1
|
Yamasaki Y, Singh P, Vimonish R, Ueti M, Bankhead T. Development and Application of an In Vitro Tick Feeding System to Identify Ixodes Tick Environment-Induced Genes of the Lyme Disease Agent, Borrelia burgdorferi. Pathogens 2024; 13:487. [PMID: 38921785 PMCID: PMC11207009 DOI: 10.3390/pathogens13060487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 06/04/2024] [Accepted: 06/05/2024] [Indexed: 06/27/2024] Open
Abstract
The bacterial agent of Lyme disease, Borrelia burgdorferi, exists in an enzootic cycle by adapting to dissimilar mammalian and tick environments. The genetic elements necessary for host and vector adaptation are spread across a bacterial genome comprised of a linear chromosome and essential linear and circular plasmids. The promoter trap system, In Vivo Expression Technology (IVET), has been used to identify promoters of B. burgdorferi that are transcriptionally active specifically during infection of a murine host. However, an observed infection bottleneck effect in mice prevented the application of this system to study promoters induced in a tick environment. In this study, we adapted a membrane-based in vitro feeding system as a novel method to infect the Ixodes spp. vector with B. burgdorferi. Once adapted, we performed IVET screens as a proof of principle via an infected bloodmeal on the system. The screen yielded B. burgdorferi promoters that are induced during tick infection and verified relative expression levels using qRT-PCR. The results of our study demonstrate the potential of our developed in vitro tick feeding system and IVET systems to gain insight into the adaptive gene expression of the Lyme disease bacteria to the tick vector.
Collapse
Affiliation(s)
- Youki Yamasaki
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA; (Y.Y.); (P.S.); (R.V.)
| | - Preeti Singh
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA; (Y.Y.); (P.S.); (R.V.)
| | - Rubikah Vimonish
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA; (Y.Y.); (P.S.); (R.V.)
| | - Massaro Ueti
- Animal Disease Research Unit, United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Pullman, WA 99164, USA;
| | - Troy Bankhead
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA; (Y.Y.); (P.S.); (R.V.)
| |
Collapse
|
2
|
Uriot O, Kebouchi M, Lorson E, Galia W, Denis S, Chalancon S, Hafeez Z, Roux E, Genay M, Blanquet-Diot S, Dary-Mourot A. Identification of Streptococcus thermophilus Genes Specifically Expressed under Simulated Human Digestive Conditions Using R-IVET Technology. Microorganisms 2021; 9:microorganisms9061113. [PMID: 34064045 PMCID: PMC8224003 DOI: 10.3390/microorganisms9061113] [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: 05/07/2021] [Revised: 05/18/2021] [Accepted: 05/19/2021] [Indexed: 11/16/2022] Open
Abstract
Despite promising health effects, the probiotic status of Streptococcus thermophilus, a lactic acid bacterium widely used in dairy industry, requires further documentation of its physiological status during human gastrointestinal passage. This study aimed to apply recombinant-based in vivo technology (R-IVET) to identify genes triggered in a S. thermophilus LMD-9 reference strain under simulated digestive conditions. First, the R-IVET chromosomal cassette and plasmid genomic library were designed to positively select activated genes. Second, recombinant clones were introduced into complementary models mimicking the human gut, the Netherlands Organization for Applied Scientific Research (TNO) gastrointestinal model imitating the human stomach and small intestine, the Caco-2 TC7 cell line as a model of intestinal epithelium, and anaerobic batch cultures of human feces as a colon model. All inserts of activated clones displayed a promoter activity that differed from one digestive condition to another. Our results also showed that S. thermophilus adapted its metabolism to stressful conditions found in the gastric and colonic competitive environment and modified its surface proteins during adhesion to Caco-2 TC7 cells. Activated genes were investigated in a collection of S. thermophilus strains showing various resistance levels to gastrointestinal stresses, a first stage in the identification of gut resistance markers and a key step in probiotic selection.
Collapse
Affiliation(s)
- Ophélie Uriot
- EA 7488 Calbinotox Composés Alimentaires Biofonctionnalités & Risque Neurotoxique, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy, France; (O.U.); (M.K.); (E.L.); (W.G.); (Z.H.); (E.R.); (M.G.)
- UMR 454 MEDIS Microbiology, Digestive Environment and Health, Université Clermont Auvergne, INRAe, 63000 Clermont-Ferrand, France; (S.D.); (S.C.); (S.B.-D.)
| | - Mounira Kebouchi
- EA 7488 Calbinotox Composés Alimentaires Biofonctionnalités & Risque Neurotoxique, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy, France; (O.U.); (M.K.); (E.L.); (W.G.); (Z.H.); (E.R.); (M.G.)
| | - Emilie Lorson
- EA 7488 Calbinotox Composés Alimentaires Biofonctionnalités & Risque Neurotoxique, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy, France; (O.U.); (M.K.); (E.L.); (W.G.); (Z.H.); (E.R.); (M.G.)
| | - Wessam Galia
- EA 7488 Calbinotox Composés Alimentaires Biofonctionnalités & Risque Neurotoxique, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy, France; (O.U.); (M.K.); (E.L.); (W.G.); (Z.H.); (E.R.); (M.G.)
- UMR 5557 Microbial Ecology, Research Group on Bacterial Opportunistic Pathogens and Environment, CNRS, VetAgro Sup, 69280 Marcy L’Etoile, France
| | - Sylvain Denis
- UMR 454 MEDIS Microbiology, Digestive Environment and Health, Université Clermont Auvergne, INRAe, 63000 Clermont-Ferrand, France; (S.D.); (S.C.); (S.B.-D.)
| | - Sandrine Chalancon
- UMR 454 MEDIS Microbiology, Digestive Environment and Health, Université Clermont Auvergne, INRAe, 63000 Clermont-Ferrand, France; (S.D.); (S.C.); (S.B.-D.)
| | - Zeeshan Hafeez
- EA 7488 Calbinotox Composés Alimentaires Biofonctionnalités & Risque Neurotoxique, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy, France; (O.U.); (M.K.); (E.L.); (W.G.); (Z.H.); (E.R.); (M.G.)
| | - Emeline Roux
- EA 7488 Calbinotox Composés Alimentaires Biofonctionnalités & Risque Neurotoxique, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy, France; (O.U.); (M.K.); (E.L.); (W.G.); (Z.H.); (E.R.); (M.G.)
- INRIA/IRISA, GenScale Bioinformatics Team, 35042 Rennes, France
| | - Magali Genay
- EA 7488 Calbinotox Composés Alimentaires Biofonctionnalités & Risque Neurotoxique, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy, France; (O.U.); (M.K.); (E.L.); (W.G.); (Z.H.); (E.R.); (M.G.)
| | - Stéphanie Blanquet-Diot
- UMR 454 MEDIS Microbiology, Digestive Environment and Health, Université Clermont Auvergne, INRAe, 63000 Clermont-Ferrand, France; (S.D.); (S.C.); (S.B.-D.)
| | - Annie Dary-Mourot
- EA 7488 Calbinotox Composés Alimentaires Biofonctionnalités & Risque Neurotoxique, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy, France; (O.U.); (M.K.); (E.L.); (W.G.); (Z.H.); (E.R.); (M.G.)
- Correspondence:
| |
Collapse
|
3
|
Application of Recombinase-Based In Vivo Expression Technology to Bifidobacterium longum subsp. longum for Identification of Genes Induced in the Gastrointestinal Tract of Mice. Microorganisms 2020; 8:microorganisms8030410. [PMID: 32183191 PMCID: PMC7143038 DOI: 10.3390/microorganisms8030410] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 03/07/2020] [Accepted: 03/10/2020] [Indexed: 12/13/2022] Open
Abstract
Bifidobacteria are one of the major components in human gut microbiota and well-known as beneficial microbes. However, clarification of commensal mechanisms of bifidobacteria in the intestines is still ongoing, especially in the presence of the gut microbiota. Here, we applied recombinase-based in vivo expression technology (R-IVET) using the bacteriophage P1 Cre/loxP system to Bifidobacterium longum subsp. longum 105-A (B. longum 105-A) to identify genes that are specifically expressed in the gastrointestinal tract of conventionally raised mice. Oral administration of the genomic DNA library of B. longum 105-A to conventionally raised mice resulted in the identification of 73 in vivo-induced genes. Four out of seven tested genes were verified in vivo-specific induction at least in the cecum by quantitative reverse transcription PCR. Although there is still room for improvement of the system, our findings can contribute to expanding our understanding of the commensal behavior of B. longum in the gut ecosystem.
Collapse
|
4
|
Adaptation to Adversity: the Intermingling of Stress Tolerance and Pathogenesis in Enterococci. Microbiol Mol Biol Rev 2019; 83:83/3/e00008-19. [PMID: 31315902 DOI: 10.1128/mmbr.00008-19] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Enterococcus is a diverse and rugged genus colonizing the gastrointestinal tract of humans and numerous hosts across the animal kingdom. Enterococci are also a leading cause of multidrug-resistant hospital-acquired infections. In each of these settings, enterococci must contend with changing biophysical landscapes and innate immune responses in order to successfully colonize and transit between hosts. Therefore, it appears that the intrinsic durability that evolved to make enterococci optimally competitive in the host gastrointestinal tract also ideally positioned them to persist in hospitals, despite disinfection protocols, and acquire new antibiotic resistances from other microbes. Here, we discuss the molecular mechanisms and regulation employed by enterococci to tolerate diverse stressors and highlight the role of stress tolerance in the biology of this medically relevant genus.
Collapse
|
5
|
Selection of Borrelia burgdorferi Promoter Sequences Active During Mammalian Infection Using In Vivo Expression Technology. Methods Mol Biol 2018; 1690:137-154. [PMID: 29032543 DOI: 10.1007/978-1-4939-7383-5_12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Abstract
In vivo expression technology (IVET) has been applied to a variety of organisms to identify active promoters in specific environments or growth conditions of interest. Here, we describe modifications to employ this genome-wide screening method for Borrelia burgdorferi, the Lyme disease spirochete, during an active murine infection. Utilization of this technique provides valuable insights into the B. burgdorferi transcriptome during infection, despite the low bacterial numbers in the mammalian host environment.
Collapse
|
6
|
A urine-dependent human urothelial organoid offers a potential alternative to rodent models of infection. Sci Rep 2018; 8:1238. [PMID: 29352171 PMCID: PMC5775255 DOI: 10.1038/s41598-018-19690-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 01/04/2018] [Indexed: 12/13/2022] Open
Abstract
Murine models describe a defined host/pathogen interaction for urinary tract infection, but human cell studies are scant. Although recent human urothelial organoid models are promising, none demonstrate long-term tolerance to urine, the natural substrate of the tissue and of the uropathogens that live there. We developed a novel human organoid from progenitor cells which demonstrates key structural hallmarks and biomarkers of the urothelium. After three weeks of transwell culture with 100% urine at the apical interface, the organoid stratified into multiple layers. The apical surface differentiated into enlarged and flattened umbrella-like cells bearing characteristic tight junctions, structures resembling asymmetric unit membrane plaques, and a glycosaminoglycan layer. The apical cells also expressed cytokeratin-20, a spatial feature of the mammalian urothelium. Urine itself was necessary for full development, and undifferentiated cells were urine-tolerant despite the lack of membrane plaques and a glycosaminoglycan layer. Infection with Enterococcus faecalis revealed the expected invasive outcome, including urothelial sloughing and the formation of intracellular colonies similar to those previously observed in patient cells. This new biomimetic model could help illuminate invasive behaviours of uropathogens, and serve as a reproducible test bed for disease formation, treatment and resolution in patients.
Collapse
|
7
|
Goh HMS, Yong MHA, Chong KKL, Kline KA. Model systems for the study of Enterococcal colonization and infection. Virulence 2017; 8:1525-1562. [PMID: 28102784 PMCID: PMC5810481 DOI: 10.1080/21505594.2017.1279766] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 12/30/2016] [Accepted: 01/04/2017] [Indexed: 02/07/2023] Open
Abstract
Enterococcus faecalis and Enterococcus faecium are common inhabitants of the human gastrointestinal tract, as well as frequent opportunistic pathogens. Enterococci cause a range of infections including, most frequently, infections of the urinary tract, catheterized urinary tract, bloodstream, wounds and surgical sites, and heart valves in endocarditis. Enterococcal infections are often biofilm-associated, polymicrobial in nature, and resistant to antibiotics of last resort. Understanding Enterococcal mechanisms of colonization and pathogenesis are important for identifying new ways to manage and intervene with these infections. We review vertebrate and invertebrate model systems applied to study the most common E. faecalis and E. faecium infections, with emphasis on recent findings examining Enterococcal-host interactions using these models. We discuss strengths and shortcomings of each model, propose future animal models not yet applied to study mono- and polymicrobial infections involving E. faecalis and E. faecium, and comment on the significance of anti-virulence strategies derived from a fundamental understanding of host-pathogen interactions in model systems.
Collapse
Affiliation(s)
- H. M. Sharon Goh
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - M. H. Adeline Yong
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Kelvin Kian Long Chong
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
- Singapore Centre for Environmental Life Sciences Engineering, Interdisciplinary Graduate School, Nanyang Technological University, Singapore
| | - Kimberly A. Kline
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| |
Collapse
|
8
|
Adams PP, Flores Avile C, Popitsch N, Bilusic I, Schroeder R, Lybecker M, Jewett MW. In vivo expression technology and 5' end mapping of the Borrelia burgdorferi transcriptome identify novel RNAs expressed during mammalian infection. Nucleic Acids Res 2017; 45:775-792. [PMID: 27913725 PMCID: PMC5314773 DOI: 10.1093/nar/gkw1180] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/18/2016] [Accepted: 11/15/2016] [Indexed: 12/28/2022] Open
Abstract
Borrelia burgdorferi, the bacterial pathogen responsible for Lyme disease, modulates its gene expression profile in response to the environments encountered throughout its tick-mammal infectious cycle. To begin to characterize the B. burgdorferi transcriptome during murine infection, we previously employed an in vivo expression technology-based approach (BbIVET). This identified 233 putative promoters, many of which mapped to un-annotated regions of the complex, segmented genome. Herein, we globally identify the 5' end transcriptome of B. burgdorferi grown in culture as a means to validate non-ORF associated promoters discovered through BbIVET. We demonstrate that 119 BbIVET promoters are associated with transcription start sites (TSSs) and validate novel RNA transcripts using Northern blots and luciferase promoter fusions. Strikingly, 49% of BbIVET promoters were not found to associate with TSSs. This finding suggests that these sequences may be primarily active in the mammalian host. Furthermore, characterization of the 6042 B. burgdorferi TSSs reveals a variety of RNAs including numerous antisense and intragenic transcripts, leaderless RNAs, long untranslated regions and a unique nucleotide frequency for initiating intragenic transcription. Collectively, this is the first comprehensive map of TSSs in B. burgdorferi and characterization of previously un-annotated RNA transcripts expressed by the spirochete during murine infection.
Collapse
Affiliation(s)
- Philip P Adams
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, FL 32827, USA
| | - Carlos Flores Avile
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, FL 32827, USA
| | - Niko Popitsch
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Ivana Bilusic
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna 1030, Austria
| | - Renée Schroeder
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna 1030, Austria
| | - Meghan Lybecker
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO 80918, USA
| | - Mollie W Jewett
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, FL 32827, USA
| |
Collapse
|
9
|
Gaca AO, Gilmore MS. Killing of VRE Enterococcus faecalis by commensal strains: Evidence for evolution and accumulation of mobile elements in the absence of competition. Gut Microbes 2016; 7:90-6. [PMID: 26939857 PMCID: PMC4856443 DOI: 10.1080/19490976.2015.1127482] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Enterococci are members of the gastrointestinal tract of humans and most animals that, over the past 3 decades, have emerged as leading causes of multidrug resistant hospital acquired infection (HAI). In addition to their general hardiness, many traits have entered enterococcal lineages through horizontal gene transfer, which has led to the evolution of pathogenic hospital-associated lineages uniquely adapted for survival and proliferation in the antibiotic perturbed ecology of the gastrointestinal tract. We recently observed that the accretion of mobile genetic elements in the prototype vancomycin resistant E. faecalis, clinical isolate V583, renders it unable to co-exist with native enterococci in healthy human fecal flora. In this addendum, we discuss how these findings inform our understanding of how multidrug resistant enterococci evolve, and the implications for the development of treatments that limit colonization and spread of highly antibiotic refractory microbes of this type.
Collapse
Affiliation(s)
- Anthony O. Gaca
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA,Department of Microbiology and Immunobiology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Michael S. Gilmore
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA,Department of Microbiology and Immunobiology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
10
|
Tsai CJY, Loh JMS, Proft T. Galleria mellonella infection models for the study of bacterial diseases and for antimicrobial drug testing. Virulence 2016; 7:214-29. [PMID: 26730990 PMCID: PMC4871635 DOI: 10.1080/21505594.2015.1135289] [Citation(s) in RCA: 445] [Impact Index Per Article: 55.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Galleria mellonella (greater wax moth or honeycomb moth) has been introduced as an alternative model to study microbial infections. G. mellonella larvae can be easily and inexpensively obtained in large numbers and are simple to use as they don't require special lab equipment. There are no ethical constraints and their short life cycle makes them ideal for large-scale studies. Although insects lack an adaptive immune response, their innate immune response shows remarkable similarities with the immune response in vertebrates. This review gives a current update of what is known about the immune system of G. mellonella and provides an extensive overview of how G. mellonella is used to study the virulence of Gram-positive and Gram-negative bacteria. In addition, the use of G. mellonella to evaluate the efficacy of antimicrobial agents and experimental phage therapy are also discussed. The review concludes with a critical assessment of the current limitatons of G. mellonella infection models.
Collapse
Affiliation(s)
- Catherine Jia-Yun Tsai
- a Department of Molecular Medicine & Pathology , School of Medical Sciences, University of Auckland , Auckland , New Zealand.,b Maurice Wilkins Center, University of Auckland , Auckland , New Zealand
| | - Jacelyn Mei San Loh
- a Department of Molecular Medicine & Pathology , School of Medical Sciences, University of Auckland , Auckland , New Zealand.,b Maurice Wilkins Center, University of Auckland , Auckland , New Zealand
| | - Thomas Proft
- a Department of Molecular Medicine & Pathology , School of Medical Sciences, University of Auckland , Auckland , New Zealand.,b Maurice Wilkins Center, University of Auckland , Auckland , New Zealand
| |
Collapse
|
11
|
Pheromone killing of multidrug-resistant Enterococcus faecalis V583 by native commensal strains. Proc Natl Acad Sci U S A 2015; 112:7273-8. [PMID: 26039987 PMCID: PMC4466700 DOI: 10.1073/pnas.1500553112] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Multidrug-resistant enterococci are leading causes of hospital infection. The antibiotic-perturbed patient gut serves as a staging ground—small numbers of resistant hospital strains colonize and then, greatly amplify in the colon. Little is known of the colonization principles involved—whether hospital strains are competitive or noncompetitive with commensal enterococci or whether mobile elements comprising over 25% of the genome of the former impose significant fitness costs. We unexpectedly found that the prototype vancomycin-resistant Enterococcus faecalis strain V583 was actively killed by fecal organisms, and we traced that to pheromone production by commensal enterococci that trigger lethal mobile element cross-talk. This work highlights the importance of maintaining commensal enterococci in the gut of the hospitalized patient. Multidrug-resistant Enterococcus faecalis possess numerous mobile elements that encode virulence and antibiotic resistance traits as well as new metabolic pathways, often constituting over one-quarter of the genome. It was of interest to determine how this large accretion of mobile elements affects competitive growth in the gastrointestinal (GI) tract consortium. We unexpectedly observed that the prototype clinical isolate strain V583 was actively killed by GI tract flora, whereas commensal enterococci flourished. It was found that killing of V583 resulted from lethal cross-talk between accumulated mobile elements and that this cross-talk was induced by a heptapeptide pheromone produced by native E. faecalis present in the fecal consortium. These results highlight two important aspects of the evolution of multidrug-resistant enterococci: (i) the accretion of mobile elements in E. faecalis V583 renders it incompatible with commensal strains, and (ii) because of this incompatibility, multidrug-resistant strains sharing features found in V583 cannot coexist with commensal strains. The accumulation of mobile elements in hospital isolates of enterococci can include those that are inherently incompatible with native flora, highlighting the importance of maintaining commensal populations as means of preventing colonization and subsequent infection by multidrug-resistant strains.
Collapse
|
12
|
Muller C, Cacaci M, Sauvageot N, Sanguinetti M, Rattei T, Eder T, Giard JC, Kalinowski J, Hain T, Hartke A. The Intraperitoneal Transcriptome of the Opportunistic Pathogen Enterococcus faecalis in Mice. PLoS One 2015; 10:e0126143. [PMID: 25978463 PMCID: PMC4433114 DOI: 10.1371/journal.pone.0126143] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 03/29/2015] [Indexed: 01/22/2023] Open
Abstract
Enterococcus faecalis is a Gram-positive lactic acid intestinal opportunistic bacterium with virulence potential. For a better understanding of the adapation of this bacterium to the host conditions, we performed a transcriptome analysis of bacteria isolated from an infection site (mouse peritonitis) by RNA-sequencing. We identified a total of 211 genes with significantly higher transcript levels and 157 repressed genes. Our in vivo gene expression database reflects well the infection process since genes encoding important virulence factors like cytolysin, gelatinase or aggregation substance as well as stress response proteins, are significantly induced. Genes encoding metabolic activities are the second most abundant in vivo induced genes demonstrating that the bacteria are metabolically active and adapt to the special nutrient conditions of the host. α- and β- glucosides seem to be important substrates for E. faecalis inside the host. Compared to laboratory conditions, the flux through the upper part of glycolysis seems to be reduced and more carbon may enter the pentose phosphate pathway. This may reflect the need of the bacteria under infection conditions to produce more reducing power for biosynthesis. Another important substrate is certainly glycerol since both pathways of glycerol catabolism are strongly induced. Strongly in vivo induced genes should be important for the infection process. This assumption has been verified in a virulence test using well characterized mutants affected in glycerol metabolism. This showed indeed that mutants unable to metabolize this sugar alcohol are affected in organ colonisation in a mouse model.
Collapse
Affiliation(s)
- Cécile Muller
- U2RM-Stress and Virulence, University of Caen Basse-Normandie, EA4655, 14032 Caen, France
- * E-mail: (AH); (CM)
| | - Margherita Cacaci
- U2RM-Stress and Virulence, University of Caen Basse-Normandie, EA4655, 14032 Caen, France
- Institute of Microbiology, Catholic University of Sacred Heart, 00168, Rome, Italy
| | - Nicolas Sauvageot
- U2RM-Stress and Virulence, University of Caen Basse-Normandie, EA4655, 14032 Caen, France
| | - Maurizio Sanguinetti
- Institute of Microbiology, Catholic University of Sacred Heart, 00168, Rome, Italy
| | - Thomas Rattei
- CUBE-Division for Computational Systems Biology, Dept. of Microbiology and Ecosystem Science, University of Vienna, 1090 Vienna, Austria
| | - Thomas Eder
- CUBE-Division for Computational Systems Biology, Dept. of Microbiology and Ecosystem Science, University of Vienna, 1090 Vienna, Austria
| | - Jean-Christophe Giard
- U2RM-Stress and Virulence, University of Caen Basse-Normandie, EA4655, 14032 Caen, France
| | - Jörn Kalinowski
- Center for Biotechnology, Bielefeld University, 33594 Bielefeld, Germany
| | - Torsten Hain
- Institute of Medicine Microbiology, Gießen University, 35392 Gießen, Germany
| | - Axel Hartke
- U2RM-Stress and Virulence, University of Caen Basse-Normandie, EA4655, 14032 Caen, France
- * E-mail: (AH); (CM)
| |
Collapse
|
13
|
Arntzen MØ, Karlskås IL, Skaugen M, Eijsink VGH, Mathiesen G. Proteomic Investigation of the Response of Enterococcus faecalis V583 when Cultivated in Urine. PLoS One 2015; 10:e0126694. [PMID: 25915650 PMCID: PMC4411035 DOI: 10.1371/journal.pone.0126694] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 04/07/2015] [Indexed: 11/19/2022] Open
Abstract
Enterococcus faecalis is a robust bacterium, which is able to survive in and adapt to hostile environments such as the urinary tract and bladder. In this label-free quantitative proteomic study based on MaxQuant LFQ algorithms, we identified 127 proteins present in the secretome of the clinical vancomycin-resistant isolate E. faecalis V583 and we compared proteins secreted in the initial phase of cultivation in urine with the secretome during cultivation in standard laboratory medium, 2xYT. Of the 54 identified proteins predicted to be secreted, six were exclusively found after cultivation in urine including the virulence factor EfaA ("endocarditis specific antigen") and its homologue EF0577 ("adhesion lipoprotein"). These two proteins are both involved in manganese transport, known to be an important determinant of colonization and infection, and may additionally function as adhesins. Other detected urine-specific proteins are involved in peptide transport (EF0063 and EF3106) and protease inhibition (EF3054). In addition, we found an uncharacterized protein (EF0764), which had not previously been linked to the adaptation of V583 to a urine environment, and which is unique to E. faecalis. Proteins found in both environments included a histone-like protein, EF1550, that was up-regulated during cultivation in urine and that has a homologue in streptococci (HlpA) known to be involved in bacterial adhesion to host cells. Up-regulated secreted proteins included autolysins. These results from secretome analyses are largely compatible with previously published data from transcriptomics studies. All in all, the present data indicate that transport, in particular metal transport, adhesion, cell wall remodelling and the unknown function carried out by the unique EF0764 are important for enterococcal adaptation to the urine environment. These results provide a basis for a more targeted exploration of novel proteins involved in the adaptability and pathogenicity of E. faecalis.
Collapse
Affiliation(s)
- Magnus Øverlie Arntzen
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
- * E-mail:
| | - Ingrid Lea Karlskås
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Morten Skaugen
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Vincent G. H. Eijsink
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Geir Mathiesen
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| |
Collapse
|
14
|
Frank KL, Colomer-Winter C, Grindle SM, Lemos JA, Schlievert PM, Dunny GM. Transcriptome analysis of Enterococcus faecalis during mammalian infection shows cells undergo adaptation and exist in a stringent response state. PLoS One 2014; 9:e115839. [PMID: 25545155 PMCID: PMC4278851 DOI: 10.1371/journal.pone.0115839] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 12/01/2014] [Indexed: 11/30/2022] Open
Abstract
As both a commensal and a major cause of healthcare-associated infections in humans, Enterococcus faecalis is a remarkably adaptable organism. We investigated how E. faecalis adapts in a mammalian host as a pathogen by characterizing changes in the transcriptome during infection in a rabbit model of subdermal abscess formation using transcriptional microarrays. The microarray experiments detected 222 and 291 differentially regulated genes in E. faecalis OG1RF at two and eight hours after subdermal chamber inoculation, respectively. The profile of significantly regulated genes at two hours post-inoculation included genes involved in stress response, metabolism, nutrient acquisition, and cell surface components, suggesting genome-wide adaptation to growth in an altered environment. At eight hours post-inoculation, 88% of the differentially expressed genes were down-regulated and matched a transcriptional profile consistent with a (p)ppGpp-mediated stringent response. Subsequent subdermal abscess infections with E. faecalis mutants lacking the (p)ppGpp synthetase/hydrolase RSH, the small synthetase RelQ, or both enzymes, suggest that intracellular (p)ppGpp levels, but not stringent response activation, influence persistence in the model. The ability of cells to synthesize (p)ppGpp was also found to be important for growth in human serum and whole blood. The data presented in this report provide the first genome-wide insights on E. faecalis in vivo gene expression and regulation measured by transcriptional profiling during infection in a mammalian host and show that (p)ppGpp levels affect viability of E. faecalis in multiple conditions relevant to mammalian infection. The subdermal abscess model can serve as a novel experimental system for studying the E. faecalis stringent response in the context of the mammalian immune system.
Collapse
Affiliation(s)
- Kristi L. Frank
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Cristina Colomer-Winter
- Center for Oral Biology and Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Suzanne M. Grindle
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - José A. Lemos
- Center for Oral Biology and Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Patrick M. Schlievert
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Gary M. Dunny
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| |
Collapse
|
15
|
Enterococcus faecalis 6-phosphogluconolactonase is required for both commensal and pathogenic interactions with Manduca sexta. Infect Immun 2014; 83:396-404. [PMID: 25385794 DOI: 10.1128/iai.02442-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Enterococcus faecalis is a commensal and pathogen of humans and insects. In Manduca sexta, E. faecalis is an infrequent member of the commensal gut community, but its translocation to the hemocoel results in a commensal-to-pathogen switch. To investigate E. faecalis factors required for commensalism, we identified E. faecalis genes that are upregulated in the gut of M. sexta using recombinase-based in vivo expression technology (RIVET). The RIVET screen produced 113 clones, from which we identified 50 genes that are more highly expressed in the insect gut than in culture. The most frequently recovered gene was locus OG1RF_11582, which encodes a 6-phosphogluconolactonase that we designated pglA. A pglA deletion mutant was impaired in both pathogenesis and gut persistence in M. sexta and produced enhanced biofilms compared with the wild type in an in vitro polystyrene plate assay. Mutation of four other genes identified by RIVET did not affect persistence in caterpillar guts but led to impaired pathogenesis. This is the first identification of genetic determinants for E. faecalis commensal and pathogenic interactions with M. sexta. Bacterial factors identified in this model system may provide insight into colonization or persistence in other host-associated microbial communities and represent potential targets for interventions to prevent E. faecalis infections.
Collapse
|
16
|
Repizo GD, Espariz M, Blancato VS, Suárez CA, Esteban L, Magni C. Genomic comparative analysis of the environmental Enterococcus mundtii against enterococcal representative species. BMC Genomics 2014; 15:489. [PMID: 24942651 PMCID: PMC4076982 DOI: 10.1186/1471-2164-15-489] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 06/02/2014] [Indexed: 11/30/2022] Open
Abstract
Background Enterococcus mundtii is a yellow-pigmented microorganism rarely found in human infections. The draft genome sequence of E. mundtii was recently announced. Its genome encodes at least 2,589 genes and 57 RNAs, and 4 putative genomic islands have been detected. The objective of this study was to compare the genetic content of E. mundtii with respect to other enterococcal species and, more specifically, to identify genes coding for putative virulence traits present in enterococcal opportunistic pathogens. Results An in-depth mining of the annotated genome was performed in order to uncover the unique properties of this microorganism, which allowed us to detect a gene encoding the antimicrobial peptide mundticin among other relevant features. Moreover, in this study a comparative genomic analysis against commensal and pathogenic enterococcal species, for which genomic sequences have been released, was conducted for the first time. Furthermore, our study reveals significant similarities in gene content between this environmental isolate and the selected enterococci strains (sharing an “enterococcal gene core” of 805 CDS), which contributes to understand the persistence of this genus in different niches and also improves our knowledge about the genetics of this diverse group of microorganisms that includes environmental, commensal and opportunistic pathogens. Conclusion Although E. mundtii CRL1656 is phylogenetically closer to E. faecium, frequently responsible of nosocomial infections, this strain does not encode the most relevant relevant virulence factors found in the enterococcal clinical isolates and bioinformatic predictions indicate that it possesses the lowest number of putative pathogenic genes among the most representative enterococcal species. Accordingly, infection assays using the Galleria mellonella model confirmed its low virulence. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-489) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
| | | | | | | | | | - Christian Magni
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET) and Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario S2002LRK, Argentina.
| |
Collapse
|
17
|
Lindenstrauss AG, Ehrmann MA, Behr J, Landstorfer R, Haller D, Sartor RB, Vogel RF. Transcriptome analysis of Enterococcus faecalis toward its adaption to surviving in the mouse intestinal tract. Arch Microbiol 2014; 196:423-33. [PMID: 24700373 DOI: 10.1007/s00203-014-0982-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 02/27/2014] [Accepted: 03/24/2014] [Indexed: 12/15/2022]
Abstract
We have performed a transcriptomic in vivo study with Enterococcus faecalis OG1RF in the intestine of living mice to identify novel latent and adaptive fitness determinants within E. faecalis. From 2,658 genes that are present in E. faecalis strain OG1RF, 124 genes were identified as significantly differentially expressed within the intestinal tract of living mice as compared to exponential growth in BHI broth. The groups of significantly up- or down-regulated genes consisted of 94 and 30 genes, respectively, for which 46 and 18 a clear annotation to a functionally described protein was found. These included genes involved in energy metabolism (e.g., dhaK and glpK pathway), transport and binding mechanisms (e.g., phosphoenolpyruvate carbohydrate PTS) as well as fatty acid metabolism (fab genes). The novel putative fitness determinants found in this work may be helpful for future studies of E. faecalis adaptation to the intestinal tract, which is also a prerequisite for infection in a compromised or inflamed host.
Collapse
Affiliation(s)
- Angela G Lindenstrauss
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München, Weihenstephaner Steig 16, 85350, Freising, Germany
| | | | | | | | | | | | | |
Collapse
|
18
|
Horsley H, Malone-Lee J, Holland D, Tuz M, Hibbert A, Kelsey M, Kupelian A, Rohn JL. Enterococcus faecalis subverts and invades the host urothelium in patients with chronic urinary tract infection. PLoS One 2013; 8:e83637. [PMID: 24363814 PMCID: PMC3868479 DOI: 10.1371/journal.pone.0083637] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 11/05/2013] [Indexed: 01/24/2023] Open
Abstract
Bacterial urinary tract infections (UTI) are a major growing concern worldwide.
Uropathogenic Escherichia coli has been shown to invade the
urothelium during acute UTI in mice and humans, forming intracellular reservoirs
that can evade antibiotics and the immune response, allowing recurrence at a
later date. Other bacterial species, such as Staphylococcus
saprophyticus, Klebsiella pneumonia and
Salmonella enterica have also been shown to be invasive in
acute UTI. However, the role of intracellular infection in chronic UTI causing
more subtle lower urinary tract symptoms (LUTS), a particular problem in the
elderly population, is poorly understood. Moreover, the species of bacteria
involved remains largely unknown. A previous study of a large cohort of
non-acute LUTS patients found that Enterococcus faecalis was
frequently found in urine specimens. E. faecalis accounts for a
significant proportion of chronic bladder infections worldwide, although the
invasive lifestyle of this uropathogen has yet to be reported. Here, we wanted
to explore this question in more detail. We harvested urothelial cells shed in
response to inflammation and, using advanced imaging techniques, inspected them
for signs of bacterial pathology and invasion. We found strong evidence of
intracellular E. faecalis harboured within urothelial cells
shed from the bladder of LUTS patients. Furthermore, using a culture model
system, these patient-isolated strains of E. faecalis were able
to invade a transitional carcinoma cell line. In contrast, we found no evidence
of cellular invasion by E. coli in the patient cells or the
culture model system. Our data show that E. faecalis is highly
competent to invade in this context; therefore, these results have implications
for both the diagnosis and treatment of chronic LUTS.
Collapse
Affiliation(s)
- Harry Horsley
- Centre for Clinical Science and Technology, Research Department of
Clinical Physiology, Division of Medicine, University College London, London,
United Kingdom
| | - James Malone-Lee
- Centre for Clinical Science and Technology, Research Department of
Clinical Physiology, Division of Medicine, University College London, London,
United Kingdom
| | - David Holland
- Centre for Clinical Science and Technology, Research Department of
Clinical Physiology, Division of Medicine, University College London, London,
United Kingdom
| | - Madeleine Tuz
- Centre for Clinical Science and Technology, Research Department of
Clinical Physiology, Division of Medicine, University College London, London,
United Kingdom
| | - Andrew Hibbert
- Imaging Suite, Royal Veterinary College, London, United
Kingdom
| | - Michael Kelsey
- Department of Microbiology, The Whittington Hospital NHS Trust, London,
United Kingdom
| | - Anthony Kupelian
- Centre for Clinical Science and Technology, Research Department of
Clinical Physiology, Division of Medicine, University College London, London,
United Kingdom
| | - Jennifer L. Rohn
- Centre for Clinical Science and Technology, Research Department of
Clinical Physiology, Division of Medicine, University College London, London,
United Kingdom
- * E-mail:
| |
Collapse
|
19
|
Ellis TC, Jain S, Linowski AK, Rike K, Bestor A, Rosa PA, Halpern M, Kurhanewicz S, Jewett MW. In vivo expression technology identifies a novel virulence factor critical for Borrelia burgdorferi persistence in mice. PLoS Pathog 2013; 9:e1003567. [PMID: 24009501 PMCID: PMC3757035 DOI: 10.1371/journal.ppat.1003567] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 07/01/2013] [Indexed: 12/15/2022] Open
Abstract
Analysis of the transcriptome of Borrelia burgdorferi, the causative agent of Lyme disease, during infection has proven difficult due to the low spirochete loads in the mammalian tissues. To overcome this challenge, we have developed an In Vivo Expression Technology (IVET) system for identification of B. burgdorferi genes expressed during an active murine infection. Spirochetes lacking linear plasmid (lp) 25 are non-infectious yet highly transformable. Mouse infection can be restored to these spirochetes by expression of the essential lp25-encoded pncA gene alone. Therefore, this IVET-based approach selects for in vivo-expressed promoters that drive expression of pncA resulting in the recovery of infectious spirochetes lacking lp25 following a three week infection in mice. Screening of approximately 15,000 clones in mice identified 289 unique in vivo-expressed DNA fragments from across all 22 replicons of the B. burgdorferi B31 genome. The in vivo-expressed candidate genes putatively encode proteins in various functional categories including antigenicity, metabolism, motility, nutrient transport and unknown functions. Candidate gene bbk46 on essential virulence plasmid lp36 was found to be highly induced in vivo and to be RpoS-independent. Immunocompetent mice inoculated with spirochetes lacking bbk46 seroconverted but no spirochetes were recovered from mouse tissues three weeks post inoculation. However, the bbk46 gene was not required for B. burgdorferi infection of immunodeficient mice. Therefore, through an initial IVET screen in B. burgdorferi we have identified a novel in vivo-induced virulence factor critical for the ability of the spirochete to evade the humoral immune response and persistently infect mice.
Collapse
Affiliation(s)
- Tisha Choudhury Ellis
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, United States of America
| | - Sunny Jain
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, United States of America
| | - Angelika K. Linowski
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, United States of America
| | - Kelli Rike
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, United States of America
| | - Aaron Bestor
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Patricia A. Rosa
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Micah Halpern
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, United States of America
| | - Stephanie Kurhanewicz
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, United States of America
| | - Mollie W. Jewett
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, United States of America
| |
Collapse
|
20
|
Golińska E, Tomusiak A, Gosiewski T, Więcek G, Machul A, Mikołajczyk D, Bulanda M, Heczko PB, Strus M. Virulence factors of Enterococcus strains isolated from patients with inflammatory bowel disease. World J Gastroenterol 2013; 19:3562-3572. [PMID: 23801857 PMCID: PMC3691038 DOI: 10.3748/wjg.v19.i23.3562] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 01/23/2013] [Accepted: 03/27/2013] [Indexed: 02/06/2023] Open
Abstract
AIM: To determine the features of Enterococcus that contribute to the development and maintenance of the inflammatory process in patients with inflammatory bowel disease (IBD).
METHODS: Multiplex polymerase chain reaction (PCR) was applied to assess the presence of genes that encode virulence factors [surface aggregating protein (asa1), gelatinase (gelE), cytolysin (cylA), extracellular surface protein (esp) and hyaluronidase (hyl)] in the genomic DNA of 28 strains of Enterococcus isolated from the intestinal tissues of children with IBD (n = 16) and of children without IBD (controls; n = 12). Additionally, strains with confirmed presence of the gelE gene were tested by PCR for the presence of quorum sensing genes (fsrA, fsrB, fsrC) that control the gelatinase production. Gelatinase activity was tested on agar plates containing 1.6% gelatin. We also analysed the ability of Enterococcus strains to release and decompose hydrogen peroxide (using Analytical Merckoquant peroxide test strips) and tested their ability to adhere to Caco-2 human gut epithelium cells and form biofilms in vitro.
RESULTS: A comparison of the genomes of Enterococcus strains isolated from the inflamed mucosa of patients with IBD with those of the control group showed statistically significant differences in the frequency of the asa1 gene and the gelE gene. Furthermore, the cumulative occurrence of different virulence genes in the genome of a single strain of Enterococcus isolated from the IBD patient group is greater than in a strain from the control group, although no significant difference was found. Statistically significant differences in the decomposition of hydrogen peroxide and adherence to the Caco-2 epithelial cell line between the strains from the patient group and control group were demonstrated. The results also showed that profuse biofilm production was more frequent among Enterococcus strains isolated from children with IBD than in control strains.
CONCLUSION: Enterococcus strains that adhere strongly to the intestinal epithelium, form biofilms and possess antioxidant defence mechanisms seem to have the greatest influence on the inflammatory process.
Collapse
|
21
|
Teixeira N, Varahan S, Gorman MJ, Palmer KL, Zaidman-Remy A, Yokohata R, Nakayama J, Hancock LE, Jacinto A, Gilmore MS, de Fátima Silva Lopes M. Drosophila host model reveals new enterococcus faecalis quorum-sensing associated virulence factors. PLoS One 2013; 8:e64740. [PMID: 23734216 PMCID: PMC3667150 DOI: 10.1371/journal.pone.0064740] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 04/17/2013] [Indexed: 01/30/2023] Open
Abstract
Enterococcus faecalis V583 is a vancomycin-resistant clinical isolate which belongs to the hospital-adapted clade, CC2. This strain harbours several factors that have been associated with virulence, including the fsr quorum-sensing regulatory system that is known to control the expression of GelE and SprE proteases. To discriminate between genes directly regulated by Fsr, and those indirectly regulated as the result of protease expression or activity, we compared gene expression in isogenic mutants of V583 variously defective in either Fsr quorum sensing or protease expression. Quorum sensing was artificially induced by addition of the quorum signal, GBAP, exogenously in a controlled manner. The Fsr regulon was found to be restricted to five genes, gelE, sprE, ef1097, ef1351 and ef1352. Twelve additional genes were found to be dependent on the presence of GBAP-induced proteases. Induction of GelE and SprE by GBAP via Fsr resulted in accumulation of mRNA encoding lrgAB, and this induction was found to be lytRS dependent. Drosophila infection was used to discern varying levels of toxicity stemming from mutations in the fsr quorum regulatory system and the genes that it regulates, highlighting the contribution of LrgAB and bacteriocin EF1097 to infection toxicity. A contribution of SprE to infection toxicity was also detected. This work brought to light new players in E. faecalis success as a pathogen and paves the way for future studies on host tolerance mechanisms to infections caused by this important nosocomial pathogen.
Collapse
Affiliation(s)
- Neuza Teixeira
- ITQB Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
- Departments of Ophthalmology, and Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- CEDOC Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Sriram Varahan
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - Matthew J. Gorman
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - Kelli L. Palmer
- Departments of Ophthalmology, and Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Anna Zaidman-Remy
- CEDOC Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Ryoji Yokohata
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Fukuoka, Japan
| | - Jiro Nakayama
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Fukuoka, Japan
| | - Lynn E. Hancock
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - António Jacinto
- CEDOC Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Michael S. Gilmore
- Departments of Ophthalmology, and Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Maria de Fátima Silva Lopes
- ITQB Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
- IBET Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
- * E-mail:
| |
Collapse
|
22
|
Fernández M, Conde S, Duque E, Ramos JL. In vivo gene expression of Pseudomonas putida KT2440 in the rhizosphere of different plants. Microb Biotechnol 2013; 6:307-13. [PMID: 23433036 PMCID: PMC3815925 DOI: 10.1111/1751-7915.12037] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 12/14/2012] [Accepted: 01/10/2013] [Indexed: 11/29/2022] Open
Abstract
Pseudomonas putida KT2440 has the ability to colonize the rhizosphere of a wide range of plants and can reach cell densities in the range of 105–106 cfu g soil−1. Using the IVET technology we investigated which KT2440 genes were expressed in the rhizosphere of four different plants: pine, cypress, evergreen oak and rosemary. We identified 39 different transcriptional fusions containing the promoters of annotated genes that were preferentially expressed in the rhizosphere. Six of them were expressed in the rhizosphere of all the plant types tested, 11 were expressed in more than one plant and the remaining 22 fusions were found to be expressed in only one type of plant. Another 40 fusions were found to correspond to likely promoters that encode antisense RNAs of unknown function, some of which were isolated as fusions from the bacteria recovered in the rhizosphere from all of the plants, while others were specific to one or several of the plants. The results obtained in this study suggest that plant-specific signals are sensed by KT2440 in the rhizosphere and that the signals and consequent gene expression are related to the bacteria's successful establishment in this niche.
Collapse
Affiliation(s)
- Matilde Fernández
- Bio-Iliberis Research and Development, I+D Department, 18210, Peligros, Granada, Spain
| | | | | | | |
Collapse
|
23
|
Identification of fitness determinants in Enterococcus faecalis by differential proteomics. Arch Microbiol 2012; 195:121-30. [PMID: 23239053 DOI: 10.1007/s00203-012-0857-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 11/14/2012] [Accepted: 11/26/2012] [Indexed: 01/25/2023]
Abstract
Enterococcus (E.) faecalis is found as commensal in healthy humans, in a variety of fermented foods. It can serve as probiotic but also as pathogen causing endocarditis, bacteremia and urinary tract infections. We have employed a proteomic study with E. faecalis strain OG1RF under different growth conditions and in contact to mouse intestinal cells to identify novel latent and adaptive fitness determinants. These relate to changes in catabolic pathways (BudA), protein biosynthesis (AsnS), cellular surface biosynthesis (RmlA) and regulatory mechanisms (OmpR). This knowledge can be used to derive novel evidence-based targets, which can be used to further elucidate gene expression changes enhancing pathogenicity or fitness in a commensal strain and possibly delineate this species into groups of higher and lower risk for applications in a food or a medical context versus improved treatment strategies of the so far hard to cure diseases.
Collapse
|
24
|
Construction and application of a luxABCDE reporter system for real-time monitoring of Enterococcus faecalis gene expression and growth. Appl Environ Microbiol 2012; 78:7003-11. [PMID: 22843522 DOI: 10.1128/aem.02018-12] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The present work describes the construction of a novel molecular tool for luciferase-based bioluminescence (BL) tagging of Enterococcus faecalis. To this end, a vector (pSL101) and its derivatives conferring a genetically encoded bioluminescent phenotype on all tested strains of E. faecalis were constructed. pSL101 harbors the luxABCDE operon from pPL2lux and the pREG696 broad-host-range replicon and axe-txe toxin-antitoxin cassette, providing segregational stability for long-term plasmid persistence in the absence of antibiotic selection. The bioluminescent signals obtained from three highly expressed promoters correlated linearly (R(2) > 0.98) with the viable-cell count. We employed lux-tagged E. faecalis strains to monitor growth in real time in milk and urine in vitro. Furthermore, bioluminescence imaging (BLI) was used to visualize the magnitude of the bacterial burden during infection in the Galleria mellonella model system. To our knowledge, pSL101 is the first substrate addition-independent reporter system developed for BLI of E. faecalis and an efficient tool for spatiotemporal tracking of bacterial growth and quantitative determination of promoter activity in real time, noninvasively, in infection model systems.
Collapse
|
25
|
Abstract
The genus Enterococcus includes some of the most important nosocomial multidrug-resistant organisms, and these pathogens usually affect patients who are debilitated by other, concurrent illnesses and undergoing prolonged hospitalization. This Review discusses the factors involved in the changing epidemiology of enterococcal infections, with an emphasis on Enterococcus faecium as an emergent and challenging nosocomial problem. The effects of antibiotics on the gut microbiota and on colonization with vancomycin-resistant enterococci are highlighted, including how enterococci benefit from the antibiotic-mediated eradication of gram-negative members of the gut microbiota. Analyses of enterococcal genomes indicate that there are certain genetic lineages, including an E. faecium clade of ancient origin, with the ability to succeed in the hospital environment, and the possible virulence determinants that are found in these genetic lineages are discussed. Finally, we review the most important mechanisms of resistance to the antibiotics that are used to treat vancomycin-resistant enterococci.
Collapse
|
26
|
Identification of Avian pathogenic Escherichia coli genes that are induced in vivo during infection in chickens. Appl Environ Microbiol 2012; 78:3343-51. [PMID: 22344666 DOI: 10.1128/aem.07677-11] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Avian pathogenic Escherichia coli (APEC) is associated with extraintestinal infections in poultry causing a variety of diseases collectively known as colibacillosis. The host and bacterial factors influencing and/or responsible for carriage and systemic translocation of APEC inside the host are poorly understood. Identification of such factors could help in the understanding of its pathogenesis and in the subsequent development of control strategies. Recombination-based in vivo expression technology (RIVET) was used to identify APEC genes specifically expressed during infection in chickens. A total of 21 clones with in vivo-induced promoters were isolated from chicken livers and spleens, indicative of systemic infection. DNA sequencing of the cloned fragments revealed that 12 of the genes were conserved E. coli genes (metH, lysA, pntA, purL, serS, ybjE, ycdK [rutC], wcaJ, gspL, sdsR, ylbE, and yjiY), 6 of the genes were phage related/associated, and 3 genes were pathogen specific (tkt1, irp2, and eitD). These genes are involved in various cellular functions, such as metabolism, cell envelope and integrity, transport systems, and virulence. Others were phage related or have yet-unknown functions.
Collapse
|
27
|
Frank KL, Barnes AMT, Grindle SM, Manias DA, Schlievert PM, Dunny GM. Use of recombinase-based in vivo expression technology to characterize Enterococcus faecalis gene expression during infection identifies in vivo-expressed antisense RNAs and implicates the protease Eep in pathogenesis. Infect Immun 2012; 80:539-49. [PMID: 22144481 PMCID: PMC3264308 DOI: 10.1128/iai.05964-11] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 11/19/2011] [Indexed: 12/28/2022] Open
Abstract
Enterococcus faecalis is a member of the mammalian gastrointestinal microflora that has become a leading cause of nosocomial infections over the past several decades. E. faecalis must be able to adapt its physiology based on its surroundings in order to thrive in a mammalian host as both a commensal and a pathogen. We employed recombinase-based in vivo expression technology (RIVET) to identify promoters on the E. faecalis OG1RF chromosome that were specifically activated during the course of infection in a rabbit subdermal abscess model. The RIVET screen identified 249 putative in vivo-activated loci, over one-third of which are predicted to generate antisense transcripts. Three predicted antisense transcripts were detected in in vitro- and in vivo-grown cells, providing the first evidence of in vivo-expressed antisense RNAs in E. faecalis. Deletions in the in vivo-activated genes that encode glutamate 5-kinase (proB [EF0038]), the transcriptional regulator EbrA (ebrA [EF1809]), and the membrane metalloprotease Eep (eep [EF2380]) did not hinder biofilm formation in in vitro assays. In a rabbit model of endocarditis, the ΔebrA strain was fully virulent, the ΔproB strain was slightly attenuated, and the Δeep strain was severely attenuated. The Δeep virulence defect could be complemented by the expression of the wild-type gene in trans. Microscopic analysis of early Δeep biofilms revealed an abundance of small cellular aggregates that were not observed in wild-type biofilms. This work illustrates the use of a RIVET screen to provide information about the temporal activation of genes during infection, resulting in the identification and confirmation of a new virulence determinant in an important pathogen.
Collapse
Affiliation(s)
- Kristi L Frank
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA.
| | | | | | | | | | | |
Collapse
|
28
|
Lebreton F, Le Bras F, Reffuveille F, Ladjouzi R, Giard JC, Leclercq R, Cattoir V. Galleria mellonella as a model for studying Enterococcus faecium host persistence. J Mol Microbiol Biotechnol 2012; 21:191-6. [PMID: 22286046 DOI: 10.1159/000332737] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Enterococcus faecium is an opportunistic pathogen responsible for numerous outbreaks worldwide. The basis for the colonization capacities, host persistence and environmental stress response of the hospital-adapted clones emerging from E. faecium are poorly understood. In this study, we propose the use of Galleria mellonella as a simple nonmammalian model to assess E. faecium host persistence. Various strains (n = 10), including hospital-adapted, commensal or animal isolates and a SodA-deficient strain were used to assess the relevance of this model. Compared to Enterococcus faecalis, E. faecium strains do not appear very lethal in a Galleria killing assay. The ability of E. faecium strains to overcome host-immune responses and multiply within the host system was evaluated by monitoring bacterial loads following Galleria infection. Among the E. faecium strains, two hospital-adapted isolates displayed increased colonization ability. In contrast, inactivation of sodA, encoding a putative manganese-dependent superoxide dismutase, significantly reduced survival of E. faecium to Galleria defenses. Galleria appears to be a suitable and convenient surrogate model to study E. faecium survival to host defenses and the role of suspected virulence factors in the colonization process.
Collapse
Affiliation(s)
- François Lebreton
- EA2128, Service de Microbiologie, Centre Hospitalier Universitaire, Université de Caen Basse-Normandie, Caen, France
| | | | | | | | | | | | | |
Collapse
|
29
|
Li ZW, Shen YH, Xiang ZH, Zhang Z. Pathogen-origin horizontally transferred genes contribute to the evolution of Lepidopteran insects. BMC Evol Biol 2011; 11:356. [PMID: 22151541 PMCID: PMC3252269 DOI: 10.1186/1471-2148-11-356] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 12/12/2011] [Indexed: 12/31/2022] Open
Abstract
Background Horizontal gene transfer (HGT), a source of genetic variation, is generally considered to facilitate hosts' adaptability to environments. However, convincing evidence supporting the significant contribution of the transferred genes to the evolution of metazoan recipients is rare. Results In this study, based on sequence data accumulated to date, we used a unified method consisting of similarity search and phylogenetic analysis to detect horizontally transferred genes (HTGs) between prokaryotes and five insect species including Drosophila melanogaster, Anopheles gambiae, Bombyx mori, Tribolium castaneum and Apis mellifera. Unexpectedly, the candidate HTGs were not detected in D. melanogaster, An. gambiae and T. castaneum, and 79 genes in Ap. mellifera sieved by the same method were considered as contamination based on other information. Consequently, 14 types of 22 HTGs were detected only in the silkworm. Additionally, 13 types of the detected silkworm HTGs share homologous sequences in species of other Lepidopteran superfamilies, suggesting that the majority of these HTGs were derived from ancient transfer events before the radiation of Ditrysia clade. On the basis of phylogenetic topologies and BLAST search results, donor bacteria of these genes were inferred, respectively. At least half of the predicted donor organisms may be entomopathogenic bacteria. The predicted biochemical functions of these genes include four categories: glycosyl hydrolase family, oxidoreductase family, amino acid metabolism, and others. Conclusions The products of HTGs detected in this study may take part in comprehensive physiological metabolism. These genes potentially contributed to functional innovation and adaptability of Lepidopteran hosts in their ancient lineages associated with the diversification of angiosperms. Importantly, our results imply that pathogens may be advantageous to the subsistence and prosperity of hosts through effective HGT events at a large evolutionary scale.
Collapse
Affiliation(s)
- Zi-Wen Li
- The Key Sericultural Laboratory of Agricultural Ministry, Southwest University, Chongqing 400715, China
| | | | | | | |
Collapse
|
30
|
PhoP and OxyR transcriptional regulators contribute to Yersinia pestis virulence and survival within Galleria mellonella. Microb Pathog 2011; 51:389-95. [PMID: 21964409 DOI: 10.1016/j.micpath.2011.08.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2011] [Revised: 08/25/2011] [Accepted: 08/27/2011] [Indexed: 11/23/2022]
Abstract
The virulence of Yersinia pestis KIM6+ was compared with multiple isolates of Yersinia pseudotuberculosis and Yersinia enterocolitica toward larvae of the greater wax moth Galleria mellonella. Although Y. pestis and Y. pseudotuberculosis were able to cause lethal infection in G. mellonella, these species appeared less virulent than the majority of Y. enterocolitica strains tested. Y. pestis survived primarily within hemocytes of G. mellonella, and induced a strong antibacterial peptide response that lasted for at least 3 days in surviving larvae. Immunization with dead bacteria to induce an antibacterial response led to increased survival of the larvae following infection. Mutant strains lacking the either phoP or oxyR, which were less resistant to antibacterial peptides and hydrogen peroxide respectively, were attenuated and restoration of the wild-type genes on plasmids restored virulence. Our results indicate that the Y. pseudotuberculosis-Y. pestis lineage is not as virulent toward G. mellonella as are the majority of Y. enterocolitica isolates. Further, we have shown that G. mellonella is a useful infection model for analyzing Y. pestis host-pathogen interactions, and antibacterial peptide resistance mediated by phoP and reactive oxygen defense mediated by oxyR are important for Y. pestis infection of this insect.
Collapse
|
31
|
Pflughoeft KJ, Versalovic J. Human microbiome in health and disease. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2011; 7:99-122. [PMID: 21910623 DOI: 10.1146/annurev-pathol-011811-132421] [Citation(s) in RCA: 305] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mammals are complex assemblages of mammalian and bacterial cells organized into functional organs, tissues, and cellular communities. Human biology can no longer concern itself only with human cells: Microbiomes at different body sites and functional metagenomics must be considered part of systems biology. The emergence of metagenomics has resulted in the generation of vast data sets of microbial genes and pathways present in different body habitats. The profound differences between microbiomes in various body sites reveal how metagenomes contribute to tissue and organ function. As next-generation DNA-sequencing methods provide whole-metagenome data in addition to gene-expression profiling, metaproteomics, and metabonomics, differences in microbial composition and function are being linked to health and disease states in different organs and tissues. Global parameters of microbial communities may provide valuable information regarding human health status and disease predisposition. More detailed knowledge of the human microbiome will yield next-generation diagnostics and therapeutics for various acute, chronic, localized, and systemic human diseases.
Collapse
Affiliation(s)
- Kathryn J Pflughoeft
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas 77030, USA.
| | | |
Collapse
|