the clinical application of phage. Here, RNA sequencing (RNA-seq) was used to examine the transcriptomics of jumbo phage SA1 and Staphylococcus JTB1-3 during a high multiplicity of infection (MOI) and RT-qPCR was used to confirm the results. The RNA-seq analysis revealed that phage SA1 took over the transcriptional resources of the host cells and that the genes were categorized as early, middle, and late, based on the expression levels during infection. A minor portion of the resources of the host was employed to enable phage replication after infection because only 35.73% (997/2790) of the host genes were identified as differentially expressed genes (DEGs). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that the phage infection mainly affected the nucleotide metabolism, protein metabolism, and energy-related metabolism of the host. Moreover, the expression of the host genes involved in anti-phage systems, virulence, and drug resistance significantly changed during infection. This research gives a fresh understanding of the relationship between jumbo phages and their Gram-positive bacteria hosts and provides a reference for studying phage treatment and antibiotics.
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13
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Krishnakumar R, Ruffing AM. OperonSEQer: A set of machine-learning algorithms with threshold voting for detection of operon pairs using short-read RNA-sequencing data. PLoS Comput Biol 2022; 18:e1009731. [PMID: 34986143 PMCID: PMC8765615 DOI: 10.1371/journal.pcbi.1009731] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 01/18/2022] [Accepted: 12/07/2021] [Indexed: 11/19/2022] Open
Abstract
Operon prediction in prokaryotes is critical not only for understanding the regulation of endogenous gene expression, but also for exogenous targeting of genes using newly developed tools such as CRISPR-based gene modulation. A number of methods have used transcriptomics data to predict operons, based on the premise that contiguous genes in an operon will be expressed at similar levels. While promising results have been observed using these methods, most of them do not address uncertainty caused by technical variability between experiments, which is especially relevant when the amount of data available is small. In addition, many existing methods do not provide the flexibility to determine the stringency with which genes should be evaluated for being in an operon pair. We present OperonSEQer, a set of machine learning algorithms that uses the statistic and p-value from a non-parametric analysis of variance test (Kruskal-Wallis) to determine the likelihood that two adjacent genes are expressed from the same RNA molecule. We implement a voting system to allow users to choose the stringency of operon calls depending on whether your priority is high recall or high specificity. In addition, we provide the code so that users can retrain the algorithm and re-establish hyperparameters based on any data they choose, allowing for this method to be expanded as additional data is generated. We show that our approach detects operon pairs that are missed by current methods by comparing our predictions to publicly available long-read sequencing data. OperonSEQer therefore improves on existing methods in terms of accuracy, flexibility, and adaptability. Bacteria and archaea, single-cell organisms collectively known as prokaryotes, live in all imaginable environments and comprise the majority of living organisms on this planet. Prokaryotes play a critical role in the homeostasis of multicellular organisms (such as animals and plants) and ecosystems. In addition, bacteria can be pathogenic and cause a variety of diseases in these same hosts and ecosystems. In short, understanding the biology and molecular functions of bacteria and archaea and devising mechanisms to engineer and optimize their properties are critical scientific endeavors with significant implications in healthcare, agriculture, manufacturing, and climate science among others. One major molecular difference between unicellular and multicellular organisms is the way they express genes–multicellular organisms make individual RNA molecules for each gene while, prokaryotes express operons (i.e., a group of genes coding functionally related proteins) in contiguous polycistronic RNA molecules. Understanding which genes exist within operons is critical for elucidating basic biology and for engineering organisms. In this work, we use a combination of statistical and machine learning-based methods to use next-generation sequencing data to predict operon structure across a range of prokaryotes. Our method provides an easily implemented, robust, accurate, and flexible way to determine operon structure in an organism-agnostic manner using readily available data.
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Affiliation(s)
- Raga Krishnakumar
- Systems Biology Department, Sandia National Laboratories, Livermore, California, United States of America
- * E-mail:
| | - Anne M. Ruffing
- Molecular and Microbiology Department, Sandia National Laboratories, Albuquerque, New Mexico, United States of America
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14
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Clostridioides difficile - phage relationship the RNA way. Curr Opin Microbiol 2021; 66:1-10. [PMID: 34922145 DOI: 10.1016/j.mib.2021.11.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/06/2021] [Accepted: 11/28/2021] [Indexed: 12/17/2022]
Abstract
Clostridioides difficile (formerly Clostridium difficile)-associated diarrhea is currently the most frequently occurring nosocomial diarrhea worldwide. During its infection cycle this pathogen needs to survive in phage-rich gut communities. Recent data strongly suggest that regulatory RNAs control gene expression in C. difficile and many of these RNAs appear to modulate C. difficile-phage interactions. Of the 200 regulatory RNAs identified by deep sequencing and targeted approaches, many function as antitoxins within type I toxin-antitoxin modules and CRISPR RNAs for anti-phage defenses. In this review, we discuss recent insights into the role of RNAs in modulating interactions between C. difficile and phages in light of intriguing data in other prokaryotes.
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15
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Nale JY, Al-Tayawi TS, Heaphy S, Clokie MRJ. Impact of Phage CDHS-1 on the Transcription, Physiology and Pathogenicity of a Clostridioides difficile Ribotype 027 Strain, R20291. Viruses 2021; 13:v13112262. [PMID: 34835068 PMCID: PMC8619979 DOI: 10.3390/v13112262] [Citation(s) in RCA: 3] [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: 10/04/2021] [Revised: 10/27/2021] [Accepted: 11/02/2021] [Indexed: 01/05/2023] Open
Abstract
All known Clostridioides difficile phages encode integrases rendering them potentially able to lyse or lysogenise bacterial strains. Here, we observed the infection of the siphovirus, CDHS-1 on a ribotype 027 strain, R20291 and determined the phage and bacterial gene expression profiles, and impacts of phage infection on bacterial physiology and pathogenicity. Using RNA-seq and RT-qPCR we analysed transcriptomic changes during early, mid-log and late phases of phage replication at an MOI of 10. The phage has a 20 min latent period, takes 80 min to lyse cells and a burst size of ~37. All phage genes are highly expressed during at least one time point. The Cro/C1-transcriptional regulator, ssDNA binding protein and helicase are expressed early, the holin is expressed during the mid-log phase and structural proteins are expressed from mid-log to late phase. Most bacterial genes, particularly the metabolism and toxin production/regulatory genes, were downregulated from early phage replication. Phage-resistant strains and lysogens showed reduced virulence during Galleria mellonella colonization as ascertained by the larval survival and expression of growth (10), reproduction (2) and infection (2) marker genes. These data suggest that phage infection both reduces colonization and negatively impacts bacterial pathogenicity, providing encouraging data to support the development of this phage for therapy to treat C. difficile infection.
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16
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Smith-Peter E, Séguin DL, St-Pierre É, Sekulovic O, Jeanneau S, Tremblay-Tétreault C, Lamontagne AM, Jacques PÉ, Lafontaine DA, Fortier LC. Inactivation of the riboswitch-controlled GMP synthase GuaA in Clostridioides difficile is associated with severe growth defects and poor infectivity in a mouse model of infection. RNA Biol 2021; 18:699-710. [PMID: 34612173 DOI: 10.1080/15476286.2021.1978768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Clostridioides difficile is the main cause of nosocomial antibiotic-associated diarrhoea. There is a need for new antimicrobials to tackle this pathogen. Guanine riboswitches have been proposed as promising new antimicrobial targets, but experimental evidence of their importance in C. difficile is missing. The genome of C. difficile encodes four distinct guanine riboswitches, each controlling a single gene involved in purine metabolism and transport. One of them controls the expression of guaA, encoding a guanosine monophosphate (GMP) synthase. Here, using in-line probing and GusA reporter assays, we show that these riboswitches are functional in C. difficile and cause premature transcription termination upon binding of guanine. All riboswitches exhibit a high affinity for guanine characterized by Kd values in the low nanomolar range. Xanthine and guanosine also bind the guanine riboswitches, although with less affinity. Inactivating the GMP synthase (guaA) in C. difficile strain 630 led to cell death in minimal growth conditions, but not in rich medium. Importantly, the capacity of a guaA mutant to colonize the mouse gut was significantly reduced. Together, these results demonstrate the importance of de novo GMP biosynthesis in C. difficile during infection, suggesting that targeting guanine riboswitches with analogues could be a viable therapeutic strategy.
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Affiliation(s)
- Erich Smith-Peter
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université De Sherbrooke, Sherbrooke, Quebec, Canada.,Department of Biology, Faculty of Science, Université De Sherbrooke, Sherbrooke, Quebec, Canada
| | - David Lalonde Séguin
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université De Sherbrooke, Sherbrooke, Quebec, Canada
| | - Émilie St-Pierre
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université De Sherbrooke, Sherbrooke, Quebec, Canada
| | - Ognjen Sekulovic
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université De Sherbrooke, Sherbrooke, Quebec, Canada
| | - Simon Jeanneau
- Department of Biology, Faculty of Science, Université De Sherbrooke, Sherbrooke, Quebec, Canada
| | | | - Anne-Marie Lamontagne
- Department of Biology, Faculty of Science, Université De Sherbrooke, Sherbrooke, Quebec, Canada
| | - Pierre-Étienne Jacques
- Department of Biology, Faculty of Science, Université De Sherbrooke, Sherbrooke, Quebec, Canada
| | - Daniel A Lafontaine
- Department of Biology, Faculty of Science, Université De Sherbrooke, Sherbrooke, Quebec, Canada
| | - Louis-Charles Fortier
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université De Sherbrooke, Sherbrooke, Quebec, Canada
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17
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Complete genome sequence of the newly discovered temperate Clostridioides difficile bacteriophage phiCDKH01 of the family Siphoviridae. Arch Virol 2021; 166:2305-2310. [PMID: 34014385 PMCID: PMC8270841 DOI: 10.1007/s00705-021-05092-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 03/22/2021] [Indexed: 12/18/2022]
Abstract
A temperate siphovirus, phiCDKH01, was obtained from a clinical isolate of Clostridioides difficile. The phage genome is a 45,089-bp linear double-stranded DNA molecule with an average G+C content of 28.7%. It shows low similarity to known phage genomes, except for phiCD24-1. Genomic and phylogenetic analysis revealed that phiCDKH01 is a newly discovered phage. Sixty-six putative ORFs were predicted in the genome, 37 of which code for proteins with predicted functions. The phiCDKH01 prophage was localized in the host genome. The results of this study increase our knowledge about the genetic diversity of tailed phages.
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18
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Campbell DE, Ly LK, Ridlon JM, Hsiao A, Whitaker RJ, Degnan PH. Infection with Bacteroides Phage BV01 Alters the Host Transcriptome and Bile Acid Metabolism in a Common Human Gut Microbe. Cell Rep 2021; 32:108142. [PMID: 32937127 PMCID: PMC8354205 DOI: 10.1016/j.celrep.2020.108142] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 07/07/2020] [Accepted: 08/21/2020] [Indexed: 12/16/2022] Open
Abstract
Gut-associated phages are hypothesized to alter the abundance and activity of their bacterial hosts, contributing to human health and disease. Although temperate phages constitute a significant fraction of the gut virome, the effects of lysogenic infection are underexplored. We report that the temperate phage, Bacteroides phage BV01, broadly alters its host's transcriptome, the prominent human gut symbiont Bacteroides vulgatus. This alteration occurs through phage-induced repression of a tryptophan-rich sensory protein (TspO) and represses bile acid deconjugation. Because microbially modified bile acids are important signals for the mammalian host, this is a mechanism by which a phage may influence mammalian phenotypes. Furthermore, BV01 and its relatives in the proposed phage family Salyersviridae are ubiquitous in human gut metagenomes, infecting a broad range of Bacteroides hosts. These results demonstrate the complexity of phage-bacteria-mammal relationships and emphasize a need to better understand the role of temperate phages in the gut microbiome.
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Affiliation(s)
| | - Lindsey K Ly
- Division of Nutritional Sciences, University of Illinois, Urbana, IL 61801, USA; Department of Animal Sciences, University of Illinois, Urbana, IL 61801, USA
| | - Jason M Ridlon
- Division of Nutritional Sciences, University of Illinois, Urbana, IL 61801, USA; Department of Animal Sciences, University of Illinois, Urbana, IL 61801, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL 61801, USA
| | - Ansel Hsiao
- Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA 92521, USA
| | - Rachel J Whitaker
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL 61801, USA
| | - Patrick H Degnan
- Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA 92521, USA.
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19
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Garrett EM, Mehra A, Sekulovic O, Tamayo R. Multiple Regulatory Mechanisms Control the Production of CmrRST, an Atypical Signal Transduction System in Clostridioides difficile. mBio 2021; 13:e0296921. [PMID: 35164558 PMCID: PMC8844915 DOI: 10.1128/mbio.02969-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 01/20/2022] [Indexed: 12/16/2022] Open
Abstract
Clostridioides difficile, an intestinal pathogen and leading cause of nosocomial infection, exhibits extensive phenotypic heterogeneity through phase variation. The signal transduction system CmrRST, which encodes two response regulators (CmrR and CmrT) and a sensor kinase (CmrS), impacts C. difficile cell and colony morphology, surface and swimming motility, biofilm formation, and virulence in an animal model. CmrRST is subject to phase variation through site-specific recombination and reversible inversion of the "cmr switch," and expression of cmrRST is also regulated by cyclic diguanylate (c-di-GMP) through a riboswitch. The goal of this study was to determine how the cmr switch and c-di-GMP work together to regulate cmrRST expression. We generated "phase-locked" strains by mutating key residues in the right inverted repeat flanking the cmr switch. Phenotypic characterization of these phase-locked cmr-ON and -OFF strains demonstrates that they cannot switch between rough and smooth colony morphologies, respectively, or other CmrRST-associated phenotypes. Manipulation of c-di-GMP levels in these mutants showed that c-di-GMP promotes cmrRST expression and associated phenotypes independently of cmr switch orientation. We identified multiple promoters controlling cmrRST transcription, including one within the ON orientation of the cmr switch and another that is positively autoregulated by CmrR. Overall, this work reveals a complex regulatory network that governs cmrRST expression and a unique intersection of phase variation and c-di-GMP signaling. These findings suggest that multiple environmental signals impact the production of this signaling transduction system. IMPORTANCE Clostridioides difficile is a leading cause of hospital-acquired intestinal infections in the United States. The CmrRST signal transduction system controls numerous physiological traits and processes in C. difficile, including cell and colony morphology, motility, biofilm formation, and virulence. Here, we define the complex, multilevel regulation of cmrRST expression, including stochastic control through phase variation, modulation by the second messenger c-di-GMP, and positive autoregulation by CmrR. The results of this study suggest that multiple, distinct environmental stimuli and selective pressures must be integrated to appropriately control cmrRST expression.
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Affiliation(s)
- Elizabeth M. Garrett
- Department of Microbiology and Immunology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina, USA
| | - Anchal Mehra
- Department of Microbiology and Immunology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina, USA
| | - Ognjen Sekulovic
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Rita Tamayo
- Department of Microbiology and Immunology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina, USA
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20
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Hernández S, Vives MJ. Phages in Anaerobic Systems. Viruses 2020; 12:E1091. [PMID: 32993161 PMCID: PMC7599459 DOI: 10.3390/v12101091] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 09/07/2020] [Accepted: 09/08/2020] [Indexed: 12/21/2022] Open
Abstract
Since the discovery of phages in 1915, these viruses have been studied mostly in aerobic systems, or without considering the availability of oxygen as a variable that may affect the interaction between the virus and its host. However, with such great abundance of anaerobic environments on the planet, the effect that a lack of oxygen can have on the phage-bacteria relationship is an important consideration. There are few studies on obligate anaerobes that investigate the role of anoxia in causing infection. In the case of facultative anaerobes, it is a well-known fact that their shifting from an aerobic environment to an anaerobic one involves metabolic changes in the bacteria. As the phage infection process depends on the metabolic state of the host bacteria, these changes are also expected to affect the phage infection cycle. This review summarizes the available information on phages active on facultative and obligate anaerobes and discusses how anaerobiosis can be an important parameter in phage infection, especially among facultative anaerobes.
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Affiliation(s)
- Santiago Hernández
- Department of Biological Sciences, Universidad de los Andes, Bogotá 111711, Colombia;
| | - Martha J. Vives
- Department of Biological Sciences, Universidad de los Andes, Bogotá 111711, Colombia;
- School of Sciences, Universidad de los Andes, Bogotá 111711, Colombia
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21
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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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22
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Isolation and Characterization of the Novel Phage JD032 and Global Transcriptomic Response during JD032 Infection of Clostridioides difficile Ribotype 078. mSystems 2020; 5:5/3/e00017-20. [PMID: 32371470 PMCID: PMC7205517 DOI: 10.1128/msystems.00017-20] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
C. difficile is one of the most clinically significant intestinal pathogens. Although phages have been shown to effectively control C. difficile infection, the host responses to phage predation have not been fully studied. In this study, we reported the isolation and characterization of a new phage, JD032, and analyzed the global transcriptomic changes in the hypervirulent RT078 C. difficile strain, TW11, during phage JD032 infection. We found that bacterial host mRNA was progressively replaced with phage transcripts, three temporal categories of JD032 gene expression, the extensive interplay between phage-bacterium, antiphage-like responses of the host and phage evasion, and decreased expression of sporulation- and virulence-related genes of the host after phage infection. These findings confirmed the complexity of interactions between C. difficile and phages and suggest that phages undergoing a lytic cycle may also cause different phenotypes in hosts, similar to prophages, which may inspire phage therapy for the control of C. difficile. Insights into the interaction between phages and their bacterial hosts are crucial for the development of phage therapy. However, only one study has investigated global gene expression of Clostridioides (formerly Clostridium) difficile carrying prophage, and transcriptional reprogramming during lytic infection has not been studied. Here, we presented the isolation, propagation, and characterization of a newly discovered 35,109-bp phage, JD032, and investigated the global transcriptomes of both JD032 and C. difficile ribotype 078 (RT078) strain TW11 during JD032 infection. Transcriptome sequencing (RNA-seq) revealed the progressive replacement of bacterial host mRNA with phage transcripts. The expressed genes of JD032 were clustered into early, middle, and late temporal categories that were functionally similar. Specifically, a gene (JD032_orf016) involved in the lysis-lysogeny decision was identified as an early expression gene. Only 17.7% (668/3,781) of the host genes were differentially expressed, and more genes were downregulated than upregulated. The expression of genes involved in host macromolecular synthesis (DNA/RNA/proteins) was altered by JD032 at the level of transcription. In particular, the expression of the ropA operon was downregulated. Most noteworthy is that the gene expression of some antiphage systems, including CRISPR-Cas, restriction-modification, and toxin-antitoxin systems, was suppressed by JD032 during infection. In addition, bacterial sporulation, adhesion, and virulence factor genes were significantly downregulated. This study provides the first description of the interaction between anaerobic spore-forming bacteria and phages during lytic infection and highlights new aspects of C. difficile phage-host interactions. IMPORTANCEC. difficile is one of the most clinically significant intestinal pathogens. Although phages have been shown to effectively control C. difficile infection, the host responses to phage predation have not been fully studied. In this study, we reported the isolation and characterization of a new phage, JD032, and analyzed the global transcriptomic changes in the hypervirulent RT078 C. difficile strain, TW11, during phage JD032 infection. We found that bacterial host mRNA was progressively replaced with phage transcripts, three temporal categories of JD032 gene expression, the extensive interplay between phage-bacterium, antiphage-like responses of the host and phage evasion, and decreased expression of sporulation- and virulence-related genes of the host after phage infection. These findings confirmed the complexity of interactions between C. difficile and phages and suggest that phages undergoing a lytic cycle may also cause different phenotypes in hosts, similar to prophages, which may inspire phage therapy for the control of C. difficile.
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23
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Garrett EM, Sekulovic O, Wetzel D, Jones JB, Edwards AN, Vargas-Cuebas G, McBride SM, Tamayo R. Phase variation of a signal transduction system controls Clostridioides difficile colony morphology, motility, and virulence. PLoS Biol 2019; 17:e3000379. [PMID: 31658249 PMCID: PMC6837544 DOI: 10.1371/journal.pbio.3000379] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 11/07/2019] [Accepted: 10/15/2019] [Indexed: 12/20/2022] Open
Abstract
Recent work has revealed that Clostridioides difficile, a major cause of nosocomial diarrheal disease, exhibits phenotypic heterogeneity within a clonal population as a result of phase variation. Many C. difficile strains representing multiple ribotypes develop two colony morphotypes, termed rough and smooth, but the biological implications of this phenomenon have not been explored. Here, we examine the molecular basis and physiological relevance of the distinct colony morphotypes produced by this bacterium. We show that C. difficile reversibly differentiates into rough and smooth colony morphologies and that bacteria derived from the isolates display discrete motility behaviors. We identified an atypical phase-variable signal transduction system consisting of a histidine kinase and two response regulators, named herein colony morphology regulators RST (CmrRST), which mediates the switch in colony morphology and motility behaviors. The CmrRST-regulated surface motility is independent of flagella and type IV pili, suggesting a novel mechanism of cell migration in C. difficile. Microscopic analysis of cell and colony structure indicates that CmrRST promotes the formation of elongated bacteria arranged in bundled chains, which may contribute to bacterial migration on surfaces. In a hamster model of acute C. difficile disease, the CmrRST system is required for disease development. Furthermore, we provide evidence that CmrRST phase varies during infection, suggesting that the intestinal environment impacts the proportion of CmrRST-expressing C. difficile. Our findings indicate that C. difficile employs phase variation of the CmrRST signal transduction system to generate phenotypic heterogeneity during infection, with concomitant effects on bacterial physiology and pathogenesis.
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Affiliation(s)
- Elizabeth M. Garrett
- Department of Microbiology and Immunology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Ognjen Sekulovic
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Daniela Wetzel
- Department of Microbiology and Immunology, Emory University, Rollins Research Center, Atlanta, Georgia, United States of America
| | - Joshua B. Jones
- Department of Microbiology and Immunology, Emory University, Rollins Research Center, Atlanta, Georgia, United States of America
| | - Adrianne N. Edwards
- Department of Microbiology and Immunology, Emory University, Rollins Research Center, Atlanta, Georgia, United States of America
| | - Germán Vargas-Cuebas
- Department of Microbiology and Immunology, Emory University, Rollins Research Center, Atlanta, Georgia, United States of America
| | - Shonna M. McBride
- Department of Microbiology and Immunology, Emory University, Rollins Research Center, Atlanta, Georgia, United States of America
| | - Rita Tamayo
- Department of Microbiology and Immunology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina, United States of America
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24
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Slater RT, Frost LR, Jossi SE, Millard AD, Unnikrishnan M. Clostridioides difficile LuxS mediates inter-bacterial interactions within biofilms. Sci Rep 2019; 9:9903. [PMID: 31289293 PMCID: PMC6616478 DOI: 10.1038/s41598-019-46143-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 06/21/2019] [Indexed: 12/18/2022] Open
Abstract
The anaerobic gut pathogen, Clostridioides difficile, forms adherent biofilms that may play an important role in recurrent C. difficile infections. The mechanisms underlying C. difficile community formation and inter-bacterial interactions are nevertheless poorly understood. C. difficile produces AI-2, a quorum sensing molecule that modulates biofilm formation across many bacterial species. We found that a strain defective in LuxS, the enzyme that mediates AI-2 production, is defective in biofilm development in vitro. Transcriptomic analyses of biofilms formed by wild type (WT) and luxS mutant (luxS) strains revealed a downregulation of prophage loci in the luxS mutant biofilms compared to the WT. Detection of phages and eDNA within biofilms may suggest that DNA release by phage-mediated cell lysis contributes to C. difficile biofilm formation. In order to understand if LuxS mediates C. difficile crosstalk with other gut species, C. difficile interactions with a common gut bacterium, Bacteroides fragilis, were studied. We demonstrate that C. difficile growth is significantly reduced when co-cultured with B. fragilis in mixed biofilms. Interestingly, the absence of C. difficile LuxS alleviates the B. fragilis-mediated growth inhibition. Dual species RNA-sequencing analyses from single and mixed biofilms revealed differential modulation of distinct metabolic pathways for C. difficile WT, luxS and B. fragilis upon co-culture, indicating that AI-2 may be involved in induction of selective metabolic responses in B. fragilis. Overall, our data suggest that C. difficile LuxS/AI-2 utilises different mechanisms to mediate formation of single and mixed species communities.
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Affiliation(s)
- Ross T Slater
- University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom
| | - Lucy R Frost
- University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom
| | - Sian E Jossi
- University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom
| | - Andrew D Millard
- University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - Meera Unnikrishnan
- University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom.
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25
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Ramisetty BCM, Sudhakari PA. Bacterial 'Grounded' Prophages: Hotspots for Genetic Renovation and Innovation. Front Genet 2019; 10:65. [PMID: 30809245 PMCID: PMC6379469 DOI: 10.3389/fgene.2019.00065] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 01/24/2019] [Indexed: 01/07/2023] Open
Abstract
Bacterial genomes are highly plastic allowing the generation of variants through mutations and acquisition of genetic information. The fittest variants are then selected by the econiche thereby allowing the bacterial adaptation and colonization of the habitat. Larger genomes, however, may impose metabolic burden and hence bacterial genomes are optimized by the loss of frivolous genetic information. The activity of temperate bacteriophages has acute consequences on the bacterial population as well as the bacterial genome through lytic and lysogenic cycles. Lysogeny is a selective advantage as the prophage provides immunity to the lysogen against secondary phage attack. Since the non-lysogens are eliminated by the lytic phages, lysogens multiply and colonize the habitat. Nevertheless, all lysogens have an imminent risk of lytic cycle activation and cell lysis. However, a mutation in the attachment sites or in the genes that encode the specific recombinase responsible for prophage excision could result in 'grounding' of the prophage. Since the lysogens with grounded prophage are immune to respective phage infection as well as dodge the induction of lytic cycle, we hypothesize that the selection of these mutant lysogens is favored relative to their normal lysogenic counterparts. These grounded prophages offer several advantages to the bacterial genome evolution through propensity for genetic variations including inversions, deletions, and insertions via horizontal gene transfer. We propose that the grounded prophages expedite bacterial genome evolution by acting as 'genetic buffer zones' thereby increasing the frequency as well as the diversity of variations on which natural selection favors the beneficial variants. The grounded prophages are also hotspots for horizontal gene transfer wherein several ecologically significant genes such as those involved in stress tolerance, antimicrobial resistance, and novel metabolic pathways, are integrated. Moreover, the high frequency of genetic changes within prophages also allows proportionate probability for the de novo genesis of genetic information. Through sequence analyses of well-characterized E. coli prophages we exemplify various roles of grounded prophages in E. coli ecology and evolution. Therefore, the temperate prophages are one of the most significant drivers of bacterial genome evolution and sites of biogenesis of genetic information.
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Affiliation(s)
- Bhaskar Chandra Mohan Ramisetty
- Laboratory of Molecular Biology and Evolution, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, India
| | - Pavithra Anantharaman Sudhakari
- Laboratory of Molecular Biology and Evolution, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, India
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26
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Lavey NP, Shadid T, Ballard JD, Duerfeldt AS. Clostridium difficile ClpP Homologues are Capable of Uncoupled Activity and Exhibit Different Levels of Susceptibility to Acyldepsipeptide Modulation. ACS Infect Dis 2019; 5:79-89. [PMID: 30411608 DOI: 10.1021/acsinfecdis.8b00199] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Caseinolytic protease P (ClpP) has emerged as a promising new target for antibacterial development. While ClpPs from single isoform expressing bacteria have been studied in detail, the function and regulation of systems with more than one ClpP homologue are still poorly understood. Herein, we present fundamental studies toward understanding the ClpP system in C. difficile, an anaerobic spore-forming pathogen that contains two chromosomally distant isoforms of ClpP. Examination of proteomic and genomic data suggest that ClpP1 is the primary isoform responsible for normal growth and virulence, but little is known about the function of ClpP2 or the context required for the formation of functional proteases. For the first time in a pathogenic bacterium, we demonstrate that both isoforms are capable of forming operative proteases. Interestingly, ClpP1 is the only homologue that possesses characteristic response to small molecule acyldepsipeptide activation. On the contrary, both ClpP1 and ClpP2 respond to cochaperone activation to degrade an ssrA-tagged substrate. These observations indicate that ClpP2 is less susceptible to acyldepsipeptide activation but retains the ability to interact with a known cochaperone. Homology models reveal no obvious characteristics that would allow one to predict less efficient acyldepsipeptide binding. The reported findings establish the uniqueness of the ClpP system in C. difficile, open new avenues of inquiry, and highlight the importance of more detailed structural, genetic, and biological characterization of the ClpP system in C. difficile.
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Affiliation(s)
- Nathan P. Lavey
- Institute for Natural Products Applications and Research Technologies and Department of Chemistry & Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Stephenson Life Sciences Research Center, Norman, Oklahoma 73019, United States
| | - Tyler Shadid
- Department of Microbiology & Immunology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, Oklahoma City, Oklahoma 73014, United States
| | - Jimmy D. Ballard
- Department of Microbiology & Immunology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, Oklahoma City, Oklahoma 73014, United States
| | - Adam S. Duerfeldt
- Institute for Natural Products Applications and Research Technologies and Department of Chemistry & Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Stephenson Life Sciences Research Center, Norman, Oklahoma 73019, United States
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27
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Fortier LC. Bacteriophages Contribute to Shaping Clostridioides (Clostridium) difficile Species. Front Microbiol 2018; 9:2033. [PMID: 30233520 PMCID: PMC6127314 DOI: 10.3389/fmicb.2018.02033] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 08/13/2018] [Indexed: 12/13/2022] Open
Abstract
Bacteriophages (phages) are bacterial viruses that parasitize bacteria. They are highly prevalent in nature, with an estimated 1031 viral particles in the whole biosphere, and they outnumber bacteria by at least 10-fold. Hence, phages represent important drivers of bacterial evolution, although our knowledge of the role played by phages in the mammalian gut is still embryonic. Several pathogens owe their virulence to the integrated phages (prophages) they harbor, which encode diverse virulence factors such as toxins. Clostridioides (Clostridium) difficile is an important opportunistic pathogen and several phages infecting this species have been described over the last decade. However, their exact contribution to the biology and virulence of this pathogen remains elusive. Current data have shown that C. difficile phages can alter virulence-associated phenotypes, in particular toxin production, by interfering with bacterial regulatory circuits through crosstalk with phage proteins for example. One phage has also been found to encode a complete binary toxin locus. Multiple regulatory genes have also been identified in phage genomes, suggesting that their impact on the host can be complex and often subtle. In this minireview, the current state of knowledge, major findings, and pending questions regarding C. difficile phages will be presented. In addition, with the apparent role played by phages in the success of fecal microbiota transplantation and the perspective of phage therapy for treatment of recurrent C. difficile infection, it has become even more crucial to understand what C. difficile phages do in the gut, how they impact their host, and how they influence the epidemiology and evolution of this clinically important pathogen.
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Affiliation(s)
- Louis-Charles Fortier
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
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28
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Fernández L, González S, Quiles-Puchalt N, Gutiérrez D, Penadés JR, García P, Rodríguez A. Lysogenization of Staphylococcus aureus RN450 by phages ϕ11 and ϕ80α leads to the activation of the SigB regulon. Sci Rep 2018; 8:12662. [PMID: 30139986 PMCID: PMC6107660 DOI: 10.1038/s41598-018-31107-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 08/10/2018] [Indexed: 12/18/2022] Open
Abstract
Staphylococcus aureus is a major opportunistic pathogen that commonly forms biofilms on various biotic and abiotic surfaces. Also, most isolates are known to carry prophages in their genomes. With this in mind, it seems that acquiring a better knowledge of the impact of prophages on the physiology of S. aureus biofilm cells would be useful for developing strategies to eliminate this pathogen. Here, we performed RNA-seq analysis of biofilm cells formed by S. aureus RN450 and two derived strains carrying prophages ϕ11 and ϕ80α. The lysogenic strains displayed increased biofilm formation and production of the carotenoid pigment staphyloxanthin. These phenotypes could be partly explained by the differences in gene expression displayed by prophage-harboring strains, namely an activation of the alternative sigma factor (SigB) regulon and downregulation of genes controlled by the Agr quorum-sensing system, especially the decreased transcription of genes encoding dispersion factors like proteases. Nonetheless, spontaneous lysis of part of the population could also contribute to the increased attached biomass. Interestingly, it appears that the phage CI protein plays a role in orchestrating these phage-host interactions, although more research is needed to confirm this possibility. Likewise, future studies should examine the impact of these two prophages during the infection.
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Affiliation(s)
- Lucía Fernández
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Río Linares s/n 33300 -, Villaviciosa, Asturias, Spain.
| | - Silvia González
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Río Linares s/n 33300 -, Villaviciosa, Asturias, Spain
| | - Nuria Quiles-Puchalt
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, G12 8TA, Glasgow, UK
| | - Diana Gutiérrez
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Río Linares s/n 33300 -, Villaviciosa, Asturias, Spain
| | - José R Penadés
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, G12 8TA, Glasgow, UK
| | - Pilar García
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Río Linares s/n 33300 -, Villaviciosa, Asturias, Spain
| | - Ana Rodríguez
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Río Linares s/n 33300 -, Villaviciosa, Asturias, Spain
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29
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Baktash A, Terveer EM, Zwittink RD, Hornung BVH, Corver J, Kuijper EJ, Smits WK. Mechanistic Insights in the Success of Fecal Microbiota Transplants for the Treatment of Clostridium difficile Infections. Front Microbiol 2018; 9:1242. [PMID: 29946308 PMCID: PMC6005852 DOI: 10.3389/fmicb.2018.01242] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Accepted: 05/23/2018] [Indexed: 12/12/2022] Open
Abstract
Fecal microbiota transplantation has proven to be an effective treatment for infections with the gram-positive enteropathogen Clostridium difficile. Despite its effectiveness, the exact mechanisms that underlie its success are largely unclear. In this review, we highlight the pleiotropic effectors that are transferred during fecal microbiota transfer and relate this to the C. difficile lifecycle. In doing so, we show that it is likely that multiple factors contribute to the elimination of symptoms of C. difficile infections after fecal microbiota transplantation.
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Affiliation(s)
- Amoe Baktash
- Clinical Microbiology Laboratory, Department of Medical Microbiology, Leiden University Medical Center, Leiden, Netherlands
| | - Elisabeth M Terveer
- Clinical Microbiology Laboratory, Department of Medical Microbiology, Leiden University Medical Center, Leiden, Netherlands.,Center for Microbiome Analyses and Therapeutics, Leiden University Medical Center, Leiden, Netherlands.,Netherlands Donor Feces Bank, Leiden, Netherlands
| | - Romy D Zwittink
- Center for Microbiome Analyses and Therapeutics, Leiden University Medical Center, Leiden, Netherlands.,Experimental Bacteriology, Department of Medical Microbiology, Leiden University Medical Center, Leiden, Netherlands
| | - Bastian V H Hornung
- Center for Microbiome Analyses and Therapeutics, Leiden University Medical Center, Leiden, Netherlands.,Experimental Bacteriology, Department of Medical Microbiology, Leiden University Medical Center, Leiden, Netherlands
| | - Jeroen Corver
- Center for Microbiome Analyses and Therapeutics, Leiden University Medical Center, Leiden, Netherlands.,Experimental Bacteriology, Department of Medical Microbiology, Leiden University Medical Center, Leiden, Netherlands
| | - Ed J Kuijper
- Clinical Microbiology Laboratory, Department of Medical Microbiology, Leiden University Medical Center, Leiden, Netherlands.,Center for Microbiome Analyses and Therapeutics, Leiden University Medical Center, Leiden, Netherlands.,Netherlands Donor Feces Bank, Leiden, Netherlands.,Experimental Bacteriology, Department of Medical Microbiology, Leiden University Medical Center, Leiden, Netherlands
| | - Wiep Klaas Smits
- Experimental Bacteriology, Department of Medical Microbiology, Leiden University Medical Center, Leiden, Netherlands
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30
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Sekulovic O, Mathias Garrett E, Bourgeois J, Tamayo R, Shen A, Camilli A. Genome-wide detection of conservative site-specific recombination in bacteria. PLoS Genet 2018; 14:e1007332. [PMID: 29621238 PMCID: PMC5903667 DOI: 10.1371/journal.pgen.1007332] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/17/2018] [Accepted: 03/24/2018] [Indexed: 12/15/2022] Open
Abstract
The ability of clonal bacterial populations to generate genomic and phenotypic heterogeneity is thought to be of great importance for many commensal and pathogenic bacteria. One common mechanism contributing to diversity formation relies on the inversion of small genomic DNA segments in a process commonly referred to as conservative site-specific recombination. This phenomenon is known to occur in several bacterial lineages, however it remains notoriously difficult to identify due to the lack of conserved features. Here, we report an easy-to-implement method based on high-throughput paired-end sequencing for genome-wide detection of conservative site-specific recombination on a single-nucleotide level. We demonstrate the effectiveness of the method by successfully detecting several novel inversion sites in an epidemic isolate of the enteric pathogen Clostridium difficile. Using an experimental approach, we validate the inversion potential of all detected sites in C. difficile and quantify their prevalence during exponential and stationary growth in vitro. In addition, we demonstrate that the master recombinase RecV is responsible for the inversion of some but not all invertible sites. Using a fluorescent gene-reporter system, we show that at least one gene from a two-component system located next to an invertible site is expressed in an on-off mode reminiscent of phase variation. We further demonstrate the applicability of our method by mining 209 publicly available sequencing datasets and show that conservative site-specific recombination is common in the bacterial realm but appears to be absent in some lineages. Finally, we show that the gene content associated with the inversion sites is diverse and goes beyond traditionally described surface components. Overall, our method provides a robust platform for detection of conservative site-specific recombination in bacteria and opens a new avenue for global exploration of this important phenomenon.
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Affiliation(s)
- Ognjen Sekulovic
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail: (OS); (AC)
| | - Elizabeth Mathias Garrett
- Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Jacob Bourgeois
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Rita Tamayo
- Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Aimee Shen
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Andrew Camilli
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail: (OS); (AC)
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31
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McClary JS, Boehm AB. Transcriptional Response of Staphylococcus aureus to Sunlight in Oxic and Anoxic Conditions. Front Microbiol 2018; 9:249. [PMID: 29599752 PMCID: PMC5863498 DOI: 10.3389/fmicb.2018.00249] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 01/31/2018] [Indexed: 12/20/2022] Open
Abstract
The transcriptional response of Staphylococcus aureus strain Newman to sunlight exposure was investigated under both oxic and anoxic conditions using RNA sequencing to gain insight into potential mechanisms of inactivation. S. aureus is a pathogenic bacterium detected at recreational beaches which can cause gastrointestinal illness and skin infections, and is of increasing public health concern. To investigate the S. aureus photostress response in oligotrophic seawater, S. aureus cultures were suspended in seawater and exposed to full spectrum simulated sunlight. Experiments were performed under oxic or anoxic conditions to gain insight into the effects of oxygen-mediated and non-oxygen-mediated inactivation mechanisms. Transcript abundance was measured after 6 h of sunlight exposure using RNA sequencing and was compared to transcript abundance in paired dark control experiments. Culturable S. aureus decayed following biphasic inactivation kinetics with initial decay rate constants of 0.1 and 0.03 m2 kJ−1 in oxic and anoxic conditions, respectively. RNA sequencing revealed that 71 genes had different transcript abundance in the oxic sunlit experiments compared to dark controls, and 18 genes had different transcript abundance in the anoxic sunlit experiments compared to dark controls. The majority of genes showed reduced transcript abundance in the sunlit experiments under both conditions. Three genes (ebpS, NWMN_0867, and NWMN_1608) were found to have the same transcriptional response to sunlight between both oxic and anoxic conditions. In the oxic condition, transcripts associated with porphyrin metabolism, nitrate metabolism, and membrane transport functions were increased in abundance during sunlight exposure. Results suggest that S. aureus responds differently to oxygen-dependent and oxygen-independent photostress, and that endogenous photosensitizers play an important role during oxygen-dependent indirect photoinactivation.
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Affiliation(s)
- Jill S McClary
- Civil and Environmental Engineering, Stanford University, Stanford, CA, United States
| | - Alexandria B Boehm
- Civil and Environmental Engineering, Stanford University, Stanford, CA, United States
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32
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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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33
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High Prevalence and Genetic Diversity of Large phiCD211 (phiCDIF1296T)-Like Prophages in Clostridioides difficile. Appl Environ Microbiol 2018; 84:AEM.02164-17. [PMID: 29150513 DOI: 10.1128/aem.02164-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 11/10/2017] [Indexed: 02/08/2023] Open
Abstract
Clostridioides difficile (formerly Clostridium difficile) is a pathogenic bacterium displaying great genetic diversity. A significant proportion of this diversity is due to the presence of integrated prophages. Here, we provide an in-depth analysis of phiCD211, also known as phiCDIF1296T, the largest phage identified in C. difficile so far, with a genome of 131 kbp. It shares morphological and genomic similarity with other large siphophages, like phage 949, infecting Lactococcus lactis, and phage c-st, infecting Clostridium botulinum A PhageTerm analysis indicated the presence of 378-bp direct terminal repeats at the phiCD211 genome termini. Among striking features of phiCD211, the presence of several transposase and integrase genes suggests past recombination events with other mobile genetic elements. Several gene products potentially influence the bacterial lifestyle and fitness, including a putative AcrB/AcrD/AcrF multidrug resistance protein, an EzrA septation ring formation regulator, and a spore protease. We also identified a CRISPR locus and a cas3 gene. We screened 2,584 C. difficile genomes available and detected 149 prophages sharing ≥80% nucleotide identity with phiCD211 (5% prevalence). Overall, phiCD211-like phages were detected in C. difficile strains corresponding to 21 different multilocus sequence type groups, showing their high prevalence. Comparative genomic analyses revealed the existence of several clusters of highly similar phiCD211-like phages. Of note, large chromosome inversions were observed in some members, as well as multiple gene insertions and module exchanges. This highlights the great plasticity and gene coding potential of the phiCD211/phiCDIF1296T genome. Our analyses also suggest active evolution involving recombination with other mobile genetic elements.IMPORTANCEClostridioides difficile is a clinically important pathogen representing a serious threat to human health. Our hypothesis is that genetic differences between strains caused by the presence of integrated prophages could explain the apparent differences observed in the virulence of different C. difficile strains. In this study, we provide a full characterization of phiCD211, also known as phiCDIF1296T, the largest phage known to infect C. difficile so far. Screening 2,584 C. difficile genomes revealed the presence of highly similar phiCD211-like phages in 5% of the strains analyzed, showing their high prevalence. Multiple-genome comparisons suggest that evolution of the phiCD211-like phage community is dynamic, and some members have acquired genes that could influence bacterial biology and fitness. Our study further supports the relevance of studying phages in C. difficile to better understand the epidemiology of this clinically important human pathogen.
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Abstract
Viruses must establish an intimate relationship with their hosts and vectors in order to infect, replicate, and disseminate; hence, viruses can be considered as symbionts with their hosts. Symbiotic relationships encompass different lifestyles, including antagonistic (or pathogenic, the most well-studied lifestyle for viruses), commensal (probably the most common lifestyle), and mutualistic (important beneficial partners). Symbiotic relationships can shape the evolution of the partners in a holobiont, and placing viruses in this context provides an important framework for understanding virus-host relationships and virus ecology. Although antagonistic relationships are thought to lead to coevolution, this is not always clear in virus-host interactions, and impacts on evolution may be complex. Commensalism implies a hitchhiking role for viruses-selfish elements just along for the ride. Mutualistic relationships have been described in detail in the past decade, and they reveal how important viruses are in considering host ecology. Ultimately, symbiosis can lead to symbiogenesis, or speciation through fusion, and the presence of large amounts of viral sequence in the genomes of everything from bacteria to humans, including some important functional genes, illustrates the significance of viral symbiogenesis in the evolution of all life on Earth.
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Affiliation(s)
- Marilyn J Roossinck
- Center for Infectious Disease Dynamics, Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, Pennsylvania 16802;
| | - Edelio R Bazán
- Center for Infectious Disease Dynamics, Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, Pennsylvania 16802;
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The Contribution of Bacteriophages to the Biology and Virulence of Pathogenic Clostridia. ADVANCES IN APPLIED MICROBIOLOGY 2017; 101:169-200. [PMID: 29050666 DOI: 10.1016/bs.aambs.2017.05.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Bacteriophages are key players in the evolution of most bacteria. Temperate phages have been associated with virulence of some of the deadliest pathogenic bacteria. Among the most notorious cases, the genes encoding the botulinum neurotoxin produced by Clostridium botulinum types C and D and the α-toxin (TcnA) produced by Clostridium novyi are both encoded within prophage genomes. Clostridium difficile is another important human pathogen and the recent identification of a complete binary toxin locus (CdtLoc) carried on a C. difficile prophage raises the potential for horizontal transfer of toxin genes by mobile genetic elements. Although the TcdA and TcdB toxins produced by C. difficile have never been found outside the pathogenicity locus (PaLoc), some prophages can still influence their production. Prophages can alter the expression of several metabolic and regulatory genes in C. difficile, as well as cell surface proteins such as CwpV, which confers phage resistance. Homologs of an Agr-like quorum sensing system have been identified in a C. difficile prophage, suggesting that it could possibly participate in cell-cell communication. Yet, other C. difficile prophages contain riboswitches predicted to recognize the secondary messenger molecule c-di-GMP involved in bacterial multicellular behaviors. Altogether, recent findings on clostridial phages underline the diversity of mechanisms and intricate relationship linking phages with their host. Here, milestone discoveries linking phages and virulence of some of the most pathogenic clostridial species will be retraced, with a focus on C. botulinum, C. novyi, C. difficile, and Clostridium perfringens phages, for which evidences are mostly available.
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Argov T, Azulay G, Pasechnek A, Stadnyuk O, Ran-Sapir S, Borovok I, Sigal N, Herskovits AA. Temperate bacteriophages as regulators of host behavior. Curr Opin Microbiol 2017; 38:81-87. [PMID: 28544996 DOI: 10.1016/j.mib.2017.05.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 05/04/2017] [Accepted: 05/08/2017] [Indexed: 12/29/2022]
Abstract
Bacteriophages are ubiquitous and affect most facets of life, from evolution of bacteria, through ecology and global biochemical cycling to human health. The interactions between phages and bacteria often lead to biological novelty and an important milestone in this process is the ability of phages to regulate their host's behavior. In this review article, we will focus on newly reported cases that demonstrate how temperate phages regulate bacterial gene expression and behavior in a variety of bacterial species, pathogenic and environmental. This regulation is mediated by diverse mechanisms such as transcription factors, sRNAs, DNA rearrangements, and even controlled bacterial lysis. The outcome is mutualistic relationships that enable adaptively enhanced communal phage-host fitness under specific conditions.
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Affiliation(s)
- Tal Argov
- Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel-Aviv 69978, Israel
| | - Gil Azulay
- Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel-Aviv 69978, Israel
| | - Anna Pasechnek
- Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel-Aviv 69978, Israel
| | - Olga Stadnyuk
- Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel-Aviv 69978, Israel
| | - Shai Ran-Sapir
- Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel-Aviv 69978, Israel
| | - Ilya Borovok
- Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel-Aviv 69978, Israel
| | - Nadejda Sigal
- Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel-Aviv 69978, Israel
| | - Anat A Herskovits
- Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel-Aviv 69978, Israel.
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Anjuwon-Foster BR, Tamayo R. A genetic switch controls the production of flagella and toxins in Clostridium difficile. PLoS Genet 2017; 13:e1006701. [PMID: 28346491 PMCID: PMC5386303 DOI: 10.1371/journal.pgen.1006701] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 04/10/2017] [Accepted: 03/16/2017] [Indexed: 12/15/2022] Open
Abstract
In the human intestinal pathogen Clostridium difficile, flagella promote adherence to intestinal epithelial cells. Flagellar gene expression also indirectly impacts production of the glucosylating toxins, which are essential to diarrheal disease development. Thus, factors that regulate the expression of the flgB operon will likely impact toxin production in addition to flagellar motility. Here, we report the identification a "flagellar switch" that controls the phase variable production of flagella and glucosylating toxins. The flagellar switch, located upstream of the flgB operon containing the early stage flagellar genes, is a 154 bp invertible sequence flanked by 21 bp inverted repeats. Bacteria with the sequence in one orientation expressed flagellum and toxin genes, produced flagella, and secreted the toxins ("flg phase ON"). Bacteria with the sequence in the inverse orientation were attenuated for flagellar and toxin gene expression, were aflagellate, and showed decreased toxin secretion ("flg phase OFF"). The orientation of the flagellar switch is reversible during growth in vitro. We provide evidence that gene regulation via the flagellar switch occurs post-transcription initiation and requires a C. difficile-specific regulatory factor to destabilize or degrade the early flagellar gene mRNA when the flagellar switch is in the OFF orientation. Lastly, through mutagenesis and characterization of flagellar phase locked isolates, we determined that the tyrosine recombinase RecV, which catalyzes inversion at the cwpV switch, is also responsible for inversion at the flagellar switch in both directions. Phase variable flagellar motility and toxin production suggests that these important virulence factors have both advantageous and detrimental effects during the course of infection.
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Affiliation(s)
- Brandon R. Anjuwon-Foster
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Rita Tamayo
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, United States of America
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Andersen JM, Shoup M, Robinson C, Britton R, Olsen KEP, Barrangou R. CRISPR Diversity and Microevolution in Clostridium difficile. Genome Biol Evol 2016; 8:2841-55. [PMID: 27576538 PMCID: PMC5630864 DOI: 10.1093/gbe/evw203] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2016] [Indexed: 12/20/2022] Open
Abstract
Virulent strains of Clostridium difficile have become a global health problem associated with morbidity and mortality. Traditional typing methods do not provide ideal resolution to track outbreak strains, ascertain genetic diversity between isolates, or monitor the phylogeny of this species on a global basis. Here, we investigate the occurrence and diversity of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated genes (cas) in C. difficile to assess the potential of CRISPR-based phylogeny and high-resolution genotyping. A single Type-IB CRISPR-Cas system was identified in 217 analyzed genomes with cas gene clusters present at conserved chromosomal locations, suggesting vertical evolution of the system, assessing a total of 1,865 CRISPR arrays. The CRISPR arrays, markedly enriched (8.5 arrays/genome) compared with other species, occur both at conserved and variable locations across strains, and thus provide a basis for typing based on locus occurrence and spacer polymorphism. Clustering of strains by array composition correlated with sequence type (ST) analysis. Spacer content and polymorphism within conserved CRISPR arrays revealed phylogenetic relationship across clades and within ST. Spacer polymorphisms of conserved arrays were instrumental for differentiating closely related strains, e.g., ST1/RT027/B1 strains and pathogenicity locus encoding ST3/RT001 strains. CRISPR spacers showed sequence similarity to phage sequences, which is consistent with the native role of CRISPR-Cas as adaptive immune systems in bacteria. Overall, CRISPR-Cas sequences constitute a valuable basis for genotyping of C. difficile isolates, provide insights into the micro-evolutionary events that occur between closely related strains, and reflect the evolutionary trajectory of these genomes.
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Affiliation(s)
- Joakim M Andersen
- Department of Food, Processing and Nutritional Sciences, North Carolina State University, NC
| | - Madelyn Shoup
- Department of Microbiology and Molecular Genetics, Michigan State University, MI
| | - Cathy Robinson
- Department of Microbiology and Molecular Genetics, Michigan State University, MI
| | - Robert Britton
- Department of Molecular Virology and Microbiology, Center for Metagenomics and Microbiome Research, Baylor College of Medicine, TX
| | - Katharina E P Olsen
- Microbial Competence Centre, Novo Nordisk, Bagsværd, Denmark (Former Employment: Department of Microbiology & Infection Control, Statens Serum Institut, Copenhagen, Denmark)
| | - Rodolphe Barrangou
- Department of Food, Processing and Nutritional Sciences, North Carolina State University, NC
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Obeng N, Pratama AA, Elsas JDV. The Significance of Mutualistic Phages for Bacterial Ecology and Evolution. Trends Microbiol 2016; 24:440-449. [DOI: 10.1016/j.tim.2015.12.009] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 12/11/2015] [Accepted: 12/21/2015] [Indexed: 12/16/2022]
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40
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Janoir C. Virulence factors of Clostridium difficile and their role during infection. Anaerobe 2016; 37:13-24. [DOI: 10.1016/j.anaerobe.2015.10.009] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/16/2015] [Accepted: 10/21/2015] [Indexed: 02/08/2023]
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Abstract
Bacteriophages (phages) are present in almost, if not all ecosystems. Some of these bacterial viruses are present as latent "prophages," either integrated within the chromosome of their host, or as episomal DNAs. Since prophages are ubiquitous throughout the bacterial world, there has been a sustained interest in trying to understand their contribution to the biology of their host. Clostridium difficile is no exception to that rule and with the recent release of hundreds of bacterial genome sequences, there has been a growing interest in trying to identify and classify these prophages. Besides their identification in bacterial genomes, there is also growing interest in determining the functionality of C. difficile prophages, i.e., their capacity to escape their host and reinfect a different strain, thereby promoting genomic evolution and horizontal transfer of genes through transduction, for example of antibiotic resistance genes. There is also some interest in using therapeutic phages to fight C. difficile infections.The objective of this chapter is to share with the broader C. difficile research community the expertise we developed in the study of C. difficile temperate phages. In this chapter, we describe a general "pipeline" comprising a series of experiments that we use in our lab to identify, induce, isolate, propagate, and characterize prophages. Our aim is to provide readers with the necessary basic tools to start studying C. difficile phages.
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Affiliation(s)
- Ognjen Sekulović
- Département de Microbiologie et d'infectiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3201 rue Jean Mignault, Sherbrooke, QC, Canada, J1E 4K8
| | - Louis-Charles Fortier
- Département de Microbiologie et d'infectiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3201 rue Jean Mignault, Sherbrooke, QC, Canada, J1E 4K8.
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Sekulovic O, Ospina Bedoya M, Fivian-Hughes AS, Fairweather NF, Fortier LC. The Clostridium difficile cell wall protein CwpV confers phase-variable phage resistance. Mol Microbiol 2015; 98:329-42. [PMID: 26179020 PMCID: PMC4737114 DOI: 10.1111/mmi.13121] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2015] [Indexed: 01/21/2023]
Abstract
Bacteriophages are present in virtually all ecosystems, and bacteria have developed multiple antiphage strategies to counter their attacks. Clostridium difficile is an important pathogen causing severe intestinal infections in humans and animals. Here we show that the conserved cell-surface protein CwpV provides antiphage protection in C. difficile. This protein, for which the expression is phase-variable, is classified into five types, each differing in their repeat-containing C-terminal domain. When expressed constitutively from a plasmid or the chromosome of locked 'ON' cells of C. difficile R20291, CwpV conferred antiphage protection. Differences in the level of phage protection were observed depending on the phage morphological group, siphophages being the most sensitive with efficiency of plaquing (EOP) values of < 5 × 10(-7) for phages ϕCD38-2, ϕCD111 and ϕCD146. Protection against the myophages ϕMMP01 and ϕCD52 was weaker, with EOP values between 9.0 × 10(-3) and 1.1 × 10(-1). The C-terminal domain of CwpV carries the antiphage activity and its deletion, or part of it, significantly reduced the antiphage protection. CwpV does not affect phage adsorption, but phage DNA replication is prevented, suggesting a mechanism reminiscent of superinfection exclusion systems normally encoded on prophages. CwpV thus represents a novel ubiquitous host-encoded and phase-variable antiphage system in C. difficile.
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Affiliation(s)
- Ognjen Sekulovic
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Maicol Ospina Bedoya
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Amanda S Fivian-Hughes
- Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, UK
| | - Neil F Fairweather
- Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, UK
| | - Louis-Charles Fortier
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
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