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Mullally CA, Fahriani M, Mowlaboccus S, Coombs GW. Non- faecium non- faecalis enterococci: a review of clinical manifestations, virulence factors, and antimicrobial resistance. Clin Microbiol Rev 2024; 37:e0012123. [PMID: 38466110 PMCID: PMC11237509 DOI: 10.1128/cmr.00121-23] [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] [Indexed: 03/12/2024] Open
Abstract
SUMMARYEnterococci are a diverse group of Gram-positive bacteria that are typically found as commensals in humans, animals, and the environment. Occasionally, they may cause clinically relevant diseases such as endocarditis, septicemia, urinary tract infections, and wound infections. The majority of clinical infections in humans are caused by two species: Enterococcus faecium and Enterococcus faecalis. However, there is an increasing number of clinical infections caused by non-faecium non-faecalis (NFF) enterococci. Although NFF enterococcal species are often overlooked, studies have shown that they may harbor antimicrobial resistance (AMR) genes and virulence factors that are found in E. faecium and E. faecalis. In this review, we present an overview of the NFF enterococci with a particular focus on human clinical manifestations, epidemiology, virulence genes, and AMR genes.
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Affiliation(s)
- Christopher A Mullally
- Antimicrobial Resistance and Infectious Diseases (AMRID) Research Laboratory, Murdoch University, Murdoch, Western Australia, Australia
- The Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Marhami Fahriani
- Antimicrobial Resistance and Infectious Diseases (AMRID) Research Laboratory, Murdoch University, Murdoch, Western Australia, Australia
| | - Shakeel Mowlaboccus
- Antimicrobial Resistance and Infectious Diseases (AMRID) Research Laboratory, Murdoch University, Murdoch, Western Australia, Australia
- The Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, The University of Western Australia, Perth, Western Australia, Australia
- PathWest Laboratory Medicine-WA, Department of Microbiology, Fiona Stanley Hospital, Murdoch, Western Australia, Australia
| | - Geoffrey W Coombs
- Antimicrobial Resistance and Infectious Diseases (AMRID) Research Laboratory, Murdoch University, Murdoch, Western Australia, Australia
- The Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, The University of Western Australia, Perth, Western Australia, Australia
- PathWest Laboratory Medicine-WA, Department of Microbiology, Fiona Stanley Hospital, Murdoch, Western Australia, Australia
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2
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Reinseth I, Diep DB, Kjos M, Tønnesen HH, Carlsen H. Exploring the feasibility of bacteriocins EntK1 and EntEJ97s in treatment of systemic vancomycin resistant enterococci infections in mice. J Appl Microbiol 2024; 135:lxae054. [PMID: 38439668 DOI: 10.1093/jambio/lxae054] [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: 12/11/2023] [Revised: 02/21/2024] [Accepted: 03/01/2024] [Indexed: 03/06/2024]
Abstract
AIMS Enterocins K1 and EJ97 have specific antimicrobial activity against Enterococcus faecium and Enterococcus faecalis, respectively. The aim of this study was to investigate the utility of these enterocins for in vivo treatment of systemic enterococcal infections. METHODS AND RESULTS The antimicrobial effect in blood was analysed and compared against the effect in saline. Colony forming unit counts revealed that the enterocins killed all the bacteria within 1 hour. Additionally, the bactericidal effect against E. faecalis was more rapid in blood, indicating a possible synergy between EntEJ97 and blood. Importantly, no enterocin resistant mutants emerged in these experiments. Injecting the enterocins intraperitoneally in an in vivo mouse model and using fluorescence and minimum inhibitory concentration determination to estimate concentrations of the peptides in plasma, indicate that the enterocins exist in circulation in therapeutic concentrations. Alanine aminotransferase detection, and haemolysis analysis indicates that there is no detectable liver damage or haemolytic effect after injection. CONCLUSIONS The study revealed that EntK1 and EntEJ97 are able to kill all bacteria ex vivo in the presence of blood. In vivo experiments determine that the enterocins exist in circulation in therapeutic concentrations without causing liver damage or haemolysis. Future experiments should test these peptides for treatment of infection in a relevant in vivo model.
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Affiliation(s)
- Ingvild Reinseth
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003 1432 Ås, Norway
| | - Dzung B Diep
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003 1432 Ås, Norway
| | - Morten Kjos
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003 1432 Ås, Norway
| | - Hanne H Tønnesen
- Section of Pharmaceutics and Social Pharmacy, Department of Pharmacy, University of Oslo, P.O. Box 1068 Blindern 0316 Oslo, Norway
| | - Harald Carlsen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003 1432 Ås, Norway
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3
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Sun WS, Lassinantti L, Järvå M, Schmitt A, ter Beek J, Berntsson RPA. Structural foundation for the role of enterococcal PrgB in conjugation, biofilm formation, and virulence. eLife 2023; 12:RP84427. [PMID: 37860966 PMCID: PMC10588982 DOI: 10.7554/elife.84427] [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] [Indexed: 10/21/2023] Open
Abstract
Type 4 Secretion Systems are a main driver for the spread of antibiotic resistance genes and virulence factors in bacteria. In Gram-positives, these secretion systems often rely on surface adhesins to enhance cellular aggregation and mating-pair formation. One of the best studied adhesins is PrgB from the conjugative plasmid pCF10 of Enterococcus faecalis, which has been shown to play major roles in conjugation, biofilm formation, and importantly also in bacterial virulence. Since prgB orthologs exist on a large number of conjugative plasmids in various different species, this makes PrgB a model protein for this widespread virulence factor. After characterizing the polymer adhesin domain of PrgB previously, we here report the structure for almost the entire remainder of PrgB, which reveals that PrgB contains four immunoglobulin (Ig)-like domains. Based on this new insight, we re-evaluate previously studied variants and present new in vivo data where specific domains or conserved residues have been removed. For the first time, we can show a decoupling of cellular aggregation from biofilm formation and conjugation in prgB mutant phenotypes. Based on the presented data, we propose a new functional model to explain how PrgB mediates its different functions. We hypothesize that the Ig-like domains act as a rigid stalk that presents the polymer adhesin domain at the right distance from the cell wall.
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Affiliation(s)
- Wei-Sheng Sun
- Department of Medical Biochemistry and Biophysics, Umeå UniversityUmeåSweden
- Wallenberg Centre for Molecular Medicine, Umeå UniversityUmeåSweden
| | - Lena Lassinantti
- Department of Medical Biochemistry and Biophysics, Umeå UniversityUmeåSweden
| | - Michael Järvå
- Department of Medical Biochemistry and Biophysics, Umeå UniversityUmeåSweden
| | - Andreas Schmitt
- Department of Medical Biochemistry and Biophysics, Umeå UniversityUmeåSweden
| | - Josy ter Beek
- Department of Medical Biochemistry and Biophysics, Umeå UniversityUmeåSweden
- Wallenberg Centre for Molecular Medicine, Umeå UniversityUmeåSweden
| | - Ronnie P-A Berntsson
- Department of Medical Biochemistry and Biophysics, Umeå UniversityUmeåSweden
- Wallenberg Centre for Molecular Medicine, Umeå UniversityUmeåSweden
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4
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Elashiry MM, Bergeron BE, Tay FR. Enterococcus faecalis in secondary apical periodontitis: Mechanisms of bacterial survival and disease persistence. Microb Pathog 2023; 183:106337. [PMID: 37683835 DOI: 10.1016/j.micpath.2023.106337] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 09/03/2023] [Accepted: 09/05/2023] [Indexed: 09/10/2023]
Abstract
Enterococcus faecalis is a commensal bacterium commonly found in the human gastrointestinal tract. However, in individuals with compromised immune systems, the pathogen can lead to severe illness. This opportunistic pathogen is associated with secondary apical diseases and is adept at resisting antibiotics and other forms of treatment because of its numerous virulence factors. Enterococcus faecalis is capable of disrupting the normal functions of immune cells, thereby hindering the body's ability to eradicate the infection. However, intensive research is needed in further understanding the adverse immunomodulatory effects of E. faecalis. Potential strategies specific for eradicating E. faecalis have proven beneficial in the treatment of persistent secondary apical periodontitis.
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Affiliation(s)
- Mohamed M Elashiry
- Department of Endodontics, Dental College of Georgia, Augusta University, Georgia, USA; Department of Endodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt.
| | - Brian E Bergeron
- Department of Endodontics, Dental College of Georgia, Augusta University, Georgia, USA
| | - Franklin R Tay
- Department of Endodontics, Dental College of Georgia, Augusta University, Georgia, USA
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5
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Yang Y, Yang X, Zhou H, Niu Y, Li J, Fu X, Wang S, Xue B, Li C, Zhao C, Zhang X, Shen Z, Wang J, Qiu Z. Bisphenols Promote the Pheromone-Responsive Plasmid-Mediated Conjugative Transfer of Antibiotic Resistance Genes in Enterococcus faecalis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:17653-17662. [PMID: 36445841 DOI: 10.1021/acs.est.2c05349] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The enrichment and spread of antibiotic resistance genes (ARGs) induced by environmental chemical pollution further exacerbated the threat to human health and ecological safety. Several compounds are known to induce R plasmid-mediated conjugation through inducing reactive oxygen species (ROS), increasing cell membrane permeability, enhancing regulatory genes expression, and so forth. Up to now, there has been no substantial breakthrough in the studies of models and related mechanisms. Here, we established a new conjugation model using pheromone-responsive plasmid pCF10 and confirmed that five kinds of bisphenols (BPs) at environmentally relevant concentrations could significantly promote the conjugation of ARGs mediated by plasmid pCF10 in E. faecalis by up to 4.5-fold compared with untreated cells. Using qPCR, gene knockout and UHPLC, we explored the mechanisms behind this phenomenon using bisphenol A (BPA) as a model of BPs and demonstrated that BPA could upregulate the expression of pheromone, promote bacterial aggregation, and even directly activate conjugation as a pheromone instead of producing ROS and enhancing cell membrane permeability. Interestingly, the result of mathematical analysis showed that the pheromone effect of most BPs is more potent than that of synthetic pheromone cCF10. These findings provide new insight into the environmental behavior and biological effect of BPs and provided new method and theory to study on enrichment and spread of ARGs induced by environmental chemical pollution.
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Affiliation(s)
- Yutong Yang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Xiaobo Yang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Hongrui Zhou
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Yuanyuan Niu
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
- Shanghai Ocean University, Shanghai201306, China
| | - Jing Li
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
- Tianjin University of Traditional Chinese Medicine, Tianjin301617, China
| | - Xinyue Fu
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
- Shanghai Ocean University, Shanghai201306, China
| | - Shang Wang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Bin Xue
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Chenyu Li
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Chen Zhao
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Xi Zhang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Zhiqiang Shen
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Jingfeng Wang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Zhigang Qiu
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
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Enterococcus Virulence and Resistant Traits Associated with Its Permanence in the Hospital Environment. Antibiotics (Basel) 2022; 11:antibiotics11070857. [PMID: 35884110 PMCID: PMC9311936 DOI: 10.3390/antibiotics11070857] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 06/23/2022] [Accepted: 06/24/2022] [Indexed: 11/17/2022] Open
Abstract
Enterococcus are opportunistic pathogens that have been gaining importance in the clinical setting, especially in terms of hospital-acquired infections. This problem has mainly been associated with the fact that these bacteria are able to present intrinsic and extrinsic resistance to different classes of antibiotics, with a great deal of importance being attributed to vancomycin-resistant enterococci. However, other aspects, such as the expression of different virulence factors including biofilm-forming ability, and its capacity of trading genetic information, makes this bacterial genus more capable of surviving harsh environmental conditions. All these characteristics, associated with some reports of decreased susceptibility to some biocides, all described in this literary review, allow enterococci to present a longer survival ability in the hospital environment, consequently giving them more opportunities to disseminate in these settings and be responsible for difficult-to-treat infections.
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Abstract
Enterococcus faecalis, an opportunistic pathogen that causes severe community-acquired and nosocomial infections, has been reported to resist phagocyte-mediated killing, which enables its long-term survival in the host. Metabolism, especially carbohydrate metabolism, plays a key role in the battle between pathogens and hosts. However, the function of carbohydrate metabolism in the long-term survival of E. faecalis in phagocytes has rarely been reported. In this study, we utilized transposon insertion sequencing (TIS) to investigate the function of carbohydrate metabolism during the survival of E. faecalis in RAW264.7 cells. The TIS results showed that the fitness of carbohydrate metabolism-related mutants, especially those associated with fructose and mannose metabolism, were significantly enhanced, suggesting that the attenuation of carbohydrate metabolism promotes the survival of E. faecalis in macrophages. The results of our investigation indicated that macrophages responded to carbohydrate metabolism of E. faecalis and polarized to M1 macrophages to increase nitric oxide (NO) production, leading to the enhancement of macrophage-mediated killing to E. faecalis. Meanwhile, E. faecalis automatically decreased carbohydrate metabolism to escape from the immune clearance of macrophages during intracellular survival. The shift of primary carbon resources for macrophages affected the ability to clear intracellular E. faecalis. In summary, the results of the present study demonstrated that carbohydrate metabolism affects the macrophage-mediated killing of E. faecalis. IMPORTANCEE. faecalis has become a major pathogen leading to a variety of infections around the world. The metabolic interaction between E. faecalis and its host is important during infection but is rarely investigated. We used transposon insertion sequencing coupled with transcriptome sequencing to explore the metabolic interaction between E. faecalis and macrophages and uncovered that the shift of carbohydrate metabolism dramatically affected the inflammatory response of macrophages. In addition, E. faecalis attenuated carbohydrate metabolism to avoid the activation of the immune response of macrophages. This study provides new insights for the reason why E. faecalis is capable of long-term survival in macrophages and may facilitate the development of novel strategies to treat infectious diseases.
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8
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Johnson CN, Sheriff EK, Duerkop BA, Chatterjee A. Let Me Upgrade You: Impact of Mobile Genetic Elements on Enterococcal Adaptation and Evolution. J Bacteriol 2021; 203:e0017721. [PMID: 34370561 PMCID: PMC8508098 DOI: 10.1128/jb.00177-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enterococci are Gram-positive bacteria that have evolved to thrive as both commensals and pathogens, largely due to their accumulation of mobile genetic elements via horizontal gene transfer (HGT). Common agents of HGT include plasmids, transposable elements, and temperate bacteriophages. These vehicles of HGT have facilitated the evolution of the enterococci, specifically Enterococcus faecalis and Enterococcus faecium, into multidrug-resistant hospital-acquired pathogens. On the other hand, commensal strains of Enterococcus harbor CRISPR-Cas systems that prevent the acquisition of foreign DNA, restricting the accumulation of mobile genetic elements. In this review, we discuss enterococcal mobile genetic elements by highlighting their contributions to bacterial fitness, examine the impact of CRISPR-Cas on their acquisition, and identify key areas of research that can improve our understanding of enterococcal evolution and ecology.
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Affiliation(s)
- Cydney N. Johnson
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Emma K. Sheriff
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Breck A. Duerkop
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Anushila Chatterjee
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
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9
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Piatti G, De Ferrari L, Schito AM, Riccio AM, Penco S, Cassia S, Bruzzone M, Ceppi M. In Vitro Reduction of Interleukin-8 Response to Enterococcus faecalis by Escherichia coli Strains Isolated from the Same Polymicrobial Urines. Microorganisms 2021; 9:microorganisms9071501. [PMID: 34361936 PMCID: PMC8307267 DOI: 10.3390/microorganisms9071501] [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: 05/12/2021] [Revised: 07/05/2021] [Accepted: 07/05/2021] [Indexed: 11/16/2022] Open
Abstract
Urinary tract infections are often polymicrobial and are mainly due to uropathogenic Escherichia coli (UPEC). We previously demonstrated a link among clinical fluoroquinolone susceptible E. coli reducing in vitro urothelial interleukin-8 (CXCL8) induced by E. coli K-12, polymicrobial cystitis, and pyuria absence. Here, we evaluated whether fifteen clinical fluoroquinolone susceptible UPEC were able to reduce CXCL8 induced by Enterococcus faecalis that had been isolated from the same mixed urines, other than CXCL8 induced by E. coli K-12. We also evaluated the connection between fluoroquinolone susceptibility and pathogenicity by evaluating the immune modulation of isogenic gyrA, a mutant UPEC resistant to ciprofloxacin. Using the 5637 bladder epithelial cell line, we observed that lower CXCL8 induced the most UPEC isolates than K-12 and the corresponding E. faecalis. During coinfections of UPEC/K-12 and UPEC/E. faecalis, we observed lower CXCL8 than during infections caused by K-12 and E. faecalis alone. UPEC strains showed host–pathogen and pathogen–pathogen interaction, which in part explained their persistence in the human urinary tract and coinfections, respectively. Mutant UPEC showed lower modulating activity with respect to the wildtypes, confirming the connection between acquired fluoroquinolone resistance and the decrease of innate microbial properties.
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Affiliation(s)
- Gabriella Piatti
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa, 16132 Genova, Italy;
- Correspondence: ; Tel.: +39-0105555193
| | - Laura De Ferrari
- Department of Internal Medicine, University of Genoa, 16132 Genova, Italy; (L.D.F.); (A.M.R.); (S.C.)
| | - Anna Maria Schito
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa, 16132 Genova, Italy;
| | - Anna Maria Riccio
- Department of Internal Medicine, University of Genoa, 16132 Genova, Italy; (L.D.F.); (A.M.R.); (S.C.)
| | - Susanna Penco
- Department of Experimental Medicine, University of Genoa, 16132 Genova, Italy;
| | - Sebastiano Cassia
- Department of Internal Medicine, University of Genoa, 16132 Genova, Italy; (L.D.F.); (A.M.R.); (S.C.)
| | - Marco Bruzzone
- Unit of Clinical Epidemiology, Ospedale Policlinico San Martino-IRCCS per l’Oncologia, 16132 Genova, Italy; (M.B.); (M.C.)
| | - Marcello Ceppi
- Unit of Clinical Epidemiology, Ospedale Policlinico San Martino-IRCCS per l’Oncologia, 16132 Genova, Italy; (M.B.); (M.C.)
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Inhibition of the Classical Pathway of Complement Activation Impairs Bacterial Clearance during Enterococcus faecalis Infection. Infect Immun 2021; 89:IAI.00660-20. [PMID: 33593889 DOI: 10.1128/iai.00660-20] [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] [Received: 10/17/2020] [Accepted: 01/07/2021] [Indexed: 12/18/2022] Open
Abstract
Enterococcus faecalis infections are considered a major public health concern worldwide. The complement system has a crucial role in the protection against different microbial pathogens, including E. faecalis Complement can be activated through three different pathways, including the classical, lectin, and alternative pathways. There is limited information on the role of the classical pathway (CP) in protection against infections caused by E. faecalis In the present study, we generated Fab fragments that successfully block the CP in mouse via inhibition of a key enzyme, C1s-A. Our results showed that anti-C1s-A Fab fragments block CP-mediated C3b and C4b deposition in vitro We further showed that administration of anti-C1s-A Fab fragments significantly impairs the CP functional activity in vivo Moreover, treatment of mice infected with E. faecalis using anti-C1s-A Fab fragments significantly impairs bacterial clearance as determined from the viable bacterial counts recovered from blood, kidneys, spleens, livers, and lungs of infected mice. Overall, this study highlights the essential role of the CP in host defense against E. faecalis.
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11
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Järvå MA, Hirt H, Dunny GM, Berntsson RPA. Polymer Adhesin Domains in Gram-Positive Cell Surface Proteins. Front Microbiol 2020; 11:599899. [PMID: 33324381 PMCID: PMC7726212 DOI: 10.3389/fmicb.2020.599899] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 10/28/2020] [Indexed: 01/12/2023] Open
Abstract
Surface proteins in Gram-positive bacteria are often involved in biofilm formation, host-cell interactions, and surface attachment. Here we review a protein module found in surface proteins that are often encoded on various mobile genetic elements like conjugative plasmids. This module binds to different types of polymers like DNA, lipoteichoic acid and glucans, and is here termed polymer adhesin domain. We analyze all proteins that contain a polymer adhesin domain and classify the proteins into distinct classes based on phylogenetic and protein domain analysis. Protein function and ligand binding show class specificity, information that will be useful in determining the function of the large number of so far uncharacterized proteins containing a polymer adhesin domain.
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Affiliation(s)
- Michael A Järvå
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Helmut Hirt
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, United States
| | - Gary M Dunny
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, United States
| | - Ronnie P-A Berntsson
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden.,Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
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Kalfopoulou E, Huebner J. Advances and Prospects in Vaccine Development against Enterococci. Cells 2020; 9:cells9112397. [PMID: 33147722 PMCID: PMC7692742 DOI: 10.3390/cells9112397] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 10/29/2020] [Accepted: 10/30/2020] [Indexed: 12/26/2022] Open
Abstract
Enterococci are the second most common Gram-positive pathogen responsible for nosocomial infections. Due to the limited number of new antibiotics that reach the medical practice and the resistance of enterococci to the current antibiotic options, passive and active immunotherapies have emerged as a potential prevention and/or treatment strategy against this opportunistic pathogen. In this review, we explore the pathogenicity of these bacteria and their interaction with the host immune response. We provide an overview of the capsular polysaccharides and surface-associated proteins that have been described as potential antigens in anti-enterococcal vaccine formulations. In addition, we describe the current status in vaccine development against enterococci and address the importance and the current advances toward the development of well-defined vaccines with broad coverage against enterococci.
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Affiliation(s)
- Ermioni Kalfopoulou
- Institute for Medical Microbiology, Immunology and Hygiene, Technical University of Munich, 81675 Munich, Germany;
| | - Johannes Huebner
- Division of Paediatric Infectious Diseases, Dr. von Hauner Children’s Hospital, Ludwig Maximilians University, 80337 Munich, Germany
- Correspondence: ; Tel.: +49-89-44005-7970
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13
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Bin-Asif H, Abid Ali S. The Genus Enterococcus and Its Associated Virulent Factors. Microorganisms 2020. [DOI: 10.5772/intechopen.89083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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14
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Sterling AJ, Snelling WJ, Naughton PJ, Ternan NG, Dooley JSG. Competent but complex communication: The phenomena of pheromone-responsive plasmids. PLoS Pathog 2020; 16:e1008310. [PMID: 32240270 PMCID: PMC7117660 DOI: 10.1371/journal.ppat.1008310] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Enterococci are robust gram-positive bacteria that are found in a variety of surroundings and that cause a significant number of healthcare-associated infections. The genus possesses a high-efficiency pheromone-responsive plasmid (PRP) transfer system for genetic exchange that allows antimicrobial-resistance determinants to spread within bacterial populations. The pCF10 plasmid system is the best characterised, and although other PRP systems are structurally similar, they lack exact functional homologues of pCF10-encoded genes. In this review, we provide an overview of the enterococcal PRP systems, incorporating functional details for the less-well-defined systems. We catalogue the virulence-associated elements of the PRPs that have been identified to date, and we argue that this reinforces the requirement for elucidation of the less studied systems.
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Affiliation(s)
- Amy J. Sterling
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Londonderry, Northern Ireland
- * E-mail:
| | - William J. Snelling
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Londonderry, Northern Ireland
| | - Patrick J. Naughton
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Londonderry, Northern Ireland
| | - Nigel G. Ternan
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Londonderry, Northern Ireland
| | - James S. G. Dooley
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Londonderry, Northern Ireland
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Jeong S, Lee Y, Yun CH, Park OJ, Han SH. Propionate, together with triple antibiotics, inhibits the growth of Enterococci. J Microbiol 2019; 57:1019-1024. [PMID: 31659687 DOI: 10.1007/s12275-019-9434-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 10/10/2019] [Indexed: 02/07/2023]
Abstract
Enterococci are Gram-positive facultative anaerobic bacteria that colonize the oral cavity and gastrointestinal tract. Enterococcal infections, mainly caused by Enterococcus faecalis and Enterococcus faecium, include apical periodontitis, endocarditis, and bloodstream infections. Recently, vancomycinresistant Enterococci are considered major pathogens that are common but difficult to treat, especially in nosocomial settings. Moreover, E. faecalis is closely associated with recurrent endodontic infections and failed endodontic treatment. In this study, we investigated the effects of short-chain fatty acids (SCFAs), acetate, propionate, and butyrate, which are metabolites fermented by gut microbiota, on the growth of Enterococci. Enterococci were cultured in the presence or absence of acetate, propionate, or butyrate, and the optical density at 600 nm was measured to determine bacterial growth. The minimum inhibitory concentration/minimum bactericidal concentration test was conducted. Bacteria were treated with a SCFA, together with clinically used endodontic treatment methods such as triple antibiotics (metronidazole, minocycline, and ciprofloxacin) and chlorhexidine gluconate (CHX) to determine the effects of combination treatment. Of the SCFAs, propionate had a bacteriostatic effect, inhibiting the growth of E. faecalis in a dose-dependent manner and also that of clinical strains of E. faecalis isolated from dental plaques. Meanwhile, acetate and butyrate had minimal effects on E. faecalis growth. Moreover, propionate inhibited the growth of other Enterococci including E. faecium. In addition, combination treatment of propionate and triple antibiotics led to further growth inhibition, whereas no cooperative effect was observed at propionate plus CHX. These results indicate that propionate attenuates the growth of Enterococci, suggesting propionate as a potential agent to control Enterococcal infections, especially when combined with triple antibiotics.
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Affiliation(s)
- Soyoung Jeong
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, 08826, Republic of Korea
| | - Yunjae Lee
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, 08826, Republic of Korea
- College of Liberal Studies, Seoul National University, Seoul, 08826, Republic of Korea
| | - Cheol-Heui Yun
- Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
- Institutes of Green Bio Science and Technology, Seoul National University, Pyeongchang, 25354, Republic of Korea
| | - Ok-Jin Park
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, 08826, Republic of Korea.
| | - Seung Hyun Han
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, 08826, Republic of Korea.
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16
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Fiore E, Van Tyne D, Gilmore MS. Pathogenicity of Enterococci. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0053-2018. [PMID: 31298205 PMCID: PMC6629438 DOI: 10.1128/microbiolspec.gpp3-0053-2018] [Citation(s) in RCA: 201] [Impact Index Per Article: 40.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Indexed: 12/19/2022] Open
Abstract
Enterococci are unusually well adapted for survival and persistence in a variety of adverse environments, including on inanimate surfaces in the hospital environment and at sites of infection. This intrinsic ruggedness undoubtedly played a role in providing opportunities for enterococci to interact with other overtly drug-resistant microbes and acquire additional resistances on mobile elements. The rapid rise of antimicrobial resistance among hospital-adapted enterococci has rendered hospital-acquired infections a leading therapeutic challenge. With about a quarter of a genome of additional DNA conveyed by mobile elements, there are undoubtedly many more properties that have been acquired that help enterococci persist and spread in the hospital setting and cause diseases that have yet to be defined. Much remains to be learned about these ancient and rugged microbes, particularly in the area of pathogenic mechanisms involved with human diseases.
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Affiliation(s)
- Elizabeth Fiore
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA 02114
- Department of Microbiology, Harvard Medical School, Boston, MA 02115
| | - Daria Van Tyne
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA 02114
- Department of Microbiology, Harvard Medical School, Boston, MA 02115
| | - Michael S Gilmore
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA 02114
- Department of Microbiology, Harvard Medical School, Boston, MA 02115
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17
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Dr. Jekyll and Mr. Hide: How Enterococcus faecalis Subverts the Host Immune Response to Cause Infection. J Mol Biol 2019; 431:2932-2945. [DOI: 10.1016/j.jmb.2019.05.030] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 05/15/2019] [Accepted: 05/20/2019] [Indexed: 02/06/2023]
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18
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Kumar S, Devi S, Sood S, Kapila S, Narayan K, Shandilya S. Antibiotic resistance and virulence genes in nisin‐resistantEnterococcus faecalisisolated from raw buffalo milk modulate the innate functions of rat macrophages. J Appl Microbiol 2019; 127:897-910. [DOI: 10.1111/jam.14343] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 05/02/2019] [Accepted: 05/30/2019] [Indexed: 12/15/2022]
Affiliation(s)
- S. Kumar
- Animal Biochemistry Division National Dairy Research Institute Karnal Haryana India
| | - S. Devi
- Animal Biochemistry Division National Dairy Research Institute Karnal Haryana India
| | - S.K. Sood
- Animal Biochemistry Division National Dairy Research Institute Karnal Haryana India
| | - S. Kapila
- Animal Biochemistry Division National Dairy Research Institute Karnal Haryana India
| | - K.S. Narayan
- Animal Biochemistry Division National Dairy Research Institute Karnal Haryana India
| | - S. Shandilya
- Department of Medicine III University Hospital Carl Gustav Carus, Technische Universität Dresden Dresden Germany
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19
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Abstract
The study of the genetics of enterococci has focused heavily on mobile genetic elements present in these organisms, the complex regulatory circuits used to control their mobility, and the antibiotic resistance genes they frequently carry. Recently, more focus has been placed on the regulation of genes involved in the virulence of the opportunistic pathogenic species Enterococcus faecalis and Enterococcus faecium. Little information is available concerning fundamental aspects of DNA replication, partition, and division; this article begins with a brief overview of what little is known about these issues, primarily by comparison with better-studied model organisms. A variety of transcriptional and posttranscriptional mechanisms of regulation of gene expression are then discussed, including a section on the genetics and regulation of vancomycin resistance in enterococci. The article then provides extensive coverage of the pheromone-responsive conjugation plasmids, including sections on regulation of the pheromone response, the conjugative apparatus, and replication and stable inheritance. The article then focuses on conjugative transposons, now referred to as integrated, conjugative elements, or ICEs, and concludes with several smaller sections covering emerging areas of interest concerning the enterococcal mobilome, including nonpheromone plasmids of particular interest, toxin-antitoxin systems, pathogenicity islands, bacteriophages, and genome defense.
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20
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Chong KKL, Tay WH, Janela B, Yong AMH, Liew TH, Madden L, Keogh D, Barkham TMS, Ginhoux F, Becker DL, Kline KA. Enterococcus faecalis Modulates Immune Activation and Slows Healing During Wound Infection. J Infect Dis 2019; 216:1644-1654. [PMID: 29045678 PMCID: PMC5854026 DOI: 10.1093/infdis/jix541] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 10/13/2017] [Indexed: 01/13/2023] Open
Abstract
Enterococcus faecalis is one of the most frequently isolated bacterial species in wounds yet little is known about its pathogenic mechanisms in this setting. Here, we used a mouse wound excisional model to characterize the infection dynamics of E faecalis and show that infected wounds result in 2 different states depending on the initial inoculum. Low-dose inocula were associated with short-term, low-titer colonization whereas high-dose inocula were associated with acute bacterial replication and long-term persistence. High-dose infection and persistence were also associated with immune cell infiltration, despite suppression of some inflammatory cytokines and delayed wound healing. During high-dose infection, the multiple peptide resistance factor, which is involved in resisting immune clearance, contributes to E faecalis fitness. These results comprehensively describe a mouse model for investigating E faecalis wound infection determinants, and suggest that both immune modulation and resistance contribute to persistent, nonhealing wounds.
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Affiliation(s)
- Kelvin Kian Long Chong
- Singapore Centre for Environmental Life Sciences Engineering, Singapore.,Nanyang Technological University Institute for Health Technologies, Singapore
| | - Wei Hong Tay
- Singapore Centre for Environmental Life Sciences Engineering, Singapore.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
| | - Baptiste Janela
- Singapore Immunology Network, Agency for Science, Technology and Research, Singapore
| | - Adeline Mei Hui Yong
- Singapore Centre for Environmental Life Sciences Engineering, Singapore.,School of Biological Sciences, Singapore
| | - Tze Horng Liew
- Singapore Centre for Environmental Life Sciences Engineering, Singapore
| | - Leigh Madden
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Damien Keogh
- Singapore Centre for Environmental Life Sciences Engineering, Singapore
| | | | - Florent Ginhoux
- Singapore Immunology Network, Agency for Science, Technology and Research, Singapore
| | | | - Kimberly A Kline
- Singapore Centre for Environmental Life Sciences Engineering, Singapore.,Singapore Immunology Network, Agency for Science, Technology and Research, Singapore
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21
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Schmitt A, Jiang K, Camacho MI, Jonna VR, Hofer A, Westerlund F, Christie PJ, Berntsson RPA. PrgB promotes aggregation, biofilm formation, and conjugation through DNA binding and compaction. Mol Microbiol 2018; 109:291-305. [PMID: 29723434 DOI: 10.1111/mmi.13980] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2018] [Indexed: 12/28/2022]
Abstract
Gram-positive bacteria deploy type IV secretion systems (T4SSs) to facilitate horizontal gene transfer. The T4SSs of Gram-positive bacteria rely on surface adhesins as opposed to conjugative pili to facilitate mating. Enterococcus faecalis PrgB is a surface adhesin that promotes mating pair formation and robust biofilm development in an extracellular DNA (eDNA) dependent manner. Here, we report the structure of the adhesin domain of PrgB. The adhesin domain binds and compacts DNA in vitro. In vivo PrgB deleted of its adhesin domain does not support cellular aggregation, biofilm development and conjugative DNA transfer. PrgB also binds lipoteichoic acid (LTA), which competes with DNA binding. We propose that PrgB binding and compaction of eDNA facilitates cell aggregation and plays an important role in establishment of early biofilms in mono- or polyspecies settings. Within these biofilms, PrgB mediates formation and stabilization of direct cell-cell contacts through alternative binding of cell-bound LTA, which in turn promotes establishment of productive mating junctions and efficient intra- or inter-species T4SS-mediated gene transfer.
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Affiliation(s)
- Andreas Schmitt
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Kai Jiang
- Department of Biology and Biological Engineering, Chalmers University of Technology, SE-41296 Gothenburg, Sweden
| | - Martha I Camacho
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, Texas 77030, USA
| | - Venkateswara Rao Jonna
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Anders Hofer
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Fredrik Westerlund
- Department of Biology and Biological Engineering, Chalmers University of Technology, SE-41296 Gothenburg, Sweden
| | - Peter J Christie
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, Texas 77030, USA
| | - Ronnie P-A Berntsson
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
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22
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Mechanistic Features of the Enterococcal pCF10 Sex Pheromone Response and the Biology of Enterococcus faecalis in Its Natural Habitat. J Bacteriol 2018; 200:JB.00733-17. [PMID: 29437851 DOI: 10.1128/jb.00733-17] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Conjugative transfer of plasmids in enterococci is promoted by intercellular communication using peptide pheromones. The regulatory mechanisms that control transfer have been extensively studied in vitro However, the complicated systems that regulate the spread of these plasmids did not evolve in the laboratory test tube, and remarkably little is known about this form of signaling in the intestinal tract, the primary niche of these organisms. Because the evolution of Enterococcus faecalis strains and their coresident pheromone-inducible plasmids, such as pCF10, have occurred in the gastrointestinal (GI) tract, it is important to consider the functions controlled by pheromones in light of this ecology. This review summarizes our current understanding of the pCF10-encoded pheromone response. We consider how selective pressures in the natural environment may have selected for the complex and very tightly regulated systems controlling conjugation, and we pay special attention to the ecology of enterococci and the pCF10 plasmid as a gut commensal. We summarize the results of recent studies of the pheromone response at the single-cell level, as well as those of the first experiments demonstrating a role for pheromone signaling in plasmid transfer and in GI tract competitive fitness. These results will serve as a foundation for further in vivo studies that could lead to novel interventions to reduce opportunistic infections and the spread of antibiotic resistance.
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23
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Abstract
Modern day endodontics is undergoing a massive change with the introduction of new molecular based techniques for microbial identification. This review focuses on the microbiota in untreated and root-filled canals. It will also describe briefly the recent developments in microbial identification and the mechanisms by which certain species of microbes are able to invade and establish themselves in the root canal.
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24
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Blagojević V, Kovačević-Jovanović V, Ćuruvija I, Petrović R, Vujnović I, Vujić V, Stanojević S. Rat strain differences in peritoneal immune cell response to selected gut microbiota: A crossroad between tolerance and autoimmunity? Life Sci 2018; 197:147-157. [DOI: 10.1016/j.lfs.2018.02.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 02/06/2018] [Accepted: 02/07/2018] [Indexed: 02/06/2023]
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25
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Abstract
Cell-cell communication mediated by peptide pheromones (cCF10 [CF]) is essential for high-frequency plasmid transfer in vitro in Enterococcus faecalis. To examine the role of pheromone signaling in vivo, we established either a CF-producing (CF+) recipient or a recipient producing a biologically inactive variant of CF (CF− recipient) in a germfree mouse model 3 days before donor inoculation and determined transfer frequencies of the pheromone-inducible plasmid pCF10. Plasmid transfer was detected in the upper and middle sections of the intestinal tract 5 h after donor inoculation and was highly efficient in the absence of antibiotic selection. The transconjugant/donor ratio reached a maximum level approaching 1 on day 4 in the upper intestinal tract. Plasmid transfer was significantly lower with the CF− recipient. While rescue of the CF− mating defect by coculture with CF+ recipients is easily accomplished in vitro, no extracellular complementation occurred in vivo. This suggests that most pheromone signaling in the gut occurs between recipient and donor cells in very close proximity. Plasmid-bearing cells (donors plus transconjugants) steadily increased in the population from 0.1% after donor inoculation to about 10% at the conclusion of the experiments. This suggests a selective advantage of pCF10 carriage distinct from antibiotic resistance or bacteriocin production. Our results demonstrate that pheromone signaling is required for efficient pCF10 transfer in vivo. In the absence of CF+ recipients, a low level of transfer to CF− recipients occurred in the gut. This may result from low-level host-mediated induction of the donors in the gastrointestinal (GI) tract, similar to that previously observed in serum. Horizontal gene transfer is a major factor in the biology of Enterococcus faecalis, an important nosocomial pathogen. Previous studies showing efficient conjugative plasmid transfer in the gastrointestinal (GI) tracts of experimental animals did not examine how the enterococcal sex pheromone response impacts the efficiency of transfer. Our study demonstrates for the first time pheromone-enhanced, high-frequency plasmid transfer of E. faecalis plasmid pCF10 in a mouse model in the absence of antibiotic or bacteriocin selection. Pheromone production by recipients dramatically increased plasmid transfer in germfree mice colonized initially with recipients, followed by donors. The presence of a coresident community of common gut microbes did not significantly reduce in vivo plasmid transfer between enterococcal donors and recipients. In mice colonized with enterococcal recipients, we detected plasmid transfer in the intestinal tract within 5 h of addition of donors, before transconjugants could be cultured from feces. Surprisingly, pCF10 carriage provided a competitive fitness advantage unrelated to antibiotic resistance or bacteriocin production.
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26
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Enterococcus faecalis Promotes Innate Immune Suppression and Polymicrobial Catheter-Associated Urinary Tract Infection. Infect Immun 2017; 85:IAI.00378-17. [PMID: 28893918 DOI: 10.1128/iai.00378-17] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 09/01/2017] [Indexed: 12/18/2022] Open
Abstract
Enterococcus faecalis, a member of the human gastrointestinal microbiota, is an opportunistic pathogen associated with hospital-acquired wound, bloodstream, and urinary tract infections. E. faecalis can subvert or evade immune-mediated clearance, although the mechanisms are poorly understood. In this study, we examined E. faecalis-mediated subversion of macrophage activation. We observed that E. faecalis actively prevents NF-κB signaling in mouse RAW264.7 macrophages in the presence of Toll-like receptor agonists and during polymicrobial infection with Escherichia coliE. faecalis and E. coli coinfection in a mouse model of catheter-associated urinary tract infection (CAUTI) resulted in a suppressed macrophage transcriptional response in the bladder compared to that with E. coli infection alone. Finally, we demonstrated that coinoculation of E. faecalis with a commensal strain of E. coli into catheterized bladders significantly augmented E. coli CAUTI. Taken together, these results support the hypothesis that E. faecalis suppression of NF-κB-driven responses in macrophages promotes polymicrobial CAUTI pathogenesis, especially during coinfection with less virulent or commensal E. coli strains.
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27
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Mansfield JM, Herrmann P, Jesionowski AM, Vickerman MM. Streptococcus gordonii pheromone s.g.cAM373 may influence the reservoir of antibiotic resistance determinants of Enterococcus faecalis origin in the oral metagenome. J Med Microbiol 2017; 66:1635-1639. [PMID: 29022550 DOI: 10.1099/jmm.0.000613] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Streptococcus gordonii produces a pheromone heptapeptide, s.g.cAM373, which induces a conjugative mating response in Enterococcus faecalis cells carrying the responsive plasmid, pAM373. We investigated the extent of this intergeneric signaling on DNA acquisition by streptococcal species likely to cohabit oral biofilms. E. faecalis/pAM373/pAMS470 cells were incubated with synthetic s.g.cAM373, reverse peptide s.g.cAM373-R, or peptide-free medium and examined for their abilities to transfer plasmid DNA to streptococcal species in the presence of DNase. Preinduction of E. faecalis donors with s.g.cAM373 resulted in transconjugation frequencies in non-pheromone producing strains of Streptococcus mutans, Streptococcus sanguinis, Streptococcus anginosus, and Streptococcus suis that were significantly higher than frequencies when donors were preincubated with s.g.cAM373-R or medium alone. Peptide-mediated communication between commensal streptococci and E. faecalis carrying pheromone-responsive plasmids may facilitate conjugative DNA transfer to bystander species, and influence the reservoir of antibiotic resistance determinants of enterococcal origin in the oral metagenome.
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Affiliation(s)
- Jillian M Mansfield
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, NY 14214, USA
| | - Paul Herrmann
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, NY 14214, USA
| | - Amy M Jesionowski
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, NY 14214, USA
| | - M Margaret Vickerman
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, NY 14214, USA
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28
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Gram-Positive Uropathogens, Polymicrobial Urinary Tract Infection, and the Emerging Microbiota of the Urinary Tract. Microbiol Spectr 2017; 4. [PMID: 27227294 DOI: 10.1128/microbiolspec.uti-0012-2012] [Citation(s) in RCA: 195] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Gram-positive bacteria are a common cause of urinary-tract infection (UTI), particularly among individuals who are elderly, pregnant, or who have other risk factors for UTI. Here we review the epidemiology, virulence mechanisms, and host response to the most frequently isolated Gram-positive uropathogens: Staphylococcus saprophyticus, Enterococcus faecalis, and Streptococcus agalactiae. We also review several emerging, rare, misclassified, and otherwise underreported Gram-positive pathogens of the urinary tract including Aerococcus, Corynebacterium, Actinobaculum, and Gardnerella. The literature strongly suggests that urologic diseases involving Gram-positive bacteria may be easily overlooked due to limited culture-based assays typically utilized for urine in hospital microbiology laboratories. Some UTIs are polymicrobial in nature, often involving one or more Gram-positive bacteria. We herein review the risk factors and recent evidence for mechanisms of bacterial synergy in experimental models of polymicrobial UTI. Recent experimental data has demonstrated that, despite being cleared quickly from the bladder, some Gram-positive bacteria can impact pathogenic outcomes of co-infecting organisms. When taken together, the available evidence argues that Gram-positive bacteria are important uropathogens in their own right, but that some can be easily overlooked because they are missed by routine diagnostic methods. Finally, a growing body of evidence demonstrates that a surprising variety of fastidious Gram-positive bacteria may either reside in or be regularly exposed to the urinary tract and further suggests that their presence is widespread among women, as well as men. Experimental studies in this area are needed; however, there is a growing appreciation that the composition of bacteria found in the bladder could be a potentially important determinant in urologic disease, including susceptibility to UTI.
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29
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Madsen KT, Skov MN, Gill S, Kemp M. Virulence Factors Associated with Enterococcus Faecalis Infective Endocarditis: A Mini Review. Open Microbiol J 2017; 11:1-11. [PMID: 28567146 PMCID: PMC5418949 DOI: 10.2174/1874285801711010001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 01/16/2017] [Accepted: 01/28/2017] [Indexed: 01/02/2023] Open
Abstract
Introduction: The enterococci are accountable for up to 20% of all cases of infective endocarditis, with Enterococcus faecalis being the primary causative isolate. Infective endocarditis is a life-threatening infection of the endocardium that results in the formation of vegetations. Based on a literature review, this paper provides an overview of the virulence factors associated with E. faecalis infective endocarditis. Furthermore, it reports the effects of active or passive immunization against some of these involved factors. Individual virulence factors: Nine virulence factors have in particular been associated with E. faecalis infective endocarditis. Absence of these factors entailed attenuation of strains in both mixed- and mono-bacterial infection endocarditis models as well as in in vitro and ex vivo assays when compared to their virulence factor expressing parental strains. Pathogenesis: The virulence factors promote a broad spectrum of events that together allow for disease development and progression. The infection is initiated through bacterial binding to ligands present at the site of infection after which the colonization can be accelerated through inter-bacterial attachment and modulation of the host immune response. The formation and growth of the vegetation provide protection and promote growth. Controlled degeneration of the vegetation appears to increase the likelihood of embolization and dissemination, without exposing protected bacteria. Prophylactic immunization: In most cases, active and passive immunization against associated virulence factors provided partial protection. Future prospects: There is a need for further evaluation of the known virulence factors. Immunization against two or more virulence factors might be an effective prophylactic tool.
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Affiliation(s)
- Kristian T Madsen
- Dept. of Clinical Microbiology, Odense University Hospital and Clinical Department, University of Southern Denmark, Denmark
| | - Marianne N Skov
- Dept. of Clinical Microbiology, Odense University Hospital and Clinical Department, University of Southern Denmark, Denmark
| | - Sabine Gill
- Dept. of Cardiology, Odense University Hospital, Odense, Denmark
| | - Michael Kemp
- Dept. of Clinical Microbiology, Odense University Hospital and Clinical Department, University of Southern Denmark, Denmark
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30
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Bhatty M, Camacho MI, Gonzalez-Rivera C, Frank KL, Dale JL, Manias DA, Dunny GM, Christie PJ. PrgU: a suppressor of sex pheromone toxicity in Enterococcus faecalis. Mol Microbiol 2016; 103:398-412. [PMID: 27785854 DOI: 10.1111/mmi.13563] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Upon sensing of the peptide pheromone cCF10, Enterococcus faecalis cells carrying pCF10 produce three surface adhesins (PrgA, PrgB or Aggregation Substance, PrgC) and the Prg/Pcf type IV secretion system and, in turn, conjugatively transfer the plasmid at high frequencies to recipient cells. Here, we report that cCF10 induction is highly toxic to cells sustaining a deletion of prgU, a small orf located immediately downstream of prgB on pCF10. Upon pheromone exposure, these cells overproduce the Prg adhesins and display impaired envelope integrity, as evidenced by antibiotic susceptibility, misplaced division septa and cell lysis. Compensatory mutations in regulatory loci controlling expression of pCF10-encoded prg/pcf genes, or constitutive PrgU overproduction, block production of the Prg adhesins and render cells insensitive to pheromone. Cells engineered to overproduce PrgB, even independently of other pCF10-encoded proteins, have severely compromised cell envelopes and strong growth defects. PrgU has an RNA-binding fold, and prgB-prgU gene pairs are widely distributed among E. faecalis isolates and other enterococcal and staphylococcal species. Together, our findings support a model in which PrgU proteins represent a novel class of RNA-binding regulators that act to mitigate toxicity accompanying overproduction of PrgB-like adhesins in E. faecalis and other clinically-important Gram-positive species.
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Affiliation(s)
- Minny Bhatty
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, Texas, 77030, USA
| | - Martha I Camacho
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, Texas, 77030, USA
| | - Christian Gonzalez-Rivera
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, Texas, 77030, USA
| | - Kristi L Frank
- Department of Microbiology and Immunology, University of Minnesota Medical School, Microbiology Research Facility, 689 23rd Ave, S.E, Minneapolis, Minnesota, 55455, USA
| | - Jennifer L Dale
- Department of Microbiology and Immunology, University of Minnesota Medical School, Microbiology Research Facility, 689 23rd Ave, S.E, Minneapolis, Minnesota, 55455, USA
| | - Dawn A Manias
- Department of Microbiology and Immunology, University of Minnesota Medical School, Microbiology Research Facility, 689 23rd Ave, S.E, Minneapolis, Minnesota, 55455, USA
| | - Gary M Dunny
- Department of Microbiology and Immunology, University of Minnesota Medical School, Microbiology Research Facility, 689 23rd Ave, S.E, Minneapolis, Minnesota, 55455, USA
| | - Peter J Christie
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, Texas, 77030, USA
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31
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SAVAŞAN S, KIRKAN Ş, ERBAŞ G, PARIN U, ÇİFTCİ A. The Determination of Virulence Factors among Fish Originated Enterococci. ACTA ACUST UNITED AC 2016. [DOI: 10.35864/evmd.514501] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Enterococcal Sex Pheromones: Evolutionary Pathways to Complex, Two-Signal Systems. J Bacteriol 2016; 198:1556-1562. [PMID: 27021562 DOI: 10.1128/jb.00128-16] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Gram-positive bacteria carry out intercellular communication using secreted peptides. Important examples of this type of communication are the enterococcal sex pheromone systems, in which the transfer of conjugative plasmids is controlled by intercellular signaling among populations of donors and recipients. This review focuses on the pheromone response system of the conjugative plasmid pCF10. The peptide pheromones regulating pCF10 transfer act by modulating the ability of the PrgX transcription factor to repress the transcription of an operon encoding conjugation functions. Many Gram-positive bacteria regulate important processes, including the production of virulence factors, biofilm formation, sporulation, and genetic exchange using peptide-mediated signaling systems. The key master regulators of these systems comprise the RRNPP (RggRap/NprR/PlcR/PrgX) family of intracellular peptide receptors; these regulators show conserved structures. While many RRNPP systems include a core module of two linked genes encoding the regulatory protein and its cognate signaling peptide, the enterococcal sex pheromone plasmids have evolved to a complex system that also recognizes a second host-encoded signaling peptide. Additional regulatory genes not found in most RRNPP systems also modulate signal production and signal import in the enterococcal pheromone plasmids. This review summarizes several structural studies that cumulatively demonstrate that the ability of three pCF10 regulatory proteins to recognize the same 7-amino-acid pheromone peptide arose by convergent evolution of unrelated proteins from different families. We also focus on the selective pressures and structure/function constraints that have driven the evolution of pCF10 from a simple, single-peptide system resembling current RRNPPs in other bacteria to the current complex inducible plasmid transfer system.
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Zou J, Shankar N. The opportunistic pathogenEnterococcus faecalisresists phagosome acidification and autophagy to promote intracellular survival in macrophages. Cell Microbiol 2016; 18:831-43. [DOI: 10.1111/cmi.12556] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 12/04/2015] [Accepted: 12/07/2015] [Indexed: 12/20/2022]
Affiliation(s)
- Jun Zou
- Department of Pharmaceutical Sciences; University of Oklahoma Health Sciences Center; Oklahoma City OK USA
| | - Nathan Shankar
- Department of Pharmaceutical Sciences; University of Oklahoma Health Sciences Center; Oklahoma City OK USA
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Thomsen K, Christophersen L, Bjarnsholt T, Jensen PØ, Moser C, Høiby N. Anti-Pseudomonas aeruginosa IgY Antibodies Induce Specific Bacterial Aggregation and Internalization in Human Polymorphonuclear Neutrophils. Infect Immun 2015; 83:2686-93. [PMID: 25895968 PMCID: PMC4468541 DOI: 10.1128/iai.02970-14] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Accepted: 04/10/2015] [Indexed: 01/24/2023] Open
Abstract
Polymorphonuclear neutrophils (PMNs) are essential cellular constituents in the innate host response, and their recruitment to the lungs and subsequent ubiquitous phagocytosis controls primary respiratory infection. Cystic fibrosis pulmonary disease is characterized by progressive pulmonary decline governed by a persistent, exaggerated inflammatory response dominated by PMNs. The principal contributor is chronic Pseudomonas aeruginosa biofilm infection, which attracts and activates PMNs and thereby is responsible for the continuing inflammation. Strategies to prevent initial airway colonization with P. aeruginosa by augmenting the phagocytic competence of PMNs may postpone the deteriorating chronic biofilm infection. Anti-P. aeruginosa IgY antibodies significantly increase the PMN-mediated respiratory burst and subsequent bacterial killing of P. aeruginosa in vitro. The mode of action is attributed to IgY-facilitated formation of immobilized bacteria in aggregates, as visualized by fluorescence microscopy and the induction of increased bacterial hydrophobicity. Thus, the present study demonstrates that avian egg yolk immunoglobulins (IgY) targeting P. aeruginosa modify bacterial fitness, which enhances bacterial killing by PMN-mediated phagocytosis and thereby may facilitate a rapid bacterial clearance in airways of people with cystic fibrosis.
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Affiliation(s)
- K Thomsen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - L Christophersen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - T Bjarnsholt
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark Department of International Health, Immunology and Microbiology, Faculty of Health Sciences University of Copenhagen, Copenhagen, Denmark
| | - P Ø Jensen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - C Moser
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - N Høiby
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark Department of International Health, Immunology and Microbiology, Faculty of Health Sciences University of Copenhagen, Copenhagen, Denmark
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The high PMNs phagocytosis resistance of enterococcal isolates from RTx patients. BIOMED RESEARCH INTERNATIONAL 2015; 2015:432579. [PMID: 25861625 PMCID: PMC4377443 DOI: 10.1155/2015/432579] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 02/22/2015] [Accepted: 02/23/2015] [Indexed: 11/17/2022]
Abstract
Infections caused by opportunistic pathogens such as enterococci remain difficult to manage, especially in immunocompromised patients. Because of infections' limited symptoms in such patients the additional problems are to find proper diagnostic criteria and the management of infection. Here we aimed to compare the resistance of commensal enterococcal strains and RTx patients' isolates, to PMNs phagocytosis. Thirty-six enterococcal urine and faecal isolates from RTx patients and 17 faecal isolates from healthy volunteers were cultured in planktonic and biofilm forms in 37°C or 42°C. Another tested variable was the addition of immunosuppressant to the culture media. Bacterial cells were stained with fluorescent reporter (CFDA, PI) and incubated with PMNs. Results of phagocytosis were estimated as a mean fluorescence intensity (MFI) of PMNs using flow cytometry. Commensal enterococci cultured in all abovementioned (37°C and 42°C/the addition of immunosuppressant) conditions were less resistant to phagocytosis compared to RTx isolates. Observed significant difference in phagocytosis resistance suggests that patients in immunosuppression are colonized with high risk strains which may lead to the development of infection.
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Bhatty M, Cruz MR, Frank KL, Gomez JAL, Andrade F, Garsin DA, Dunny GM, Kaplan HB, Christie PJ. Enterococcus faecalis pCF10-encoded surface proteins PrgA, PrgB (aggregation substance) and PrgC contribute to plasmid transfer, biofilm formation and virulence. Mol Microbiol 2014; 95:660-77. [PMID: 25431047 DOI: 10.1111/mmi.12893] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2014] [Indexed: 01/24/2023]
Abstract
Enterococcus faecalis pCF10 transfers at high frequencies upon pheromone induction of the prgQ transfer operon. This operon codes for three cell wall-anchored proteins - PrgA, PrgB (aggregation substance) and PrgC - and a type IV secretion system through which the plasmid is delivered to recipient cells. Here, we defined the contributions of the Prg surface proteins to plasmid transfer, biofilm formation and virulence using the Caenorhabditis elegans infection model. We report that a combination of PrgB and extracellular DNA (eDNA), but not PrgA or PrgC, was required for extensive cellular aggregation and pCF10 transfer at wild-type frequencies. In addition to PrgB and eDNA, production of PrgA was necessary for extensive binding of enterococci to abiotic surfaces and development of robust biofilms. However, although PrgB is a known virulence factor in mammalian infection models, we determined that PrgA and PrgC, but not PrgB, were required for efficient killing in the worm infection model. We propose that the pheromone-responsive, conjugative plasmids of E. faecalis have retained Prg-like surface functions over evolutionary time for attachment, colonization and robust biofilm development. In natural settings, these biofilms are polymicrobial in composition and constitute optimal environments for signal exchange, mating pair formation and widespread lateral gene transfer.
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Affiliation(s)
- Minny Bhatty
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX, 77030, USA
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Abstract
Gram-positive bacteria are leading causes of many types of human infection, including pneumonia, skin and nasopharyngeal infections, as well as urinary tract and surgical wound infections among hospitalized patients. These infections have become particularly problematic because many of the species causing them have become highly resistant to antibiotics. The role of mobile genetic elements, such as plasmids, in the dissemination of antibiotic resistance among Gram-positive bacteria has been well studied; less well understood is the role of mobile elements in the evolution and spread of virulence traits among these pathogens. While these organisms are leading agents of infection, they are also prominent members of the human commensal ecology. It appears that these bacteria are able to take advantage of the intimate association between host and commensal, via virulence traits that exacerbate infection and cause disease. However, evolution into an obligate pathogen has not occurred, presumably because it would lead to rejection of pathogenic organisms from the host ecology. Instead, in organisms that exist as both commensal and pathogen, selection has favored the development of mechanisms for variability. As a result, many virulence traits are localized on mobile genetic elements, such as virulence plasmids and pathogenicity islands. Virulence traits may occur within a minority of isolates of a given species, but these minority populations have nonetheless emerged as a leading problem in infectious disease. This chapter reviews virulence plasmids in nonsporulating Gram-positive bacteria, and examines their contribution to disease pathogenesis.
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Prophages in enterococcal isolates from renal transplant recipients: renal failure etiologies promote selection of strains. BIOMED RESEARCH INTERNATIONAL 2014; 2014:514689. [PMID: 25105126 PMCID: PMC4106134 DOI: 10.1155/2014/514689] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 06/11/2014] [Accepted: 06/16/2014] [Indexed: 11/23/2022]
Abstract
Infections caused by commensal bacteria may be fatal for the patients under immunosuppressive therapy. This results also from difficulty in identification of high risk strains. Enterococcal infections are increasingly frequent but despite many studies on virulence traits, the difference between commensal and pathogenic strains remains unclear. Prophages are newly described as important elements in competition between strains during colonization, as well as pathogenicity of the strains.
Here we evaluate a difference in presence of pp4, pp1, and pp7 prophages and ASA (aggregation substance) gene expression in enterococcal isolates from renal transplant recipients (RTx) with different etiology of the end-stage renal failure.
Prophages sequence was screened by PCR in strains of Enterococcus faecalis isolated from urine and feces of 19 RTx hospitalized at Medical University of Gdansk and 18 healthy volunteers. FLOW-FISH method with use of linear locked nucleic acid (LNA) probe was used to assess the ASA gene expression. Additionally, ability of biofilm formation was screened by crystal violet staining method.
Presence of prophages was more frequent in fecal isolates from immunocompromised patients than in isolates from healthy volunteers. Additionally, both composition of prophages and ASA gene expression were related to the etiology of renal disease.
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Yuen GJ, Ausubel FM. Enterococcus infection biology: lessons from invertebrate host models. J Microbiol 2014; 52:200-10. [PMID: 24585051 PMCID: PMC4556283 DOI: 10.1007/s12275-014-4011-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 01/21/2014] [Indexed: 12/29/2022]
Abstract
The enterococci are commensals of the gastrointestinal tract of many metazoans, from insects to humans. While they normally do not cause disease in the intestine, they can become pathogenic when they infect sites outside of the gut. Recently, the enterococci have become important nosocomial pathogens, with the majority of human enterococcal infections caused by two species, Enterococcus faecalis and Enterococcus faecium. Studies using invertebrate infection models have revealed insights into the biology of enterococcal infections, as well as general principles underlying host innate immune defense. This review highlights recent findings on Enterococcus infection biology from two invertebrate infection models, the greater wax moth Galleria mellonella and the free-living bacteriovorous nematode Caenorhabditis elegans.
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Affiliation(s)
- Grace J. Yuen
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - Frederick M. Ausubel
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
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Affiliation(s)
- Gary M. Dunny
- Department of Microbiology, University of Minnesota, Minneapolis, Minnesota 55455;
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Cho SY, Lee DG, Choi SM, Kwon JC, Kim SH, Choi JK, Park SH, Park YJ, Choi JH, Yoo JH. Impact of vancomycin resistance on mortality in neutropenic patients with enterococcal bloodstream infection: a retrospective study. BMC Infect Dis 2013; 13:504. [PMID: 24164924 PMCID: PMC3870976 DOI: 10.1186/1471-2334-13-504] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Accepted: 10/22/2013] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Vancomycin-resistant Enterococcus (VRE) bloodstream infection (BSI) is generally associated with the delayed administration of adequate antibiotics. The identification of risk factors and outcomes of VRE BSI is necessary for establishing strategies for managing neutropenic fever in patients with hematological malignancies. METHODS We retrospectively analysed consecutive cases of enterococcal BSI in patients with neutropenia after chemotherapy or stem cell transplantation between July 2009 and December 2011 at a single center. RESULTS During the 30-month period, among 1,587 neutropenic patients, the incidence rate of enterococcal BSI was 1.76 cases per 1,000 person-days. Of the 91 enterococcal BSIs, there were 24 cases of VRE. VRE BSI was associated with E. faecium infection (P < .001), prolonged hospitalization (P = .025) and delayed administration (≥ 48 hours after the febrile episode) of adequate antibiotics (P = .002). The attributable mortality was 17% and 9% for VRE and vancomycin-susceptible Enterococcus (VSE), respectively (P = .447). The 30-day crude mortality was 27% and 23% for VRE and VSE, respectively (OR 1.38, 95% CI 0.53-3.59; P = .059). Only SAPS-II was an independent predictive factor for death (adjusted OR 1.12, 95% CI 1.08-1.17; P < .001). CONCLUSIONS In conclusion, vancomycin resistance showed some trend towards increasing 30-day mortality, but is not statistically significant despite the delayed use of adequate antibiotics (≥48 hours). Only underlying severity of medical condition predicts poor outcome in a relatively homogeneous group of neutropenic patients.
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Affiliation(s)
| | - Dong-Gun Lee
- Division of Infectious Diseases, Department of Internal Medicine, Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
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Jarzembowski T, Daca A, Witkowski J, Rutkowski B, Gołębiewska J, Dębska-Ślizień A. Does CMV infection impact the virulence of Enterococcus faecalis? Virulence 2013; 4:641-5. [PMID: 24162854 PMCID: PMC3906299 DOI: 10.4161/viru.26315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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Abstract
Enterococcus faecalis is an opportunistic pathogen responsible for a wide range of life-threatening nosocomial infections, such as septicemia, peritonitis, and endocarditis. E. faecalis infections are associated with a high mortality and substantial health care costs and cause therapeutic problems due to the intrinsic resistance of this bacterium to antibiotics. Several factors contributing to E. faecalis virulence have been identified. Due to the variety of infections caused by this organism, numerous animal models have been used to mimic E. faecalis infections, but none of them is considered ideal for monitoring pathogenesis. Here, we studied for the first time E. faecalis pathogenesis in zebrafish larvae. Using model strains, chosen isogenic mutants, and fluorescent derivatives expressing green fluorescent protein (GFP), we analyzed both lethality and bacterial dissemination in infected larvae. Genetically engineered immunocompromised zebrafish allowed the identification of two critical steps for successful establishment of disease: (i) host phagocytosis evasion mediated by the Epa rhamnopolysaccharide and (ii) tissue damage mediated by the quorum-sensing Fsr regulon. Our results reveal that the zebrafish is a novel, powerful model for studying E. faecalis pathogenesis, enabling us to dissect the mechanism of enterococcal virulence.
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Enterococcus faecalis overcomes foreign body-mediated inflammation to establish urinary tract infections. Infect Immun 2012; 81:329-39. [PMID: 23132492 DOI: 10.1128/iai.00856-12] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Urinary catheterization elicits major histological and immunological changes that render the bladder susceptible to microbial invasion, colonization, and dissemination. However, it is not understood how catheters induce these changes, how these changes act to promote infection, or whether they may have any protective benefit. In the present study, we examined how catheter-associated inflammation impacts infection by Enterococcus faecalis, a leading cause of catheter-associated urinary tract infection (CAUTI), a source of significant societal and clinical challenges. Using a recently optimized murine model of foreign body-associated UTI, we found that the implanted catheter itself was the primary inducer of inflammation. In the absence of the silicone tubing implant, E. faecalis induced only minimal inflammation and was rapidly cleared from the bladder. The catheter-induced inflammation was only minimally altered by subsequent enterococcal infection and was not suppressed by inhibitors of the neurogenic pathway and only partially by dexamethasone. Despite the robust inflammatory response induced by urinary implantation, E. faecalis produced biofilm and high bladder titers in these animals. Induction of inflammation in the absence of an implanted catheter failed to promote infection, suggesting that the presence of the catheter itself is essential for E. faecalis persistence in the bladder. Immunosuppression prior to urinary catheterization enhanced E. faecalis colonization, suggesting that implant-mediated inflammation contributes to the control of enterococcal infection. Thus, this study underscores the need for novel strategies against CAUTIs that seek to reduce the deleterious effects of implant-mediated inflammation on bladder homeostasis while maintaining an active immune response that effectively limits bacterial invaders.
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Kwon KH, Hwang SY, Moon BY, Park YK, Shin S, Hwang CY, Park YH. Occurrence of antimicrobial resistance and virulence genes, and distribution of enterococcal clonal complex 17 from animals and human beings in Korea. J Vet Diagn Invest 2012; 24:924-31. [PMID: 22855376 DOI: 10.1177/1040638712455634] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Enterococci are major zoonotic bacteria that cause opportunistic infections in human beings and animals. Moreover, pathogenic strains can be disseminated between human beings and animals, particularly companion animals that come into frequent contact with people. Recently, Enterococcus faecium clonal complex 17 (CC17) has emerged as a pandemic clone. Most CC17 strains are ampicillin resistant and possess virulence genes such as esp and hyl. Despite the possible dissemination of CC17 between human beings and animals, prevalence data about CC17 in animals is limited. In the present study, the phenotypes and genotypes of antimicrobial resistance were compared, as well as virulence gene profiles from 184 enterococci strains isolated from chickens, pigs, companion animals, and human patients in Korea. Ampicillin-resistant E. faecium (AREF) strains were selected, and multilocus sequence typing was performed to investigate the dispersion of CC17 among animals and human beings. The companion animal and human isolates showed high resistance rates to ampicillin and ciprofloxacin, whereas food animal isolates showed high tetracycline and erythromycin resistance rates. Ampicillin-resistant E. faecium was only detected in human (21/21 E. faecium, 100%) and companion animal (3/5 E. faecium, 60%) isolates, and all human AREF strains and 1 canine AREF strain were confirmed as CC17. In conclusion, the occurrence of antimicrobial resistance and virulence genes, and the distribution of enterococcal CC17 in companion animal enterococcal strains were similar to those of human strains rather than to those of food animal strains.
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Affiliation(s)
- Ka Hee Kwon
- Department of Veterinary Microbiology and Brain Korea 21 Program for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
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Kojic M, Jovcic B, Strahinic I, Begovic J, Lozo J, Veljovic K, Topisirovic L. Cloning and expression of a novel lactococcal aggregation factor from Lactococcus lactis subsp. lactis BGKP1. BMC Microbiol 2011; 11:265. [PMID: 22182285 PMCID: PMC3282668 DOI: 10.1186/1471-2180-11-265] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Accepted: 12/19/2011] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Aggregation may play a main role in the adhesion of bacteria to the gastrointestinal epithelium and their colonization ability, as well as in probiotic effects through co-aggregation with intestinal pathogens and their subsequent removal. The aggregation phenomenon in lactococci is directly associated with the sex factor and lactose plasmid co-integration event or duplication of the cell wall spanning (CWS) domain of PrtP proteinase. RESULTS Lactococcus lactis subsp. lactis BGKP1 was isolated from artisanal semi-hard homemade cheese and selected due to its strong auto-aggregation phenotype. Subsequently, non-aggregating derivative (Agg-) of BGKP1, designated as BGKP1-20, was isolated, too. Comparative analysis of cell surface proteins of BGKP1 and derivative BGKP1-20 revealed a protein of approximately 200 kDa only in the parental strain BGKP1. The gene involved in aggregation (aggL) was mapped on plasmid pKP1 (16.2 kb), cloned and expressed in homologous and heterologous lactococci and enterococci. This novel lactococcal aggregation protein was shown to be sufficient for cell aggregation in all tested hosts. In addition to the aggL gene, six more ORFs involved in replication (repB and repX), restriction and modification (hsdS), transposition (tnp) and possible interaction with mucin (mbpL) were also located on plasmid pKP1. CONCLUSION AggL is a new protein belonging to the collagen-binding superfamily of proteins and is sufficient for cell aggregation in lactococci.
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Affiliation(s)
- Milan Kojic
- Laboratory for Molecular Genetics of Industrial Microorganisms, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444/a, P.O. Box 23, Belgrade 11010, Serbia
| | - Branko Jovcic
- Laboratory for Molecular Genetics of Industrial Microorganisms, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444/a, P.O. Box 23, Belgrade 11010, Serbia
| | - Ivana Strahinic
- Laboratory for Molecular Genetics of Industrial Microorganisms, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444/a, P.O. Box 23, Belgrade 11010, Serbia
| | - Jelena Begovic
- Laboratory for Molecular Genetics of Industrial Microorganisms, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444/a, P.O. Box 23, Belgrade 11010, Serbia
| | - Jelena Lozo
- Laboratory for Molecular Genetics of Industrial Microorganisms, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444/a, P.O. Box 23, Belgrade 11010, Serbia
| | - Katarina Veljovic
- Laboratory for Molecular Genetics of Industrial Microorganisms, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444/a, P.O. Box 23, Belgrade 11010, Serbia
| | - Ljubisa Topisirovic
- Laboratory for Molecular Genetics of Industrial Microorganisms, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444/a, P.O. Box 23, Belgrade 11010, Serbia
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Franz CMAP, Huch M, Abriouel H, Holzapfel W, Gálvez A. Enterococci as probiotics and their implications in food safety. Int J Food Microbiol 2011; 151:125-40. [PMID: 21962867 DOI: 10.1016/j.ijfoodmicro.2011.08.014] [Citation(s) in RCA: 449] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 08/03/2011] [Accepted: 08/13/2011] [Indexed: 11/29/2022]
Abstract
Enterococci belong to the lactic acid bacteria (LAB) and they are of importance in foods due to their involvement in food spoilage and fermentations, as well as their utilisation as probiotics in humans and slaughter animals. However, they are also important nosocomial pathogens that cause bacteraemia, endocarditis and other infections. Some strains are resistant to many antibiotics and possess virulence factors such as adhesins, invasins, pili and haemolysin. The role of enterococci in disease has raised questions on their safety for use in foods or as probiotics. Studies on the incidence of virulence traits among enterococcal strains isolated from food showed that some can harbour virulence traits, but it is also thought that virulence is not the result of the presence of specific virulence determinants alone, but is rather a more intricate process. Specific genetic lineages of hospital-adapted strains have emerged, such as E. faecium clonal complex (CC) 17 and E. faecalis CC2, CC9, CC28 and CC40, which are high risk enterococcal clonal complexes. These are characterised by the presence of antibiotic resistance determinants and/or virulence factors, often located on pathogenicity islands or plasmids. Mobile genetic elements thus are considered to play a major role in the establishment of problematic lineages. Although enterococci occur in high numbers in certain types of fermented cheeses and sausages, they are not deliberately added as starter cultures. Some E. faecium and E. faecalis strains are used as probiotics and are ingested in high numbers, generally in the form of pharmaceutical preparations. Such probiotics are administered to treat diarrhoea, antibiotic-associated diarrhoea or irritable bowel syndrome, to lower cholesterol levels or to improve host immunity. In animals, enterococcal probiotics are mainly used to treat or prevent diarrhoea, for immune stimulation or to improve growth. From a food microbiological point of view, the safety of the bacteria used as probiotics must be assured, and data on the major strains in use so far indicate that they are safe. The advantage of use of probiotics in slaughter animals, from a food microbiological point of view, lies in the reduction of zoonotic pathogens in the gastrointestinal tract of animals which prevents the transmission of these pathogens via food. The use of enterococcal probiotics should, in view of the development of problematic lineages and the potential for gene transfer in the gastrointestinal tract of both humans and animals, be carefully monitored, and the advantages of using these and new strains should be considered in a well contemplated risk/benefit analysis.
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Affiliation(s)
- Charles M A P Franz
- Department of Safety and Quality of Fruit and Vegetables, Max Rubner-Institute, Federal Research Institute of Nutrition and Food, Haid-und-Neu-Str.9, D-76131 Karlsruhe, Germany.
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Ma Z, Wang Y, Zhu X, Zhang C, Li S, Jin L, Shen Y, Haapasalo M. Role of polymorphonuclear neutrophils in the clearance of Enterococcus faecalis derived from saliva and infected root canals. J Endod 2011; 37:346-52. [PMID: 21329819 DOI: 10.1016/j.joen.2010.11.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 11/24/2010] [Accepted: 11/30/2010] [Indexed: 01/12/2023]
Abstract
OBJECTIVES The goal of this study was to measure (1) the ability of polymorphonuclear neutrophil leukocytes (PMNs) to kill oral Enterococcus faecalis strains, (2) up-regulation of inflammatory mediators by PMNs in interaction with E. faecalis, and (3) the ability of E. faecalis to cause inflammation in mouse muscle tissue. METHODS Fifteen endodontic and nine saliva strains of E. faecalis were isolated and identified by specific 16S ribosomal RNA (16S rRNA) primers. The bacteria were grown in BHI broth and incubated with mouse PMN in appropriate media to determine the ability of the PMNs to kill the bacteria. In other experiments up-regulation of interleukin (IL)-1α, tumor necrosis factor α (TNF-α), matrix metalloproteinase-8 (MMP-8), and cyclooxygenase (COX)-2 messenger RNA in the PMNs was measured after exposure of the leukocytes to the bacteria using real-time polymerase chain reaction. Finally, the inflammatory potential of and PMN response to E. faecalis suspension in mouse muscle tissue was examined from histological sections using hematoxylin-eosin staining and immunostaining. RESULTS Murine PMNs killed about 80% of the E. faecalis cells in 1 hour, irrespective of the source of isolation of the strains. Quantitative PCR results showed that IL-1α, TNF-α, MMP-8, and COX-2 messenger RNA were markedly up-regulated in E. faecalis-stimulated PMNs or in E. faecalis-invaded muscular tissues. MMP-8 messenger RNA level was positively related to COX-2 messenger RNA level. Histological evaluation and immunostaining disclosed that all E. faecalis strains could recruit PMNs to the local infectious sites and cause abscess formation. CONCLUSION E. faecalis strains from saliva and infected root canals have the potential to recruit PMNs in the infectious sites leading to inflammation via up-regulation of PMN IL-1α, TNF-α, MMP-8, and COX-2. PMNs can play an important role in killing of E. faecalis.
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Affiliation(s)
- Zeyun Ma
- Department of Special Dentistry, Peking University School and Hospital of Stomatology, Beijing, China
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49
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Clewell DB. Tales of conjugation and sex pheromones: A plasmid and enterococcal odyssey. Mob Genet Elements 2011; 1:38-54. [PMID: 22016844 PMCID: PMC3190283 DOI: 10.4161/mge.1.1.15409] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 03/03/2011] [Indexed: 12/11/2022] Open
Abstract
This review covers highlights of the author's experience becoming and working as a plasmid biologist. The account chronicles a progression from studies of ColE1 DNA in Escherichia coli to Gram-positive bacteria with an emphasis on conjugation in enterococci. It deals with gene amplification, conjugative transposons and sex pheromones in the context of bacterial antibiotic resistance.
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Affiliation(s)
- Don B Clewell
- Biologic and Materials Sciences; School of Dentistry and Microbiology and Immunology; Medical School; The University of Michigan; Ann Arbor, MI USA
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50
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Hajishengallis G, Lambris JD. Microbial manipulation of receptor crosstalk in innate immunity. Nat Rev Immunol 2011; 11:187-200. [PMID: 21350579 DOI: 10.1038/nri2918] [Citation(s) in RCA: 218] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In the arms race of host-microbe co-evolution, successful microbial pathogens have evolved ingenious ways to evade host immune responses. In this Review, we focus on 'crosstalk manipulation' - the microbial strategies that instigate, subvert or disrupt the molecular signalling crosstalk between receptors of the innate immune system. This proactive interference undermines host defences and contributes to microbial adaptive fitness and persistent infections. Understanding how pathogens exploit host receptor crosstalk mechanisms and infiltrate the host signalling network is essential for developing interventions to redirect the host response and achieve protective immunity.
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Affiliation(s)
- George Hajishengallis
- University of Louisville, Department of Microbiology and Immunology, Louisville, Kentucky 40292, USA.
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