1
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Colomer-Winter C, Yong AMH, Chong KKL, Veleba M, Choo PY, Gao IH, Matysik A, Ho FK, Chen SL, Kline KA. The HtrA chaperone monitors sortase-assembled pilus biogenesis in Enterococcus faecalis. PLoS Genet 2024; 20:e1011071. [PMID: 39102428 PMCID: PMC11326707 DOI: 10.1371/journal.pgen.1011071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 08/15/2024] [Accepted: 07/09/2024] [Indexed: 08/07/2024] Open
Abstract
Sortase-assembled pili contribute to virulence in many Gram-positive bacteria. In Enterococcus faecalis, the endocarditis and biofilm-associated pilus (Ebp) is polymerized on the membrane by sortase C (SrtC) and attached to the cell wall by sortase A (SrtA). In the absence of SrtA, polymerized pili remain anchored to the membrane (i.e. off-pathway). Here we show that the high temperature requirement A (HtrA) bifunctional chaperone/protease of E. faecalis is a quality control system that clears aberrant off-pathway pili from the cell membrane. In the absence of HtrA and SrtA, accumulation of membrane-bound pili leads to cell envelope stress and partially induces the regulon of the ceftriaxone resistance-associated CroRS two-component system, which in turn causes hyper-piliation and cell morphology alterations. Inactivation of croR in the OG1RF ΔsrtAΔhtrA background partially restores the observed defects of the ΔsrtAΔhtrA strain, supporting a role for CroRS in the response to membrane perturbations. Moreover, absence of SrtA and HtrA decreases basal resistance of E. faecalis against cephalosporins and daptomycin. The link between HtrA, pilus biogenesis and the CroRS two-component system provides new insights into the E. faecalis response to endogenous membrane perturbations.
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Affiliation(s)
- Cristina Colomer-Winter
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Adeline M H Yong
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Kelvin K L Chong
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Mark Veleba
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Pei Yi Choo
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Iris Hanxing Gao
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Artur Matysik
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Foo Kiong Ho
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Swaine L Chen
- Genome Institute of Singapore, Agency for Science, Technology, and Research, Genome #02-01, Singapore, Singapore
| | - Kimberly A Kline
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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2
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Sivaramalingam SS, Jothivel D, Govindarajan DK, Kadirvelu L, Sivaramakrishnan M, Chithiraiselvan DD, Kandaswamy K. Structural and functional insights of sortases and their interactions with antivirulence compounds. Curr Res Struct Biol 2024; 8:100152. [PMID: 38989133 PMCID: PMC11231552 DOI: 10.1016/j.crstbi.2024.100152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 05/18/2024] [Accepted: 06/11/2024] [Indexed: 07/12/2024] Open
Abstract
Sortase proteins play a crucial role as integral membrane proteins in anchoring bacterial surface proteins by recognizing them through a Cell-Wall Sorting (CWS) motif and cleaving them at specific sites before initiating pilus assembly. Both sortases and their substrate proteins are major virulence factors in numerous Gram-positive pathogens, making them attractive targets for antimicrobial intervention. Recognizing the significance of virulence proteins, a comprehensive exploration of their structural and functional characteristics is essential to enhance our understanding of pilus assembly in diverse Gram-positive bacteria. Therefore, this review article discusses the structural features of different classes of sortases and pilin proteins, primarily serving as substrates for sortase-assembled pili. Moreover, it thoroughly examines the molecular-level interactions between sortases and their inhibitors, providing insights from both structural and functional perspectives. In essence, this review article will provide a contemporary and complete understanding of both sortase pathways and various strategies to target them effectively to counteract the virulence.
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Affiliation(s)
- Sowmiya Sri Sivaramalingam
- Research Center for Excellence in Microscopy, Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, 641049, Tamil Nadu, India
| | - Deepsikha Jothivel
- Research Center for Excellence in Microscopy, Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, 641049, Tamil Nadu, India
| | - Deenadayalan Karaiyagowder Govindarajan
- Research Center for Excellence in Microscopy, Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, 641049, Tamil Nadu, India
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore
| | - Lohita Kadirvelu
- Research Center for Excellence in Microscopy, Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, 641049, Tamil Nadu, India
| | - Muthusaravanan Sivaramakrishnan
- Research Center for Excellence in Microscopy, Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, 641049, Tamil Nadu, India
- Department of Biotechnology, Mepco Schlenk Engineering College, Tamil Nadu, India
| | - Dhivia Dharshika Chithiraiselvan
- Research Center for Excellence in Microscopy, Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, 641049, Tamil Nadu, India
| | - Kumaravel Kandaswamy
- Research Center for Excellence in Microscopy, Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, 641049, Tamil Nadu, India
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3
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Șchiopu P, Toc DA, Colosi IA, Costache C, Ruospo G, Berar G, Gălbău ȘG, Ghilea AC, Botan A, Pană AG, Neculicioiu VS, Todea DA. An Overview of the Factors Involved in Biofilm Production by the Enterococcus Genus. Int J Mol Sci 2023; 24:11577. [PMID: 37511337 PMCID: PMC10380289 DOI: 10.3390/ijms241411577] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/08/2023] [Accepted: 07/14/2023] [Indexed: 07/30/2023] Open
Abstract
Enterococcus species are known for their ability to form biofilms, which contributes to their survival in extreme environments and involvement in persistent bacterial infections, especially in the case of multi-drug-resistant strains. This review aims to provide a comprehensive understanding of the mechanisms underlying biofilm formation in clinically important species such as Enterococcus faecalis and the less studied but increasingly multi-drug-resistant Enterococcus faecium, and explores potential strategies for their eradication. Biofilm formation in Enterococcus involves a complex interplay of genes and virulence factors, including gelatinase, cytolysin, Secreted antigen A, pili, microbial surface components that recognize adhesive matrix molecules (MSCRAMMs), and DNA release. Quorum sensing, a process of intercellular communication, mediated by peptide pheromones such as Cob, Ccf, and Cpd, plays a crucial role in coordinating biofilm development by targeting gene expression and regulation. Additionally, the regulation of extracellular DNA (eDNA) release has emerged as a fundamental component in biofilm formation. In E. faecalis, the autolysin N-acetylglucosaminidase and proteases such as gelatinase and serin protease are key players in this process, influencing biofilm development and virulence. Targeting eDNA may offer a promising avenue for intervention in biofilm-producing E. faecalis infections. Overall, gaining insights into the intricate mechanisms of biofilm formation in Enterococcus may provide directions for anti-biofilm therapeutic research, with the purpose of reducing the burden of Enterococcus-associated infections.
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Affiliation(s)
- Pavel Șchiopu
- Department of Microbiology, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
- Department of Pneumology, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400332 Cluj-Napoca, Romania
| | - Dan Alexandru Toc
- Department of Microbiology, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Ioana Alina Colosi
- Department of Microbiology, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Carmen Costache
- Department of Microbiology, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Giuseppe Ruospo
- Faculty of Medicine, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - George Berar
- Faculty of Medicine, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Ștefan-Gabriel Gălbău
- Faculty of Medicine, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Alexandra Cristina Ghilea
- Faculty of Medicine, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Alexandru Botan
- Faculty of Medicine, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Adrian-Gabriel Pană
- Department of Microbiology, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Vlad Sever Neculicioiu
- Department of Microbiology, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Doina Adina Todea
- Department of Pneumology, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400332 Cluj-Napoca, Romania
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4
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Caldwell M, Hughes M, Wei F, Ngo C, Pascua R, Pugazhendhi AS, Coathup MJ. Promising applications of D-amino acids in periprosthetic joint infection. Bone Res 2023; 11:14. [PMID: 36894568 PMCID: PMC9998894 DOI: 10.1038/s41413-023-00254-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 02/02/2023] [Accepted: 02/10/2023] [Indexed: 03/11/2023] Open
Abstract
Due to the rise in our aging population, a disproportionate demand for total joint arthroplasty (TJA) in the elderly is forecast. Periprosthetic joint infection (PJI) represents one of the most challenging complications that can occur following TJA, and as the number of primary and revision TJAs continues to rise, an increasing PJI burden is projected. Despite advances in operating room sterility, antiseptic protocols, and surgical techniques, approaches to prevent and treat PJI remain difficult, primarily due to the formation of microbial biofilms. This difficulty motivates researchers to continue searching for an effective antimicrobial strategy. The dextrorotatory-isoforms of amino acids (D-AAs) are essential components of peptidoglycan within the bacterial cell wall, providing strength and structural integrity in a diverse range of species. Among many tasks, D-AAs regulate cell morphology, spore germination, and bacterial survival, evasion, subversion, and adhesion in the host immune system. When administered exogenously, accumulating data have demonstrated that D-AAs play a pivotal role against bacterial adhesion to abiotic surfaces and subsequent biofilm formation; furthermore, D-AAs have substantial efficacy in promoting biofilm disassembly. This presents D-AAs as promising and novel targets for future therapeutic approaches. Despite their emerging antibacterial efficacy, their role in disrupting PJI biofilm formation, the disassembly of established TJA biofilm, and the host bone tissue response remains largely unexplored. This review aims to examine the role of D-AAs in the context of TJAs. Data to date suggest that D-AA bioengineering may serve as a promising future strategy in the prevention and treatment of PJI.
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Affiliation(s)
- Matthew Caldwell
- Biionix Cluster & College of Medicine, University of Central Florida, 6900 Lake Nona Blvd, Orlando, FL, 32827, USA
| | - Megan Hughes
- School of Biosciences, Cardiff University, CF10 3AT, Wales, UK
| | - Fei Wei
- Biionix Cluster & College of Medicine, University of Central Florida, 6900 Lake Nona Blvd, Orlando, FL, 32827, USA
| | - Christopher Ngo
- Biionix Cluster & College of Medicine, University of Central Florida, 6900 Lake Nona Blvd, Orlando, FL, 32827, USA
| | - Raven Pascua
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, 6900 Lake Nona Blvd, Orlando, FL, 32827, USA
| | - Abinaya Sindu Pugazhendhi
- Biionix Cluster & College of Medicine, University of Central Florida, 6900 Lake Nona Blvd, Orlando, FL, 32827, USA
| | - Melanie J Coathup
- Biionix Cluster & College of Medicine, University of Central Florida, 6900 Lake Nona Blvd, Orlando, FL, 32827, USA.
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5
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Dong J, Liu L, Chen L, Xiang Y, Wang Y, Zhao Y. The Coexistence of Bacterial Species Restructures Biofilm Architecture and Increases Tolerance to Antimicrobial Agents. Microbiol Spectr 2023; 11:e0358122. [PMID: 36847543 PMCID: PMC10100793 DOI: 10.1128/spectrum.03581-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 02/05/2023] [Indexed: 03/01/2023] Open
Abstract
Chronic infections caused by polymicrobial biofilms are often difficult to treat effectively, partially due to the elevated tolerance of polymicrobial biofilms to antimicrobial treatments. It is known that interspecific interactions influence polymicrobial biofilm formation. However, the underlying role of the coexistence of bacterial species in polymicrobial biofilm formation is not fully understood. Here, we investigated the effect of the coexistence of Enterococcus faecalis, Escherichia coli O157:H7, and Salmonella enteritidis on triple-species biofilm formation. Our results demonstrated that the coexistence of these three species enhanced the biofilm biomass and led to restructuring of the biofilm into a tower-like architecture. Furthermore, the proportions of polysaccharides, proteins, and eDNAs in the extracellular matrix (ECM) composition of the triple-species biofilm were significantly changed compared to those in the E. faecalis mono-species biofilm. Finally, we analyzed the transcriptomic profile of E. faecalis in response to coexistence with E. coli and S. enteritidis in the triple-species biofilm. The results suggested that E. faecalis established dominance and restructured the triple-species biofilm by enhancing nutrient transport and biosynthesis of amino acids, upregulating central carbon metabolism, manipulating the microenvironment through "biological weapons," and activating versatile stress response regulators. Together, the results of this pilot study reveal the nature of E. faecalis-harboring triple-species biofilms with a static biofilm model and provide novel insights for further understanding interspecies interactions and the clinical treatment of polymicrobial biofilms. IMPORTANCE Bacterial biofilms possess distinct community properties that affect various aspects of our daily lives. In particular, biofilms exhibit increased tolerance to chemical disinfectants, antimicrobial agents, and host immune responses. Multispecies biofilms are undoubtedly the dominant form of biofilms in nature. Thus, there is a pressing need for more research directed at delineating the nature of multispecies biofilms and the effects of the properties on the development and survival of the biofilm community. Here, we address the effects of the coexistence of Enterococcus faecalis, Escherichia coli, and Salmonella enteritidis on triple-species biofilm formation with a static model. In combination with transcriptomic analyses, this pilot study explores the potential underlying mechanisms that lead to the dominance of E. faecalis in triple-species biofilms. Our findings provide novel insights into the nature of triple-species biofilms and indicate that the composition of multispecies biofilms should be a key consideration when determining antimicrobial treatments.
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Affiliation(s)
- Jiajun Dong
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China
- Key Laboratory for Animal-derived Food Safety of Henan Province, Zhengzhou, Henan, China
| | - Luhan Liu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China
- Key Laboratory for Animal-derived Food Safety of Henan Province, Zhengzhou, Henan, China
| | - Liying Chen
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China
- Key Laboratory for Animal-derived Food Safety of Henan Province, Zhengzhou, Henan, China
| | - Yuqiang Xiang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China
- Key Laboratory for Animal-derived Food Safety of Henan Province, Zhengzhou, Henan, China
| | - Yabin Wang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China
- Key Laboratory for Animal-derived Food Safety of Henan Province, Zhengzhou, Henan, China
| | - Youbao Zhao
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China
- Key Laboratory for Animal-derived Food Safety of Henan Province, Zhengzhou, Henan, China
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6
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Lin PY, Chan SY, Stern A, Chen PH, Yang HC. Epidemiological profiles and pathogenicity of Vancomycin-resistant Enterococcus faecium clinical isolates in Taiwan. PeerJ 2023; 11:e14859. [PMID: 36855433 PMCID: PMC9968458 DOI: 10.7717/peerj.14859] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 01/16/2023] [Indexed: 02/25/2023] Open
Abstract
The emerging Vancomycin-resistant Enterococcus faecium (VRE-fm) is an opportunistic pathogen causing nosocomial infections. The identification of VRE-fm is important for successful prevention and control in healthcare settings. VRE-fm clinical isolates obtained from regional hospitals in northern Taiwan were characterized for antimicrobial susceptibility, virulence genes and biofilm production. Most isolates exhibited multi-drug resistance and carried the virulence genes, esp and hyl. While all isolates produce biofilms, those isolates that carried esp exhibited greater biofilm production. Isolates with different virulence gene carriages were examined for pathogenicity by using a nematode model, Caenorhabditis elegans, for determining microbial-host interactions. The survival assay showed that C. elegans was susceptible to Linezolid-resistant VRE-fm isolates with hyl. Combining the molecular epidemiological profiles regarding pathogenesis in C. elegans can serve as a guide for physicians in limiting opportunistic infections caused by VRE-fm.
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Affiliation(s)
- Pei-Yun Lin
- Department of Laboratory, Taipei City Hospital, Yang-Ming Branch, Taipei, Taiwan
| | - Shang-Yih Chan
- Department of Internal Medicine, Taipei City Hospital, Yang-Ming Branch, Taipei, Taiwan,Department of Exercise and Health Sciences, University of Taipei, Taipei, Taiwan,Department of Health Care Management, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan
| | - Arnold Stern
- Grossman School of Medicine, New York University, New York, USA
| | - Po-Hsiang Chen
- Research Center for Chinese Herbal Medicine, Graduate Institute of Health Industry Technology, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan
| | - Hung-Chi Yang
- Department of Medical Laboratory Science and Biotechnology, Yuanpei University of Medical Technology, Hsinchu, Taiwan
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7
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Deng Z, Lin B, Liu F, Zhao W. Role of Enterococcus faecalis in refractory apical periodontitis: from pathogenicity to host cell response. J Oral Microbiol 2023; 15:2184924. [PMID: 36891193 PMCID: PMC9987735 DOI: 10.1080/20002297.2023.2184924] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023] Open
Abstract
BACKGROUND Refractory apical periodontitis (RAP) is an oral infectious disease characterised by persistent inflammation, progressive alveolar bone destruction, and delayed bone healing. RAP has received increasing attention, because it cannot be cured after repeated root canal therapies. The aetiology of RAP is related to the complex interplay between the pathogen and its host. However, the exact pathogenesis of RAP remains unclarified and includes several factors, such as microorganism immunogenicity, host immunity and inflammation, and tissue destruction and repair. Enterococcus faecalis is the dominant pathogen involved in RAP, and has evolved multiple strategies to ensure survival, which cause persistent intraradicular and extraradicular infections. OBJECTIVE To review the crucial role of E. faecalis in the pathogenesis of RAP, and open new avenues for prevention and treatment of RAP. METHODS The PubMed and Web of Science databases were searched for pertinent publications, employing the search terms "Enterococcus faecalis", "refractory apical periodontitis", "persistent periapical periodontitis", "pathogenicity", "virulence", "biofilm formation", "dentine tubule", "immune cell", "macrophage", and "osteoblast". RESULTS AND CONCLUSION Besides its high pathogenicity due to various virulence mechanisms, E. faecalis modulates the macrophage and osteoblast responses, including regulated cell death, cell polarisation, cell differentiation, and inflammatory response. An in-depth understanding of the multifaceted host cell responses modulated by E. faecalis will help to design potential future therapeutic strategies and overcome the challenges of sustained infection and delayed tissue healing in RAP.
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Affiliation(s)
- Zilong Deng
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,School of Stomatology, Southern Medical University, Guangzhou, China
| | - Binbin Lin
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,School of Stomatology, Southern Medical University, Guangzhou, China
| | - Fan Liu
- School of Stomatology, Southern Medical University, Guangzhou, China
| | - Wanghong Zhao
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,School of Stomatology, Southern Medical University, Guangzhou, China
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8
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Choo PY, Wang CY, VanNieuwenhze MS, Kline KA. Spatial and temporal localization of cell wall associated pili in Enterococcus faecalis. Mol Microbiol 2023; 119:1-18. [PMID: 36420961 PMCID: PMC10107303 DOI: 10.1111/mmi.15008] [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: 05/16/2022] [Revised: 11/15/2022] [Accepted: 11/17/2022] [Indexed: 11/27/2022]
Abstract
Enterococcus faecalis virulence requires cell wall-associated proteins, including the sortase-assembled endocarditis and biofilm associated pilus (Ebp), important for biofilm formation in vitro and in vivo. The current paradigm for sortase-assembled pilus biogenesis in Gram-positive bacteria is that sortases attach substrates to lipid II peptidoglycan (PG) precursors, prior to their incorporation into the growing cell wall. Contrary to prevailing dogma, by following the distribution of Ebp and PG throughout the E. faecalis cell cycle, we found that cell surface Ebp do not co-localize with newly synthesized PG. Instead, surface-exposed Ebp are localized to the older cell hemisphere and excluded from sites of new PG synthesis at the septum. Moreover, Ebp deposition on the younger hemisphere of the E. faecalis diplococcus appear as foci adjacent to the nascent septum. We propose a new model whereby sortase substrate deposition can occur on older PG rather than at sites of new cell wall synthesis. Consistent with this model, we demonstrate that sequestering lipid II to block PG synthesis via ramoplanin, does not impact new Ebp deposition at the cell surface. These data support an alternative paradigm for sortase substrate deposition in E. faecalis, in which Ebp are anchored directly onto uncrosslinked cell wall, independent of new PG synthesis.
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Affiliation(s)
- Pei Yi Choo
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Charles Y Wang
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | | | - Kimberly A Kline
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
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9
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Wong JJ, Ho FK, Choo PY, Chong KKL, Ho CMB, Neelakandan R, Keogh D, Barkham T, Chen J, Liu CF, Kline KA. Escherichia coli BarA-UvrY regulates the pks island and kills Staphylococci via the genotoxin colibactin during interspecies competition. PLoS Pathog 2022; 18:e1010766. [PMID: 36067266 PMCID: PMC9481169 DOI: 10.1371/journal.ppat.1010766] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 09/16/2022] [Accepted: 07/25/2022] [Indexed: 11/19/2022] Open
Abstract
Wound infections are often polymicrobial in nature, biofilm associated and therefore tolerant to antibiotic therapy, and associated with delayed healing. Escherichia coli and Staphylococcus aureus are among the most frequently cultured pathogens from wound infections. However, little is known about the frequency or consequence of E. coli and S. aureus polymicrobial interactions during wound infections. Here we show that E. coli kills Staphylococci, including S. aureus, both in vitro and in a mouse excisional wound model via the genotoxin, colibactin. Colibactin biosynthesis is encoded by the pks locus, which we identified in nearly 30% of human E. coli wound infection isolates. While it is not clear how colibactin is released from E. coli or how it penetrates target cells, we found that the colibactin intermediate N-myristoyl-D-Asn (NMDA) disrupts the S. aureus membrane. We also show that the BarA-UvrY two component system (TCS) senses the environment created during E. coli and S. aureus mixed species interaction, leading to upregulation of pks island genes. Further, we show that BarA-UvrY acts via the carbon storage global regulatory (Csr) system to control pks expression. Together, our data demonstrate the role of colibactin in interspecies competition and show that it is regulated by BarA-UvrY TCS during interspecies competition. Wound infections are often polymicrobial in nature and are associated with poor disease prognoses. Escherichia coli and Staphylococcus aureus are among the top five most cultured pathogens from wound infections. However, little is known about the polymicrobial interactions between E. coli and S. aureus during wound infections. In this study, we show that E. coli kills S. aureus both in vitro and in a mouse excisional wound model via the genotoxin, colibactin. We also show that the BarA-UvrY two component system (TCS) regulates the pks island during this mixed species interaction, acting through the carbon storage global regulatory (Csr) system to control colibactin production. Together, our data demonstrate the role of colibactin in interspecies competition and show that it is regulated by BarA-UvrY TCS during interspecies competition.
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Affiliation(s)
- Jun Jie Wong
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- Singapore Centre for Environmental Life Sciences Engineering, Interdisciplinary Graduate Programme, Nanyang Technological University, Singapore, Singapore
| | - Foo Kiong Ho
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Pei Yi Choo
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Kelvin K. L. Chong
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- Nanyang Technological University Institute for Health Technologies, Interdisciplinary Graduate School, Nanyang Technological University, Singapore, Singapore
| | - Chee Meng Benjamin Ho
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, Singapore
| | - Ramesh Neelakandan
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Damien Keogh
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Timothy Barkham
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Laboratory Medicine, Tan Tock Seng Hospital, Singapore, Singapore
| | - John Chen
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Chuan Fa Liu
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Kimberly A. Kline
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
- * E-mail:
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10
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Venkateswaran P, Lakshmanan PM, Muthukrishnan S, Bhagavathi H, Vasudevan S, Neelakantan P, Solomon AP. Hidden agenda of Enterococcus faecalis lifestyle transition: planktonic to sessile state. Future Microbiol 2022; 17:1051-1069. [PMID: 35899477 DOI: 10.2217/fmb-2021-0212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Enterococcus faecalis, a human gastrointestinal tract commensal, is known to cause nosocomial infections. Interestingly, the pathogen's host colonization and persistent infections are possibly linked to its lifestyle changes from planktonic to sessile state. Also, the multidrug resistance and survival fitness acquired in the sessile stage of E. faecalis has challenged treatment regimes. This situation exists because of the critical role played by several root genes and their molecular branches, which are part of quorum sensing, aggregation substance, surface adhesions, stress-related response and sex pheromones in the sessile state. It is therefore imperative to decode the hidden agenda of E. faecalis and understand the significant factors influencing biofilm formation. This would, in turn, augment the development of novel strategies to tackle E. faecalis infections.
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Affiliation(s)
- Parvathy Venkateswaran
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical & Biotechnology, SASTRA Deemed to be University, Thanjavur, 613401, India
| | - Priya M Lakshmanan
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical & Biotechnology, SASTRA Deemed to be University, Thanjavur, 613401, India
| | - Sudhiksha Muthukrishnan
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical & Biotechnology, SASTRA Deemed to be University, Thanjavur, 613401, India
| | - Hema Bhagavathi
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical & Biotechnology, SASTRA Deemed to be University, Thanjavur, 613401, India
| | - Sahana Vasudevan
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical & Biotechnology, SASTRA Deemed to be University, Thanjavur, 613401, India
| | | | - Adline P Solomon
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical & Biotechnology, SASTRA Deemed to be University, Thanjavur, 613401, India
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11
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Xie J, Meng Z, Han X, Li S, Ma X, Chen X, Liang Y, Deng X, Xia K, Zhang Y, Zhu H, Fu T. Cholesterol Microdomain Enhances the Biofilm Eradication of Antibiotic Liposomes. Adv Healthc Mater 2022; 11:e2101745. [PMID: 35037424 DOI: 10.1002/adhm.202101745] [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: 08/21/2021] [Revised: 01/09/2022] [Indexed: 11/06/2022]
Abstract
Resistance and tolerance of biofilms to antibiotics is the greatest challenge in the treatment of bacterial infections. Therefore, developing an effective strategy against biofilms is a top priority. Liposomes are widely used as antibiotic drug carriers; however, common liposomes lack affinity for biofilms. Herein, biofilm-targeted antibiotic liposomes are created by simply adjusting their cholesterol content. The tailored liposomes exhibit significantly enhanced bacterial inhibition and biofilm eradication effects that are positively correlated with the cholesterol content of liposomes. The experiments further demonstrate that this enhanced effect can be ascribed to the effective drug release through the pores, which are formed by the combination of cholesterol microdomains in liposomal lipid bilayers with membrane-damaged toxins in biofilms. Consequently, liposome encapsulation with a high cholesterol concentration improves noticeably the pharmacodynamics and biocompatibility of antibiotics after pulmonary administration. This work may provide a new direction for the development of antibiofilm formulations that can be widely used for the treatment of infections caused by bacterial biofilms.
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Affiliation(s)
- Jianjun Xie
- School of Pharmacy Nanjing University of Chinese Medicine Nanjing 210023 China
| | - Zhiping Meng
- School of Pharmacy Nanjing University of Chinese Medicine Nanjing 210023 China
| | - Xingxing Han
- School of Pharmacy Nanjing University of Chinese Medicine Nanjing 210023 China
| | - Sipan Li
- School of Pharmacy Nanjing University of Chinese Medicine Nanjing 210023 China
| | - Xinai Ma
- School of Pharmacy Nanjing University of Chinese Medicine Nanjing 210023 China
| | - Xuanyu Chen
- School of Pharmacy Nanjing University of Chinese Medicine Nanjing 210023 China
| | - Yinmei Liang
- School of Pharmacy Nanjing University of Chinese Medicine Nanjing 210023 China
| | - Xiaomin Deng
- School of Pharmacy Nanjing University of Chinese Medicine Nanjing 210023 China
| | - Kexin Xia
- School of Pharmacy Nanjing University of Chinese Medicine Nanjing 210023 China
| | - Yue Zhang
- School of Pharmacy Nanjing University of Chinese Medicine Nanjing 210023 China
| | - Huaxu Zhu
- School of Pharmacy Nanjing University of Chinese Medicine Nanjing 210023 China
| | - Tingming Fu
- School of Pharmacy Nanjing University of Chinese Medicine Nanjing 210023 China
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12
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Tong Q, Li T, Jiang L, Wang Z, Qian Y. Nanoparticle, a promising therapeutic strategy for the treatment of infective endocarditis. Anatol J Cardiol 2022; 26:90-99. [PMID: 35190356 PMCID: PMC8878918 DOI: 10.5152/anatoljcardiol.2021.867] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/05/2021] [Indexed: 07/30/2023] Open
Abstract
Infective endocarditis (IE) has been recognized as a biofilm-related disease caused by pathogenic microorganisms, such as bacteria and fungi that invade and damage the heart valves and endocardium. There are many difficulties and challenges in the antimicrobial treatment of IE, including multi-drug resistant pathogens, large dose of drug administration with following side effects, and poor prognosis. For the past few years, the development of nanotechnology has promoted the use of nanoparticles as antimicrobial nano-pharmaceuticals or novel drug delivery systems (NDDS) in antimicrobial therapy for chronic infections and biofilm-related infectious disease as these molecules exhibit several advantages. Therefore, nanoparticles have a potential role to play in solving problems in the treatment of IE, including improving antimicrobial activity, increasing drug bioavailability, minimizing frequency of drug administration, and preventing side effects. In this article, we review the latest advances in nanoparticles against drug-resistant bacteria in biofilm and recommends nanoparticles as an alternative strategy to the antibiotic treatment of IE.
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Affiliation(s)
- Qi Tong
- Department of Cardiovascular Surgery, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University; Chengdu-China
| | - Tao Li
- Department of Cardiovascular Surgery, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University; Chengdu-China
| | - Lu Jiang
- Department of Cardiovascular Surgery, Sichuan Provincial People's University of Electronic Science and Technology of China; Chengdu-China
| | - Zhengjie Wang
- Department of Cardiovascular Surgery, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University; Chengdu-China
| | - Yongjun Qian
- Department of Cardiovascular Surgery, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University; Chengdu-China
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13
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Dong J, Zhang L, He H, Jin Y, Wang Y, Chen L. Prevalence and conservation of ebp genes in Enterococcus faecalis originated from animals. J Appl Microbiol 2021; 132:3293-3301. [PMID: 34897902 DOI: 10.1111/jam.15409] [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: 08/09/2021] [Revised: 12/03/2021] [Accepted: 12/08/2021] [Indexed: 11/26/2022]
Abstract
AIMS The study aimed to investigate the prevalence and conservation of endocarditis and biofilm-associated pili (ebp) genes in Enterococcus faecalis originated from animals and the potential of developing Ebp into serological diagnostic and vaccine targets. METHODS AND RESULTS In this work, we investigated the prevalence and conservation of ebp genes in 116 strains of E. faecalis originated from animals by using PCR and sequencing methods. The results demonstrated the presence of ebp genes (ebpA, ebpB and ebpC) in all 116 strains of E. faecalis, and their amino acid homology ranges from 96.6% to 100.0%. Moreover, the phylogenetic analysis of ebp genes in all 164 E. faecalis strains (including 48 reference strains) revealed that ebp genes show no significant correlation with species origins and regions of E. faecalis, indicating that ebp genes are conserved features in E. faecalis, even though it evolved under environmental pressures from various regions and origins. Given that EbpA1 as a part of the adhesion protein EbpA has immunogenicity, we further determined whether amino acid mutations have effects on the function and 3D structure of EbpA1. The results showed that two of the 26 mutations, at amino acids positions 178 and 387, had deleterious effects on the biological function of EbpA1 protein, while all mutations had no effect on the 3D structure or binding pockets of EbpA1 protein. CONCLUSIONS This study suggests that ebp genes are prevalent and conserved in E. faecalis originated from diverse animal origins and regions. EbpA1 could be a potential target for serological diagnosis and vaccine development to prevent E. faecalis infection. SIGNIFICANCE AND IMPACT OF STUDY The current study provides data to support further research on Ebp as a serological diagnostic and vaccine target against E. faecalis infection.
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Affiliation(s)
- Jiajun Dong
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, Henan, China.,Key Laboratory for Animal-derived Food Safety of Henan Province, Zhengzhou, 450002, Henan, China
| | - Liujun Zhang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, Henan, China
| | - Hengxu He
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, Henan, China.,Key Laboratory for Animal-derived Food Safety of Henan Province, Zhengzhou, 450002, Henan, China
| | - Yue Jin
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, Henan, China.,Key Laboratory for Animal-derived Food Safety of Henan Province, Zhengzhou, 450002, Henan, China
| | - Yabin Wang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, Henan, China.,Key Laboratory for Animal-derived Food Safety of Henan Province, Zhengzhou, 450002, Henan, China
| | - Liying Chen
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, Henan, China.,Key Laboratory for Animal-derived Food Safety of Henan Province, Zhengzhou, 450002, Henan, China
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14
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Kuang X, Zhang J, Peng X, Xie Q, Li J, Zhou X, Luo Y, Xu X. A small molecule II-6s inhibits Enterococcus faecalis biofilms. J Oral Microbiol 2021; 13:1978756. [PMID: 34552703 PMCID: PMC8451641 DOI: 10.1080/20002297.2021.1978756] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Background Limitations of current intracanal irrigants such as sodium hypochlorite (NaOCl) and chlorhexidine (CHX) necessitate the development of novel antimicrobial agents to control endodontic infection. Aim This study investigated the antimicrobial activities of a small molecule II-6s against Enterococcus faecalis associated with endodontic diseases. Methods The susceptibility of E. faecalis to II-6s was evaluated by the microdilution method and time-kill assay. Microbial resistance was assessed by repeated exposure of E. faecalis to II-6s. Cytotoxicity of II-6s was evaluated by CCK-8 assay. Virulence gene expression of the II-6s-treated E. faecalis cells was measured by RT-qPCR. Bacterial reductions in the dentinal tubules were further assessed by confocal laser scanning microscopy. Results II-6s exhibited potent antimicrobial activity against E. faecalis and down-regulated virulence-associated genes in E. faecalis. II-6s induced no drug resistance in E. faecalis with lower cytotoxicity as compared to NaOCl and CHX. More importantly, 0.003125% II-6s exhibited significant bactericidal effect against E. faecalis residing in the dentinal tubules, which was comparable to 5.25% NaOCl and 2% CHX. Conclusions II-6s has excellent antimicrobial activity, moderate cytotoxicity and induces no drug resistance, and thus is a promising agent for the treatment of endodontic infection.
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Affiliation(s)
- Xinyi Kuang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jin Zhang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xian Peng
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Qian Xie
- Department of Endodontics, College of Dentistry, University of Illinois at Chicago, Chicago, ChicagoU.S.A
| | - Jiyao Li
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Youfu Luo
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Xin Xu
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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15
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Lengliz S, Abbassi MS, Rehaiem A, Ben Chehida N, Najar T. Characterization of bacteriocinogenic Enterococcus isolates from wild and laboratory rabbits for the selection of autochthonous probiotic strains in Tunisia. J Appl Microbiol 2021; 131:1474-1486. [PMID: 33629433 DOI: 10.1111/jam.15047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 01/06/2021] [Accepted: 02/22/2021] [Indexed: 01/22/2023]
Abstract
AIM The objective of this study was to characterize lactic acid bacteria (LAB) from rabbits to be used as potential autochthonous probiotic. METHODS AND RESULTS Fifteen faecal samples were collected from wild and laboratory rabbits. One hundred and eight isolates were collected and tested for their inhibitory power against eight pathogenic bacteria. Among them, 43 Enterococcus isolates were able to inhibit at least one pathogen. Enterocine genes entA, entB and entP were detected in 14, 17 and 22 isolates, respectively. These isolates were tested for their antibiotic susceptibility and genes encoding virulence factors. Relevant phenotypes of antibiotic resistance were observed especially for ampicillin, vancomycin and linezolid. The following virulence genes were detected (number of positive isolates): hyl (5), esp (8), gelE (30), agg (2), ace (21), efa (6), CylLL/s (5), cob (26), cpd (32) and ccf (33). Five isolates were considered as safe and showed tolerance to both acid and bile salt. CONCLUSION Bacteriocinogenic enterococci isolates from rabbits may show relevant resistance phenotypes and virulence factors. In addition, one Enterococcus durans isolate presents promising autochthonous probiotic candidate. SIGNIFICANCE AND IMPACT OF THE STUDY This study reveals interesting properties for E. durans isolate and supports their utilization as autochthonous probiotic in rabbit husbandry.
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Affiliation(s)
- S Lengliz
- Laboratory of Materials, Molecules and Application, Preparatory Institute for Scientific and Technical Studies LR11ES22, University of Carthage, Tunis, Tunisia.,Institute of Veterinary Research of Tunisia, University of Tunis El Manar, Tunis, Tunisia
| | - M S Abbassi
- Institute of Veterinary Research of Tunisia, University of Tunis El Manar, Tunis, Tunisia.,Faculty of Medecine of Tunis, Research Laboratory "Antimicrobial Resistance" LR99ES09, University of Tunis El Manar, Tunis, Tunisia
| | - A Rehaiem
- Faculty of Medecine of Tunis, Research Laboratory "Antimicrobial Resistance" LR99ES09, University of Tunis El Manar, Tunis, Tunisia.,Laboratory of Microbiology, Charles Nicolle Hospital, Tunis, Tunisia
| | - N Ben Chehida
- Institute of Veterinary Research of Tunisia, University of Tunis El Manar, Tunis, Tunisia
| | - T Najar
- Laboratory of Materials, Molecules and Application, Preparatory Institute for Scientific and Technical Studies LR11ES22, University of Carthage, Tunis, Tunisia.,Department of Animal Sciences, National Institute of Agronomy of Tunisia, University of Carthage, Tunis, Tunisia
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16
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Multiplex CRISPRi System Enables the Study of Stage-Specific Biofilm Genetic Requirements in Enterococcus faecalis. mBio 2020; 11:mBio.01101-20. [PMID: 33082254 PMCID: PMC7587440 DOI: 10.1128/mbio.01101-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Enterococcus faecalis causes multidrug-resistant life-threatening infections and is often coisolated with other pathogenic bacteria from polymicrobial biofilm-associated infections. Genetic tools to dissect complex interactions in mixed microbial communities are largely limited to transposon mutagenesis and traditional time- and labor-intensive allelic-exchange methods. Built upon streptococcal dCas9, we developed an easily modifiable, inducible CRISPRi system for E. faecalis that can efficiently silence single and multiple genes. This system can silence genes involved in biofilm formation and antibiotic resistance and can be used to interrogate gene essentiality. Uniquely, this tool is optimized to study genes important for biofilm initiation, maturation, and maintenance and can be used to perturb preformed biofilms. This system will be valuable to rapidly and efficiently investigate a wide range of aspects of complex enterococcal biology. Enterococcus faecalis is an opportunistic pathogen, which can cause multidrug-resistant life-threatening infections. Gaining a complete understanding of enterococcal pathogenesis is a crucial step in identifying a strategy to effectively treat enterococcal infections. However, bacterial pathogenesis is a complex process often involving a combination of genes and multilevel regulation. Compared to established knockout methodologies, CRISPR interference (CRISPRi) approaches enable the rapid and efficient silencing of genes to interrogate gene products and pathways involved in pathogenesis. As opposed to traditional gene inactivation approaches, CRISPRi can also be quickly repurposed for multiplexing or used to study essential genes. Here, we have developed a novel dual-vector nisin-inducible CRISPRi system in E. faecalis that can efficiently silence via both nontemplate and template strand targeting. Since the nisin-controlled gene expression system is functional in various Gram-positive bacteria, the developed CRISPRi tool can be extended to other genera. This system can be applied to study essential genes, genes involved in antimicrobial resistance, and genes involved in biofilm formation and persistence. The system is robust and can be scaled up for high-throughput screens or combinatorial targeting. This tool substantially enhances our ability to study enterococcal biology and pathogenesis, host-bacterium interactions, and interspecies communication.
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17
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Alhajjar N, Chatterjee A, Spencer BL, Burcham LR, Willett JLE, Dunny GM, Duerkop BA, Doran KS. Genome-Wide Mutagenesis Identifies Factors Involved in Enterococcus faecalis Vaginal Adherence and Persistence. Infect Immun 2020; 88:e00270-20. [PMID: 32778611 PMCID: PMC7504943 DOI: 10.1128/iai.00270-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 07/26/2020] [Indexed: 02/08/2023] Open
Abstract
Enterococcus faecalis is a Gram-positive commensal bacterium native to the gastrointestinal tract and an opportunistic pathogen of increasing clinical concern. E. faecalis also colonizes the female reproductive tract, and reports suggest vaginal colonization increases following antibiotic treatment or in patients with aerobic vaginitis. Currently, little is known about specific factors that promote E. faecalis vaginal colonization and subsequent infection. We modified an established mouse vaginal colonization model to explore E. faecalis vaginal carriage and demonstrate that both vancomycin-resistant and -sensitive strains colonize the murine vaginal tract. Following vaginal colonization, we observed E. faecalis in vaginal, cervical, and uterine tissue. A mutant lacking endocarditis- and biofilm-associated pili (Ebp) exhibited a decreased ability to associate with human vaginal and cervical cells in vitro but did not contribute to colonization in vivo Thus, we screened a low-complexity transposon (Tn) mutant library to identify novel genes important for E. faecalis colonization and persistence in the vaginal tract. This screen revealed 383 mutants that were underrepresented during vaginal colonization at 1, 5, and 8 days postinoculation compared to growth in culture medium. We confirmed that mutants deficient in ethanolamine catabolism or in the type VII secretion system were attenuated in persisting during vaginal colonization. These results reveal the complex nature of vaginal colonization and suggest that multiple factors contribute to E. faecalis persistence in the reproductive tract.
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Affiliation(s)
- Norhan Alhajjar
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Anushila Chatterjee
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Brady L Spencer
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Lindsey R Burcham
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Julia L E Willett
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Gary M Dunny
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Breck A Duerkop
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Kelly S Doran
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
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18
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Liu F, Jin P, Gong H, Sun Z, Du L, Wang D. Antibacterial and antibiofilm activities of thyme oil against foodborne multiple antibiotics-resistant Enterococcus faecalis. Poult Sci 2020; 99:5127-5136. [PMID: 32988551 PMCID: PMC7598324 DOI: 10.1016/j.psj.2020.06.067] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 06/16/2020] [Accepted: 06/17/2020] [Indexed: 01/09/2023] Open
Abstract
The inhibitory and bactericidal activities of thyme oil against the foodborne multiple antibiotics-resistant Enterococcus faecalis biofilm were evaluated in this study. Gas chromatography-mass spectrometry revealed that more than 70% of the composition of thyme oil is thymol. Crystal violet staining assay showed that 128 and 256 μg/mL thyme oil significantly inhibited the biofilm formation of E. faecalis. The cell adherence of E. faecalis, as shown by its swimming and swarming motilities, was reduced by thyme oil. The exopolysaccharide (EPS) quantification assay showed that thyme oil inhibited the EPS synthesis in E. faecalis biofilms. The 3D-view observations through confocal laser scanning and scanning electron microscopy suggested that cell adherence and biofilm thickness were decreased in thyme oil–treated biofilms. Quantitative real-time analyses showed that the transcription of ebp and epa gene clusters, which were related to cell mobility and EPS production, was inhibited by thyme oil. Thus, thyme oil effectively inhibited the biofilm formation of E. faecalis by affecting cell adherence and EPS synthesis. Furthermore, 2,048 and 4,096 μg/mL thyme oil can effectively inactivate E. faecalis population in the mature E. faecalis biofilms by 5.75 and 7.20 log CFU/mL, respectively, after 30 min of treatment. Thus, thyme oil at different concentrations can be used as an effective antibiofilm or germicidal agent to control E. faecalis biofilms.
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Affiliation(s)
- Fang Liu
- Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Panpan Jin
- Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Hansheng Gong
- School of Food Engineering, Ludong University, Yantai 264025, China
| | - Zhilan Sun
- Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Lihui Du
- College of Food Science and Engineering, Collaborative Innovation Center for Modern Grain Circulation and Safety, Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China.
| | - Daoying Wang
- Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
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19
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Metabolic Shift of an Isogenic Strain of Enterococcus faecalis 14, Deficient in Its Own Bacteriocin Synthesis, as Revealed by a Transcriptomic Analysis. Int J Mol Sci 2020; 21:ijms21134653. [PMID: 32629918 PMCID: PMC7369866 DOI: 10.3390/ijms21134653] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/19/2020] [Accepted: 06/29/2020] [Indexed: 01/07/2023] Open
Abstract
The production of antimicrobial molecules often involves complex biological pathways. This study aimed at understanding the metabolic and physiological networks of enterocin EntDD14-associated function, in the bacteriocinogenic strain, Enterococcus faecalis 14. A global and comparative transcriptomic study was carried out on E. faecalis 14 and its isogenic mutant Δbac, inactivated in genes coding for EntDD14. The in vitro ability to form biofilm on polystyrene plates was assessed by the crystal violet method, while the cytotoxicity on human colorectal adenocarcinoma Caco-2 cells was determined by the Cell Counting Kit-8. Transcriptomic data revealed that 71 genes were differentially expressed in both strains. As expected, genes coding for EntDD14 were downregulated in the Δbac mutant, whereas the other 69 genes were upregulated. Upregulated genes were associated with phage-related chromosomal islands, biofilm formation capability, resistance to environmental stresses, and metabolic reprogramming. Interestingly, the Δbac mutant showed an improved bacterial growth, a high capacity to form biofilm on inanimate surfaces and a very weak cytotoxicity level. These multiple metabolic rearrangements delineate a new line of defense to counterbalance the loss of EntDD14.
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20
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Enterococcus faecalis Manganese Exporter MntE Alleviates Manganese Toxicity and Is Required for Mouse Gastrointestinal Colonization. Infect Immun 2020; 88:IAI.00058-20. [PMID: 32229614 DOI: 10.1128/iai.00058-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 03/21/2020] [Indexed: 01/13/2023] Open
Abstract
Bacterial pathogens encounter a variety of nutritional environments in the human host, including nutrient metal restriction and overload. Uptake of manganese (Mn) is essential for Enterococcus faecalis growth and virulence; however, it is not known how this organism prevents Mn toxicity. In this study, we examine the role of the highly conserved MntE transporter in E. faecalis Mn homeostasis and virulence. We show that inactivation of mntE results in growth restriction in the presence of excess Mn, but not other metals, demonstrating its specific role in Mn detoxification. Upon growth in the presence of excess Mn, an mntE mutant accumulates intracellular Mn, iron (Fe), and magnesium (Mg), supporting a role for MntE in Mn and Fe export and a role for Mg in offsetting Mn toxicity. Growth of the mntE mutant in excess Fe also results in increased levels of intracellular Fe, but not Mn or Mg, providing further support for MntE in Fe efflux. Inactivation of mntE in the presence of excess iron also results in the upregulation of glycerol catabolic genes and enhanced biofilm growth, and addition of glycerol is sufficient to augment biofilm growth for both the mntE mutant and its wild-type parental strain, demonstrating that glycerol availability significantly enhances biofilm formation. Finally, we show that mntE contributes to colonization of the antibiotic-treated mouse gastrointestinal (GI) tract, suggesting that E. faecalis encounters excess Mn in this niche. Collectively, these findings demonstrate that the manganese exporter MntE plays a crucial role in E. faecalis metal homeostasis and virulence.
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21
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Liu F, Sun Z, Wang F, Liu Y, Zhu Y, Du L, Wang D, Xu W. Inhibition of biofilm formation and exopolysaccharide synthesis of Enterococcus faecalis by phenyllactic acid. Food Microbiol 2020; 86:103344. [DOI: 10.1016/j.fm.2019.103344] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 07/23/2019] [Accepted: 09/27/2019] [Indexed: 12/15/2022]
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