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Alves Â, Magalhães R, Brandão TR, Pimentel L, Rodríguez-Alcalá LM, Teixeira P, Ferreira V. Impact of exposure to cold and cold-osmotic stresses on virulence-associated characteristics of Listeria monocytogenes strains. Food Microbiol 2020; 87:103351. [DOI: 10.1016/j.fm.2019.103351] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 10/08/2019] [Accepted: 10/18/2019] [Indexed: 11/26/2022]
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2
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Whitman KJ, Bono JL, Clawson ML, Loy JD, Bosilevac JM, Arthur TM, Ondrak JD. Genomic-based identification of environmental and clinical Listeria monocytogenes strains associated with an abortion outbreak in beef heifers. BMC Vet Res 2020; 16:70. [PMID: 32087722 PMCID: PMC7036198 DOI: 10.1186/s12917-020-2276-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 02/05/2020] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND In a beef cattle facility an outbreak of abortions occurred over a 36-day period and included samples from two aborted (non-viable) fetuses and 21 post-abortion clinical cases. There are numerous etiologies, including clinical listeriosis. At the species level, Listeria monocytogenes is ubiquitous in cattle production environments, including soil, feed, and occasionally water sources, and is a common enteric resident of cattle and other mammals. There are four genetically distinct lineages of L. monocytogenes (I-IV), with most lineage III and IV isolates obtained from ruminants. Definitive diagnosis of L. monocytogenes as a causative agent in disease outbreaks relies upon case identification, appropriate sample collection, and laboratory confirmation. Furthermore, clearly establishing a relationship between a pathogen source and clinical disease is difficult. RESULTS Of the two fetal and 21 clinical case submissions, 19 were positive for L. monocytogenes. Subsequent culture for L. monocytogenes from water and silage sources identified both as potential origins of infection. Using whole-genome sequencing and phylogenetic analyses, clinical, water and silage L. monocytogenes strains grouped into two of four lineages. All water and silage strains, plus 11 clinical strains placed in lineage III, with identical or nearly identical genomic sequences. The remaining eight clinical strains placed in lineage I, with seven having nearly identical sequences and one distinctly different. CONCLUSION Three genetically distinct strains within two lineages of L. monocytogenes caused the abortion outbreak. The etiology of abortion in 11 cases was directly linked to water and silage contamination from a lineage III L. monocytogenes strain. The source of infection for the remaining abortion cases with two different strains from lineage I is unknown. This is the first report of L. monocytogenes genomics being used as part of an outbreak investigation of cattle abortion.
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Affiliation(s)
- Katherine J Whitman
- University of Nebraska-Lincoln, School of Veterinary Medicine and Biomedical Sciences, Great Plains Veterinary Educational Center, Clay Center, NE, 68933, USA.
| | - James L Bono
- USDA ARS US Meat Animal Research Center, Clay Center, NE, 68933, USA.
| | - Michael L Clawson
- USDA ARS US Meat Animal Research Center, Clay Center, NE, 68933, USA
| | - John D Loy
- University of Nebraska-Lincoln, School of Veterinary Medicine and Biomedical Sciences, Nebraska Veterinary Diagnostic Center, Lincoln, NE, 68583-0907, USA
| | | | - Terrance M Arthur
- USDA ARS US Meat Animal Research Center, Clay Center, NE, 68933, USA
| | - Jeff D Ondrak
- University of Nebraska-Lincoln, School of Veterinary Medicine and Biomedical Sciences, Great Plains Veterinary Educational Center, Clay Center, NE, 68933, USA
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3
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Maury MM, Bracq-Dieye H, Huang L, Vales G, Lavina M, Thouvenot P, Disson O, Leclercq A, Brisse S, Lecuit M. Hypervirulent Listeria monocytogenes clones' adaption to mammalian gut accounts for their association with dairy products. Nat Commun 2019; 10:2488. [PMID: 31171794 PMCID: PMC6554400 DOI: 10.1038/s41467-019-10380-0] [Citation(s) in RCA: 123] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 05/09/2019] [Indexed: 11/09/2022] Open
Abstract
Listeria monocytogenes (Lm) is a major human and animal foodborne pathogen. Here we show that hypervirulent Lm clones, particularly CC1, are strongly associated with dairy products, whereas hypovirulent clones, CC9 and CC121, are associated with meat products. Clone adaptation to distinct ecological niches and/or different food products contamination routes may account for this uneven distribution. Indeed, hypervirulent clones colonize better the intestinal lumen and invade more intestinal tissues than hypovirulent ones, reflecting their adaption to host environment. Conversely, hypovirulent clones are adapted to food processing environments, with a higher prevalence of stress resistance and benzalkonium chloride tolerance genes and a higher survival and biofilm formation capacity in presence of sub-lethal benzalkonium chloride concentrations. Lm virulence heterogeneity therefore reflects the diversity of the ecological niches in which it evolves. These results also have important public health implications and may help in reducing food contamination and improving food consumption recommendations to at-risk populations.
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Affiliation(s)
- Mylène M Maury
- Biology of Infection Unit, Inserm U1117, Institut Pasteur, 75015, Paris, France.,National Reference Centre and WHO Collaborating Centre for Listeria, Institut Pasteur, 75015, Paris, France.,Microbial Evolutionary Genomics Unit, CNRS UMR 3525, Institut Pasteur, 75015, Paris, France
| | - Hélène Bracq-Dieye
- Biology of Infection Unit, Inserm U1117, Institut Pasteur, 75015, Paris, France.,National Reference Centre and WHO Collaborating Centre for Listeria, Institut Pasteur, 75015, Paris, France
| | - Lei Huang
- Biology of Infection Unit, Inserm U1117, Institut Pasteur, 75015, Paris, France.,Université Paris Diderot, Université de Paris, 75013, Paris, France
| | - Guillaume Vales
- Biology of Infection Unit, Inserm U1117, Institut Pasteur, 75015, Paris, France.,National Reference Centre and WHO Collaborating Centre for Listeria, Institut Pasteur, 75015, Paris, France
| | - Morgane Lavina
- Biology of Infection Unit, Inserm U1117, Institut Pasteur, 75015, Paris, France
| | - Pierre Thouvenot
- Biology of Infection Unit, Inserm U1117, Institut Pasteur, 75015, Paris, France.,National Reference Centre and WHO Collaborating Centre for Listeria, Institut Pasteur, 75015, Paris, France
| | - Olivier Disson
- Biology of Infection Unit, Inserm U1117, Institut Pasteur, 75015, Paris, France
| | - Alexandre Leclercq
- Biology of Infection Unit, Inserm U1117, Institut Pasteur, 75015, Paris, France.,National Reference Centre and WHO Collaborating Centre for Listeria, Institut Pasteur, 75015, Paris, France
| | - Sylvain Brisse
- Microbial Evolutionary Genomics Unit, CNRS UMR 3525, Institut Pasteur, 75015, Paris, France.,Biodiversity and Epidemiology of Bacterial Pathogens Unit, Institut Pasteur, 75015, Paris, France
| | - Marc Lecuit
- Biology of Infection Unit, Inserm U1117, Institut Pasteur, 75015, Paris, France. .,National Reference Centre and WHO Collaborating Centre for Listeria, Institut Pasteur, 75015, Paris, France. .,Paris Descartes University, Institut Imagine, Necker-Enfants Malades University Hospital, Division of Infectious Diseases and Tropical Medicine, APHP, 75006, Paris, France.
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4
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Dreyer M, Aguilar-Bultet L, Rupp S, Guldimann C, Stephan R, Schock A, Otter A, Schüpbach G, Brisse S, Lecuit M, Frey J, Oevermann A. Listeria monocytogenes sequence type 1 is predominant in ruminant rhombencephalitis. Sci Rep 2016; 6:36419. [PMID: 27848981 PMCID: PMC5111077 DOI: 10.1038/srep36419] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 10/14/2016] [Indexed: 12/18/2022] Open
Abstract
Listeria (L.) monocytogenes is an opportunistic pathogen causing life-threatening infections in diverse mammalian species including humans and ruminants. As little is known on the link between strains and clinicopathological phenotypes, we studied potential strain-associated virulence and organ tropism in L. monocytogenes isolates from well-defined ruminant cases of clinical infections and the farm environment. The phylogeny of isolates and their virulence-associated genes were analyzed by multilocus sequence typing (MLST) and sequence analysis of virulence-associated genes. Additionally, a panel of representative isolates was subjected to in vitro infection assays. Our data suggest the environmental exposure of ruminants to a broad range of strains and yet the strong association of sequence type (ST) 1 from clonal complex (CC) 1 with rhombencephalitis, suggesting increased neurotropism of ST1 in ruminants, which is possibly related to its hypervirulence. This study emphasizes the importance of considering clonal background of L. monocytogenes isolates in surveillance, epidemiological investigation and disease control.
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Affiliation(s)
- Margaux Dreyer
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, Theodor Kocher Institute, University of Bern, Switzerland
| | - Lisandra Aguilar-Bultet
- Graduate School for Cellular and Biomedical Sciences, Theodor Kocher Institute, University of Bern, Switzerland.,Institute of Veterinary Bacteriology, Department of Infectious Diseases and Pathobiology, University of Bern, Switzerland
| | - Sebastian Rupp
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, Theodor Kocher Institute, University of Bern, Switzerland
| | - Claudia Guldimann
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, Theodor Kocher Institute, University of Bern, Switzerland
| | - Roger Stephan
- Institute for Food Safety and Hygiene, University of Zurich, Switzerland
| | - Alexandra Schock
- Department of Pathology, AHVLA Lasswade, Pentlands Science Park, Bush Loan, Penicuik Midlothian, United Kingdom
| | - Arthur Otter
- AHVLA Shrewsbury Kendal Road, Harlscott, Shrewsbury, Shropshire, United Kingdom
| | | | - Sylvain Brisse
- Institut Pasteur, Microbial Evolutionary Genomics, Paris, France
| | - Marc Lecuit
- Institut Pasteur, Biology of Infection Unit, Paris, France.,Inserm U1117, Paris, France.,French National Reference Center and WHO Collaborating Center Listeria, Institut Pasteur, Paris, France.,Paris Descartes University, Sorbonne Paris Cité, Division of Infectious Diseases and Tropical Medicine, Necker-Enfants Malades University Hospital, Institut Imagine, Paris, France
| | - Joachim Frey
- Institute of Veterinary Bacteriology, Department of Infectious Diseases and Pathobiology, University of Bern, Switzerland
| | - Anna Oevermann
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Switzerland
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5
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Strydom A, Witthuhn CR. Listeria monocytogenes: A Target for Bacteriophage Biocontrol. Compr Rev Food Sci Food Saf 2015. [DOI: 10.1111/1541-4337.12153] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Amy Strydom
- Dept. of Microbial, Biochemical and Food Biotechnology; Univ. of the Free State; Private Bag 339 Bloemfontein 9300 South Africa
| | - Corli R. Witthuhn
- Dept. of Microbial, Biochemical and Food Biotechnology; Univ. of the Free State; Private Bag 339 Bloemfontein 9300 South Africa
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6
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Guldimann C, Bärtschi M, Frey J, Zurbriggen A, Seuberlich T, Oevermann A. Increased spread and replication efficiency of Listeria monocytogenes in organotypic brain-slices is related to multilocus variable number of tandem repeat analysis (MLVA) complex. BMC Microbiol 2015; 15:134. [PMID: 26138984 PMCID: PMC4490720 DOI: 10.1186/s12866-015-0454-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 05/28/2015] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Listeria (L.) monocytogenes causes fatal infections in many species including ruminants and humans. In ruminants, rhombencephalitis is the most prevalent form of listeriosis. Using multilocus variable number tandem repeat analysis (MLVA) we recently showed that L. monocytogenes isolates from ruminant rhombencephalitis cases are distributed over three genetic complexes (designated A, B and C). However, the majority of rhombencephalitis strains and virtually all those isolated from cattle cluster in MLVA complex A, indicating that strains of this complex may have increased neurotropism and neurovirulence. The aim of this study was to investigate whether ruminant rhombencephalitis strains have an increased ability to propagate in the bovine hippocampal brain-slice model and can be discriminated from strains of other sources. For this study, forty-seven strains were selected and assayed on brain-slice cultures, a bovine macrophage cell line (BoMac) and a human colorectal adenocarcinoma cell line (Caco-2). They were isolated from ruminant rhombencephalitis cases (n = 21) and other sources including the environment, food, human neurolisteriosis cases and ruminant/human non-encephalitic infection cases (n = 26). RESULTS All but one L. monocytogenes strain replicated in brain slices, irrespectively of the source of the isolate or MLVA complex. The replication of strains from MLVA complex A was increased in hippocampal brain-slice cultures compared to complex C. Immunofluorescence revealed that microglia are the main target cells for L. monocytogenes and that strains from MLVA complex A caused larger infection foci than strains from MLVA complex C. Additionally, they caused larger plaques in BoMac cells, but not CaCo-2 cells. CONCLUSIONS Our brain slice model data shows that all L. monocytogenes strains should be considered potentially neurovirulent. Secondly, encephalitis strains cannot be conclusively discriminated from non-encephalitis strains with the bovine organotypic brain slice model. The data indicates that MLVA complex A strains are particularly adept at establishing encephalitis possibly by virtue of their higher resistance to antibacterial defense mechanisms in microglia cells, the main target of L. monocytogenes.
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Affiliation(s)
- Claudia Guldimann
- Division of Neurological Sciences, Neurocenter, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
- Graduate school for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.
| | - Michelle Bärtschi
- Division of Neurological Sciences, Neurocenter, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
| | - Joachim Frey
- Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
| | - Andreas Zurbriggen
- Division of Neurological Sciences, Neurocenter, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
| | - Torsten Seuberlich
- Division of Neurological Sciences, Neurocenter, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
| | - Anna Oevermann
- Division of Neurological Sciences, Neurocenter, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
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7
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Kuenne C, Billion A, Mraheil MA, Strittmatter A, Daniel R, Goesmann A, Barbuddhe S, Hain T, Chakraborty T. Reassessment of the Listeria monocytogenes pan-genome reveals dynamic integration hotspots and mobile genetic elements as major components of the accessory genome. BMC Genomics 2013; 14:47. [PMID: 23339658 PMCID: PMC3556495 DOI: 10.1186/1471-2164-14-47] [Citation(s) in RCA: 154] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 12/15/2012] [Indexed: 12/14/2022] Open
Abstract
Background Listeria monocytogenes is an important food-borne pathogen and model organism for host-pathogen interaction, thus representing an invaluable target considering research on the forces governing the evolution of such microbes. The diversity of this species has not been exhaustively explored yet, as previous efforts have focused on analyses of serotypes primarily implicated in human listeriosis. We conducted complete genome sequencing of 11 strains employing 454 GS FLX technology, thereby achieving full coverage of all serotypes including the first complete strains of serotypes 1/2b, 3c, 3b, 4c, 4d, and 4e. These were comparatively analyzed in conjunction with publicly available data and assessed for pathogenicity in the Galleria mellonella insect model. Results The species pan-genome of L. monocytogenes is highly stable but open, suggesting an ability to adapt to new niches by generating or including new genetic information. The majority of gene-scale differences represented by the accessory genome resulted from nine hyper variable hotspots, a similar number of different prophages, three transposons (Tn916, Tn554, IS3-like), and two mobilizable islands. Only a subset of strains showed CRISPR/Cas bacteriophage resistance systems of different subtypes, suggesting a supplementary function in maintenance of chromosomal stability. Multiple phylogenetic branches of the genus Listeria imply long common histories of strains of each lineage as revealed by a SNP-based core genome tree highlighting the impact of small mutations for the evolution of species L. monocytogenes. Frequent loss or truncation of genes described to be vital for virulence or pathogenicity was confirmed as a recurring pattern, especially for strains belonging to lineages III and II. New candidate genes implicated in virulence function were predicted based on functional domains and phylogenetic distribution. A comparative analysis of small regulatory RNA candidates supports observations of a differential distribution of trans-encoded RNA, hinting at a diverse range of adaptations and regulatory impact. Conclusions This study determined commonly occurring hyper variable hotspots and mobile elements as primary effectors of quantitative gene-scale evolution of species L. monocytogenes, while gene decay and SNPs seem to represent major factors influencing long-term evolution. The discovery of common and disparately distributed genes considering lineages, serogroups, serotypes and strains of species L. monocytogenes will assist in diagnostic, phylogenetic and functional research, supported by the comparative genomic GECO-LisDB analysis server (http://bioinfo.mikrobio.med.uni-giessen.de/geco2lisdb).
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Affiliation(s)
- Carsten Kuenne
- Institute of Medical Microbiology, German Centre for Infection Research, Justus-Liebig-University, D-35392, Giessen, Germany
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8
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Valderrama WB, Cutter CN. An Ecological Perspective ofListeria monocytogenesBiofilms in Food Processing Facilities. Crit Rev Food Sci Nutr 2013; 53:801-17. [DOI: 10.1080/10408398.2011.561378] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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9
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Pizarro-Cerdá J, Kühbacher A, Cossart P. Entry of Listeria monocytogenes in mammalian epithelial cells: an updated view. Cold Spring Harb Perspect Med 2012; 2:2/11/a010009. [PMID: 23125201 DOI: 10.1101/cshperspect.a010009] [Citation(s) in RCA: 183] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Listeria monocytogenes is a bacterial pathogen that promotes its internalization into host epithelial cells. Interaction between the bacterial surface molecules InlA and InlB and their cellular receptors E-cadherin and Met, respectively, triggers the recruitment of endocytic effectors, the subversion of the phosphoinositide metabolism, and the remodeling of the actin cytoskeleton that lead to bacterial engulfment. Additional bacterial surface and secreted virulence factors also contribute to entry, albeit to a lesser extent. Here we review the increasing number of signaling effectors that are reported as being subverted by L. monocytogenes during invasion of cultured cell lines. We also update the current knowledge of the early steps of in vivo cellular infection, which, as shown recently, challenges previous concepts generated from in vitro data.
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10
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The Listeria monocytogenes σB regulon and its virulence-associated functions are inhibited by a small molecule. mBio 2011; 2:mBio.00241-11. [PMID: 22128349 PMCID: PMC3225968 DOI: 10.1128/mbio.00241-11] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The stress-responsive alternative sigma factor σB is conserved across diverse Gram-positive bacterial genera. In Listeria monocytogenes, σB regulates transcription of >150 genes, including genes contributing to virulence and to bacterial survival under host-associated stress conditions, such as those encountered in the human gastrointestinal lumen. An inhibitor of L. monocytogenes σB activity was identified by screening ~57,000 natural and synthesized small molecules using a high-throughput cell-based assay. The compound fluoro-phenyl-styrene-sulfonamide (FPSS) (IC50 = 3.5 µM) downregulated the majority of genes previously identified as members of the σB regulon in L. monocytogenes 10403S, thus generating a transcriptional profile comparable to that of a 10403S ΔsigB strain. Specifically, of the 208 genes downregulated by FPSS, 75% had been identified previously as positively regulated by σB. Downregulated genes included key virulence and stress response genes, such as inlA, inlB, bsh, hfq, opuC, and bilE. From a functional perspective, FPSS also inhibited L. monocytogenes invasion of human intestinal epithelial cells and bile salt hydrolase activity. The ability of FPSS to inhibit σB activity in both L. monocytogenes and Bacillus subtilis indicates its utility as a specific inhibitor of σB across multiple Gram-positive genera. The σB transcription factor regulates expression of genes responsible for bacterial survival under changing environmental conditions and for virulence; therefore, this alternative sigma factor is important for transmission of L. monocytogenes and other Gram-positive bacteria. Regulation of σB activity is complex and tightly controlled, reflecting the key role of this factor in bacterial metabolism. We present multiple lines of evidence indicating that fluoro-phenyl-styrene-sulfonamide (FPSS) specifically inhibits activity of σB across Gram-positive bacterial genera, i.e., in both Listeria monocytogenes and Bacillus subtilis. Therefore, FPSS is an important new tool that will enable novel approaches for exploring complex regulatory networks in L. monocytogenes and other Gram-positive pathogens and for investigating small-molecule applications for controlling pathogen transmission.
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García-del Portillo F, Calvo E, D'Orazio V, Pucciarelli MG. Association of ActA to peptidoglycan revealed by cell wall proteomics of intracellular Listeria monocytogenes. J Biol Chem 2011; 286:34675-89. [PMID: 21846725 DOI: 10.1074/jbc.m111.230441] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Listeria monocytogenes is a Gram-positive intracellular bacterial pathogen that colonizes the cytosol of eukaryotic cells. Recent transcriptomic studies have revealed that intracellular L. monocytogenes alter expression of genes encoding envelope components. However, no comparative global analysis of this cell wall remodeling process is yet known at the protein level. Here, we used high resolution mass spectrometry to define the cell wall proteome of L. monocytogenes growing inside epithelial cells. When compared with extracellular bacteria growing in a nutrient-rich medium, a major difference found in the proteome was the presence of the actin assembly-inducing protein ActA in peptidoglycan purified from intracellular bacteria. ActA was also identified in the peptidoglycan of extracellular bacteria growing in a chemically defined minimal medium. In this condition, ActA maintains its membrane anchoring domain and promotes efficient bacterial entry into nonphagocytic host cells. Unexpectedly, Internalin-A, which mediates entry of extracellular L. monocytogenes into eukaryotic cells, was identified at late infection times (6 h) as an abundant protein in the cell wall of intracellular bacteria. Other surface proteins covalently bound to the peptidoglycan, as Lmo0514 and Lmo2085, were detected exclusively in intracellular and extracellular bacteria, respectively. Altogether, these data provide the first insights into the changes occurring at the protein level in the L. monocytogenes cell wall as the pathogen transits from the extracellular environment to an intracytosolic lifestyle inside eukaryotic cells. Some of these changes include alterations in the relative amount and the mode of association of certain surface proteins.
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Affiliation(s)
- Francisco García-del Portillo
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
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12
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Anti-Listeria activities of Galleria mellonella hemolymph proteins. Appl Environ Microbiol 2011; 77:4237-40. [PMID: 21531838 DOI: 10.1128/aem.02435-10] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report the use of antimicrobial hemolymph proteins from the model host Galleria mellonella as an inhibitor for various Listeria strains, providing a novel source for antilisterial therapeutics. We also have shown that specific virulence-associated genes known to mediate antimicrobial resistance of Listeria in mammalian models indicated a similar function in Galleria.
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13
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Galleria mellonella as a model system for studying Listeria pathogenesis. Appl Environ Microbiol 2009; 76:310-7. [PMID: 19897755 DOI: 10.1128/aem.01301-09] [Citation(s) in RCA: 174] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Essential aspects of the innate immune response to microbial infection are conserved between insects and mammals. This has generated interest in using insects as model organisms to study host-microbe interactions. We used the greater wax moth Galleria mellonella, which can be reared at 37 degrees C, as a model host for examining the virulence potential of Listeria spp. Here we report that Galleria is an excellent surrogate model of listerial septic infection, capable of clearly distinguishing between pathogenic and nonpathogenic Listeria strains and even between virulent and attenuated Listeria monocytogenes strains. Virulence required listerial genes hitherto implicated in the mouse infection model and was linked to strong antimicrobial activities in both hemolymph and hemocytes of infected larvae. Following Listeria infection, the expression of immune defense genes such as those for lysozyme, galiomycin, gallerimycin, and insect metalloproteinase inhibitor (IMPI) was sequentially induced. Preinduction of antimicrobial activity by treatment of larvae with lipopolysaccharide (LPS) significantly improved survival against subsequent L. monocytogenes challenge and strong antilisterial activity was detected in the hemolymph of LPS pretreated larvae. We conclude that the severity of septic infection with L. monocytogenes is modulated primarily by innate immune responses, and we suggest the use of Galleria as a relatively simple, nonmammalian model system that can be used to assess the virulence of strains of Listeria spp. isolated from a wide variety of settings from both the clinic and the environment.
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14
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Some Listeria monocytogenes outbreak strains demonstrate significantly reduced invasion, inlA transcript levels, and swarming motility in vitro. Appl Environ Microbiol 2009; 75:5647-58. [PMID: 19581477 DOI: 10.1128/aem.00367-09] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Listeria monocytogenes can cause a severe invasive food-borne disease known as listeriosis, and large outbreaks of this disease occur occasionally. Based on molecular-subtype data, epidemic clone (EC) strains have been defined, including ECI and ECIa, which have caused listeriosis outbreaks on different continents. While a number of molecular-subtyping studies of outbreak strains have been reported, few comprehensive data sets of virulence-associated characteristics of these strains are available. We assembled a set of human clinical isolates from 15 outbreaks that occurred worldwide between 1975 and 2002. Initial characterization of these strains showed significant variation in the ability to invade human Caco-2 intestinal epithelial cells and HepG2 hepatic cells; four strains showed consistently reduced invasion in both cell lines. DNA sequencing of inlA, which encodes a protein required for efficient Caco-2 and HepG2 invasion, showed that none of the invasion-attenuated strains contained known virulence-attenuating mutations in inlA. Phylogenetic analyses of inlA sequences revealed a well-supported clade containing a fully invasive ECI strain and three invasion-attenuated ECI strains, along with a fully invasive ECIa strain and an invasion-attenuated ECIa strain. Of the four invasion-attenuated strains, one strain showed both reduced inlA transcript levels and impaired swarming, one strain showed reduced inlA transcript levels, and two strains showed reduced swarming. Overall, our data show that (i) L. monocytogenes strains from outbreaks vary significantly in invasion efficiency and (ii) different mechanisms may contribute to reduced invasion efficiency. Association between EC strains and listeriosis outbreaks may involve characteristics other than virulence phenotypes, including survival and growth in food-associated environments.
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15
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Subtyping of Listeria monocytogenes isolates by actA gene sequencing, PCR-fingerprinting, and cell-invasion assay. Folia Microbiol (Praha) 2009; 54:17-24. [DOI: 10.1007/s12223-009-0003-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Revised: 06/12/2008] [Indexed: 11/26/2022]
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Nestler U, Rollnik S, Schulz C, Chakraborty T, Domann E, Hain T. Expression of the reporter genes lacZ and EGFP in human glioblastoma cells using Listeria monocytogenes as vector for gene transfer. Neurol Res 2009; 31:859-68. [PMID: 19215661 DOI: 10.1179/174313209x403896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVE Glioblastoma has become a model target for viral gene therapy approaches. To circumvent some of the inherent problems of viral vectors, we examined the feasibility of Listeria monocytogenes for foreign gene expression in glioblastoma cells. METHODS The internalin-dependent uptake of L. monocytogenes into human glioma cell lines and into 22 cell cultures obtained during neurosurgery was studied by in vitro infection assays. Internalization rates of wild-type L. monocytogenes were compared with a deletion mutant and to four strains with plasmid-based recomplementation of the internalin A/B operon. For gene transfer experiments, plasmids encoding lacZ or EGFP under control of the cytomegalovirus promotor were transfected into Listeriae. Incubation times in cell culture were studied regarding infection of cells, intracellular listerial replication and reporter gene translation. Gene transfer efficiency was determined by beta-galactosidase activity and by fluorescence microscopy. RESULTS The internalin-defective strain (DeltainlAB2) showed less uptake compared with the wild type. An increased invasion rate was observed in strain DeltainlAB2 + inlB(PinlA) overexpressing internalin B; complementation of the entire operon (DeltainlAB2 + inlAB(PinlA)) revealed a synergistic effect. For gene transfer experiments into glioblastoma cells, the pathogenic strain 4bL312 was employed, and efficiencies up to 5% were achieved. DISCUSSION Internalins A and B are major determinants for listerial uptake into neuroepithelial tumors. The L. monocytogenes vector system enables foreign gene expression in glioblastoma cells. Ongoing research deals with optimization of transfection efficiencies, with the use of less pathogenic substrains and the cloning of suicide gene vectors.
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Affiliation(s)
- Ulf Nestler
- Department of Neurosurgery, Justus-Liebig-University, Giessen, Germany.
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Liu D, Lawrence ML, Ainsworth AJ, Austin FW. Toward an improved laboratory definition of Listeria monocytogenes virulence. Int J Food Microbiol 2007; 118:101-15. [PMID: 17727992 DOI: 10.1016/j.ijfoodmicro.2007.07.045] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Revised: 04/07/2007] [Accepted: 07/28/2007] [Indexed: 11/23/2022]
Abstract
Listeria monocytogenes is an opportunistic foodborne pathogen that encompasses a diversity of strains with varied virulence. The ability to rapidly determine the pathogenic potential of L. monocytogenes strains is integral to the control and prevention campaign against listeriosis. Early methods for assessing L. monocytogenes virulence include in vivo bioassays and in vitro cell assays. While in vivo bioassays provide a measurement of all virulence determinants of L. monocytogenes, they are not applied routinely due to their reliance on experimental animals whose costs have become increasingly prohibitive. As a low cost alternative, in vitro cell assays are useful for estimating the virulence of L. monocytogenes strains. However, these assays are often slow, and at times variable. Prior attempts to ascertain L. monocytogenes virulence by targeting virulence-associated proteins and genes have been largely unsuccessful, since many of the assay targets are present in both virulent and avirulent strains. Recent identification of novel virulence-specific genes (particularly internalin gene inlJ) has opened a new avenue for rapid, sensitive, and precise differentiation of virulent L. monocytogenes strains from avirulent strains. The application of DNA sequencing technique also offers an additional tool for assessing L. monocytogenes virulence potential. By providing an update on the laboratory methods that have been reported for the determination of L. monocytogenes pathogenicity, this review discusses future research needs that may help achieve an improved laboratory definition of L. monocytogenes virulence.
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Affiliation(s)
- Dongyou Liu
- College of Veterinary Medicine, Mississippi State University, PO Box 6100, Mississippi State, MS 39762, USA.
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