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Fang X, Yuan M, Zheng M, Guo Q, Yang Y, Yang Y, Liang X, Liu J, Fang C. Deletion of glycosyltransferase galE impairs the InlB anchoring and pathogenicity of Listeria monocytogenes. Virulence 2024; 15:2422539. [PMID: 39492668 PMCID: PMC11540102 DOI: 10.1080/21505594.2024.2422539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 06/01/2024] [Accepted: 10/21/2024] [Indexed: 11/05/2024] Open
Abstract
Listeria monocytogenes (L. monocytogenes) is a foodborne intracellular pathogen that causes serious disease in both humans and animals. InlB is the major internalin protein of L. monocytogenes, which anchors to the bacterial surface and mediates its invasion into various host cells. Recent studies have shown that galactosylation of the cell wall polymer wall teichoic acid (WTA) is essential for InlB anchoring on the cell surface of L. monocytogenes serotype 4b strains. Galactosylation of WTA is exerted by the coordinated action of several glycosyltransferases, including GalU, GalE, GtcA, GttA, and GttB. Among these glycosyltransferases, GttA and GttB are specific to serotype 4b strains, whereas GalE, GalU, and GtcA are conserved across all serotypes. The role of GalE in InlB anchoring and L. monocytogenes pathogenicity remains unclear. In this study, we deleted the galE gene, which is involved in galactosylation, from L. monocytogenes strain ScottA. We found that galE deletion reduced InlB anchoring, weakened bacterial adhesion and invasion of Caco-2 cells (human colorectal adenocarcinoma cells) and MGC803 cells (human gastric carcinoma cells), increased phagocytosis but decreased proliferation in RAW264.7 cells (mouse mononuclear macrophage leukaemia cells), and decreased bacteria load, mortality, and tissue damage in infected mice. Taken together, galE deletion significantly reduced the anchoring of InlB and weakened the pathogenicity of L. monocytogenes. This finding provides new insights into the correlation between cell wall modification and pathogenicity of L. monocytogenes.
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Affiliation(s)
- Xiaowei Fang
- College of Animal Science and Technology, Yangtze University, Jingzhou, China
- College of Agriculture, Yangtze University, Jingzhou, China
| | - Mei Yuan
- College of Animal Science and Technology, Yangtze University, Jingzhou, China
| | - Minghao Zheng
- College of Animal Science and Technology, Yangtze University, Jingzhou, China
| | - Qian Guo
- College of Animal Science and Technology, Yangtze University, Jingzhou, China
| | - Yuting Yang
- College of Animal Science and Technology, Yangtze University, Jingzhou, China
| | - Yuying Yang
- College of Animal Science and Technology, Yangtze University, Jingzhou, China
| | - Xiongyan Liang
- College of Animal Science and Technology, Yangtze University, Jingzhou, China
| | - Jing Liu
- College of Animal Science and Technology, Yangtze University, Jingzhou, China
| | - Chun Fang
- College of Animal Science and Technology, Yangtze University, Jingzhou, China
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Contrasting Genetic Diversity of Listeria Pathogenicity Islands 3 and 4 Harbored by Nonpathogenic Listeria spp. Appl Environ Microbiol 2023; 89:e0209722. [PMID: 36728444 PMCID: PMC9973017 DOI: 10.1128/aem.02097-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Listeria monocytogenes causes the severe foodborne disease listeriosis. Several clonal groups of L. monocytogenes possess the pathogenicity islands Listeria pathogenicity island 3 (LIPI-3) and LIPI-4. Here, we investigated the prevalence and genetic diversity of LIPI-3 and LIPI-4 among 63 strains of seven nonpathogenic Listeria spp. from the natural environment, i.e., wildlife (black bears [Ursus americanus]) and surface water. Analysis of the whole-genome sequence data suggested that both islands were horizontally acquired but differed considerably in their incidence and genetic diversity. LIPI-3 was identified among half of the L. innocua strains in the same genomic location as in L. monocytogenes (guaA hot spot) in a truncated form, with only three strains harboring full-length LIPI-3, and a highly divergent partial LIPI-3 was observed in three Listeria seeligeri strains, outside the guaA hot spot. Premature stop codons (PMSCs) and frameshifts were frequently noted in the LIPI-3 gene encoding listeriolysin S. On the other hand, full-length LIPI-4 without any PMSCs was found in all Listeria innocua strains, in the same genomic location as L. monocytogenes and with ~85% similarity to the L. monocytogenes counterpart. Our study provides intriguing examples of genetic changes that pathogenicity islands may undergo in nonpathogenic bacterial species, potentially in response to environmental pressures that promote either maintenance or degeneration of the islands. Investigations of the roles that LIPI-3 and LIPI-4 play in nonpathogenic Listeria spp. are warranted to further understand the differential evolution of genetic elements in pathogenic versus nonpathogenic hosts of the same genus. IMPORTANCE Listeria monocytogenes is a serious foodborne pathogen that can harbor the pathogenicity islands Listeria pathogenicity island 3 (LIPI-3) and LIPI-4. Intriguingly, these have also been reported in nonpathogenic L. innocua from food and farm environments, though limited information is available for strains from the natural environment. Here, we analyzed whole-genome sequence data of nonpathogenic Listeria spp. from wildlife and surface water to further elucidate the genetic diversity and evolution of LIPI-3 and LIPI-4 in Listeria. While the full-length islands were found only in L. innocua, LIPI-3 was uncommon and exhibited frequent truncation and genetic diversification, while LIPI-4 was remarkable in being ubiquitous, albeit diversified from L. monocytogenes. These contrasting features demonstrate that pathogenicity islands in nonpathogenic hosts can evolve along different trajectories, leading to either degeneration or maintenance, and highlight the need to examine their physiological roles in nonpathogenic hosts.
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Abril AG, Carrera M, Böhme K, Barros-Velázquez J, Calo-Mata P, Sánchez-Pérez A, Villa TG. Proteomic Characterization of Antibiotic Resistance in Listeria and Production of Antimicrobial and Virulence Factors. Int J Mol Sci 2021; 22:8141. [PMID: 34360905 PMCID: PMC8348566 DOI: 10.3390/ijms22158141] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 07/25/2021] [Accepted: 07/26/2021] [Indexed: 01/01/2023] Open
Abstract
Some Listeria species are important human and animal pathogens that can be found in contaminated food and produce a variety of virulence factors involved in their pathogenicity. Listeria strains exhibiting multidrug resistance are known to be progressively increasing and that is why continuous monitoring is needed. Effective therapy against pathogenic Listeria requires identification of the bacterial strain involved, as well as determining its virulence factors, such as antibiotic resistance and sensitivity. The present study describes the use of liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) to do a global shotgun proteomics characterization for pathogenic Listeria species. This method allowed the identification of a total of 2990 non-redundant peptides, representing 2727 proteins. Furthermore, 395 of the peptides correspond to proteins that play a direct role in Listeria pathogenicity; they were identified as virulence factors, toxins and anti-toxins, or associated with either antibiotics (involved in antibiotic-related compounds production or resistance) or resistance to toxic substances. The proteomic repository obtained here can be the base for further research into pathogenic Listeria species and facilitate the development of novel therapeutics for these pathogens.
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Affiliation(s)
- Ana G. Abril
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Campus Sur 15782, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain;
| | - Mónica Carrera
- Marine Research Institute (IIM), Spanish National Research Council (CSIC), Eduardo Cabello 6, 36208 Vigo, Spain
| | - Karola Böhme
- Agroalimentary Technological Center of Lugo, Montirón 154, 27002 Lugo, Spain;
| | - Jorge Barros-Velázquez
- Departamento de Química Analítica, Nutrición y Bromatología, Área de Tecnología de los Alimentos, Facultad de Veterinaria, Campus Lugo, Universidad de Santiago de Compostela, 27002 Santiago de Compostela, Spain; (J.B.-V.); (P.C.-M.)
| | - Pilar Calo-Mata
- Departamento de Química Analítica, Nutrición y Bromatología, Área de Tecnología de los Alimentos, Facultad de Veterinaria, Campus Lugo, Universidad de Santiago de Compostela, 27002 Santiago de Compostela, Spain; (J.B.-V.); (P.C.-M.)
| | - Angeles Sánchez-Pérez
- Sydney School of Veterinary Science, Faculty of Science, University of Sydney, Sydney, NSW 2006, Australia;
| | - Tomás G. Villa
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Campus Sur 15782, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain;
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Janež N, Škrlj B, Sterniša M, Klančnik A, Sabotič J. The role of the Listeria monocytogenes surfactome in biofilm formation. Microb Biotechnol 2021; 14:1269-1281. [PMID: 34106516 PMCID: PMC8313260 DOI: 10.1111/1751-7915.13847] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 05/12/2021] [Accepted: 05/17/2021] [Indexed: 12/11/2022] Open
Abstract
Listeria monocytogenes is a highly pathogenic foodborne bacterium that is ubiquitous in the natural environment and capable of forming persistent biofilms in food processing environments. This species has a rich repertoire of surface structures that enable it to survive, adapt and persist in various environments and promote biofilm formation. We review current understanding and advances on how L. monocytogenes organizes its surface for biofilm formation on surfaces associated with food processing settings, because they may be an important target for development of novel antibiofilm compounds. A synthesis of the current knowledge on the role of Listeria surfactome, comprising peptidoglycan, teichoic acids and cell wall proteins, during biofilm formation on abiotic surfaces is provided. We consider indications gained from genome-wide studies and discuss surfactome structures with established mechanistic aspects in biofilm formation. Additionally, we look at the analogies to the species L. innocua, which is closely related to L. monocytogenes and often used as its model (surrogate) organism.
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Affiliation(s)
- Nika Janež
- Department of BiotechnologyJožef Stefan InstituteLjubljanaSlovenia
| | - Blaž Škrlj
- Department of Knowledge TechnologiesJožef Stefan InstituteLjubljanaSlovenia
- Jožef Stefan International Postgraduate SchoolLjubljanaSlovenia
| | - Meta Sterniša
- Department of Food Science and TechnologyBiotechnical FacultyUniversity of LjubljanaLjubljanaSlovenia
| | - Anja Klančnik
- Department of Food Science and TechnologyBiotechnical FacultyUniversity of LjubljanaLjubljanaSlovenia
| | - Jerica Sabotič
- Department of BiotechnologyJožef Stefan InstituteLjubljanaSlovenia
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Abstract
For assessing isolates of Listeria monocytogenes, serotype designation is the first subtyping method used. Methodologies used to assign serotype are currently evolving and will eventually be replaced with whole genome sequencing. Traditionally, serotyping has been done with agglutination reactions; however, alternative methods utilizing enzyme linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) are common. Described here are the three non-genomic methods and the advantages and disadvantages of each.
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Affiliation(s)
- Lisa Gorski
- Produce Safety and Microbiology Research Unit, Agricultural Research Service, United States Department of Agriculture, Albany, CA, USA.
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Sumrall ET, Keller AP, Shen Y, Loessner MJ. Structure and function of Listeria teichoic acids and their implications. Mol Microbiol 2020; 113:627-637. [PMID: 31972870 DOI: 10.1111/mmi.14472] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 01/10/2020] [Accepted: 01/17/2020] [Indexed: 01/13/2023]
Abstract
Teichoic acids (TAs) are the most abundant glycopolymers in the cell wall of Listeria, an opportunistic Gram-positive pathogen that causes severe foodborne infections. Two different structural classes of Listeria TA exist: the polyribitolphosphate-based wall teichoic acid (WTA) that is covalently anchored to the peptidoglycan, and the polyglycerolphosphate-based lipoteichoic acid (LTA) that is tethered to the cytoplasmic membrane. While TA polymers govern many important physiological processes, the diverse glycosylation patterns of WTA result in a high degree of surface variation across the species and serovars of Listeria, which in turn bestows varying effects on fitness, biofilm formation, bacteriophage susceptibility and virulence. We review the advances made over the past two decades, and our current understanding of the relationship between TA structure and function. We describe the various types of TA that have been structurally determined to date, and discuss the genetic determinants known to be involved in TA glycosylation. We elaborate on surface proteins functionally related to TA decoration, as well as the molecular and analytical tools used to probe TAs. We anticipate that the growing knowledge of the Listeria surface chemistry will also be exploited to develop novel diagnostic and therapeutic strategies for this pathogen.
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Affiliation(s)
- Eric T Sumrall
- Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Anja P Keller
- Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Yang Shen
- Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Martin J Loessner
- Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
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Rismondo J, Haddad TFM, Shen Y, Loessner MJ, Gründling A. GtcA is required for LTA glycosylation in Listeria monocytogenes serovar 1/2a and Bacillus subtilis. ACTA ACUST UNITED AC 2020; 6:100038. [PMID: 32743150 PMCID: PMC7389260 DOI: 10.1016/j.tcsw.2020.100038] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/16/2020] [Accepted: 02/11/2020] [Indexed: 11/26/2022]
Abstract
The cell wall polymers wall teichoic acid (WTA) and lipoteichoic acid (LTA) are often modified with glycosyl and D-alanine residues. Recent studies have shown that a three-component glycosylation system is used for the modification of LTA in several Gram-positive bacteria including Bacillus subtilis and Listeria monocytogenes. In the L. monocytogenes 1/2a strain 10403S, the cytoplasmic glycosyltransferase GtlA is thought to use UDP-galactose to produce the C55-P-galactose lipid intermediate, which is transported across the membrane by an unknown flippase. Next, the galactose residue is transferred onto the LTA backbone on the outside of the cell by the glycosyltransferase GtlB. Here we show that GtcA is necessary for the glycosylation of LTA in L. monocytogenes 10403S and B. subtilis 168 and we hypothesize that these proteins act as C55-P-sugar flippases. With this we revealed that GtcA is involved in the glycosylation of both teichoic acid polymers in L. monocytogenes 10403S, namely WTA with N-acetylglucosamine and LTA with galactose residues. These findings indicate that the L. monocytogenes GtcA protein can act on different C55-P-sugar intermediates. Further characterization of GtcA in L. monocytogenes led to the identification of residues essential for its overall function as well as residues, which predominately impact WTA or LTA glycosylation.
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Affiliation(s)
- Jeanine Rismondo
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Talal F M Haddad
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Yang Shen
- Institute of Food, Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland
| | - Martin J Loessner
- Institute of Food, Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland
| | - Angelika Gründling
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
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Fukao M, Zendo T, Inoue T, Nakayama J, Suzuki S, Fukaya T, Yajima N, Sonomoto K. Plasmid-encoded glycosyltransferase operon is responsible for exopolysaccharide production, cell aggregation, and bile resistance in a probiotic strain, Lactobacillus brevis KB290. J Biosci Bioeng 2019; 128:391-397. [DOI: 10.1016/j.jbiosc.2019.04.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/04/2019] [Accepted: 04/10/2019] [Indexed: 12/26/2022]
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9
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Abay S, Çakır Bayram L, Aydin F, Müştak HK, Diker KS, Erol İ. Pathogenicity, genotyping and antibacterial susceptibility of the Listeria spp. recovered from stray dogs. Microb Pathog 2018; 126:123-133. [PMID: 30381253 DOI: 10.1016/j.micpath.2018.10.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 09/25/2018] [Accepted: 10/27/2018] [Indexed: 12/22/2022]
Abstract
The present study aimed to determine the prevalence of Listeria spp. in stray dogs in the Kayseri province of Turkey. In addition, serotyping, genotyping and virulence gene analysis of the isolated Listeria spp. were performed and their pathogenicity and antibacterial susceptibility were investigated. The study included 80 rectal swaps taken from 80 stray dogs of different ages and gender that were sheltered in the Kayseri Municipal Dog Shelter. Listeria selective broth and Listeria selective agar were used for the isolation of Listeria spp. and the isolates were identified using a Microbact 12L (Oxoid, England) identification test kit. 16S rDNA sequencing and species-specific polymerase chain reaction (PCR) were performed for molecular identification of the isolates, multiplex PCR and a serological test were performed for serotyping, and PCR was used for virulence gene analysis. For determining the pathogenicity of L. monocytogenes and L. innocua isolates, a total of 100 mice (50 pregnant and 50 non-pregnant) were used. The mice were infected intraperitoneally; the inoculation dose was 1 × 109 CFU/mL and 0.2 mL was used for each animal. Tissue samples obtained from infected mice were processed for the re-isolation of the Listeria spp. and then stained with hematoxylin eosin and Brown-Brenn Gram stain. The antibiotic susceptibilities of the isolates were determined by the disk diffusion method. Listeria spp. were isolated from 5 (6.25%) of the 80 fecal samples. While 1 of the isolates was identified as L. monocytogenes, 4 of them were identified as L. innocua. Serotyping by serological and molecular methods revealed the isolate of L. monocytogenes to be serotype 1/2a. According to the phylogenetic trees, L. innocua and L. monocytogenes strains were clustered in different groups. The L. monocytogenes isolate was positive for all virulence genes tested. All L. innocua isolates were positive for the plcB gene. While all L. innocua isolates were negative for the lin1068 gene, 3 L. innocua isolates were found to be positive for the lin0558 gene. In mice infected with L. monocytogenes, pathological findings were observed in the uterus, intestines, pancreas, and heart. In mice infected with L. innocua, pathological findings were observed in the stomach, intestines and spleen. L. monocytogenes- or L. innocua-related infections or other inflammatory reactions were not observed in the brains of infected animals. On histopathological examination with Gram stain, an abundance of Listeria spp. was observed in the lesions of the liver, spleen, uterus, and kidney. Moreover, while abortion was observed in all animals infected with L. monocytogenes, it was not observed in any of the animals infected with L. innocua. Antibiotic susceptibility testing revealed that all 5 isolates were sensitive to ampicillin, amoxicillin/clavulanic acid, erythromycin, gentamicin, penicillin G, and trimethoprim-sulfamethoxazole and were resistant to nalidixic acid, streptomycin, and cefuroxime sodium. Considering also the pathogenicity of the isolated microorganisms, it can be suggested that stray dogs as carriers of Listeria spp. are a significant risk to public health. As L. innocua isolates, which are considered apathogenic, led to the occurrence of lesions similar to those caused by L. monocytogenes, detailed studies on the pathogenesis of L. innocua infections caused by L. innocua isolates recovered from various sources are required.
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Affiliation(s)
- Seçil Abay
- Erciyes University, Veterinary Faculty, Department of Microbiology, Kayseri, Turkey.
| | - Latife Çakır Bayram
- Erciyes University, Veterinary Faculty, Department of Pathology, Kayseri, Turkey
| | - Fuat Aydin
- Erciyes University, Veterinary Faculty, Department of Microbiology, Kayseri, Turkey
| | - Hamit Kaan Müştak
- Ankara University, Veterinary Faculty, Department of Microbiology, Ankara, Turkey
| | - Kadir Serdar Diker
- Ankara University, Veterinary Faculty, Department of Microbiology, Ankara, Turkey
| | - İrfan Erol
- Ankara University, Veterinary Faculty, Department of Food Hygiene and Technology, Ankara, Turkey
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Nguyen XH, Trinh TL, Vu TBH, Le QH, To KA. Isolation of phage-display library-derived scFv antibody specific toListeria monocytogenesby a novel immobilized method. J Appl Microbiol 2018; 124:591-597. [DOI: 10.1111/jam.13648] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/14/2017] [Accepted: 11/15/2017] [Indexed: 11/29/2022]
Affiliation(s)
- X.-H. Nguyen
- Centre de Physiopathologie Toulouse-Purpan; INSERM UMR1043; CNRS UMR5282; Toulouse III University; Toulouse France
- School of Biotechnology and Food technology; Hanoi University of Science and Technology; Hanoi Vietnam
| | - T.-L. Trinh
- Department of Immunology; Moffitt Cancer Center; Tampa FL USA
- School of Biotechnology and Food technology; Hanoi University of Science and Technology; Hanoi Vietnam
| | - T.-B.-H. Vu
- Department of Cytogenetics and Molecular Biology; National Institute of Hematology and Blood Transfusion; Hanoi Vietnam
| | - Q.-H. Le
- Institute of Biotechnology; Vietnamese Academy of Science and Technology; Hanoi Vietnam
| | - K.-A. To
- School of Biotechnology and Food technology; Hanoi University of Science and Technology; Hanoi Vietnam
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Gorski L. Serotype assignment by sero-agglutination, ELISA, and PCR. Methods Mol Biol 2014; 1157:41-61. [PMID: 24792547 DOI: 10.1007/978-1-4939-0703-8_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
For assessing isolates of Listeria monocytogenes serotype designation is the foremost subtyping method used. Traditionally, serotyping has been done with agglutination reactions. In the last decade, alternative serotyping methods were described using enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). Herein are described the three methods, and the advantages and disadvantages of each.
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Affiliation(s)
- Lisa Gorski
- United States Department of Agriculture, Agricultural Research Service, Produce Safety and Microbiology Research Unit, 800 Buchanan Street, Albany, CA, 94710, USA,
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12
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Phage display-derived binders able to distinguish Listeria monocytogenes from other Listeria species. PLoS One 2013; 8:e74312. [PMID: 24040227 DOI: 10.1371/journal.pone.0074312] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 07/28/2013] [Indexed: 11/19/2022] Open
Abstract
The objective of this study was to produce phage display-derived binders with the ability to distinguish Listeria monocytogenes from other Listeria spp., which may have potential utility to enhance detection of Listeria monocytogenes. To obtain binders with the desired binding specificity a series of surface and solution phage-display biopannings were performed. Initially, three rounds of surface biopanning against gamma-irradiated L. monocytogenes serovar 4b cells were performed followed by an additional surface biopanning round against L. monocytogenes 4b which included prior subtraction biopanning against gamma-irradiated L. innocua cells. In an attempt to further enhance binder specificity for L. monocytogenes 4b two rounds of solution biopanning were performed, both rounds included initial subtraction solution biopanning against L. innocua. Subsequent evaluations were performed on the phage clones by phage binding ELISA. All phage clones tested from the second round of solution biopanning had higher specificity for L. monocytogenes 4b than for L. innocua and three other foodborne pathogens (Salmonella spp., Escherichia coli and Campylobacter jejuni). Further evaluation with five other Listeria spp. revealed that one phage clone in particular, expressing peptide GRIADLPPLKPN, was highly specific for L. monocytogenes with at least 43-fold more binding capability to L. monocytogenes 4b than to any other Listeria sp. This proof-of-principle study demonstrates how a combination of surface, solution and subtractive biopanning was used to maximise binder specificity. L. monocytogenes-specific binders were obtained which could have potential application in novel detection tests for L. monocytogenes, benefiting both the food and medical industries.
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den Bakker HC, Desjardins CA, Griggs AD, Peters JE, Zeng Q, Young SK, Kodira CD, Yandava C, Hepburn TA, Haas BJ, Birren BW, Wiedmann M. Evolutionary dynamics of the accessory genome of Listeria monocytogenes. PLoS One 2013; 8:e67511. [PMID: 23825666 PMCID: PMC3692452 DOI: 10.1371/journal.pone.0067511] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 05/23/2013] [Indexed: 11/18/2022] Open
Abstract
Listeria monocytogenes, a foodborne bacterial pathogen, is comprised of four phylogenetic lineages that vary with regard to their serotypes and distribution among sources. In order to characterize lineage-specific genomic diversity within L. monocytogenes, we sequenced the genomes of eight strains from several lineages and serotypes, and characterized the accessory genome, which was hypothesized to contribute to phenotypic differences across lineages. The eight L. monocytogenes genomes sequenced range in size from 2.85-3.14 Mb, encode 2,822-3,187 genes, and include the first publicly available sequenced representatives of serotypes 1/2c, 3a and 4c. Mapping of the distribution of accessory genes revealed two distinct regions of the L. monocytogenes chromosome: an accessory-rich region in the first 65° adjacent to the origin of replication and a more stable region in the remaining 295°. This pattern of genome organization is distinct from that of related bacteria Staphylococcus aureus and Bacillus cereus. The accessory genome of all lineages is enriched for cell surface-related genes and phosphotransferase systems, and transcriptional regulators, highlighting the selective pressures faced by contemporary strains from their hosts, other microbes, and their environment. Phylogenetic analysis of O-antigen genes and gene clusters predicts that serotype 4 was ancestral in L. monocytogenes and serotype 1/2 associated gene clusters were putatively introduced through horizontal gene transfer in the ancestral population of L. monocytogenes lineage I and II.
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Affiliation(s)
- Henk C den Bakker
- Department of Food Science, Cornell University, Ithaca, New York, United States of America.
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Tsai YHL, Maron SB, McGann P, Nightingale KK, Wiedmann M, Orsi RH. Recombination and positive selection contributed to the evolution of Listeria monocytogenes lineages III and IV, two distinct and well supported uncommon L. monocytogenes lineages. INFECTION GENETICS AND EVOLUTION 2011; 11:1881-90. [PMID: 21854875 DOI: 10.1016/j.meegid.2011.08.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 08/03/2011] [Accepted: 08/04/2011] [Indexed: 10/17/2022]
Abstract
Listeriamonocytogenes lineages III and IV represent two uncommon lineages of the human and animal pathogen L. monocytogenes, characterized by occurrence of unusual phenotypic and genetic characteristics that differentiate them from the common lineages I and II. To gain further insights into the evolution of lineages III and IV, we amplified and sequenced housekeeping genes (i.e., gap, prs, purM, ribC, and sigB), internalin genes (i.e., inlA, inlB, inlC, inlG, inlC2, inlD, inlE, inlF, and inlH) and the virulence gene cluster containing prfA, plcA, hly, mpl, actA, and plcB for lineages III (n = 7) and IV (n = 4) isolates. Phylogenetic analyses of the sequences obtained along with previously reported sequence data for 40 isolates representing lineages I (n = 18), II (n = 21), and III (n = 1), showed that lineages III and IV represent divergent and monophyletic lineages. The virulence gene cluster as well as the inlAB operon were present in all isolates, with inlF absent from all lineages III and IV isolates. While all lineage IV isolates contained only inlC (in addition to inlAB), lineage III isolates showed considerable diversity with regard to internalin gene presence, including presence of (i) only inlC (n = 2), (ii) inlC and inlGC2DE (n = 3), (iii) only inlGC2DE (n = 2), and (iv) inlC and inlC2DE (n = 1). In addition to evidence for horizontal gene transfer events, among lineages III and IV isolates, in prs, actA, plcB, mpl, inlA, inlB, inlG, inlD, and inlE, we also found significant evidence for positive selection in the hly promoter region and, along the lineages III and IV branches, for actA (including in sites recognized for interactions with proteins involved in actin tail polymerization). In conclusion, lineages III and IV represent two distinct monophyletic groups with contributions of intragenic recombination to the evolution of their internalin genes as well as contributions of positive selection to evolution of the virulence genes island.
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Stress survival islet 1 (SSI-1) survey in Listeria monocytogenes reveals an insert common to listeria innocua in sequence type 121 L. monocytogenes strains. Appl Environ Microbiol 2011; 77:2169-73. [PMID: 21239547 DOI: 10.1128/aem.02159-10] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Listeria monocytogenes strains (n = 117) were screened for the presence of stress survival islet 1 (SSI-1). SSI-1(+) strains (32.5%) belonged mainly to serotypes 1/2c, 3b, and 3c. All sequence type 121 (ST-121) strains included (n = 7) possessed homologues to Listeria innocua genes lin0464 and lin0465 instead of SSI-1.
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16
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Orsi RH, Sun Q, Wiedmann M. Genome-wide analyses reveal lineage specific contributions of positive selection and recombination to the evolution of Listeria monocytogenes. BMC Evol Biol 2008; 8:233. [PMID: 18700032 PMCID: PMC2532693 DOI: 10.1186/1471-2148-8-233] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2007] [Accepted: 08/12/2008] [Indexed: 12/30/2022] Open
Abstract
Background The genus Listeria includes two closely related pathogenic and non-pathogenic species, L. monocytogenes and L. innocua. L. monocytogenes is an opportunistic human foodborne and animal pathogen that includes two common lineages. While lineage I is more commonly found among human listeriosis cases, lineage II appears to be overrepresented among isolates from foods and environmental sources. This study used the genome sequences for one L. innocua strain and four L. monocytogenes strains representing lineages I and II, to characterize the contributions of positive selection and recombination to the evolution of the L. innocua/L. monocytogenes core genome. Results Among the 2267 genes in the L. monocytogenes/L. innocua core genome, 1097 genes showed evidence for recombination and 36 genes showed evidence for positive selection. Positive selection was strongly associated with recombination. Specifically, 29 of the 36 genes under positive selection also showed evidence for recombination. Recombination was more common among isolates in lineage II than lineage I; this trend was confirmed by sequencing five genes in a larger isolate set. Positive selection was more abundant in the ancestral branch of lineage II (20 genes) as compared to the ancestral branch of lineage I (9 genes). Additional genes under positive selection were identified in the branch separating the two species; for this branch, genes in the role category "Cell wall and membrane biogenesis" were significantly more likely to have evidence for positive selection. Positive selection of three genes was confirmed in a larger isolate set, which also revealed occurrence of multiple premature stop codons in one positively selected gene involved in flagellar motility (flaR). Conclusion While recombination and positive selection both contribute to evolution of L. monocytogenes, the relative contributions of these evolutionary forces seem to differ by L. monocytogenes lineages and appear to be more important in the evolution of lineage II, which seems to be found in a broader range of environments, as compared to the apparently more host adapted lineage I. Diversification of cell wall and membrane biogenesis and motility-related genes may play a particularly important role in the evolution of L. monocytogenes.
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Affiliation(s)
- Renato H Orsi
- Department of Food Science, Cornell University, Ithaca, NY, USA.
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17
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Friedly E, Crandall P, Ricke S, O'Bryan C, Martin E, Boyd L. Identification of Listeria innocua Surrogates for Listeria monocytogenes in Hamburger Patties. J Food Sci 2008; 73:M174-8. [DOI: 10.1111/j.1750-3841.2008.00719.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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18
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Bae E, Banada PP, Huff K, Bhunia AK, Robinson JP, Hirleman ED. Biophysical modeling of forward scattering from bacterial colonies using scalar diffraction theory. APPLIED OPTICS 2007; 46:3639-48. [PMID: 17514326 DOI: 10.1364/ao.46.003639] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
A model for forward scattering from bacterial colonies is presented. The colonies of interest consist of approximately 10(12) - 10(13) individual bacteria densely packed in a configuration several millimeters in diameter and approximately 0.1-0.2 mm in thickness. The model is based on scalar diffraction theory and accounts for amplitude and phase modulation created by three macroscopic properties of the colonies: phase modulation due to the surface topography, phase modulation due to the radial structure observed from some strains and species, and diffraction from the outline of the colony. Phase contrast and confocal microscopy were performed to provide quantitative information on the shape and internal structure of the colonies. The computed results showed excellent agreement with the experimental scattering data for three different Listeria species: Listeria innocua, Listeria ivanovii, and Listeria monocytogenes. The results provide a physical explanation for the unique and distinctive scattering signatures produced by colonies of closely related Listeria species and support the efficacy of forward scattering for rapid detection and classification of pathogens without tagging.
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Affiliation(s)
- Euiwon Bae
- School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47906, USA.
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BHUNIA ARUNK, BANADA PADMAPRIYA, BANERJEE PRATIK, VALADEZ ANGELA, HIRLEMAN EDANIEL. LIGHT SCATTERING, FIBER OPTIC- AND CELL-BASED SENSORS FOR SENSITIVE DETECTION OF FOODBORNE PATHOGENS. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1745-4581.2007.00077.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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20
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Evans MR, Swaminathan B, Graves LM, Altermann E, Klaenhammer TR, Fink RC, Kernodle S, Kathariou S. Genetic markers unique to Listeria monocytogenes serotype 4b differentiate epidemic clone II (hot dog outbreak strains) from other lineages. Appl Environ Microbiol 2004; 70:2383-90. [PMID: 15066835 PMCID: PMC383029 DOI: 10.1128/aem.70.4.2383-2390.2004] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A small number of closely related strains of Listeria monocytogenes serotype 4b, designated epidemic clone I (ECI), have been implicated in numerous outbreaks of food-borne listeriosis described during the past two decades in Europe and North America. In 1998 to 1999, a multistate outbreak traced to contaminated hot dogs involved a different strain type of serotype 4b, with genetic fingerprints rarely encountered before. In spite of the profound economic and public health impact of this outbreak, the implicated bacteria (designated epidemic clone II [ECII]) have remained poorly characterized genetically, and nucleotide sequences specific for these strains have not been reported. Using genome sequence information, PCR, and Southern blots, we identified DNA fragments which appeared to be either absent or markedly divergent in the hot dog outbreak strains but conserved among other serotype 4b strains. PCR with primers derived from these fragments as well as Southern blots with the amplicons as probes readily differentiated ECII from other serotype 4b strains. The serotype 4b-specific region harboring these fragments was adjacent to inlA, which encodes a well-characterized virulence determinant. The findings suggest that ECII strains have undergone divergence in portions of a serotype-specific region that is conserved in other serotype 4b strains. Although the mechanisms that drive this divergence remain to be identified, DNA-based tools from this region can facilitate the detection and further characterization of strains belonging to this lineage.
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Affiliation(s)
- Matthew R Evans
- Department of Food Science, North Carolina State University, Raleigh, North Carolina 27695, USA
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21
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Zhang C, Zhang M, Ju J, Nietfeldt J, Wise J, Terry PM, Olson M, Kachman SD, Wiedmann M, Samadpour M, Benson AK. Genome diversification in phylogenetic lineages I and II of Listeria monocytogenes: identification of segments unique to lineage II populations. J Bacteriol 2003; 185:5573-84. [PMID: 12949110 PMCID: PMC193770 DOI: 10.1128/jb.185.18.5573-5584.2003] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Thirteen different serotypes of Listeria monocytogenes can be distinguished on the basis of variation in somatic and flagellar antigens. Although the known virulence genes are present in all serotypes, greater than 90% of human cases of listeriosis are caused by serotypes 1/2a, 1/2b, and 4b and nearly all outbreaks of food-borne listeriosis have been caused by serotype 4b strains. Phylogenetic analysis of these three common clinical serotypes places them into two different lineages, with serotypes 1/2b and 4b belonging to lineage I and 1/2a belonging to lineage II. To begin examining evolution of the genome in these serotypes, DNA microarray analysis was used to identify lineage-specific and serotype-specific differences in genome content. A set of 44 strains representing serotypes 1/2a, 1/2b, and 4b was probed with a shotgun DNA microarray constructed from the serotype 1/2a strain 10403s. Clones spanning 47 different genes in 16 different contiguous segments relative to the lineage II 1/2a genome were found to be absent in all lineage I strains tested (serotype 4b and 1/2b) and an additional nine were altered exclusively in 4b strains. Southern hybridization confirmed that conserved alterations were, in all but two loci, due to absence of the segments from the genome. Genes within these contiguous segments comprise five functional categories, including genes involved in synthesis of cell surface molecules and regulation of virulence gene expression. Phylogenetic reconstruction and examination of compositional bias in the regions of difference are consistent with a model in which the ancestor of the two lineages had the 1/2 somatic serotype and the regions absent in the lineage I genome arose by loss of ancestral sequences.
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Affiliation(s)
- Chaomei Zhang
- Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska 68583, USA
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22
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Salcedo C, Arreaza L, Alcalá B, de la Fuente L, Vázquez JA. Development of a multilocus sequence typing method for analysis of Listeria monocytogenes clones. J Clin Microbiol 2003; 41:757-62. [PMID: 12574278 PMCID: PMC149676 DOI: 10.1128/jcm.41.2.757-762.2003] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study is a first step in the development of multilocus sequence typing (MLST) method for Listeria monocytogenes. Nine housekeeping genes were analyzed in a set of 62 strains isolated from different sources and geographic locations in Spain. These strains were previously characterized by pulsed-field gel electrophoresis (PFGE). Because of low diversity, two loci were discarded from the study. The sequence analysis of the seven remaining genes showed 29 different allelic combinations, with 22 of them represented by only one strain. The results of this sequence analysis were generally consistent with those of PFGE. Because MLST allows the easy comparison and exchange of results obtained in different laboratories, the future application of this new molecular method could be a useful tool for the listeriosis surveillance systems that will allow the identification and distribution of analysis of L. monocytogenes clones in the environment.
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Affiliation(s)
- C Salcedo
- Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain
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Loessner MJ, Kramer K, Ebel F, Scherer S. C-terminal domains of Listeria monocytogenes bacteriophage murein hydrolases determine specific recognition and high-affinity binding to bacterial cell wall carbohydrates. Mol Microbiol 2002; 44:335-49. [PMID: 11972774 DOI: 10.1046/j.1365-2958.2002.02889.x] [Citation(s) in RCA: 278] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Listeria monocytogenes phage endolysins Ply118 and Ply500 share a unique enzymatic activity and specifically hydrolyse Listeria cells at the completion of virus multiplication in order to release progeny phage. With the aim of determining the molecular basis for the lytic specificity of these enzymes, we have elucidated their domain structure and examined the function of their unrelated and unique C-terminal cell wall binding domains (CBDs). Analysis of deletion mutants showed that both domains are needed for lytic activity. Fusions of CBDs with green fluorescent protein (GFP) demonstrated that the C-terminal 140 amino acids of Ply500 and the C-terminal 182 residues of Ply118 are necessary and sufficient to direct the murein hydrolases to the bacterial cell wall. CBD500 was able to target GFP to the surface of Listeria cells belonging to serovar groups 4, 5 and 6, resulting in an even staining of the entire cell surface. In contrast, the CBD118 hybrid bound to a ligand predominantly present at septal regions and cell poles, but only on cells of serovars 1/2, 3 and 7. Non-covalent binding to surface carbohydrate ligands occurred in a rapid, saturation-dependent manner. We measured 4 x 104 and 8 x 104 binding sites for CBD118 and CBD500 respectively. Surface plasmon resonance analysis revealed unexpected high molecular affinity constants for the CBD-ligand interactions, corresponding to nanomolar affinities. In conclusion, we show that the CBDs are responsible for targeting the phage endolysins to their substrates and function to confer recognition specificity on the proteins. As the CBD sequences contain no repeats and lack all known sequence motifs for anchoring of proteins to the bacterial cell, we conclude that they use unique structural motifs for specific association with the surface of Gram-positive bacteria.
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Affiliation(s)
- Martin J Loessner
- Institut für Mikrobiologie, FML Weihenstephan, Technische Universität München, Weihenstephaner Berg 3, D-85350 Freising, Germany.
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Tran HL, Kathariou S. Restriction fragment length polymorphisms detected with novel DNA probes differentiate among diverse lineages of serogroup 4 Listeria monocytogenes and identify four distinct lineages in serotype 4b. Appl Environ Microbiol 2002; 68:59-64. [PMID: 11772609 PMCID: PMC126560 DOI: 10.1128/aem.68.1.59-64.2002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Listeria monocytogenes of serotype 4b has been implicated in numerous outbreaks of food-borne listeriosis and in ca. 40% of sporadic cases. Strains of this serotype appear to be relatively homogeneous genetically, and molecular markers specific for distinct serotype 4b lineages have not been frequently identified. Here we show that DNA fragments derived from the putative mannitol permease locus of Listeria monocytogenes had an unexpectedly high potential to differentiate among different strains of serotype 4b when used as probes in Southern blotting of EcoRI-digested genomic DNA, yielding four distinct restriction fragment length polymorphism (RFLP) patterns. Strains of two epidemic-associated lineages, including the major epidemic clone implicated in several outbreaks in Europe and North America, had distinct RFLPs which differed from those of all other serotype 4b strains that we screened but which were encountered among strains of serotypes 1/2b and 3b. In addition, three serogroup 4 lineages were found to have unique RFLPs that were not encountered among any other L. monocytogenes strains. One was an unusual lineage of serotype 4b, and the other two were members of the serotype 4a and 4c group. The observed polymorphisms may reflect evolutionary relationships among lineages of L. monocytogenes and may facilitate detection and population genetic analysis of specific lineages.
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Affiliation(s)
- Huyen L Tran
- Department of Microbiology, University of Hawaii, Honolulu, Hawaii, USA
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Herd M, Kocks C. Gene fragments distinguishing an epidemic-associated strain from a virulent prototype strain of Listeria monocytogenes belong to a distinct functional subset of genes and partially cross-hybridize with other Listeria species. Infect Immun 2001; 69:3972-9. [PMID: 11349066 PMCID: PMC98459 DOI: 10.1128/iai.69.6.3972-3979.2001] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Most major food-borne outbreaks of listeriosis in Europe and in the United States have been caused by genetically closely related Listeria monocytogenes strains of serotype 4b. In order to assess whether genomic loci exist that could underlie this increased epidemic potential, we subtracted the genome of the virulent prototype L. monocytogenes strain EGD from a prototype epidemic strain. A total of 39 DNA fragments corresponding to 20% of an estimated total of 150 to 190 kb of differential genome material were isolated. For 21 of these fragments, no function on the basis of homology could be predicted. Of the remaining 18 fragments, 15 had homologies to bacterial surface proteins, some of which have been implicated in virulence mechanisms such as cell invasion, adhesion, or immune escape. Southern hybridization of arrays containing the epidemic-clone-specific DNA segments with genomic DNA of different L. monocytogenes strains was consistent with the current lineage division. Surprisingly, however, some of the fragments hybridized in a mosaic-like fashion to genomes of two other Listeria species, the animal pathogen L. ivanovii and the nonpathogen L. innocua. Taken together, our results provide a starting point for the identification of epidemic-trait-associated genes.
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Affiliation(s)
- M Herd
- Institute for Genetics, University of Cologne, D-50674 Cologne, Germany
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26
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Lei XH, Fiedler F, Lan Z, Kathariou S. A novel serotype-specific gene cassette (gltA-gltB) is required for expression of teichoic acid-associated surface antigens in Listeria monocytogenes of serotype 4b. J Bacteriol 2001; 183:1133-9. [PMID: 11157924 PMCID: PMC94985 DOI: 10.1128/jb.183.4.1133-1139.2001] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Listeria monocytogenes serotype 4b strains account for about 40% of sporadic cases and many epidemics of listeriosis. Mutations in a chromosomal locus resulted in loss of reactivity with all three monoclonal antibodies (MAbs) which were specific to serotype 4b and the closely related serotypes 4d and 4e. Here we show that this locus contains a serotype 4b-4d-4e-specific gene cassette (3,071 bp) which consists of two genes, gltA and gltB, and is flanked by palindromic sequences (51 and 44 nucleotides). Complete loss of reactivity with the three serotype-specific MAbs resulted from insertional inactivation of either gltA or gltB. The gltA and gltB mutants were characterized by loss and severe reduction, respectively, of glucose in the teichoic acid, whereas galactose, the other serotype-specific sugar substituent in the teichoic acid, was not affected. Within L. monocytogenes, only strains of serotypes 4b, 4d, and 4e harbored the gltA-gltB cassette, whereas coding sequences on either side of the cassette were conserved among all serotypes. Comparative genomic analysis of a serotype 1/2b strain showed that the 3,071-bp gltA-gltB cassette was replaced by a much shorter (528-bp) and unrelated region, flanked by inverted repeats similar to their counterparts in serotype 4b. These findings indicate that in the evolution of different serotypes of L. monocytogenes, this site in the genome has become occupied by serotype-specific sequences which, in the case of serotype 4b, are essential for expression of serotype-specific surface antigens and presence of glucose substituents in the teichoic acids in the cell wall.
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Affiliation(s)
- X H Lei
- Department of Microbiology, University of Hawaii, Honolulu, Hawaii 96822, USA
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