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Choudhary E, Sharma R, Pal P, Agarwal N. Deciphering the Proteomic Landscape of Mycobacterium tuberculosis in Response to Acid and Oxidative Stresses. ACS OMEGA 2022; 7:26749-26766. [PMID: 35936415 PMCID: PMC9352160 DOI: 10.1021/acsomega.2c03092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 07/05/2022] [Indexed: 06/15/2023]
Abstract
The fundamental to the pathogenicity of Mycobacterium tuberculosis (Mtb) is the modulation in the control mechanisms that play a role in sensing and counteracting the microbicidal milieu encompassing various cellular stresses inside the human host. To understand such changes, we measured the cellular proteome of Mtb subjected to different stresses using a quantitative proteomics approach. We identified defined sets of Mtb proteins that are modulated in response to acid and a sublethal dose of diamide and H2O2 treatments. Notably, proteins involved in metabolic, catalytic, and binding functions are primarily affected under these stresses. Moreover, our analysis led to the observations that during acidic stress Mtb enters into energy-saving mode simultaneously modulating the acid tolerance system, whereas under diamide and H2O2 stresses, there were prominent changes in the biosynthesis and homeostasis pathways, primarily modifying the resistance mechanism in diamide-treated bacteria while causing metabolic arrest in H2O2-treated bacilli. Overall, we delineated the adaptive mechanisms that Mtb may utilize under physiological stresses and possible overlap between the responses to these stress conditions. In addition to offering important protein signatures that can be exploited for future mechanistic studies, our study highlights the importance of proteomics in understanding complex adjustments made by the human pathogen during infection.
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Affiliation(s)
- Eira Choudhary
- Laboratory
of Mycobacterial Genetics, Translational
Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad121001, Haryana, India
- Symbiosis
School of Biomedical Sciences, Symbiosis
International (Deemed University), Pune412115, Maharashtra, India
| | - Rishabh Sharma
- Laboratory
of Mycobacterial Genetics, Translational
Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad121001, Haryana, India
| | - Pramila Pal
- Laboratory
of Mycobacterial Genetics, Translational
Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad121001, Haryana, India
- Jawaharlal
Nehru University, New
Mehrauli Road, New Delhi110067, India
| | - Nisheeth Agarwal
- Laboratory
of Mycobacterial Genetics, Translational
Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad121001, Haryana, India
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2
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Adaptation of the gut pathobiont Enterococcus faecalis to deoxycholate and taurocholate bile acids. Sci Rep 2022; 12:8485. [PMID: 35590028 PMCID: PMC9120511 DOI: 10.1038/s41598-022-12552-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 05/11/2022] [Indexed: 11/24/2022] Open
Abstract
Enterococcus faecalis is a natural inhabitant of the human gastrointestinal tract. This bacterial species is subdominant in a healthy physiological state of the gut microbiota (eubiosis) in adults, but can become dominant and cause infections when the intestinal homeostasis is disrupted (dysbiosis). The relatively high concentrations of bile acids deoxycholate (DCA) and taurocholate (TCA) hallmark eubiosis and dysbiosis, respectively. This study aimed to better understand how E. faecalis adapts to DCA and TCA. We showed that DCA impairs E. faecalis growth and possibly imposes a continuous adjustment in the expression of many essential genes, including a majority of ribosomal proteins. This may account for slow growth and low levels of E. faecalis in the gut. In contrast, TCA had no detectable growth effect. The evolving transcriptome upon TCA adaptation showed the early activation of an oligopeptide permease system (opp2) followed by the adjustment of amino acid and nucleotide metabolisms. We provide evidence that TCA favors the exploitation of oligopeptide resources to fuel amino acid needs in limiting oligopeptide conditions. Altogether, our data suggest that the combined effects of decreased DCA and increased TCA concentrations can contribute to the rise of E. faecalis population during dysbiosis.
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3
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van Hal SJ, Willems RJL, Gouliouris T, Ballard SA, Coque TM, Hammerum AM, Hegstad K, Pinholt M, Howden BP, Malhotra-Kumar S, Werner G, Yanagihara K, Earl AM, Raven KE, Corander J, Bowden R. The interplay between community and hospital Enterococcus faecium clones within health-care settings: a genomic analysis. THE LANCET. MICROBE 2022; 3:e133-e141. [PMID: 35146465 PMCID: PMC8810393 DOI: 10.1016/s2666-5247(21)00236-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND The genomic relationships among Enterococcus faecium isolates are the subject of ongoing research that seeks to clarify the origins of observed lineages and the extent of horizontal gene transfer between them, and to robustly identify links between genotypes and phenotypes. E faecium is considered to form distinct groups-A and B-corresponding to isolates derived from patients who were hospitalised (A) and isolates from humans in the community (B). The additional separation of A into the so-called clades A1 and A2 remains an area of uncertainty. We aimed to investigate the relationships between A1 and non-A1 groups and explore the potential role of non-A1 isolates in shaping the population structure of hospital E faecium. METHODS We collected short-read sequence data from invited groups that had previously published E faecium genome data. This hospital-based isolate collection could be separated into three groups (or clades, A1, A2, and B) by augmenting the study genomes with published sequences derived from human samples representing the previously defined genomic clusters. We performed phylogenetic analyses, by constructing maximum-likelihood phylogenetic trees, and identified historical recombination events. We assessed the pan-genome, did resistome analysis, and examined the genomic data to identify mobile genetic elements. Each genome underwent chromosome painting by use of ChromoPainter within FineSTRUCTURE software to assess ancestry and identify hybrid groups. We further assessed highly admixed regions to infer recombination directionality. FINDINGS We assembled a collection of 1095 hospital E faecium sequences from 34 countries, further augmented by 33 published sequences. 997 (88%) of 1128 genomes clustered as A1, 92 (8%) as A2, and 39 (4%) as B. We showed that A1 probably emerged as a clone from within A2 and that, because of ongoing gene flow, hospital isolates currently identified as A2 represent a genetic continuum between A1 and community E faecium. This interchange of genetic material between isolates from different groups results in the emergence of hybrid genomes between clusters. Of the 1128 genomes, 49 (4%) hybrid genomes were identified: 33 previously labelled as A2 and 16 previously labelled as A1. These interactions were fuelled by a directional pattern of recombination mediated by mobile genetic elements. By contrast, the contribution of B group genetic material to A1 was limited to a few small regions of the genome and appeared to be driven by genomic sweep events. INTERPRETATION A2 and B isolates coming into the hospital form an important reservoir for ongoing A1 adaptation, suggesting that effective long-term control of the effect of E faecium could benefit from strategies to reduce these genomic interactions, such as a focus on reducing the acquisition of hospital A1 strains by patients entering the hospital. FUNDING Wellcome Trust.
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Affiliation(s)
- Sebastiaan J van Hal
- Department of Infectious Diseases and Microbiology, Royal Prince Alfred Hospital, Sydney, NSW, Australia,Central Clinical School, University of Sydney, Sydney, NSW, Australia,Correspondence to: Sebastiaan J van Hal, Royal Prince Alfred Hospital, Sydney, NSW 2050, Australia
| | - Rob J L Willems
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, Netherlands
| | | | - Susan A Ballard
- Microbiological Diagnostic Unit Public Health Laboratory, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Teresa M Coque
- Department of Microbiology, Ramón y Cajal University Hospital and Ramón y Cajal Health Research Institute, Madrid, Spain,Network Research Centre for Epidemiology and Public Health, Madrid, Spain
| | | | - Kristin Hegstad
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, University Hospital of North-Norway, Department of Microbiology and Infection Control, Tromsø, Norway
| | - Mette Pinholt
- Department of Clinical Microbiology, Hvidovre University Hospital, Hvidovre, Denmark
| | - Benjamin P Howden
- Microbiological Diagnostic Unit Public Health Laboratory, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Surbhi Malhotra-Kumar
- Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, Universiteit Antwerpen, Wilrijk, Belgium
| | - Guido Werner
- National Reference Centre for Staphylococci and Enterococci, Division of Nosocomial Pathogens and Antibiotic Resistances, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Wernigerode, Germany
| | - Katsunori Yanagihara
- Department of Laboratory Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Ashlee M Earl
- Infectious Disease & Microbiome Program, Broad Institute, Cambridge, MA, USA
| | | | - Jukka Corander
- Department of Biostatistics, University of Oslo, Oslo, Norway,Parasites and Microbes, Wellcome Sanger Institute, Saffron Walden, UK
| | - Rory Bowden
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia,Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
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4
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Nogueira WG, Jaiswal AK, Tiwari S, Ramos RTJ, Ghosh P, Barh D, Azevedo V, Soares SC. Computational identification of putative common genomic drug and vaccine targets in Mycoplasma genitalium. Genomics 2021; 113:2730-2743. [PMID: 34118385 DOI: 10.1016/j.ygeno.2021.06.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 05/17/2021] [Accepted: 06/07/2021] [Indexed: 10/21/2022]
Abstract
Mycoplasma genitalium is an obligate intracellular bacterium that is responsible for several sexually transmitted infections, including non-gonococcal urethritis in men and several inflammatory reproductive tract syndromes in women. Here, we applied subtractive genomics and reverse vaccinology approaches for in silico prediction of potential vaccine and drug targets against five strains of M. genitalium. We identified 403 genes shared by all five strains, from which 104 non-host homologous proteins were selected, comprising of 44 exposed/secreted/membrane proteins and 60 cytoplasmic proteins. Based on the essentiality, functionality, and structure-based binding affinity, we finally predicted 19 (14 novel) putative vaccine and 7 (2 novel) candidate drug targets. The docking analysis showed six molecules from the ZINC database as promising drug candidates against the identified targets. Altogether, both vaccine candidates and drug targets identified here may contribute to the future development of therapeutic strategies to control the spread of M. genitalium worldwide.
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Affiliation(s)
- Wylerson G Nogueira
- Laboratório de Genética Celular e Molecular, Departamento de Genetica, Ecologia e Evolucao, Instituto de Ciências Biológicas,Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Arun Kumar Jaiswal
- Laboratório de Genética Celular e Molecular, Departamento de Genetica, Ecologia e Evolucao, Instituto de Ciências Biológicas,Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.; Department of Immunology, Microbiology and Parasitology, Universidade Federal do Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Sandeep Tiwari
- Laboratório de Genética Celular e Molecular, Departamento de Genetica, Ecologia e Evolucao, Instituto de Ciências Biológicas,Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil..
| | - Rommel T J Ramos
- Laboratory of Genomic and Bioinformatics, Center of Genomics and System Biology, Universidade Federal do Pará, Belém, Pará, Brazil
| | - Preetam Ghosh
- Department of Computer Science, Virginia Commonwealth University, Richmond VA-23284, USA
| | - Debmalya Barh
- Centre for Genomics and Applied Gene Technology, Institute of Integrative Omics and Applied Biotechnology (IIOAB), Nonakuri, Purba Medinipur, West Bengal, India
| | - Vasco Azevedo
- Laboratório de Genética Celular e Molecular, Departamento de Genetica, Ecologia e Evolucao, Instituto de Ciências Biológicas,Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Siomar C Soares
- Department of Immunology, Microbiology and Parasitology, Universidade Federal do Triângulo Mineiro, Uberaba, Minas Gerais, Brazil.
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5
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Forrest S, Welch M. Arming the troops: Post-translational modification of extracellular bacterial proteins. Sci Prog 2020; 103:36850420964317. [PMID: 33148128 PMCID: PMC10450907 DOI: 10.1177/0036850420964317] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Protein secretion is almost universally employed by bacteria. Some proteins are retained on the cell surface, whereas others are released into the extracellular milieu, often playing a key role in virulence. In this review, we discuss the diverse types and potential functions of post-translational modifications (PTMs) occurring to extracellular bacterial proteins.
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Affiliation(s)
- Suzanne Forrest
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Martin Welch
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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6
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Identification of the Lyso-Form N-Acyl Intramolecular Transferase in Low-GC Firmicutes. J Bacteriol 2017; 199:JB.00099-17. [PMID: 28320885 DOI: 10.1128/jb.00099-17] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 03/14/2017] [Indexed: 12/25/2022] Open
Abstract
Bacterial lipoproteins are embedded in the cell membrane of both Gram-positive and Gram-negative bacteria, where they serve numerous functions central to cell envelope physiology. Lipoproteins are tethered to the membrane by an N-acyl-S-(mono/di)-acyl-glyceryl-cysteine anchor that is variously acylated depending on the genus. In several low-GC, Gram-positive firmicutes, a monoacyl-glyceryl-cysteine with an N-terminal fatty acid (known as the lyso form) has been reported, though how it is formed is unknown. Here, through an intergenic complementation rescue assay in Escherichia coli, we report the identification of a common orthologous transmembrane protein in both Enterococcus faecalis and Bacillus cereus that is capable of forming lyso-form lipoproteins. When deleted from the native host, lipoproteins remain diacylated with a free N terminus, as maturation to the N-acylated lyso form is abolished. Evidence is presented suggesting that the previously unknown gene product functions through a novel intramolecular transacylation mechanism, transferring a fatty acid from the diacylglycerol moiety to the α-amino group of the lipidated cysteine. As such, the discovered gene has been named lipoprotein intramolecular transacylase (lit), to differentiate it from the gene for the intermolecular N-acyltransferase (lnt) involved in triacyl lipoprotein biosynthesis in Gram-negative organisms.IMPORTANCE This study identifies a new enzyme, conserved among low-GC, Gram-positive bacteria, that is involved in bacterial lipoprotein biosynthesis and synthesizes lyso-form lipoproteins. Its discovery is an essential first step in determining the physiological role of N-terminal lipoprotein acylation in Gram-positive bacteria and how these modifications impact bacterial cell envelope function.
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7
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Ikolo F, Zhang M, Harrington DJ, Robinson C, Waller AS, Sutcliffe IC, Black GW. Characterisation of SEQ0694 (PrsA/PrtM) of Streptococcus equi as a functional peptidyl-prolyl isomerase affecting multiple secreted protein substrates. MOLECULAR BIOSYSTEMS 2016; 11:3279-86. [PMID: 26466087 DOI: 10.1039/c5mb00543d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Peptidyl-prolyl isomerase (PPIase) lipoproteins have been shown to influence the virulence of a number of Gram-positive bacterial human and animal pathogens, most likely through facilitating the folding of cell envelope and secreted virulence factors. Here, we used a proteomic approach to demonstrate that the Streptococcus equi PPIase SEQ0694 alters the production of multiple secreted proteins, including at least two putative virulence factors (FNE and IdeE2). We demonstrate also that, despite some unusual sequence features, recombinant SEQ0694 and its central parvulin domain are functional PPIases. These data add to our knowledge of the mechanisms by which lipoprotein PPIases contribute to the virulence of streptococcal pathogens.
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Affiliation(s)
- Felicia Ikolo
- Department of Applied Sciences, Faculty of Health & Life Sciences, University of Northumbria at Newcastle, Newcastle upon Tyne, NE1 8ST, UK. and Department of Biochemistry, School of Medicine, St. George's University, True Blue, St. George's, Grenada
| | - Meng Zhang
- Department of Applied Sciences, Faculty of Health & Life Sciences, University of Northumbria at Newcastle, Newcastle upon Tyne, NE1 8ST, UK.
| | - Dean J Harrington
- Division of Biomedical Science, School of Life Sciences, University of Bradford, West Yorkshire, BD7 1DP, UK
| | - Carl Robinson
- Centre for Preventive Medicine, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU, UK
| | - Andrew S Waller
- Centre for Preventive Medicine, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU, UK
| | - Iain C Sutcliffe
- Department of Applied Sciences, Faculty of Health & Life Sciences, University of Northumbria at Newcastle, Newcastle upon Tyne, NE1 8ST, UK.
| | - Gary W Black
- Department of Applied Sciences, Faculty of Health & Life Sciences, University of Northumbria at Newcastle, Newcastle upon Tyne, NE1 8ST, UK.
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8
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Lipoproteins of Gram-Positive Bacteria: Key Players in the Immune Response and Virulence. Microbiol Mol Biol Rev 2016; 80:891-903. [PMID: 27512100 DOI: 10.1128/mmbr.00028-16] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Since the discovery in 1973 of the first of the bacterial lipoproteins (Lpp) in Escherichia coli, Braun's lipoprotein, the ever-increasing number of publications indicates the importance of these proteins. Bacterial Lpp belong to the class of lipid-anchored proteins that in Gram-negative bacteria are anchored in both the cytoplasmic and outer membranes and in Gram-positive bacteria are anchored only in the cytoplasmic membrane. In contrast to the case for Gram-negative bacteria, in Gram-positive bacteria lipoprotein maturation and processing are not vital. Physiologically, Lpp play an important role in nutrient and ion acquisition, allowing particularly pathogenic species to better survive in the host. Bacterial Lpp are recognized by Toll-like receptor 2 (TLR2) of the innate immune system. The important role of Lpp in Gram-positive bacteria, particularly in the phylum Firmicutes, as key players in the immune response and pathogenicity has emerged only in recent years. In this review, we address the role of Lpp in signaling and modulating the immune response, in inflammation, and in pathogenicity. We also address the potential of Lpp as promising vaccine candidates.
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9
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Becker K, Sander P. Mycobacterium tuberculosis lipoproteins in virulence and immunity - fighting with a double-edged sword. FEBS Lett 2016; 590:3800-3819. [PMID: 27350117 DOI: 10.1002/1873-3468.12273] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 06/06/2016] [Accepted: 06/26/2016] [Indexed: 02/06/2023]
Abstract
Bacterial lipoproteins are secreted membrane-anchored proteins characterized by a lipobox motif. This lipobox motif directs post-translational modifications at the conserved cysteine through the consecutive action of three enzymes: Lgt, LspA and Lnt, which results in di- or triacylated forms. Lipoproteins are abundant in all bacteria including Mycobacterium tuberculosis and often involved in virulence and immunoregulatory processes. On the one hand, disruption of the biosynthesis pathway of lipoproteins leads to attenuation of M. tuberculosis in vivo, and mycobacteria deficient for certain lipoproteins have been assessed as attenuated live vaccine candidates. On the other hand, several mycobacterial lipoproteins form immunodominant antigens which promote an immune response. Some of these have been explored in DNA or subunit vaccination approaches against tuberculosis. The immune recognition of specific lipoproteins, however, might also benefit long-term survival of M. tuberculosis through immune modulation, while others induce protective responses. Exploiting lipoproteins as vaccines is thus a complex matter which requires deliberative investigation. The dual role of lipoproteins in the immunity to and pathogenicity of mycobacteria is discussed here.
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Affiliation(s)
- Katja Becker
- Institute of Medical Microbiology, University of Zurich, Switzerland
| | - Peter Sander
- Institute of Medical Microbiology, University of Zurich, Switzerland
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10
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Qin W, Wang L, Zhai R, Ma Q, Liu J, Bao C, Zhang H, Sun C, Feng X, Gu J, Du C, Han W, Langford PR, Lei L. Trimeric autotransporter adhesins contribute to Actinobacillus pleuropneumoniae pathogenicity in mice and regulate bacterial gene expression during interactions between bacteria and porcine primary alveolar macrophages. Antonie van Leeuwenhoek 2015; 109:51-70. [PMID: 26494209 DOI: 10.1007/s10482-015-0609-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Accepted: 10/14/2015] [Indexed: 11/27/2022]
Abstract
Actinobacillus pleuropneumoniae is an important pathogen that causes respiratory disease in pigs. Trimeric autotransporter adhesin (TAA) is a recently discovered bacterial virulence factor that mediates bacterial adhesion and colonization. Two TAA coding genes have been found in the genome of A. pleuropneumoniae strain 5b L20, but whether they contribute to bacterial pathogenicity is unclear. In this study, we used homologous recombination to construct a double-gene deletion mutant, ΔTAA, in which both TAA coding genes were deleted and used it in in vivo and in vitro studies to confirm that TAAs participate in bacterial auto-aggregation, biofilm formation, cell adhesion and virulence in mice. A microarray analysis was used to determine whether TAAs can regulate other A. pleuropneumoniae genes during interactions with porcine primary alveolar macrophages. The results showed that deletion of both TAA coding genes up-regulated 36 genes, including ene1514, hofB and tbpB2, and simultaneously down-regulated 36 genes, including lgt, murF and ftsY. These data illustrate that TAAs help to maintain full bacterial virulence both directly, through their bioactivity, and indirectly by regulating the bacterial type II and IV secretion systems and regulating the synthesis or secretion of virulence factors. This study not only enhances our understanding of the role of TAAs but also has significance for those studying A. pleuropneumoniae pathogenesis.
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Affiliation(s)
- Wanhai Qin
- College of Veterinary Medicine, Jilin University, Changchun, People's Republic of China
| | - Lei Wang
- College of Veterinary Medicine, Jilin University, Changchun, People's Republic of China.,College of Animal Science, Henan Institute of Science and Technology, Xinxiang, People's Republic of China
| | - Ruidong Zhai
- College of Veterinary Medicine, Jilin University, Changchun, People's Republic of China
| | - Qiuyue Ma
- College of Veterinary Medicine, Jilin University, Changchun, People's Republic of China
| | - Jianfang Liu
- College of Veterinary Medicine, Jilin University, Changchun, People's Republic of China
| | - Chuntong Bao
- College of Veterinary Medicine, Jilin University, Changchun, People's Republic of China
| | - Hu Zhang
- School of Public Health, Jilin University, Changchun, People's Republic of China
| | - Changjiang Sun
- College of Veterinary Medicine, Jilin University, Changchun, People's Republic of China
| | - Xin Feng
- College of Veterinary Medicine, Jilin University, Changchun, People's Republic of China
| | - Jingmin Gu
- College of Veterinary Medicine, Jilin University, Changchun, People's Republic of China
| | - Chongtao Du
- College of Veterinary Medicine, Jilin University, Changchun, People's Republic of China
| | - Wenyu Han
- College of Veterinary Medicine, Jilin University, Changchun, People's Republic of China
| | - P R Langford
- Section of Paediatrics, Imperial College London, London, UK
| | - Liancheng Lei
- College of Veterinary Medicine, Jilin University, Changchun, People's Republic of China.
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11
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Romero-Saavedra F, Laverde D, Budin-Verneuil A, Muller C, Bernay B, Benachour A, Hartke A, Huebner J. Characterization of Two Metal Binding Lipoproteins as Vaccine Candidates for Enterococcal Infections. PLoS One 2015; 10:e0136625. [PMID: 26322633 PMCID: PMC4556446 DOI: 10.1371/journal.pone.0136625] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 08/05/2015] [Indexed: 12/19/2022] Open
Abstract
Background Enterococcus faecium and faecalis are Gram-positive opportunistic pathogens that have become leading causes of nosocomial infections over the last decades. Especially multidrug resistant enterococci have become a challenging clinical problem worldwide. Therefore, new treatment options are needed and the identification of alternative targets for vaccine development has emerged as a feasible alternative to fight the infections caused by these pathogens. Results We extrapolate the transcriptomic data from a mice peritonitis infection model in E. faecalis to identify putative up-regulated surface proteins under infection conditions in E. faecium. After the bionformatic analyses two metal binding lipoproteins were identified to have a high homology (>72%) between the two species, the manganese ABC transporter substrate-binding lipoprotein (PsaAfm,) and the zinc ABC transporter substrate-binding lipoprotein (AdcAfm). These candidate lipoproteins were overexpressed in Escherichia coli and purified. The recombinant proteins were used to produce rabbit polyclonal antibodies that were able to induce specific opsonic antibodies that mediated killing of the homologous strain E. faecium E155 as well as clinical strains E. faecium E1162, Enterococcus faecalis 12030, type 2 and type 5. Mice were passively immunized with the antibodies raised against recombinant lipoproteins, showing significant reduction of colony counts in mice livers after the bacterial challenge and demonstrating the efficacy of these metal binding lipoproteins as promising vaccine candidates to treat infections caused by these enterococcal pathogens. Conclusion Overall, our results demonstrate that these two metal binding lipoproteins elicited specific, opsonic and protective antibodies, with an extensive cross-reactivity and serotype-independent coverage among these two important nocosomial pathogens. Pointing these two protein antigens as promising immunogens, that can be used as single components or as carrier proteins together with polysaccharide antigens in vaccine development against enterococcal infections.
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Affiliation(s)
- Felipe Romero-Saavedra
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Freiburg, Germany
- EA4655 U2RM Stress/Virulence, University of Caen Lower-Normandy, Caen, France
| | - Diana Laverde
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Freiburg, Germany
- EA4655 U2RM Stress/Virulence, University of Caen Lower-Normandy, Caen, France
| | | | - Cécile Muller
- EA4655 U2RM Stress/Virulence, University of Caen Lower-Normandy, Caen, France
| | - Benoit Bernay
- Proteogen platform SFR ICORE 4206, University of Caen Lower-Normandy, Caen, France
| | - Abdellah Benachour
- EA4655 U2RM Stress/Virulence, University of Caen Lower-Normandy, Caen, France
| | - Axel Hartke
- EA4655 U2RM Stress/Virulence, University of Caen Lower-Normandy, Caen, France
| | - Johannes Huebner
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Freiburg, Germany
- Division of Pediatric Infectious Diseases, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
- * E-mail:
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12
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Theilacker C, Diederich AK, Otto A, Sava IG, Wobser D, Bao Y, Hese K, Broszat M, Henneke P, Becher D, Huebner J. Enterococcus faecalis Glycolipids Modulate Lipoprotein-Content of the Bacterial Cell Membrane and Host Immune Response. PLoS One 2015; 10:e0132949. [PMID: 26172831 PMCID: PMC4501811 DOI: 10.1371/journal.pone.0132949] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Accepted: 06/21/2015] [Indexed: 12/25/2022] Open
Abstract
In this study, we investigated the impact of the cell membrane composition of E. faecalis on its recognition by the host immune system. To this end, we employed an E. faecalis deletion mutant (ΔbgsA) that does not synthesize the major cell membrane glycolipid diglycosyl-diacylglycerol (DGlcDAG). Proteomic analysis revealed that 13 of a total of 21 upregulated surface-associated proteins of E. faecalis ΔbgsA were lipoproteins. This led to a total lipoprotein content in the cell membrane of 35.8% in ΔbgsA compared to only 9.4% in wild-type bacteria. Increased lipoprotein content strongly affected the recognition of ΔbgsA by mouse macrophages in vitro with an increased stimulation of TNF-α production by heat-fixed bacteria and secreted antigens. Inactivation of the prolipoprotein diacylglycerol transferase (lgt) in ΔbgsA abrogated TNF-α induction by a ΔbgsA_lgt double mutant indicating that lipoproteins mediate increased activation of mouse macrophages by ΔbgsA. Heat-fixed ΔbgsA bacteria, culture supernatant, or cell membrane lipid extract activated transfected HEK cells in a TLR2-dependent fashion; the same was not true of wild-type bacteria. In mice infected intraperitoneally with a sublethal dose of E. faecalis we observed a 70% greater mortality in mice infected with ΔbgsA compared with wild-type-infected mice. Increased mortality due to ΔbgsA infection was associated with elevated plasma levels of the inflammatory cytokines TNF-α, IL-6 and MIP-2. In summary, our results provide evidence that an E. faecalis mutant lacking its major bilayer forming glycolipid DGlcDAG upregulates lipoprotein expression leading to increased activation of the host innate immune system and virulence in vivo.
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Affiliation(s)
- Christian Theilacker
- Center for Chronic Immunodeficiency (CCI), University Medical Center Freiburg, Freiburg, Germany
- Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany
- * E-mail:
| | - Ann-Kristin Diederich
- Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany
- Division of Pediatric Infectious Diseases, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
- Department of Microbiology, Faculty of Biology, Albert-Ludwigs-University, Freiburg, Germany
| | - Andreas Otto
- Institute for Microbiology, Department of Microbial Physiology, Ernst-Moritz-Arndt-University, Greifswald, Germany
| | - Irina G. Sava
- Research Center for Nutrition and Food Science, Technical University Munich, Freising, Germany
| | - Dominique Wobser
- Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany
| | - Yinyin Bao
- Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany
| | - Katrin Hese
- Center for Chronic Immunodeficiency (CCI), University Medical Center Freiburg, Freiburg, Germany
| | - Melanie Broszat
- Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany
| | - Philipp Henneke
- Center for Chronic Immunodeficiency (CCI), University Medical Center Freiburg, Freiburg, Germany
- Center for Paediatrics and Adolescent Medicine, University Medical Center Freiburg, Freiburg, Germany
| | - Dörte Becher
- Institute for Microbiology, Department of Microbial Physiology, Ernst-Moritz-Arndt-University, Greifswald, Germany
| | - Johannes Huebner
- Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany
- Division of Pediatric Infectious Diseases, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
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Hao X, Lüthje FL, Qin Y, McDevitt SF, Lutay N, Hobman JL, Asiani K, Soncini FC, German N, Zhang S, Zhu YG, Rensing C. Survival in amoeba--a major selection pressure on the presence of bacterial copper and zinc resistance determinants? Identification of a "copper pathogenicity island". Appl Microbiol Biotechnol 2015; 99:5817-24. [PMID: 26088177 DOI: 10.1007/s00253-015-6749-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 05/22/2015] [Accepted: 05/27/2015] [Indexed: 11/24/2022]
Abstract
The presence of metal resistance determinants in bacteria usually is attributed to geological or anthropogenic metal contamination in different environments or associated with the use of antimicrobial metals in human healthcare or in agriculture. While this is certainly true, we hypothesize that protozoan predation and macrophage killing are also responsible for selection of copper/zinc resistance genes in bacteria. In this review, we outline evidence supporting this hypothesis, as well as highlight the correlation between metal resistance and pathogenicity in bacteria. In addition, we introduce and characterize the "copper pathogenicity island" identified in Escherichia coli and Salmonella strains isolated from copper- and zinc-fed Danish pigs.
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Affiliation(s)
- Xiuli Hao
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, People's Republic of China
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14
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Ocvirk S, Sava IG, Lengfelder I, Lagkouvardos I, Steck N, Roh JH, Tchaptchet S, Bao Y, Hansen JJ, Huebner J, Carroll IM, Murray BE, Sartor RB, Haller D. Surface-Associated Lipoproteins Link Enterococcus faecalis Virulence to Colitogenic Activity in IL-10-Deficient Mice Independent of Their Expression Levels. PLoS Pathog 2015; 11:e1004911. [PMID: 26067254 PMCID: PMC4466351 DOI: 10.1371/journal.ppat.1004911] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 04/24/2015] [Indexed: 12/22/2022] Open
Abstract
The commensal Enterococcus faecalis is among the most common causes of nosocomial infections. Recent findings regarding increased abundance of enterococci in the intestinal microbiota of patients with inflammatory bowel diseases and induction of colitis in IL-10-deficient (IL-10-/-) mice put a new perspective on the contribution of E. faecalis to chronic intestinal inflammation. Based on the expression of virulence-related genes in the inflammatory milieu of IL-10-/- mice using RNA-sequencing analysis, we characterized the colitogenic role of two bacterial structures that substantially impact on E. faecalis virulence by different mechanisms: the enterococcal polysaccharide antigen and cell surface-associated lipoproteins. Germ-free wild type and IL-10-/- mice were monoassociated with E. faecalis wild type OG1RF or the respective isogenic mutants for 16 weeks. Intestinal tissue and mesenteric lymph nodes (MLN) were collected to characterize tissue pathology, loss of intestinal barrier function, bacterial adhesion to intestinal epithelium and immune cell activation. Bone marrow-derived dendritic cells (BMDC) were stimulated with bacterial lysates and E. faecalis virulence was additionally investigated in three invertebrate models. Colitogenic activity of wild type E. faecalis (OG1RF score: 7.2±1.2) in monoassociated IL-10-/- mice was partially impaired in E. faecalis lacking enterococcal polysaccharide antigen (ΔepaB score: 4.7±2.3; p<0.05) and was almost completely abrogated in E. faecalis deficient for lipoproteins (Δlgt score: 2.3±2.3; p<0.0001). Consistently both E. faecalis mutants showed significantly impaired virulence in Galleria mellonella and Caenorhabditis elegans. Loss of E-cadherin in the epithelium was shown for all bacterial strains in inflamed IL-10-/- but not wild type mice. Inactivation of epaB in E. faecalis reduced microcolony and biofilm formation in vitro, altered bacterial adhesion to intestinal epithelium of germ-free Manduca sexta larvae and impaired penetration into the colonic mucus layer of IL-10-/- mice. Lipoprotein-deficient E. faecalis exhibited an impaired TLR2-mediated activation of BMDCs in vitro despite their ability to fully reactivate MLN cells as well as MLN-derived colitogenic T cells ex vivo. E. faecalis virulence factors accounting for bacterial adhesion to mucosal surfaces as well as intestinal barrier disruption partially contribute to colitogenic activity of E. faecalis. Beyond their well-known role in infections, cell surface-associated lipoproteins are essential structures for colitogenic activity of E. faecalis by mediating innate immune cell activation. Enterococcus faecalis is a commensal of the human intestinal core microbiota harboring several putative virulence factors, which highlight its role as opportunistic pathogen. This dualistic character is supported by recent evidence linking Enterococcus spp. to the pathogenesis of inflammatory bowel diseases (IBD). Although several studies suggest a crucial role for opportunistic pathogens in IBD pathogenesis targeting genetically susceptible individuals, the dynamic relationship between disease-relevant host compartments and specific bacterial structures able to trigger intestinal inflammation remain unclear. Here, we report that cell surface-associated lipoproteins and the enterococcal polysaccharide antigen, which are relevant for E. faecalis virulence in invertebrate infection models, but whose expression is minimally affected by the intestinal inflammatory milieu, exhibit colitogenic activity in a mouse model susceptible for chronic colitis. Bacterial lipoproteins trigger innate immune cell activation and are a critical prerequisite for E. faecalis-induced colitis. The enterococcal polysaccharide antigen mediates bacterial mucus penetration and adhesion to mucosal surfaces, promotes the formation of biofilm and contributes to E. faecalis colitogenic activity. Using E. faecalis as a model organism, we demonstrate that colitogenic activity of opportunistic pathogens can be assigned to specific bacterial structures, a finding that may help to identify the most essential steps in IBD-related microbe-host interactions.
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Affiliation(s)
- Soeren Ocvirk
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
| | - Irina G. Sava
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
| | - Isabella Lengfelder
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
| | - Ilias Lagkouvardos
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
| | - Natalie Steck
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
| | - Jung H. Roh
- Division of Infectious Diseases, Department of Internal Medicine, The University of Texas Medical School, Houston, Texas, United States of America
| | - Sandrine Tchaptchet
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Yinyin Bao
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Freiburg, Germany
| | - Jonathan J. Hansen
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Johannes Huebner
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Freiburg, Germany
| | - Ian M. Carroll
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Barbara E. Murray
- Division of Infectious Diseases, Department of Internal Medicine, The University of Texas Medical School, Houston, Texas, United States of America
| | - R. Balfour Sartor
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Dirk Haller
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
- * E-mail:
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A genomic virulence reference map of Enterococcus faecalis reveals an important contribution of phage03-like elements in nosocomial genetic lineages to pathogenicity in a Caenorhabditis elegans infection model. Infect Immun 2015; 83:2156-67. [PMID: 25776747 DOI: 10.1128/iai.02801-14] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 03/07/2015] [Indexed: 02/07/2023] Open
Abstract
In the present study, the commensal and pathogenic host-microbe interaction of Enterococcus faecalis was explored using a Caenorhabditis elegans model system. The virulence of 28 E. faecalis isolates representing 24 multilocus sequence types (MLSTs), including human commensal and clinical isolates as well as isolates from animals and of insect origin, was investigated using C. elegans strain glp-4 (bn2ts); sek-1 (km4). This revealed that 6 E. faecalis isolates behaved in a commensal manner with no nematocidal effect, while the remaining strains showed a time to 50% lethality ranging from 47 to 120 h. Principal component analysis showed that the difference in nematocidal activity explained 94% of the variance in the data. Assessment of known virulence traits revealed that gelatinase and cytolysin production accounted for 40.8% and 36.5% of the observed pathogenicity, respectively. However, coproduction of gelatinase and cytolysin did not increase virulence additively, accounting for 50.6% of the pathogenicity and therefore indicating a significant (26.7%) saturation effect. We employed a comparative genomic analysis approach using the 28 isolates comprising a collection of 82,356 annotated coding sequences (CDS) to identify 2,325 patterns of presence or absence among the investigated strains. Univariate statistical analysis of variance (ANOVA) established that individual patterns positively correlated (n = 61) with virulence. The patterns were investigated to identify potential new virulence traits, among which we found five patterns consisting of the phage03-like gene clusters. Strains harboring phage03 showed, on average, 17% higher killing of C. elegans (P = 4.4e(-6)). The phage03 gene cluster was also present in gelatinase-and-cytolysin-negative strain E. faecalis JH2-2. Deletion of this phage element from the JH2-2 clinical strain rendered the mutant apathogenic in C. elegans, and a similar mutant of the nosocomial V583 isolate showed significantly attenuated virulence. Bioinformatics investigation indicated that, unlike other E. faecalis virulence traits, phage03-like elements were found at a higher frequency among nosocomial isolates. In conclusion, our report provides a valuable virulence map that explains enhancement in E. faecalis virulence and contributes to a deeper comprehension of the genetic mechanism leading to the transition from commensalism to a pathogenic lifestyle.
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16
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Romero-Saavedra F, Laverde D, Wobser D, Michaux C, Budin-Verneuil A, Bernay B, Benachour A, Hartke A, Huebner J. Identification of peptidoglycan-associated proteins as vaccine candidates for enterococcal infections. PLoS One 2014; 9:e111880. [PMID: 25369230 PMCID: PMC4219796 DOI: 10.1371/journal.pone.0111880] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 10/02/2014] [Indexed: 01/17/2023] Open
Abstract
Infections by opportunistic bacteria have significant contributions to morbidity and mortality of hospitalized patients and also lead to high expenses in healthcare. In this setting, one of the major clinical problems is caused by Gram-positive bacteria such as enterococci and staphylococci. In this study we extract, purify, identify and characterize immunogenic surface-exposed proteins present in the vancomycin resistant enterococci (VRE) strain Enterococcus faecium E155 using three different extraction methods: trypsin shaving, biotinylation and elution at high pH. Proteomic profiling was carried out by gel-free and gel-nanoLC-MS/MS analyses. The total proteins found with each method were 390 by the trypsin shaving, 329 by the elution at high pH, and 45 using biotinylation. An exclusively extracytoplasmic localization was predicted in 39 (10%) by trypsin shaving, in 47 (15%) by elution at high pH, and 27 (63%) by biotinylation. Comparison between the three extraction methods by Venn diagram and subcellular localization predictors (CELLO v.2.5 and Gpos-mPLoc) allowed us to identify six proteins that are most likely surface-exposed: the SCP-like extracellular protein, a low affinity penicillin-binding protein 5 (PBP5), a basic membrane lipoprotein, a peptidoglycan-binding protein LysM (LysM), a D-alanyl-D-alanine carboxypeptidase (DdcP) and the peptidyl-prolyl cis-trans isomerase (PpiC). Due to their close relationship with the peptidoglycan, we chose PBP5, LysM, DdcP and PpiC to test their potential as vaccine candidates. These putative surface-exposed proteins were overexpressed in Escherichia coli and purified. Rabbit polyclonal antibodies raised against the purified proteins were able to induce specific opsonic antibodies that mediated killing of the homologous strain E. faecium E155 as well as clinical strains E. faecium E1162, Enterococcus faecalis 12030, type 2 and type 5. Passive immunization with rabbit antibodies raised against these proteins reduced significantly the colony counts of E. faecium E155 in mice, indicating the effectiveness of these surface-related proteins as promising vaccine candidates to target different enterococcal pathogens.
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Affiliation(s)
- Felipe Romero-Saavedra
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Freiburg, Germany
- EA4655 U2RM Stress/Virulence, University of Caen Lower-Normandy, Caen, France
| | - Diana Laverde
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Freiburg, Germany
- EA4655 U2RM Stress/Virulence, University of Caen Lower-Normandy, Caen, France
| | - Dominique Wobser
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Freiburg, Germany
| | - Charlotte Michaux
- EA4655 U2RM Stress/Virulence, University of Caen Lower-Normandy, Caen, France
| | | | - Benoit Bernay
- Proteogen platform SFR ICORE 4206, University of Caen Lower-Normandy, Caen, France
| | - Abdellah Benachour
- EA4655 U2RM Stress/Virulence, University of Caen Lower-Normandy, Caen, France
| | - Axel Hartke
- EA4655 U2RM Stress/Virulence, University of Caen Lower-Normandy, Caen, France
| | - Johannes Huebner
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Freiburg, Germany
- Division of Pediatric Infectious Diseases, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
- German Center for Infection Research (DZIF), Partnersite Munich, Munich, Germany
- * E-mail:
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17
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Abstract
Enterococci are leading causes of hospital-acquired infection in the United States and continue to develop resistances to new antibiotics. Many Enterococcus faecalis isolates harbor pheromone-responsive plasmids that mediate horizontal transfer of even large blocks of chromosomal genes, resulting in hospital-adapted strains over a quarter of whose genomes consist of mobile elements. Pheromones to which the donor cells respond derive from lipoprotein signal peptides. Using a novel bacterial killing assay dependent on the presence of sex pheromones, we screened a transposon mutant library for functions that relate to the production and/or activity of the effector pheromone. Here we describe a previously uncharacterized, but well-conserved, ABC transporter that contributes to pheromone production. Using three distinct pheromone-dependent mating systems, we show that mutants defective in expressing this transporter display a 5- to 6-order-of-magnitude reduction in conjugation efficiency. In addition, we demonstrate that the ABC transporter mutant displays an altered biofilm architecture, with a significant reduction in biofilm biomass compared to that of its isogenic parent, suggesting that pheromone activity also influences biofilm development. The conservation of this peptide transporter across the Firmicutes suggests that it may also play an important role in cell-cell communication in other species within this important phylum. Enterococcus faecalis ranks as one of the leading causes of hospital-associated infections. Strains possessing resistance to multiple antibiotics are becoming all too common in clinical settings. Pheromone-responsive plasmids play an important role in harboring and disseminating these antibiotic resistance genes. Here we have identified a novel ABC transporter that is responsible for the secretion of peptide pheromones, which enables communication between cells to mediate plasmid transfer. We have also shown that this transporter is important for biofilm formation, providing a strong rationale for its use as a viable therapeutic target which could be targeted to curb infection, as well as the spread of existing drug resistance.
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18
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Rigottier-Gois L, Madec C, Navickas A, Matos RC, Akary-Lepage E, Mistou MY, Serror P. The surface rhamnopolysaccharide epa of Enterococcus faecalis is a key determinant of intestinal colonization. J Infect Dis 2014; 211:62-71. [PMID: 25035517 DOI: 10.1093/infdis/jiu402] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Enterococcus faecalis is a commensal bacterium of the human intestine and a major opportunistic pathogen in immunocompromised and elderly patients. The pathogenesis of E. faecalis infection relies in part on its capacity to colonize the gut. Following disruption of intestinal homeostasis, E. faecalis can overgrow, cross the intestinal barrier, and enter the lymph and bloodstream. To identify and characterize E. faecalis genes that are key to intestinal colonization, our strategy consisted in screening mutants for the following phenotypes related to intestinal lifestyle: antibiotic resistance, overgrowth, and competition against microbiota. From the identified colonization genes, epaX encodes a glycosyltransferase located in a variable region of the enterococcal polysaccharide antigen (epa) locus. We demonstrated that EpaX acts on sugar composition, promoting resistance to bile salts and cell wall integrity. Given that EpaX is enriched in hospital-adapted isolates, this study points to the importance of the epa variability as a key determinant for enterococcal intestinal colonization.
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Affiliation(s)
| | - Clément Madec
- INRA, UMR1319 Micalis AgroParisTech, UMR Micalis, Jouy-en-Josas, France
| | - Albertas Navickas
- INRA, UMR1319 Micalis AgroParisTech, UMR Micalis, Jouy-en-Josas, France
| | - Renata C Matos
- INRA, UMR1319 Micalis AgroParisTech, UMR Micalis, Jouy-en-Josas, France
| | | | | | - Pascale Serror
- INRA, UMR1319 Micalis AgroParisTech, UMR Micalis, Jouy-en-Josas, France
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Michaux C, Saavedra LFR, Reffuveille F, Bernay B, Goux D, Hartke A, Verneuil N, Giard JC. Cold-shock RNA-binding protein CspR is also exposed to the surface of
Enterococcus faecalis. Microbiology (Reading) 2013; 159:2153-2161. [DOI: 10.1099/mic.0.071076-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Charlotte Michaux
- Unité de Recherche Risques Microbiens (U2RM), Equipe Stress Virulence Université de Caen Basse-Normandie, Caen, France
| | - Luis Felipe Romero Saavedra
- Unité de Recherche Risques Microbiens (U2RM), Equipe Stress Virulence Université de Caen Basse-Normandie, Caen, France
| | - Fany Reffuveille
- Plateforme Proteogen SFR ICORE 4206, Université de Caen Basse-Normandie, Caen, France
| | - Benoît Bernay
- Centre de Microscopie Appliquée à la Biologie, Université de Caen Basse-Normandie IFR ICORE, Caen, France
| | - Didier Goux
- Equipe Antibio-résistance, Université de Caen Basse-Normandie, Caen, France
| | - Axel Hartke
- Unité de Recherche Risques Microbiens (U2RM), Equipe Stress Virulence Université de Caen Basse-Normandie, Caen, France
| | - Nicolas Verneuil
- Unité de Recherche Risques Microbiens (U2RM), Equipe Stress Virulence Université de Caen Basse-Normandie, Caen, France
| | - Jean-Christophe Giard
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
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Cain JA, Solis N, Cordwell SJ. Beyond gene expression: the impact of protein post-translational modifications in bacteria. J Proteomics 2013; 97:265-86. [PMID: 23994099 DOI: 10.1016/j.jprot.2013.08.012] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 07/08/2013] [Accepted: 08/10/2013] [Indexed: 12/12/2022]
Abstract
The post-translational modification (PTM) of proteins plays a critical role in the regulation of a broad range of cellular processes in eukaryotes. Yet their role in governing similar systems in the conventionally presumed 'simpler' forms of life has been largely neglected and, until recently, was thought to occur only rarely, with some modifications assumed to be limited to higher organisms alone. Recent developments in mass spectrometry-based proteomics have provided an unparalleled power to enrich, identify and quantify peptides with PTMs. Additional modifications to biological molecules such as lipids and carbohydrates that are essential for bacterial pathophysiology have only recently been detected on proteins. Here we review bacterial protein PTMs, focusing on phosphorylation, acetylation, proteolytic degradation, methylation and lipidation and the roles they play in bacterial adaptation - thus highlighting the importance of proteomic techniques in a field that is only just in its infancy. This article is part of a Special Issue entitled: Trends in Microbial Proteomics.
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Affiliation(s)
- Joel A Cain
- School of Molecular Bioscience, School of Medical Sciences, The University of Sydney, 2006, Australia
| | - Nestor Solis
- School of Molecular Bioscience, School of Medical Sciences, The University of Sydney, 2006, Australia
| | - Stuart J Cordwell
- School of Molecular Bioscience, School of Medical Sciences, The University of Sydney, 2006, Australia; Discipline of Pathology, School of Medical Sciences, The University of Sydney, 2006, Australia.
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21
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Massier S, Bouffartigues E, Rincé A, Maillot O, Feuilloley MGJ, Orange N, Chevalier S. Effects of a pulsed light-induced stress on Enterococcus faecalis. J Appl Microbiol 2012; 114:186-95. [PMID: 23035907 DOI: 10.1111/jam.12029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 09/16/2012] [Accepted: 09/25/2012] [Indexed: 01/28/2023]
Abstract
AIMS Pulsed light (PL) technology is a surface decontamination process that can be used on food, packaging or water. PL efficiency may be limited by its low degree of penetration or because of a shadow effect. In these cases, surviving bacteria will be able to perceive PL as a stress. Such a stress was mimicked using low transmitted energy conditions, and its effects were investigated on the highly environmental adaptable bacterium Enterococcus faecalis V583. METHODS AND RESULTS In these laboratory conditions, a complete decontamination of the artificially inoculated medium was performed using energy doses as low as 1.8 J cm(-2) , while a treatment of 0.5, 1 and 1.2 J cm(-2) led to a 2.2, 6 and 7-log(10) CFU ml(-1) reduction in the initial bacterial population, respectively. Application of a 0.5 J cm(-2) pretreatment allowed the bacteria to resist more efficiently a 1.2 J cm(-2) subsequent PL dose. This 0.5 J cm(-2) treatment increased the bacterial mutation frequency and affected the abundance of 19 proteins as revealed by a global proteome analysis. CONCLUSIONS Enterococcus faecalis is able to adapt to a PL treatment, providing a molecular response to low-energy PL dose, leading to enhanced resistance to a subsequent treatment and increasing the mutation frequency. SIGNIFICANCE AND IMPACT OF THE STUDY This study gives further insights on Ent. faecalis capacities to adapt and to resist to stress.
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Affiliation(s)
- S Massier
- LMSM, Laboratoire de Microbiologie-Signaux et Microenvironnement, EA 4312, Université de Rouen, Evreux, France
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22
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Involvement of peptidylprolyl cis/trans isomerases in Enterococcus faecalis virulence. Infect Immun 2012; 80:1728-35. [PMID: 22331431 DOI: 10.1128/iai.06251-11] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Peptidylprolyl cis/trans isomerases (PPIases) are enzymes involved in protein folding. Analysis of the genome sequence of Enterococcus faecalis V583 allowed for identification of 3 PPIases carrying genes. ef2898 encodes an intracellular PPIase which was not shown to be important for the E. faecalis stress response or virulence. The other two PPIases, the parvulin family rotamase EF0685 and the cyclophilin family member EF1534, are expected to be surface-exposed proteins. They were shown to be important for virulence and resistance to NaCl. A Δef0685 Δef1534 mutant was also more resistant to oxidative stress, was able to grow under a high manganese concentration, and showed altered resistance to ampicillin and quinolone antibiotics.
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Massier S, Rincé A, Maillot O, Feuilloley MGJ, Orange N, Chevalier S. Adaptation of Pseudomonas aeruginosa to a pulsed light-induced stress. J Appl Microbiol 2012; 112:502-11. [PMID: 22188372 DOI: 10.1111/j.1365-2672.2011.05224.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS Pulsed light (PL) technology is an efficient surface decontamination process. Used in low transmitted energy conditions, PL induces a stress that can be perceived by bacteria. The effect of such a PL stress was investigated on the highly environmental adaptable germ Pseudomonas aeruginosa PAO1. METHODS AND RESULTS Pulses of transmitted energy (fluence) reaching 1·8Jcm(-2) can kill 10(9) bacteria. Application of a lower sublethal PL dose allowed the bacteria to resist and survive more efficiently to a subsequent dose of PL. This sublethal dose was not increasing the mutation frequency of Ps. aeruginosa, but altered the abundance of 15 proteins as revealed by a global proteome analysis, including stress-induced proteins, phage-related proteins, energy and carbon metabolisms, cell motility, and transcription and translation regulators. CONCLUSIONS A response to a low-energy PL dose takes place in Ps. aeruginosa, reducing the energy conversion systems, while increasing transcription and translation processes to produce proteins involved in chaperone mechanisms and phage-related proteins, probably to protect the bacterium against a new PL-induced stress. SIGNIFICANCE AND IMPACT OF THE STUDY Taken together, these results suggest that a low-energy PL dose is sufficient to provoke adaptation of Ps. aeruginosa, leading to enhancing its resistance to a subsequent lethal treatment.
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Affiliation(s)
- S Massier
- LMDF-SME, Laboratoire de Microbiologie du Froid-Signaux et Micro-Environnement, EA 4312, Université de Rouen, Rouen, France
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