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Abstract
The ability to acquire iron from the environment is often an important virulence factor for pathogenic bacteria and Vibrios are no exception to this. Vibrios are reported mainly from marine habitats and most of the species are pathogenic. Among those, the pathogenic vibrios eg. V cholerae, V. parahaemolyticus, V. vulnificus causes foodborne illnesses. Vibrios are capable of producing all different classes of siderophores like hydroxamate (aerobactin), catecholate (vibriobactin, fluvibactin), carboxylate (vibrioferrin), and amphiphilic (amphibactin). Every different species of vibrios are capable of utilizing some endogenous or xenosiderophores. Being Gram-negative bacteria, Vibrios import iron siderophore via TonB dependent transport system and unlike other Gamma proteobacteria these usually possess two or even three partially redundant TonB systems for iron siderophore transport. Other than selected few iron siderophores, most pathogenic Vibrios are known to be able to utilize heme as the sole iron source, while some species are capable of importing free iron from the environment. As per the present knowledge, the spectrum of iron compound transport and utilization in Vibrios is better understood than the siderophore biosynthetic capability of individual species.
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Li Y, Ma Q. Iron Acquisition Strategies of Vibrio anguillarum. Front Cell Infect Microbiol 2017; 7:342. [PMID: 28791260 PMCID: PMC5524678 DOI: 10.3389/fcimb.2017.00342] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 07/11/2017] [Indexed: 12/03/2022] Open
Abstract
The hemorrhagic septicemic disease vibriosis caused by Vibrio anguillarum shows noticeable similarities to invasive septicemia in humans, and in this case, the V. anguillarum–host system has the potential to serve as a model for understanding native eukaryotic host–pathogen interactions. Iron acquisition, as a fierce battle occurring between pathogenic V. anguillarum and the fish host, is a pivotal step for virulence. In this article, advances in defining the roles of iron uptake pathways in growth and virulence of V. anguillarum have been summarized, divided into five aspects, including siderophore biosynthesis and secretion, iron uptake, iron release, and regulation of iron uptake. Understanding the molecular mechanisms of iron acquisition will have important implications for the pathogenicity of this organism.
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Affiliation(s)
- Yingjie Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of SciencesQingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and TechnologyQingdao, China
| | - Qingjun Ma
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of SciencesQingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and TechnologyQingdao, China
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Busschaert P, Frans I, Crauwels S, Zhu B, Willems K, Bossier P, Michiels C, Verstrepen K, Lievens B, Rediers H. Comparative genome sequencing to assess the genetic diversity and virulence attributes of 15 Vibrio anguillarum isolates. JOURNAL OF FISH DISEASES 2015; 38:795-807. [PMID: 25073650 DOI: 10.1111/jfd.12290] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/14/2014] [Accepted: 06/19/2014] [Indexed: 06/03/2023]
Abstract
Vibrio anguillarum is the causative agent of vibriosis, a deadly haemorrhagic septicaemic disease affecting various marine and fresh/brackish water fish, bivalves and crustaceans. However, the diversity and virulence mechanisms of this pathogen are still insufficiently known. In this study, we aimed to increase our understanding of V. anguillarum diversity and virulence through comparative genome analysis of 15 V. anguillarum strains, obtained from different hosts or non-host niches and geographical regions, among which 10 and 5 strains were found to be virulent and avirulent, respectively, against sea bass larvae. First, the 15 draft genomes were annotated and screened for putative virulence factors, including genes encoding iron uptake systems, transport systems and non-ribosomal peptide synthetases. Second, comparative genome analysis was performed, focusing on single nucleotide polymorphisms (SNPs) and small insertions and deletions (InDels). Five V. anguillarum strains showed a remarkably high nucleotide identity. However, these strains comprise both virulent and avirulent strains towards sea bass larvae, suggesting that differences in virulence may be caused by subtle nucleotide variations. Clearly, the draft genome sequence of these 15 strains represents a starting point for further genetic research of this economically important fish pathogen.
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Affiliation(s)
- P Busschaert
- Laboratory for Process Microbial Ecology and Bioinspirational Management, Cluster for Bioengineering Technology (CBeT), Department of Microbial and Molecular Systems (M2S), KU Leuven - Campus De Nayer, Sint-Katelijne-Waver, Belgium
| | - I Frans
- Laboratory for Process Microbial Ecology and Bioinspirational Management, Cluster for Bioengineering Technology (CBeT), Department of Microbial and Molecular Systems (M2S), KU Leuven - Campus De Nayer, Sint-Katelijne-Waver, Belgium
| | - S Crauwels
- Laboratory for Process Microbial Ecology and Bioinspirational Management, Cluster for Bioengineering Technology (CBeT), Department of Microbial and Molecular Systems (M2S), KU Leuven - Campus De Nayer, Sint-Katelijne-Waver, Belgium
| | - B Zhu
- VIB Lab for Systems Biology & Centre of Microbial and Plant Genetics (CMPG), Lab for Genetics and Genomics, M2S, KU Leuven, Leuven, Belgium
| | - K Willems
- Laboratory for Process Microbial Ecology and Bioinspirational Management, Cluster for Bioengineering Technology (CBeT), Department of Microbial and Molecular Systems (M2S), KU Leuven - Campus De Nayer, Sint-Katelijne-Waver, Belgium
| | - P Bossier
- Laboratory of Aquaculture & Artemia Reference Centre, Department of Animal Production, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - C Michiels
- Centre for Food and Microbial Technology, M2S, KU Leuven, Leuven, Belgium
| | - K Verstrepen
- VIB Lab for Systems Biology & Centre of Microbial and Plant Genetics (CMPG), Lab for Genetics and Genomics, M2S, KU Leuven, Leuven, Belgium
| | - B Lievens
- Laboratory for Process Microbial Ecology and Bioinspirational Management, Cluster for Bioengineering Technology (CBeT), Department of Microbial and Molecular Systems (M2S), KU Leuven - Campus De Nayer, Sint-Katelijne-Waver, Belgium
| | - H Rediers
- Laboratory for Process Microbial Ecology and Bioinspirational Management, Cluster for Bioengineering Technology (CBeT), Department of Microbial and Molecular Systems (M2S), KU Leuven - Campus De Nayer, Sint-Katelijne-Waver, Belgium
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Li X, Defoirdt T, Bossier P. Relation between virulence of Vibrio anguillarum strains and response to the host factors mucin, bile salts and cholesterol. J Appl Microbiol 2015; 119:25-32. [PMID: 25807847 DOI: 10.1111/jam.12813] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/18/2015] [Accepted: 03/20/2015] [Indexed: 11/28/2022]
Abstract
AIMS In this study, we investigated the responsiveness of 15 Vibrio anguillarum strains to three host factors (mucin, bile salts and cholesterol). METHODS AND RESULTS Three virulence-related phenotypes were investigated in this respect, i.e. motility, biofilm formation and exopolysaccharide production. Almost all V. anguillarum strains showed a significantly increased motility in the presence of either of the three host factors. Only five of the strains showed increased biofilm formation in the presence of host factors and only three strains showed increased exopolysaccharide production in the presence of the host factors. CONCLUSIONS There were no significant correlations between the three putatively virulence-linked phenotypes (in the absence of host factors) and virulence to sea bass larvae. There was no correlation between responsiveness to the host factors (percentage increase in motility, biofilm formation or exopolysaccharide production in the presence of the three host factors) and virulence to sea bass larvae. However, the responses of these virulence-related phenotypes upon the addition of either of the three host factors were significantly correlated with each other. This result suggests that the mechanisms by which V. anguillarum responds to these three host factors is linked. SIGNIFICANCE AND IMPACT OF THE STUDY Although the mechanism by which V. anguillarum responds to the host factors mucin, bile salts and cholesterol seems to be linked, there is no correlation between host factor responsiveness and virulence towards sea bass larvae. This emphasizes that one should be careful when extrapolating results obtained for one particular strain to reach general conclusions on a species of pathogenic bacteria.
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Affiliation(s)
- X Li
- Laboratory of Aquaculture & Artemia Reference Center, Ghent University, Ghent, Belgium
| | - T Defoirdt
- Laboratory of Aquaculture & Artemia Reference Center, Ghent University, Ghent, Belgium
| | - P Bossier
- Laboratory of Aquaculture & Artemia Reference Center, Ghent University, Ghent, Belgium
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Abstract
ABSTRACT
Plasmids confer genetic information that benefits the bacterial cells containing them. In pathogenic bacteria, plasmids often harbor virulence determinants that enhance the pathogenicity of the bacterium. The ability to acquire iron in environments where it is limited, for instance the eukaryotic host, is a critical factor for bacterial growth. To acquire iron, bacteria have evolved specific iron uptake mechanisms. These systems are often chromosomally encoded, while those that are plasmid-encoded are rare. Two main plasmid types, ColV and pJM1, have been shown to harbor determinants that increase virulence by providing the cell with essential iron for growth. It is clear that these two plasmid groups evolved independently from each other since they do not share similarities either in the plasmid backbones or in the iron uptake systems they harbor. The siderophores aerobactin and salmochelin that are found on ColV plasmids fall in the hydroxamate and catechol group, respectively, whereas both functional groups are present in the anguibactin siderophore, the only iron uptake system found on pJM1-type plasmids. Besides siderophore-mediated iron uptake, ColV plasmids carry additional genes involved in iron metabolism. These systems include ABC transporters, hemolysins, and a hemoglobin protease. ColV- and pJM1-like plasmids have been shown to confer virulence to their bacterial host, and this trait can be completely ascribed to their encoded iron uptake systems.
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Frans I, Dierckens K, Crauwels S, Van Assche A, Leisner J, Larsen MH, Michiels CW, Willems KA, Lievens B, Bossier P, Rediers H. Does virulence assessment of Vibrio anguillarum using sea bass (Dicentrarchus labrax) larvae correspond with genotypic and phenotypic characterization? PLoS One 2013; 8:e70477. [PMID: 23936439 PMCID: PMC3735585 DOI: 10.1371/journal.pone.0070477] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Accepted: 06/10/2013] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Vibriosis is one of the most ubiquitous fish diseases caused by bacteria belonging to the genus Vibrio such as Vibrio (Listonella) anguillarum. Despite a lot of research efforts, the virulence factors and mechanism of V. anguillarum are still insufficiently known, in part because of the lack of standardized virulence assays. METHODOLOGY/PRINCIPAL FINDINGS We investigated and compared the virulence of 15 V. anguillarum strains obtained from different hosts or non-host niches using a standardized gnotobiotic bioassay with European sea bass (Dicentrarchus labrax L.) larvae as model hosts. In addition, to assess potential relationships between virulence and genotypic and phenotypic characteristics, the strains were characterized by random amplified polymorphic DNA (RAPD) and repetitive extragenic palindromic PCR (rep-PCR) analyses, as well as by phenotypic analyses using Biolog's Phenotype MicroArray™ technology and some virulence factor assays. CONCLUSIONS/SIGNIFICANCE Virulence testing revealed ten virulent and five avirulent strains. While some relation could be established between serotype, genotype and phenotype, no relation was found between virulence and genotypic or phenotypic characteristics, illustrating the complexity of V. anguillarum virulence. Moreover, the standardized gnotobiotic system used in this study has proven its strength as a model to assess and compare the virulence of different V. anguillarum strains in vivo. In this way, the bioassay contributes to the study of mechanisms underlying virulence in V. anguillarum.
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Affiliation(s)
- Ingeborg Frans
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Thomas More Mechelen, Campus De Nayer, Department of Microbial and Molecular Systems (M2S), KU Leuven Association, Sint-Katelijne-Waver, Belgium
- Scientia Terrae Research Institute, Sint-Katelijne-Waver, Belgium
- Centre for Food and Microbial Technology, M2S, KU Leuven, Heverlee, Belgium
- Laboratory of Aquaculture and Artemia Reference Center, Department of Animal Production, Ghent University, Gent, Belgium
| | - Kristof Dierckens
- Laboratory of Aquaculture and Artemia Reference Center, Department of Animal Production, Ghent University, Gent, Belgium
| | - Sam Crauwels
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Thomas More Mechelen, Campus De Nayer, Department of Microbial and Molecular Systems (M2S), KU Leuven Association, Sint-Katelijne-Waver, Belgium
- Scientia Terrae Research Institute, Sint-Katelijne-Waver, Belgium
| | - Ado Van Assche
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Thomas More Mechelen, Campus De Nayer, Department of Microbial and Molecular Systems (M2S), KU Leuven Association, Sint-Katelijne-Waver, Belgium
- Scientia Terrae Research Institute, Sint-Katelijne-Waver, Belgium
| | - Jørgen Leisner
- Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark
| | - Marianne H. Larsen
- Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark
| | - Chris W. Michiels
- Centre for Food and Microbial Technology, M2S, KU Leuven, Heverlee, Belgium
| | - Kris A. Willems
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Thomas More Mechelen, Campus De Nayer, Department of Microbial and Molecular Systems (M2S), KU Leuven Association, Sint-Katelijne-Waver, Belgium
- Scientia Terrae Research Institute, Sint-Katelijne-Waver, Belgium
| | - Bart Lievens
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Thomas More Mechelen, Campus De Nayer, Department of Microbial and Molecular Systems (M2S), KU Leuven Association, Sint-Katelijne-Waver, Belgium
- Scientia Terrae Research Institute, Sint-Katelijne-Waver, Belgium
| | - Peter Bossier
- Laboratory of Aquaculture and Artemia Reference Center, Department of Animal Production, Ghent University, Gent, Belgium
| | - Hans Rediers
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Thomas More Mechelen, Campus De Nayer, Department of Microbial and Molecular Systems (M2S), KU Leuven Association, Sint-Katelijne-Waver, Belgium
- Scientia Terrae Research Institute, Sint-Katelijne-Waver, Belgium
- * E-mail:
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Plasmid- and chromosome-encoded siderophore anguibactin systems found in marine vibrios: biosynthesis, transport and evolution. Biometals 2013; 26:537-47. [PMID: 23660776 DOI: 10.1007/s10534-013-9629-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 04/28/2013] [Indexed: 01/04/2023]
Abstract
Vibrio anguillarum is a marine pathogen that causes vibriosis, a hemorrhagic septicemia in aquatic invertebrate as well as vertebrate animals. The siderophore anguibactin system is one of the most important virulence factors of this bacterium. Most of the anguibactin biosynthesis and transport genes are located in the 65-kb pJM1 virulence plasmid although some of them are found in the chromosome of this fish pathogen. Over 30 years of research unveiled the role numerous chromosomal and pJM1 genes play in the synthesis of anguibactin and the transport of cognate ferric complexes into the bacterial cell. Furthermore, these studies showed that pJM1-carrying strains might be originated from pJM1-less strains producing the chromosome-mediated siderophore vanchrobactin. Additionally, we recently identified a chromosome-mediated anguibactin system in V. harveyi suggesting the possible evolutional origin of the V. anguillarum anguibactin system. In this review, we present our current understanding of the mechanisms and evolution hypothesis of the anguibactin system that might have occurred in these pathogenic vibrios.
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Lemos ML, Balado M, Osorio CR. Anguibactin- versus vanchrobactin-mediated iron uptake in Vibrio anguillarum: evolution and ecology of a fish pathogen. ENVIRONMENTAL MICROBIOLOGY REPORTS 2010; 2:19-26. [PMID: 23765994 DOI: 10.1111/j.1758-2229.2009.00103.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Vibrio anguillarum is a marine bacterium that is present in many marine aquatic environments and that is the main cause of vibriosis in diverse wild and cultured fish species. Two siderophore-mediated iron uptake systems have been described in V. anguillarum. One, mediated by the siderophore anguibactin, is encoded by the pJM1-type plasmids and is restricted to serotype O1 strains. The second one is mediated by the vanchrobactin siderophore and is widespread in many strains belonging to different serotypes. Both siderophores belong to the catecholate group of siderophores, sharing a 2,3-dihydroxybenzoic acid moiety. Vanchrobactin biosynthesis and transport genes are present in all strains examined although the siderophore is not produced in serotype O1 strains harbouring a pJM1-type plasmid. In these strains the insertion of an IS element in the main vanchrobactin biosynthetic gene vabF leads to the fact that only anguibactin is produced. From our current knowledge we can presume that vanchrobactin is the ancestral siderophore in this species and that the anguibactin-mediated system was later acquired during evolution, likely by horizontal transfer. The role of these two different iron uptake mechanisms in the biology, evolution and ecology of V. anguillarum is discussed although they are still far from being completely understood.
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Affiliation(s)
- Manuel L Lemos
- Department of Microbiology and Parasitology, Institute of Aquaculture, University of Santiago de Compostela, Campus Sur, Santiago de Compostela 15782, Spain
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FvtA is the receptor for the siderophore vanchrobactin in Vibrio anguillarum: utility as a route of entry for vanchrobactin analogues. Appl Environ Microbiol 2009; 75:2775-83. [PMID: 19270115 DOI: 10.1128/aem.02897-08] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Some strains of Vibrio anguillarum, the causative agent of vibriosis in a variety of marine animals, produce a catechol-type siderophore named vanchrobactin. The biosynthetic pathway and regulation of vanchrobactin are quite well understood. However, aspects concerning its entry into the cell have remained uncharacterized. In the present study we characterized two genes, fvtA and orf13, encoding potential TonB-dependent ferric-vanchrobactin receptors in serotype O2 V. anguillarum strain RV22. We found that an fvtA mutant was defective for growth under iron limitation conditions and for utilization of vanchrobactin, suggesting that fvtA encodes the vanchrobactin receptor of V. anguillarum. Interestingly, an orf13 mutant was not significantly affected, and results of reverse transcriptase PCR, as well as analysis of outer membrane proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, suggested that this gene is not expressed. Furthermore, fatA, a plasmid gene coding for the anguibactin receptor in plasmid pJM1-harboring strains, is also present in the chromosome of RV22, although it is inactivated by insertion of transposases. In addition, we found that FvtA is the route of entry for vanchrobactin analogues, and there is evidence that it recognizes primarily the catechol-iron center. These analogues are potential candidate vectors for a Trojan horse strategy aimed at generating antimicrobial compounds exploiting the same route of entry for native siderophores. We found that fvtA and vanchrobactin biosynthesis genes are ubiquitous in both vanchrobactin- and anguibactin-producing V. anguillarum strains, which reinforces the utility of the vanchrobactin route of entry for the design of future strategies for the control of vibriosis.
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