1
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Kadibalban AS, Landan G, Dagan T. The extent and characteristics of DNA transfer between plasmids and chromosomes. Curr Biol 2024; 34:3189-3200.e5. [PMID: 38964320 DOI: 10.1016/j.cub.2024.06.030] [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: 11/10/2023] [Revised: 03/29/2024] [Accepted: 06/10/2024] [Indexed: 07/06/2024]
Abstract
Plasmids are extrachromosomal genetic elements that reside in prokaryotes. The acquisition of plasmids encoding beneficial traits can facilitate short-term survival in harsh environmental conditions or long-term adaptation of new ecological niches. Due to their ability to transfer between cells, plasmids are considered agents of gene transfer. Nonetheless, the frequency of DNA transfer between plasmids and chromosomes remains understudied. Using a novel approach for detection of homologous loci between genome pairs, we uncover gene sharing with the chromosome in 1,974 (66%) plasmids residing in 1,016 (78%) taxonomically diverse isolates. The majority of homologous loci correspond to mobile elements, which may be duplicated in the host chromosomes in tens of copies. Neighboring shared genes often encode similar functional categories, indicating the transfer of multigene functional units. Rare transfer events of antibiotics resistance genes are observed mainly with mobile elements. The frequent erosion of sequence similarity in homologous regions indicates that the transferred DNA is often devoid of function. DNA transfer between plasmids and chromosomes thus generates genetic variation that is akin to workings of endosymbiotic gene transfer in eukaryotic evolution. Our findings imply that plasmid contribution to gene transfer most often corresponds to transfer of the plasmid entity rather than transfer of protein-coding genes between plasmids and chromosomes.
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Affiliation(s)
- A Samer Kadibalban
- Institute of General Microbiology, Kiel University, Am Botanischen Garten 11, Kiel 24118, Germany
| | - Giddy Landan
- Institute of General Microbiology, Kiel University, Am Botanischen Garten 11, Kiel 24118, Germany
| | - Tal Dagan
- Institute of General Microbiology, Kiel University, Am Botanischen Garten 11, Kiel 24118, Germany.
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2
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Carril G, Winther-Larsen HC, Løvoll M, Sørum H. Cohabitation of Piscirickettsia salmonis genogroups (LF-89 and EM-90): synergistic effect on growth dynamics. Front Cell Infect Microbiol 2023; 13:1253577. [PMID: 37953796 PMCID: PMC10634514 DOI: 10.3389/fcimb.2023.1253577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 09/25/2023] [Indexed: 11/14/2023] Open
Abstract
Piscirickettsia salmonis, the biological agent of Salmonid Rickettsial Septicemia (SRS), is a facultative intracellular bacterium that can be divided into two genogroups (LF-89 and EM-90) with different virulence levels and patterns. Studies have found co-infection of these genogroups in salmonid farms in Chile, but it is essential to assess whether this interaction within the host is related to virulence and changes in pathogen dynamics. In this study, we studied four isolates from EM-90 and one LF-89 isolate chosen based on their genomic differences. The aim was to evaluate how co-cultivation affects bacterial growth performance and virulence factor expression in Atlantic salmon (Salmo salar) in vitro and in vivo. In vitro results using FN2 medium, showed a similar growth curve between co-cultures of LF-89 and EM-90 compared to EM-90 monocultures. This was explained by the higher ratio of EM-90 to LF-89 in all co-cultures. When evaluating the expression of virulence factors, it was discovered that the luxR gene was expressed only in EM-90-like isolates and that there were significant differences between mono- and co-cultures for flaA and cheA, suggesting a response to cohabitation. Moreover, during in vivo co-cultures, transcriptomic analysis revealed an upregulation of transposases, flagellum-related genes (fliI and flgK), transporters, and permeases that could unveil novel virulence effectors used in the early infection process of P. salmonis. Thus, our work has shown that cohabitation of P. salmonis genogroups can modulate their behavior and virulence effector expression. These data can contribute to new strategies and approaches to improve the current health treatments against this salmonid pathogen.
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Affiliation(s)
- Gabriela Carril
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Hanne C. Winther-Larsen
- Department of Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | | | - Henning Sørum
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
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3
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Rozas-Serri M, Peña A, Gardner I, Peñaloza E, Maldonado L, Muñoz A, Mardones FO, Rodríguez C, Ildefonso R, Senn C, Aranis F. Co-Infection by Lf-89-like and Em-90-like Genogroups of Pis-Cirickettsia Salmonis in Farmed Atlantic Salmon in Chile: Implications for Surveillance and Control of Piscirickettsiosis. Pathogens 2023; 12:pathogens12030450. [PMID: 36986371 PMCID: PMC10053882 DOI: 10.3390/pathogens12030450] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/03/2023] [Accepted: 03/09/2023] [Indexed: 03/14/2023] Open
Abstract
Piscirickettsiosis (SRS), caused by Piscirickettsia salmonis, is the main infectious disease that affects farmed Atlantic salmon in Chile. Currently, the official surveillance and control plan for SRS in Chile is based only on the detection of P. salmonis, but neither of its genogroups (LF-89-like and EM-90-like) are included. Surveillance at the genogroup level is essential not only for defining and evaluating the vaccination strategy against SRS, but it is also of utmost importance for early diagnosis, clinical prognosis in the field, treatment, and control of the disease. The objectives of this study were to characterize the spatio-temporal distribution of P. salmonis genogroups using genogroup-specific real-time probe-based polymerase chain reaction (qPCR) to discriminate between LF-89-like and EM-90-like within and between seawater farms, individual fish, and tissues/organs during early infection in Atlantic salmon under field conditions. The spatio-temporal distribution of LF-89-like and EM-90-like was shown to be highly variable within and between seawater farms. P. salmonis infection was also proven to be caused by both genogroups at farm, fish, and tissue levels. Our study demonstrated for the first time a complex co-infection by P. salmonis LF-89-like and EM-90-like in Atlantic salmon. Liver nodules (moderate and severe) were strongly associated with EM-90-like infection, but this phenotype was not detected by infection with LF-89-like or co-infection of both genogroups. The detection rate of P. salmonis LF-89-like increased significantly between 2017 and 2021 and was the most prevalent genogroup in Chilean salmon aquaculture during this period. Lastly, a novel strategy to identify P. salmonis genogroups based on novel genogroup-specific qPCR for LF-89-like and EM-90-like genogroups is suggested.
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Affiliation(s)
| | - Andrea Peña
- Pathovet Labs SpA, Puerto Montt 5480000, Chile
| | - Ian Gardner
- Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE C1A 4P3, Canada
| | | | | | - Ariel Muñoz
- Pathovet Labs SpA, Puerto Montt 5480000, Chile
| | - Fernando O. Mardones
- Escuela de Medicina Veterinaria, Facultad de Agronomía e Ingeniería Forestal, Facultad de Ciencias Biológicas, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 3542000, Chile
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4
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Valenzuela-Aviles P, Torrealba D, Figueroa C, Mercado L, Dixon B, Conejeros P, Gallardo-Matus J. Why vaccines fail against Piscirickettsiosis in farmed salmon and trout and how to avoid it: A review. Front Immunol 2022; 13:1019404. [PMID: 36466828 PMCID: PMC9714679 DOI: 10.3389/fimmu.2022.1019404] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 10/24/2022] [Indexed: 09/28/2023] Open
Abstract
Piscirickettsiosis is the most severe, persistent, and damaging disease that has affected the Chilean salmon industry since its origins in the 1980s. As a preventive strategy for this disease, different vaccines have been developed and used over the last 30 years. However, vaccinated salmon and trout frequently die in the sea cages and the use of antibiotics is still high demonstrating the low efficiency of the available vaccines. The reasons why the vaccines fail so often are still debated, but it could involve different extrinsic and intrinsic factors. Among the extrinsic factors, mainly associated with chronic stress, we can distinguish: 1) biotic including coinfection with sea lice, sealions attacks or harmful algal blooms; 2) abiotic including low oxygen or high temperature; and 3) farm-management factors including overcrowding or chemical delousing treatments. Among the intrinsic factors, we can distinguish: 1) fish-related factors including host's genetic variability (species, population and individual), sex or age; 2) pathogen-related factors including their variability and ability to evade host immune responses; and 3) vaccine-related factors including low immunogenicity and poor matches with the circulating pathogen strain. Based on the available evidence, in order to improve the development and the efficacy of vaccines against P. salmonis we recommend: a) Do not perform efficacy evaluations by intraperitoneal injection of pathogens because they generate an artificial protective immune response, instead cohabitation or immersion challenges must be used; b) Evaluate the diversity of pathogen strains in the field and ensure a good antigenic match with the vaccines; c) Investigate whether host genetic diversity could be improved, e.g. through selection, in favor of better and longer responses to vaccination; d) To reduce the stressful effects at the cage level, controlling the co-infection of pathogens and avoiding fish overcrowding. To date, we do not know the immunological mechanisms by which the vaccines against P. salmonis may or may not generate protection. More studies are required to identify what type of response, cellular or molecular, is required to develop effective vaccines.
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Affiliation(s)
- Paula Valenzuela-Aviles
- Laboratorio de Genética y Genómica Aplicada, Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Débora Torrealba
- Laboratorio de Genética y Genómica Aplicada, Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Carolina Figueroa
- Laboratorio de Genética y Genómica Aplicada, Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Luis Mercado
- Grupo de Marcadores Inmunológicos en Organismos Acuáticos, Pontificia Universidad Católica de Valparaíso, Instituto de Biología, Valparaíso, Chile
| | - Brian Dixon
- Department of Biology, Faculty of Science, University of Waterloo, Waterloo, Canada
| | - Pablo Conejeros
- Centro de Investigación y Gestión de Recursos Naturales (CIGREN), Facultad de Ciencias, Instituto de Biología, Universidad de Valparaíso, Valparaíso, Chile
| | - José Gallardo-Matus
- Laboratorio de Genética y Genómica Aplicada, Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
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5
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Commercial Vaccines Do Not Confer Protection against Two Genogroups of Piscirickettsia salmonis, LF-89 and EM-90, in Atlantic Salmon. BIOLOGY 2022; 11:biology11070993. [PMID: 36101374 PMCID: PMC9312220 DOI: 10.3390/biology11070993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/17/2022] [Accepted: 06/21/2022] [Indexed: 11/17/2022]
Abstract
Simple Summary Vaccination represents one of the most relevant strategies to prevent and control infectious diseases in aquaculture. However, vaccines have failed to control and prevent Piscirickettsia salmonis, a bacterium that causes large economic losses to the industry. Therefore, we evaluated the performance of two commercial vaccines in Atlantic salmon through a cohabitation challenge (healthy fish were challenged by cohabitation with infected fish) of the two most prevalent and ubiquitous Piscirickettsia genetic variants in Chile. We found no evidence that vaccines confer protection against the LF-89 or EM-90 genogroups in Atlantic salmon. Abstract In Atlantic salmon, vaccines have failed to control and prevent Piscirickettsiosis, for reasons that remain elusive. In this study, we report the efficacy of two commercial vaccines developed with the Piscirickettsia salmonis isolates AL100005 and AL 20542 against another two genogroups which are considered highly and ubiquitously prevalent in Chile: LF-89 and EM-90. Two cohabitation trials were performed to mimic field conditions and vaccine performance: (1) post-smolt fish were challenged with a single infection of LF-89, (2) adults were coinfected with EM-90, and a low level coinfection of sea lice. In the first trial, the vaccine delayed smolt mortalities by two days; however, unvaccinated and vaccinated fish did not show significant differences in survival (unvaccinated: 60.3%, vaccinated: 56.7%; p = 0.28). In the second trial, mortality started three days later for vaccinated fish than unvaccinated fish. However, unvaccinated and vaccinated fish did not show significant differences in survival (unvaccinated: 64.6%, vaccinated: 60.2%, p = 0.58). Thus, we found no evidence that the evaluated vaccines confer effective protection against the genogroups LF-89 and EM-90 of P. salmonis with estimated relative survival proportions (RPSs) of −9% and −12%, respectively. More studies are necessary to evaluate whether pathogen heterogeneity is a key determinant of the lack of vaccine efficacy against P. salmonis.
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6
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Fuentes DE, Acuña LG, Calderón IL. Stress response and virulence factors in bacterial pathogens relevant for Chilean aquaculture: current status and outlook of our knowledge. Biol Res 2022; 55:21. [PMID: 35642071 PMCID: PMC9153119 DOI: 10.1186/s40659-022-00391-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 05/17/2022] [Indexed: 11/10/2022] Open
Abstract
The study of the stress responses in bacteria has given us a wealth of information regarding the mechanisms employed by these bacteria in aggressive or even non-optimal living conditions. This information has been applied by several researchers to identify molecular targets related to pathogeny, virulence, and survival, among others, and to design new prophylactic or therapeutic strategies against them. In this study, our knowledge of these mechanisms has been summarized with emphasis on some aquatic pathogenic bacteria of relevance to the health and productive aspects of Chilean salmon farming (Piscirickettsia salmonis, Tenacibaculum spp., Renibacterium salmoninarum, and Yersinia ruckeri). This study will aid further investigations aimed at shedding more light on possible lines of action for these pathogens in the coming years.
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Affiliation(s)
- Derie E Fuentes
- Aquaculture and Marine Ecosystems, Center For Systems Biotechnology, Fraunhofer Chile Research, Santiago, Chile. .,Environmental Sustainability, Center for Systems Biotechnology (CSB-UNAB), Universidad Andres Bello, Facultad de Ciencias de la Vida, Santiago, Chile.
| | - Lillian G Acuña
- Laboratorio de RNAs Bacterianos, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile.,Interdisciplinary Center for Aquaculture Research, Universidad Andres Bello, Viña del Mar, Santiago, Chile
| | - Iván L Calderón
- Laboratorio de RNAs Bacterianos, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
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7
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Rozas-Serri M. Why Does Piscirickettsia salmonis Break the Immunological Paradigm in Farmed Salmon? Biological Context to Understand the Relative Control of Piscirickettsiosis. Front Immunol 2022; 13:856896. [PMID: 35386699 PMCID: PMC8979166 DOI: 10.3389/fimmu.2022.856896] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 02/22/2022] [Indexed: 11/28/2022] Open
Abstract
Piscirickettsiosis (SRS) has been the most important infectious disease in Chilean salmon farming since the 1980s. It was one of the first to be described, and to date, it continues to be the main infectious cause of mortality. How can we better understand the epidemiological situation of SRS? The catch-all answer is that the Chilean salmon farming industry must fight year after year against a multifactorial disease, and apparently only the environment in Chile seems to favor the presence and persistence of Piscirickettsia salmonis. This is a fastidious, facultative intracellular bacterium that replicates in the host’s own immune cells and antigen-presenting cells and evades the adaptive cell-mediated immune response, which is why the existing vaccines are not effective in controlling it. Therefore, the Chilean salmon farming industry uses a lot of antibiotics—to control SRS—because otherwise, fish health and welfare would be significantly impaired, and a significantly higher volume of biomass would be lost per year. How can the ever-present risk of negative consequences of antibiotic use in salmon farming be balanced with the productive and economic viability of an animal production industry, as well as with the care of the aquatic environment and public health and with the sustainability of the industry? The answer that is easy, but no less true, is that we must know the enemy and how it interacts with its host. Much knowledge has been generated using this line of inquiry, however it remains insufficient. Considering the state-of-the-art summarized in this review, it can be stated that, from the point of view of fish immunology and vaccinology, we are quite far from reaching an effective and long-term solution for the control of SRS. For this reason, the aim of this critical review is to comprehensively discuss the current knowledge on the interaction between the bacteria and the host to promote the generation of more and better measures for the prevention and control of SRS.
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8
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Herrera V, Olavarría N, Saavedra J, Yuivar Y, Bustos P, Almarza O, Mancilla M. Complete Lipopolysaccharide of Piscirickettsia salmonis Is Required for Full Virulence in the Intraperitoneally Challenged Atlantic Salmon, Salmo salar, Model. Front Cell Infect Microbiol 2022; 12:845661. [PMID: 35372121 PMCID: PMC8972169 DOI: 10.3389/fcimb.2022.845661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 02/21/2022] [Indexed: 11/13/2022] Open
Abstract
Bacterial cell envelopes play a critical role in host-pathogen interactions. Macromolecular components of these structures have been closely linked to the virulence of pathogens. Piscirickettsia salmonis is a relevant salmonid pathogen with a worldwide distribution. This bacterium is the etiological agent of piscirickettsiosis, a septicemic disease that causes a high economic burden, especially for the Chilean salmon farming industry. Although P. salmonis has been discovered long ago, its pathogenicity and virulence mechanisms are not completely understood. In this work, we present a genetic approach for producing in-frame deletion mutants on genes related to the biosynthesis of membrane-associated polysaccharides. We provide a detailed in vitro phenotype description of knock-out mutants on wzx and wcaJ genes, which encode predicted lipopolysaccharide (LPS) flippase and undecaprenyl-phosphate glucose phosphotransferase enzymes, respectively. We exhibit evidence that the wzx mutant strain carries a defect in the probably most external LPS moiety, while the wcaJ mutant proved to be highly susceptible to the bactericidal action of serum but retained the ability of biofilm production. Beyond that, we demonstrate that the deletion of wzx, but not wcaJ, impairs the virulence of P. salmonis in an intraperitoneally infected Atlantic salmon, Salmo salar, model of piscirickettsiosis. Our findings support a role for LPS in the virulence of P. salmonis during the onset of piscirickettsiosis.
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Affiliation(s)
| | - Nicole Olavarría
- Laboratorio de Diagnóstico y Biotecnología, R & D Department, ADL Diagnostic Chile, Puerto Montt, Chile
| | - José Saavedra
- Laboratorio de Diagnóstico y Biotecnología, R & D Department, ADL Diagnostic Chile, Puerto Montt, Chile
| | - Yassef Yuivar
- Laboratorio de Diagnóstico y Biotecnología, R & D Department, ADL Diagnostic Chile, Puerto Montt, Chile
| | - Patricio Bustos
- Laboratorio de Diagnóstico y Biotecnología, R & D Department, ADL Diagnostic Chile, Puerto Montt, Chile
| | - Oscar Almarza
- Blue Genomics SpA, Puerto Varas, Chile
- *Correspondence: Oscar Almarza, ; Marcos Mancilla,
| | - Marcos Mancilla
- Laboratorio de Diagnóstico y Biotecnología, R & D Department, ADL Diagnostic Chile, Puerto Montt, Chile
- *Correspondence: Oscar Almarza, ; Marcos Mancilla,
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9
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Isla A, Martinez-Hernandez JE, Levipan HA, Haussmann D, Figueroa J, Rauch MC, Maracaja-Coutinho V, Yañez A. Development of a Multiplex PCR Assay for Genotyping the Fish Pathogen Piscirickettsia salmonis Through Comparative Genomics. Front Microbiol 2021; 12:673216. [PMID: 34177855 PMCID: PMC8226252 DOI: 10.3389/fmicb.2021.673216] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 05/17/2021] [Indexed: 11/20/2022] Open
Abstract
Piscirickettsia salmonis is a bacterial pathogen that severely impact the aquaculture in several countries as Canada, Scotland, Ireland, Norway, and Chile. It provokes Piscirickettsiosis outbreaks in the marine phase of salmonid farming, resulting in economic losses. The monophyletic genogroup LF-89 and a divergent genogroup EM-90 are responsible for the most severe Piscirickettsiosis outbreaks in Chile. Therefore, the development of methods for quick genotyping of P. salmonis genogroups in field samples is vital for veterinary diagnoses and understanding the population structure of this pathogen. The present study reports the development of a multiplex PCR for genotyping LF-89 and EM-90 genogroups based on comparative genomics of 73 fully sequenced P. salmonis genomes. The results revealed 2,322 sequences shared between 35 LF-89 genomes, 2,280 sequences in the core-genome of 38 EM-90 genomes, and 331 and 534 accessory coding sequences each genogroup, respectively. A total of 1,801 clusters of coding sequences were shared among all tested genomes of P. salmonis (LF-89 and EM-90), with 253 and 291 unique sequences for LF-89 and EM-90 genogroups, respectively. The Multiplex-1 prototype was chosen for reliable genotyping because of differences in annealing temperatures and respective reaction efficiencies. This method also identified the pathogen in field samples infected with LF-89 or EM-90 strains, which is not possible with other methods currently available. Finally, the genome-based multiplex PCR protocol presented in this study is a rapid and affordable alternative to classical sequencing of PCR products and analyzing the length of restriction fragment polymorphisms.
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Affiliation(s)
- Adolfo Isla
- Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile.,Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepcion, Concepción, Chile.,Departamento de Ciencias Básicas, Facultad de Ciencias, Universidad Santo Tomás, Santiago, Chile
| | - J Eduardo Martinez-Hernandez
- Centro de Modelamiento Molecular, Biofísica y Bioinformática - CM2B2, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile.,Programa de Doctorado en Genómica Integrativa, Vicerrectoría de Investigación, Universidad Mayor, Santiago, Chile.,Laboratorio de Biología de Redes, Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Héctor A Levipan
- Laboratorio de Ecopatología y Nanobiomateriales, Departamento de Biología, Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha, Valparaiso, Chile
| | - Denise Haussmann
- Departamento de Ciencias Básicas, Facultad de Ciencias, Universidad Santo Tomás, Santiago, Chile
| | - Jaime Figueroa
- Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile.,Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepcion, Concepción, Chile
| | - Maria Cecilia Rauch
- Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile
| | - Vinicius Maracaja-Coutinho
- Centro de Modelamiento Molecular, Biofísica y Bioinformática - CM2B2, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile.,Instituto Vandique, João Pessoa, Brazil.,Beagle Bioinformatics, Santiago, Chile
| | - Alejandro Yañez
- Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepcion, Concepción, Chile.,Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
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10
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Laurin E, Gardner IA, Peña A, Rozas-Serri M, Gayosa J, Neumann Heise J, Mardones FO. Bayesian estimation of diagnostic sensitivity and specificity of a qPCR and a bacteriological culture method for Piscirickettsia salmonis in farmed Atlantic salmon (Salmo salar L.) in Chile. JOURNAL OF FISH DISEASES 2020; 43:1167-1175. [PMID: 32716071 DOI: 10.1111/jfd.13226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/30/2020] [Accepted: 07/02/2020] [Indexed: 06/11/2023]
Abstract
Early detection of piscirickettsiosis is an important purpose of government- and industry-based surveillance for the disease in Atlantic salmon farms in Chile. Real-time qPCRs are currently used for surveillance because bacterial isolation is inadequately sensitive or rapid enough for routine use. Since no perfect tests exist, we used Bayesian latent class models to estimate diagnostic sensitivity (DSe) and specificity (DSp) of qPCR and culture using separate two-test, single-population models for three farms (n = 148, 151, 44). Informative priors were used for DSp (culture (beta(999,1); qPCR (beta(98,2)), and flat priors (beta 1,1) for DSe and prevalence. Models were run for liver and kidney tissues combined and separately, based on the presence of selected gross-pathological signs. Across all models, qPCR DSe was 5- to 30-fold greater than for culture. Combined-tissue qPCR median DSe was highest in Farm 3 (sampled during P. salmonis outbreak (DSe = 97.6%)) versus Farm 1 (DSe = 85.6%) or Farm 2 (DSe = 83.5%), both sampled before clinical disease. Median DSe of qPCR was similar for liver and kidney, but higher when gross-pathological signs were evident at necropsy. High DSe and DSp and rapid turnaround-time indicate that the qPCR is fit for surveillance programmes and diagnosis during an outbreak. Targeted testing of salmon with gross-pathological signs can enhance DSe.
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Affiliation(s)
- Emilie Laurin
- Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Ian A Gardner
- Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Andrea Peña
- Pathovet Laboratory Ltd, Puerto Montt, Chile
| | | | | | | | - Fernando O Mardones
- School of Veterinary Medicine, Pontifical Catholic University, Santiago, Chile
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11
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Aravena P, Pulgar R, Ortiz-Severín J, Maza F, Gaete A, Martínez S, Serón E, González M, Cambiazo V. PCR-RFLP Detection and Genogroup Identification of Piscirickettsia salmonis in Field Samples. Pathogens 2020; 9:pathogens9050358. [PMID: 32397152 PMCID: PMC7281544 DOI: 10.3390/pathogens9050358] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 04/28/2020] [Accepted: 04/30/2020] [Indexed: 02/01/2023] Open
Abstract
Piscirickettsia salmons, the causative agent of piscirickettsiosis, is genetically divided into two genomic groups, named after the reference strains as LF-89-like or EM-90-like. Phenotypic differences have been detected between the P. salmonis genogroups, including antibiotic susceptibilities, host specificities and pathogenicity. In this study, we aimed to develop a rapid, sensitive and cost-effective assay for the differentiation of the P. salmonis genogroups. Using an in silico analysis of the P. salmonis 16S rDNA digestion patterns, we have designed a genogroup-specific assay based on PCR-restriction fragment length polymorphism (RFLP). An experimental validation was carried out by comparing the restriction patterns of 13 P. salmonis strains and 57 field samples obtained from the tissues of dead or moribund fish. When the bacterial composition of a set of field samples, for which we detected mixtures of bacterial DNA, was analyzed by a high-throughput sequencing of the 16S rRNA gene amplicons, a diversity of taxa could be identified, including pathogenic and commensal bacteria. Despite the presence of mixtures of bacterial DNA, the characteristic digestion pattern of the P. salmonis genogroups could be detected in the field samples without the need of a microbiological culture and bacterial isolation.
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Affiliation(s)
- Pamela Aravena
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Santiago 7830490, Chile; (P.A.); (R.P.); (J.O.-S.); (F.M.); (A.G.); (M.G.)
- FONDAP Center for Genome Regulation, Santiago 8370415, Chile
| | - Rodrigo Pulgar
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Santiago 7830490, Chile; (P.A.); (R.P.); (J.O.-S.); (F.M.); (A.G.); (M.G.)
| | - Javiera Ortiz-Severín
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Santiago 7830490, Chile; (P.A.); (R.P.); (J.O.-S.); (F.M.); (A.G.); (M.G.)
| | - Felipe Maza
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Santiago 7830490, Chile; (P.A.); (R.P.); (J.O.-S.); (F.M.); (A.G.); (M.G.)
- FONDAP Center for Genome Regulation, Santiago 8370415, Chile
| | - Alexis Gaete
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Santiago 7830490, Chile; (P.A.); (R.P.); (J.O.-S.); (F.M.); (A.G.); (M.G.)
- FONDAP Center for Genome Regulation, Santiago 8370415, Chile
| | - Sebastián Martínez
- Laboratorio Especialidades Técnicas Marinas (ETECMA), Puerto Montt 5500001, Chile; (S.M.); (E.S.)
| | - Ervin Serón
- Laboratorio Especialidades Técnicas Marinas (ETECMA), Puerto Montt 5500001, Chile; (S.M.); (E.S.)
| | - Mauricio González
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Santiago 7830490, Chile; (P.A.); (R.P.); (J.O.-S.); (F.M.); (A.G.); (M.G.)
- FONDAP Center for Genome Regulation, Santiago 8370415, Chile
| | - Verónica Cambiazo
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Santiago 7830490, Chile; (P.A.); (R.P.); (J.O.-S.); (F.M.); (A.G.); (M.G.)
- FONDAP Center for Genome Regulation, Santiago 8370415, Chile
- Correspondence:
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12
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Zúñiga A, Aravena P, Pulgar R, Travisany D, Ortiz-Severín J, Chávez FP, Maass A, González M, Cambiazo V. Transcriptomic Changes of Piscirickettsia salmonis During Intracellular Growth in a Salmon Macrophage-Like Cell Line. Front Cell Infect Microbiol 2020; 9:426. [PMID: 31998656 PMCID: PMC6964531 DOI: 10.3389/fcimb.2019.00426] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 11/29/2019] [Indexed: 12/15/2022] Open
Abstract
Piscirickettsia salmonis is the causative agent of Piscirickettsiosis, a systemic infection of salmonid fish species. P. salmonis infects and survives in its host cell, a process that correlates with the expression of virulence factors including components of the type IVB secretion system. To gain further insights into the cellular and molecular mechanism behind the adaptive response of P. salmonis during host infection, we established an in vitro model of infection using the SHK-1 cell line from Atlantic salmon head kidney. The results indicated that in comparison to uninfected SHK-1 cells, infection significantly decreased cell viability after 10 days along with a significant increment of P. salmonis genome equivalents. At that time, the intracellular bacteria were localized within a spacious cytoplasmic vacuole. By using a whole-genome microarray of P. salmonis LF-89, the transcriptome of this bacterium was examined during intracellular growth in the SHK-1 cell line and exponential growth in broth. Transcriptome analysis revealed a global shutdown of translation during P. salmonis intracellular growth and suggested an induction of the stringent response. Accordingly, key genes of the stringent response pathway were up-regulated during intracellular growth as well as at stationary phase bacteria, suggesting a role of the stringent response on bacterial virulence. Our results also reinforce the participation of the Dot/Icm type IVB secretion system during P. salmonis infection and reveals many unexplored genes with potential roles in the adaptation to intracellular growth. Finally, we proposed that intracellular P. salmonis alternates between a replicative phase and a stationary phase in which the stringent response is activated.
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Affiliation(s)
- Alejandro Zúñiga
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Santiago, Chile.,Blue Genomics Chile, Puerto Varas, Chile
| | - Pamela Aravena
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Santiago, Chile.,FONDAP Center for Genome Regulation, Santiago, Chile
| | - Rodrigo Pulgar
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Santiago, Chile
| | - Dante Travisany
- FONDAP Center for Genome Regulation, Santiago, Chile.,Center for Mathematical Modeling (PIA AFB17001) and Department of Mathematical Engineering, Universidad de Chile - UMI CNRS 2807, Santiago, Chile
| | - Javiera Ortiz-Severín
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Santiago, Chile.,Laboratorio de Microbiología de Sistemas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Francisco P Chávez
- Center for Mathematical Modeling (PIA AFB17001) and Department of Mathematical Engineering, Universidad de Chile - UMI CNRS 2807, Santiago, Chile
| | - Alejandro Maass
- FONDAP Center for Genome Regulation, Santiago, Chile.,Center for Mathematical Modeling (PIA AFB17001) and Department of Mathematical Engineering, Universidad de Chile - UMI CNRS 2807, Santiago, Chile
| | - Mauricio González
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Santiago, Chile.,FONDAP Center for Genome Regulation, Santiago, Chile
| | - Verónica Cambiazo
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Santiago, Chile.,FONDAP Center for Genome Regulation, Santiago, Chile
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13
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Rozas-Serri M, Peña A, Maldonado L. Gene expression associated with immune response in Atlantic salmon head-kidney vaccinated with inactivated whole-cell bacterin of Piscirickettsia salmonis and pathogenic isolates. FISH & SHELLFISH IMMUNOLOGY 2019; 93:789-795. [PMID: 31419537 DOI: 10.1016/j.fsi.2019.08.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 08/02/2019] [Accepted: 08/12/2019] [Indexed: 06/10/2023]
Abstract
Piscirickettsiosis is the most challenging disease present in the Chilean salmon industry. The aim of this study was to describe the expression of genes associated with immune response of Atlantic salmon intraperitoneally infected with LF-89 and EM-90 Piscirickettsia salmonis and vaccinated with inactivated whole-cell bacterin of P. salmonis. The fish infected with PS-LF-89 showed an anti-inflammatory response, whereas this finding was not observed in the PS-EM-90-infected fish and vaccinated fish. Fish infected with both P. salmonis isolates showed mhc1-mhc2, cd4-cd8b and igm overexpression, suggesting that P. salmonis promotes a T CD4+ and T CD8+ cell response and a humoral immune response. The vaccinated-fish exhibited mhc1, mhc2 and cd4 overexpression but a significant downregulation of cd8b and igm, suggesting that the vaccine supported the CD4+ T-cell response but did not induce an immune response mediated by CD8+ T cells or a humoral response. In conclusion, the expression pattern of genes related to the humoral and cell-mediated adaptive immune response showed upregulation in fish infected with P. salmonis and down-regulation in vaccinated fish. The results of this study contribute to our understanding of the immune response against P. salmonis and can be used in the optimization of SRS prevention and control measures.
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Affiliation(s)
- Marco Rozas-Serri
- Pathovet Laboratory Ltd., Puerto Montt, Chile; Newenko Group SpA, Puerto Montt, Chile.
| | - Andrea Peña
- Pathovet Laboratory Ltd., Puerto Montt, Chile
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14
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Saavedra J, Grandón M, Villalobos-González J, Bohle H, Bustos P, Mancilla M. Isolation, Functional Characterization and Transmissibility of p3PS10, a Multidrug Resistance Plasmid of the Fish Pathogen Piscirickettsia salmonis. Front Microbiol 2018; 9:923. [PMID: 29867834 PMCID: PMC5952111 DOI: 10.3389/fmicb.2018.00923] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 04/20/2018] [Indexed: 12/25/2022] Open
Abstract
Antibiotic resistance is a major public health concern due to its association with the loss of efficacy of antimicrobial therapies. Horizontal transfer events may play a significant role in the dissemination of resistant bacterial phenotypes, being mobilizable plasmids a well-known mechanism. In this study, we aimed to gain insights into the genetics underlying the development of antibiotic resistance by Piscirickettsia salmonis isolates, a bacterial fish pathogen and causative agent of salmonid piscirickettsiosis, and the main target of antibiotics used in Chilean salmon farming. We provide experimental evidence that the plasmid p3PS10, which harbors multidrug resistance genes for chloramphenicol (cat2), tetracyclines [tet(31)], aminoglycosides (sat1 and aadA1), and sulfonamides (sul2), is carried by a group of P. salmonis isolates exhibiting a markedly reduced susceptibility to oxytetracycline in vitro (128–256 μg/mL of minimal inhibitory concentration, MIC). Antibiotic susceptibility analysis extended to those antibiotics showed that MIC of chloramphenicol, streptomycin, and sulfamethoxazole/trimethoprim were high, but the MIC of florfenicol remained at the wild-type level. By means of molecular cloning, we demonstrate that those genes encoding putative resistance markers are indeed functional. Interestingly, mating assays clearly show that p3PS10 is able to be transferred into and replicate in different hosts, thereby conferring phenotypes similar to those found in the original host. According to epidemiological data, this strain is distributed across aquaculture settings in southern Chile and is likely to be responsible for oxytetracycline treatment failures. This work demonstrates that P. salmonis is more versatile than it was thought, capable of horizontally transferring DNA, and probably playing a role as a vector of resistance traits among the seawater bacterial population. However, the low transmission frequency of p3PS10 suggests a negligible chance of resistance markers being spread to human pathogens.
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Affiliation(s)
- José Saavedra
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile SpA, Puerto Montt, Chile
| | - Maritza Grandón
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile SpA, Puerto Montt, Chile
| | | | - Harry Bohle
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile SpA, Puerto Montt, Chile
| | - Patricio Bustos
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile SpA, Puerto Montt, Chile
| | - Marcos Mancilla
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile SpA, Puerto Montt, Chile
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15
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Millar AD, Tapia P, Gómez FA, Marshall SH, Fuentes DE, Valdes JH. Draft genomes and reference transcriptomes extend the coding potential of the fish pathogen Piscirickettsia salmonis. ELECTRON J BIOTECHN 2018. [DOI: 10.1016/j.ejbt.2018.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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16
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Mancilla M, Saavedra J, Grandón M, Tapia E, Navas E, Grothusen H, Bustos P. The mutagenesis of a type IV secretion system locus of Piscirickettsia salmonis leads to the attenuation of the pathogen in Atlantic salmon, Salmo salar. JOURNAL OF FISH DISEASES 2018; 41:625-634. [PMID: 29251345 DOI: 10.1111/jfd.12762] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 11/06/2017] [Accepted: 11/10/2017] [Indexed: 06/07/2023]
Abstract
Piscirickettsiosis is a threatening infectious disease for the salmon industry, due to it being responsible for significant economic losses. The control of outbreaks also poses considerable environmental challenges. Despite Piscirickettsia salmonis having been discovered as the aetiological agent of the disease more than 25 years ago, its pathogenicity remains poorly understood. Among virulence factors identified so far, type four secretion systems (T4SS) seem to play a key role during the infection caused by the bacterium. We report here the genetic manipulation of P. salmonis by means of the transference of plasmid DNA in mating assays. An insertion cassette was engineered for targeting the icmB gene, which encodes a putative T4SS-ATPase and is carried by one of the chromosomal T4SS clusters found within the genome of P. salmonis PM15972A1, a virulent representative of the EM-90-like strain. The molecular characterization of the resulting mutant strain demonstrated that the insertion interrupted the target gene. Further in vitro testing of the icmB mutant showed a dramatic drop in infectivity as tested in CHSE-214 cells, which is in agreement with its attenuated behaviour observed in vivo. Altogether, our results demonstrate that, similar to other facultative intracellular pathogens, P. salmonis' virulence relies on an intact T4SS.
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Affiliation(s)
- M Mancilla
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile, Puerto Montt, Chile
| | - J Saavedra
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile, Puerto Montt, Chile
| | - M Grandón
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile, Puerto Montt, Chile
| | - E Tapia
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile, Puerto Montt, Chile
| | - E Navas
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile, Puerto Montt, Chile
| | - H Grothusen
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile, Puerto Montt, Chile
| | - P Bustos
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile, Puerto Montt, Chile
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17
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Rozas-Serri M, Peña A, Maldonado L. Transcriptomic profiles of post-smolt Atlantic salmon challenged with Piscirickettsia salmonis reveal a strategy to evade the adaptive immune response and modify cell-autonomous immunity. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 81:348-362. [PMID: 29288676 DOI: 10.1016/j.dci.2017.12.023] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 12/23/2017] [Accepted: 12/23/2017] [Indexed: 06/07/2023]
Abstract
Piscirickettsiosis is the main bacterial disease affecting the Chilean salmon farming industry and is responsible for high economic losses. The development of effective strategies to control piscirickettsiosis has been limited in part by insufficient knowledge of the host response. The aim of this study was to use RNA sequencing to describe the transcriptional profiles of the responses of post-smolt Atlantic salmon infected with LF-89-like or EM-90-like Piscirickettsia salmonis. Enrichment and pathway analyses of the differentially expressed genes revealed several central signatures following infection, including positive regulation of DC-SIGN and TLR5 signalling, which converged at the NF-κB level to modulate the pro-inflammatory cytokine response, particularly in the PS-EM-90-infected fish. P. salmonis induced an IFN-inducible response (e.g., IRF-1 and GBP-1) but inhibited the humoral and cell-mediated immune responses. P. salmonis induced significant cytoskeletal reorganization but decreased lysosomal protease activity and caused the degradation of proteins associated with cellular stress. Infection with these isolates also delayed protein transport, antigen processing, vesicle trafficking and autophagy. Both P. salmonis isolates promoted cell survival and proliferation and inhibited apoptosis. Both groups of Trojan fish used similar pathways to modulate the immune response at 5 dpi, but the transcriptomic profiles in the head kidneys of the cohabitant fish infected with PS-LF-89 and PS-MS-90 were relatively different at day 35 post-infection of the Trojan fish, probably due to the different degree of pathogenicity of each isolate. Our study showed the most important biological mechanisms used by P. salmonis, regardless of the isolate, to evade the immune response, maintain the viability of host cells and increase intracellular replication and persistence at the infection site. These results improve the understanding of the mechanisms by which P. salmonis interacts with its host and may serve as a basis for the development of effective strategies for the control of piscirickettsiosis.
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Affiliation(s)
| | - Andrea Peña
- Pathovet Laboratory Ltd., Puerto Montt, Chile.
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18
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Calquín P, Ruiz P, Oliver C, Sánchez P, Haro R, Oliva H, Vargas-Chacoff L, Avendaño-Herrera R, Yáñez AJ. Physiological evidence that Piscirickettsia salmonis produces siderophores and uses iron from different sources. JOURNAL OF FISH DISEASES 2018; 41:553-558. [PMID: 29193147 DOI: 10.1111/jfd.12745] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 09/16/2017] [Accepted: 09/24/2017] [Indexed: 06/07/2023]
Affiliation(s)
- P Calquín
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile
- Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile
| | - P Ruiz
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile
- Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile
| | - C Oliver
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile
- Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile
- Laboratorio de Patología de Organismos Acuáticos y Biotecnología Acuícola, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Viña del Mar, Chile
| | - P Sánchez
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile
- Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile
| | - R Haro
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile
| | - H Oliva
- Veterquímica S.A., Cerrillos, Santiago, Chile
| | - L Vargas-Chacoff
- Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile
- Centro Fondap de Investigación de Altas Latitudes (IDEAL), Universidad Austral de Chile, Valdivia, Chile
| | - R Avendaño-Herrera
- Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile
- Laboratorio de Patología de Organismos Acuáticos y Biotecnología Acuícola, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Viña del Mar, Chile
- Centro de Investigación Marina Quintay (CIMARQ), Quintay, Chile
| | - A J Yáñez
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile
- Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile
- Austral-OMICS, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
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19
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Marshall SH, Flores-Herrera P, Henríquez FA, Gómez FA. Identification and characterization of two variants of the Hfq-sRNA-chaperone in the fish pathogen Piscirickettsia salmonis. JOURNAL OF FISH DISEASES 2018; 41:501-509. [PMID: 29159897 DOI: 10.1111/jfd.12752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 10/02/2017] [Indexed: 06/07/2023]
Abstract
Small RNA and chaperone proteins form synergistic duos that play pivotal roles in controlling gene expression in bacteria. This is the case for Hfq, a highly pleiotropic pretranslational modulator of general protein expression, which responds to harsh environmental conditions and influences fitness and virulence in a wide range of pathogenic Enterobacteria. Given this relevancy, we evaluated the presence and potential role of Hfq in the fish pathogen Piscirickettsia salmonis, a Gram-negative bacterium that threatens the sustainability of Chilean salmon production. Using bioinformatics tools were identified and characterized two variants of Hfq, which share the consensus RNA-binding domains and the active sites described functional Hfq other bacteria. Additionally, we demonstrated that hfq-1 and hfq-2 were transcriptionally active when growing in cell-free media and in infected susceptible fish cell line. Expression of both genes differed under different growth conditions and under stress, suggesting that their roles might be independent and different, depending on the bacterial physiological status. In conclusion, we demonstrate the existence of two different and functional ORF coding for the hfq marker in marine bacteria and a preliminary analysis indicating that these two novel proteins might have relevant roles in the biology and pathogenic potential of P. salmonis.
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Affiliation(s)
- S H Marshall
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - P Flores-Herrera
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - F A Henríquez
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - F A Gómez
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
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20
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Rozas-Serri M, Peña A, Arriagada G, Enríquez R, Maldonado L. Comparison of gene expression in post-smolt Atlantic salmon challenged by LF-89-like and EM-90-like Piscirickettsia salmonis isolates reveals differences in the immune response associated with pathogenicity. JOURNAL OF FISH DISEASES 2018; 41:539-552. [PMID: 29143962 DOI: 10.1111/jfd.12756] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 10/14/2017] [Accepted: 10/17/2017] [Indexed: 06/07/2023]
Abstract
Piscirickettsiosis is the main bacterial disease affecting the Chilean salmon farming industry and is responsible for high economic losses. The aim of this study was to describe and comparatively quantify the immune response of post-smolt Atlantic salmon infected by cohabitation with fish bearing LF-89-like and EM-90-like Piscirickettsia salmonis. The expression of 17 genes related to the immune response was studied in head kidney from cohabitant fish by RT-qPCR. Our results at the transcriptomic level suggest that P. salmonis is able to manipulate the kinetics of cytokine production in a way that might constitute a virulence mechanism that promotes intracellular bacterial replication in cells of Atlantic salmon. This strategy involves the creation of an ideal environment for the microorganism based on induction of the inflammatory and IFN-mediated response, modulation of Th1 polarization, reduced antigen processing and presentation, modulation of the evasion of the immune response mediated by CD8+ T cells and promotion of the CD4+ T-cell response during the late stage of infection as a mechanism to escape host defences. This response was significantly exacerbated in fish infected by PS-EM-90 compared with fish infected by PS-LF-89, a finding that is probably associated with the higher pathogenicity of PS-EM-90.
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Affiliation(s)
- M Rozas-Serri
- Pathovet Laboratory Ltd., Puerto Montt, Chile
- Faculty of Veterinary Sciences, Graduate School, Austral University of Chile, Valdivia, Chile
| | - A Peña
- Pathovet Laboratory Ltd., Puerto Montt, Chile
| | - G Arriagada
- EPI-data Research & Consulting, Santiago, Chile
| | - R Enríquez
- Laboratory of Aquatic Pathology and Biotechnology, Faculty of Veterinary Sciences, Animal Pathology Institute, Universidad Austral de Chile, Valdivia, Chile
| | - L Maldonado
- Pathovet Laboratory Ltd., Puerto Montt, Chile
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21
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Cortés MP, Mendoza SN, Travisany D, Gaete A, Siegel A, Cambiazo V, Maass A. Analysis of Piscirickettsia salmonis Metabolism Using Genome-Scale Reconstruction, Modeling, and Testing. Front Microbiol 2017; 8:2462. [PMID: 29321769 PMCID: PMC5732189 DOI: 10.3389/fmicb.2017.02462] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 11/27/2017] [Indexed: 01/27/2023] Open
Abstract
Piscirickettsia salmonis is an intracellular bacterial fish pathogen that causes piscirickettsiosis, a disease with highly adverse impact in the Chilean salmon farming industry. The development of effective treatment and control methods for piscireckttsiosis is still a challenge. To meet it the number of studies on P. salmonis has grown in the last couple of years but many aspects of the pathogen's biology are still poorly understood. Studies on its metabolism are scarce and only recently a metabolic model for reference strain LF-89 was developed. We present a new genome-scale model for P. salmonis LF-89 with more than twice as many genes as in the previous model and incorporating specific elements of the fish pathogen metabolism. Comparative analysis with models of different bacterial pathogens revealed a lower flexibility in P. salmonis metabolic network. Through constraint-based analysis, we determined essential metabolites required for its growth and showed that it can benefit from different carbon sources tested experimentally in new defined media. We also built an additional model for strain A1-15972, and together with an analysis of P. salmonis pangenome, we identified metabolic features that differentiate two main species clades. Both models constitute a knowledge-base for P. salmonis metabolism and can be used to guide the efficient culture of the pathogen and the identification of specific drug targets.
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Affiliation(s)
- María P Cortés
- Mathomics, Center for Mathematical Modeling, Universidad de Chile, Santiago, Chile.,Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Santiago, Chile.,Fondap Center for Genome Regulation (CGR), Santiago, Chile
| | - Sebastián N Mendoza
- Mathomics, Center for Mathematical Modeling, Universidad de Chile, Santiago, Chile.,Fondap Center for Genome Regulation (CGR), Santiago, Chile
| | - Dante Travisany
- Mathomics, Center for Mathematical Modeling, Universidad de Chile, Santiago, Chile.,Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Santiago, Chile.,Fondap Center for Genome Regulation (CGR), Santiago, Chile
| | - Alexis Gaete
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Santiago, Chile
| | - Anne Siegel
- DYLISS (INRIA-IRISA)-INRIA, CNRS UMR 6074, Université de Rennes 1, Rennes, France
| | - Verónica Cambiazo
- Fondap Center for Genome Regulation (CGR), Santiago, Chile.,Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Santiago, Chile
| | - Alejandro Maass
- Mathomics, Center for Mathematical Modeling, Universidad de Chile, Santiago, Chile.,Fondap Center for Genome Regulation (CGR), Santiago, Chile.,Department of Mathematical Engineering, Universidad de Chile, Santiago, Chile
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22
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Nourdin-Galindo G, Sánchez P, Molina CF, Espinoza-Rojas DA, Oliver C, Ruiz P, Vargas-Chacoff L, Cárcamo JG, Figueroa JE, Mancilla M, Maracaja-Coutinho V, Yañez AJ. Comparative Pan-Genome Analysis of Piscirickettsia salmonis Reveals Genomic Divergences within Genogroups. Front Cell Infect Microbiol 2017; 7:459. [PMID: 29164068 PMCID: PMC5671498 DOI: 10.3389/fcimb.2017.00459] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 10/16/2017] [Indexed: 11/13/2022] Open
Abstract
Piscirickettsia salmonis is the etiological agent of salmonid rickettsial septicemia, a disease that seriously affects the salmonid industry. Despite efforts to genomically characterize P. salmonis, functional information on the life cycle, pathogenesis mechanisms, diagnosis, treatment, and control of this fish pathogen remain lacking. To address this knowledge gap, the present study conducted an in silico pan-genome analysis of 19 P. salmonis strains from distinct geographic locations and genogroups. Results revealed an expected open pan-genome of 3,463 genes and a core-genome of 1,732 genes. Two marked genogroups were identified, as confirmed by phylogenetic and phylogenomic relationships to the LF-89 and EM-90 reference strains, as well as by assessments of genomic structures. Different structural configurations were found for the six identified copies of the ribosomal operon in the P. salmonis genome, indicating translocation throughout the genetic material. Chromosomal divergences in genomic localization and quantity of genetic cassettes were also found for the Dot/Icm type IVB secretion system. To determine divergences between core-genomes, additional pan-genome descriptions were compiled for the so-termed LF and EM genogroups. Open pan-genomes composed of 2,924 and 2,778 genes and core-genomes composed of 2,170 and 2,228 genes were respectively found for the LF and EM genogroups. The core-genomes were functionally annotated using the Gene Ontology, KEGG, and Virulence Factor databases, revealing the presence of several shared groups of genes related to basic function of intracellular survival and bacterial pathogenesis. Additionally, the specific pan-genomes for the LF and EM genogroups were defined, resulting in the identification of 148 and 273 exclusive proteins, respectively. Notably, specific virulence factors linked to adherence, colonization, invasion factors, and endotoxins were established. The obtained data suggest that these genes could be directly associated with inter-genogroup differences in pathogenesis and host-pathogen interactions, information that could be useful in designing novel strategies for diagnosing and controlling P. salmonis infection.
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Affiliation(s)
- Guillermo Nourdin-Galindo
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile.,Laboratory of Integrative Bioinformatics, Facultad de Ciencias, Centro de Genómica y Bioinformática, Universidad Mayor, Santiago, Chile
| | - Patricio Sánchez
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile.,Centro FONDAP, Interdisciplinary Center for Aquaculture Research, Concepción, Chile
| | - Cristian F Molina
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile.,AUSTRAL-omics, Universidad Austral de Chile, Valdivia, Chile
| | - Daniela A Espinoza-Rojas
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile.,Laboratory of Integrative Bioinformatics, Facultad de Ciencias, Centro de Genómica y Bioinformática, Universidad Mayor, Santiago, Chile
| | - Cristian Oliver
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile.,Centro FONDAP, Interdisciplinary Center for Aquaculture Research, Concepción, Chile.,Laboratorio de Patología de Organismos Acuáticos y Biotecnología Acuícola, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Viña del Mar, Chile
| | - Pamela Ruiz
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile.,Centro FONDAP, Interdisciplinary Center for Aquaculture Research, Concepción, Chile
| | - Luis Vargas-Chacoff
- Facultad de Ciencias, Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile
| | - Juan G Cárcamo
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile.,Centro FONDAP, Interdisciplinary Center for Aquaculture Research, Concepción, Chile
| | - Jaime E Figueroa
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile.,Centro FONDAP, Interdisciplinary Center for Aquaculture Research, Concepción, Chile
| | - Marcos Mancilla
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile SpA., Puerto Montt, Chile
| | - Vinicius Maracaja-Coutinho
- Laboratory of Integrative Bioinformatics, Facultad de Ciencias, Centro de Genómica y Bioinformática, Universidad Mayor, Santiago, Chile.,Laboratory of Integrative Bioinformatics, Instituto Vandique, João Pessoa, Brazil.,Beagle Bioinformatics, Santiago, Chile
| | - Alejandro J Yañez
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile.,Centro FONDAP, Interdisciplinary Center for Aquaculture Research, Concepción, Chile.,AUSTRAL-omics, Universidad Austral de Chile, Valdivia, Chile
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23
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Lagos F, Cartes C, Vera T, Haussmann D, Figueroa J. Identification of genomic islands in Chilean Piscirickettsia salmonis strains and analysis of gene expression involved in virulence. JOURNAL OF FISH DISEASES 2017; 40:1321-1331. [PMID: 28150307 DOI: 10.1111/jfd.12604] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 11/23/2016] [Accepted: 11/27/2016] [Indexed: 06/06/2023]
Abstract
Piscirickettsia salmonis, an agent of Piscirickettsiosis, is the cause of major losses in the Chilean salmon industry. We identified, characterized and bioinformatically analysed genomic islands in field strains of P. Salmonis, using the bioinformatic software PIPS, that uses the characteristics of the islands of pathogenicity to identify them. We analysed nine partially sequenced genomes in different new field strains, and compared them with the LF-89 (Type strain) genome, selecting a genomic island present in all of them. We then evaluated the relative expression of three genes present in that island. From the obtained results, we conclude that the expression of the tcf gene is directly proportional to the cytopathogenicity in vitro of the bacteria; the product of the dnsa gene could contribute to its pathogenicity, but would be potentiated by one or more factors. The product of the gene liso is necessary for the virulence process and could have functions in early stages of infection. Regarding the strains, the IBM-040 strain showed a significant increase in the expression of all the genes in the study. Contrarily, LF-89 only presented a significant increase in expression of the gene liso, which correlates with the cytopathogenicity in vitro observed in the SHK-1 cells.
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Affiliation(s)
- F Lagos
- Centro FONDAP: Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile
| | - C Cartes
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile
| | - T Vera
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile
| | - D Haussmann
- Centro FONDAP: Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile
- Departmento de Ciencias Básicas, Facultad de Ciencias, Universidad Santo Tomás, Valdivia, Chile
| | - J Figueroa
- Centro FONDAP: Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile
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24
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Rozas-Serri M, Ildefonso R, Peña A, Enríquez R, Barrientos S, Maldonado L. Comparative pathogenesis of piscirickettsiosis in Atlantic salmon (Salmo salar L.) post-smolt experimentally challenged with LF-89-like and EM-90-like Piscirickettsia salmonis isolates. JOURNAL OF FISH DISEASES 2017; 40:1451-1472. [PMID: 28745821 DOI: 10.1111/jfd.12671] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 05/23/2017] [Accepted: 05/24/2017] [Indexed: 05/20/2023]
Abstract
Piscirickettsiosis (SRS) is the most prevalent bacterial disease in Chilean salmon aquaculture and is responsible for high economic losses. The aim of this study was to comparatively characterize the pathogenesis of SRS in post-smolt Atlantic salmon during the early and late stages of infection with Piscirickettsia salmonis LF-89-like (PS-LF-89) and EM-90-like (PS-EM-90) using a cohabitation challenge. The pathogenesis of cohabitant fish infected with the two isolates was relatively different due to cohabitant fish infected with PS-EM-90 showing higher cumulative mortality and shorter time until death compared with PS-LF-89 fish. PS-LF-89 caused an SRS infection characterized by kidney and liver lesions, whereas PS-EM-90 caused systemic and haemorrhagic disease characterized by kidney, liver, heart, brain, skeletal muscle and intestine lesions. Decreased serum concentration of total proteins and albumin as well as increased serum ALT, AST and creatinine levels in fish infected with both isolates confirmed that changes in liver and kidney function occurred during infection. Tissue damage, expressed as an SRS histoscore, showed a strong positive correlation with the bacterial load expressed as abundance of P. salmonis 16S rRNA transcripts in the livers and kidneys of fish affected with either isolate, but the correlation was significantly higher in fish infected with PS-EM-90. The results contribute to improving the understanding of the bacteria-host interaction.
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Affiliation(s)
- M Rozas-Serri
- Pathovet Laboratory Ltd., Puerto Montt, Chile
- Faculty of Veterinary Sciences, Graduate School, Universidad Austral de Chile, Valdivia, Chile
| | - R Ildefonso
- Pathovet Laboratory Ltd., Puerto Montt, Chile
| | - A Peña
- Pathovet Laboratory Ltd., Puerto Montt, Chile
| | - R Enríquez
- Laboratory of Aquatic Pathology and Biotechnology, Faculty of Veterinary Sciences, Animal Pathology Institute, Universidad Austral de Chile, Valdivia, Chile
| | | | - L Maldonado
- Pathovet Laboratory Ltd., Puerto Montt, Chile
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25
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Saavedra J, Hernandez N, Osses A, Castillo A, Cancino A, Grothusen H, Navas E, Henriquez P, Bohle H, Bustamante F, Bustos P, Mancilla M. Prevalence, geographic distribution and phenotypic differences of Piscirickettsia salmonis EM-90-like isolates. JOURNAL OF FISH DISEASES 2017; 40:1055-1063. [PMID: 28075013 DOI: 10.1111/jfd.12581] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 10/12/2016] [Accepted: 10/13/2016] [Indexed: 06/06/2023]
Abstract
Early reports accounted for two main genotypes of Piscirickettsia salmonis, a fish pathogen and causative agent of piscirickettsiosis, placing the single isolate EM-90 apart from the prototypic LF-89 and related isolates. In this study, we provide evidence that, contrary to what has been supposed, the EM-90-like isolates are highly prevalent and disseminated across Chilean marine farms. Molecular analysis of 507 P. salmonis field isolates derived from main rearing areas, diverse hosts and collected over 6 years, revealed that nearly 50% of the entire collection were indeed typed as EM-90-like. Interestingly, these isolates showed a marked host preference, being recovered exclusively from Atlantic salmon (Salmo salar) samples. Although both strains produce undistinguishable pathological outcomes, differences regarding growth kinetics and susceptibility to the antibiotics and bactericidal action of serum could be identified. In sum, our results allow to conclude that the EM-90-like isolates represent an epidemiologically relevant group in the current situation of piscirickettsiosis. Based on the consistency between genotype and phenotype exhibited by this strain, we point out the need for genotypic studies that may be as important for the Chilean salmon industry as the continuous surveillance of antimicrobial susceptibility patterns.
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Affiliation(s)
- J Saavedra
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile Ltda, Puerto Montt, Chile
| | - N Hernandez
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile Ltda, Puerto Montt, Chile
| | - A Osses
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile Ltda, Puerto Montt, Chile
| | - A Castillo
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile Ltda, Puerto Montt, Chile
| | - A Cancino
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile Ltda, Puerto Montt, Chile
| | - H Grothusen
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile Ltda, Puerto Montt, Chile
| | - E Navas
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile Ltda, Puerto Montt, Chile
| | - P Henriquez
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile Ltda, Puerto Montt, Chile
| | - H Bohle
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile Ltda, Puerto Montt, Chile
| | - F Bustamante
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile Ltda, Puerto Montt, Chile
| | - P Bustos
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile Ltda, Puerto Montt, Chile
| | - M Mancilla
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile Ltda, Puerto Montt, Chile
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26
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Carril GP, Gómez FA, Marshall SH. Expression of flagellin and key regulatory flagellar genes in the non-motile bacterium Piscirickettsia salmonis. DISEASES OF AQUATIC ORGANISMS 2017; 123:29-43. [PMID: 28177291 DOI: 10.3354/dao03079] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The Piscirickettsia salmonis genome was screened to evaluate potential flagella-related open reading frames, as well as their genomic organization and eventual expression. A complete and organized set of flagellar genes was found for P. salmonis, although no structural flagellum has ever been reported for this bacterium. To gain further understanding, the hierarchical flagellar cascade described for Legionella pneumophila was used as a reference model for putative analysis in P. salmonis. Specifically, 5 of the most relevant genes from this cascade were chosen, including 3 regulatory genes (fleQ, triggers the cascade; fliA, regulates the σ28-coding gene; and rpoN, an RNA polymerase-dependent gene) and 2 terminal structural genes (flaA and flaB, flagellin and a flagellin-like protein, respectively). Kinetic experiments evaluated gene expressions over time, with P. salmonis assessed in 2 liquid, cell-free media and during infection of the SHK-1 fish cell line. Under all conditions, the 5 target genes were primarily expressed during early growth/infection and were differentially expressed when bacteria encountered environmental stress (i.e. a high-salt concentration). Intriguingly, the flagellin monomer was fully expressed under all growth conditions and was located near the bacterial membrane. While no structural flagellum was detected under any condition, the recombinant flagellin monomer induced a proinflammatory response in SHK-1 cells, suggesting a possible immunomodulatory function. The potential implications of these observations are discussed in the context of P. salmonis biology and pathogenic potential.
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Affiliation(s)
- Gabriela P Carril
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso 2340000, Chile
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27
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Maisey K, Montero R, Christodoulides M. Vaccines for piscirickettsiosis (salmonid rickettsial septicaemia, SRS): the Chile perspective. Expert Rev Vaccines 2016; 16:215-228. [DOI: 10.1080/14760584.2017.1244483] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Kevin Maisey
- Laboratorio de Inmunología Comparativa, Centro de Biotecnología Acuícola (CBA), Universidad de Santiago de Chile, Santiago, Chile
| | - Ruth Montero
- Laboratorio de Inmunología Comparativa, Centro de Biotecnología Acuícola (CBA), Universidad de Santiago de Chile, Santiago, Chile
| | - Myron Christodoulides
- Neisseria Research, Molecular Microbiology, Academic Unit of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Faculty of Medicine, Southampton, UK
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28
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Bravo C, Martinez V. Whole-genome comparative analysis of the pathogen Piscirickettsia salmonis. Vet Microbiol 2016; 196:36-43. [PMID: 27939153 DOI: 10.1016/j.vetmic.2016.10.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 10/07/2016] [Accepted: 10/09/2016] [Indexed: 12/12/2022]
Abstract
The intracellular pathogen Piscirickettsia salmonis is the etiological agent of piscirickettsiosis, the most important bacterial disease that affects the Chilean salmon industry. Despite its importance, little is known regarding the biology of the pathogen. In this study, recently published sequencing data was used in order to characterize the genome of P. salmonis, defining groups of genes associated with bacterial processes such as, invasion and intracellular survival. Moreover, one Chilean P. salmonis isolate, which is known to be virulent at in vitro and in vivo assays, was sequenced, assembled, annotated and functionally characterized. Whole-genome comparisons between public P. salmonis isolates confirmed the existence of two different genogroups associated with the LF-89 and EM-90 strains, and the bacterial pan and core genome were defined. Additionally, differences were observed at the genomic level between the P. salmonis reference strain and a Norwegian isolate, which is known to produce milder piscirickettsiosis outbreaks. Finally, candidate genes for invasion and intracellular survival were chosen from phylogenetically related bacteria, and annotated in P. salmonis using comparative genomics. These results showed the presence of several genes that might be related to bacterial pathogenesis, for example those of the type III, IV and VI secretion systems, in which some amino acidic differences within both genogroups and the Norwegian isolate were established. Altogether, these results will be relevant for understanding the host-pathogen interaction and further studies, aimed at generating new disease control strategies, should be devised using this information.
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Affiliation(s)
- Cristian Bravo
- FAVET-INBIOGEN, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Avda. Santa Rosa, 11735, Santiago, Chile.
| | - Victor Martinez
- FAVET-INBIOGEN, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Avda. Santa Rosa, 11735, Santiago, Chile.
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29
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Draft Genome Sequence of a New Zealand Rickettsia-Like Organism Isolated from Farmed Chinook Salmon. GENOME ANNOUNCEMENTS 2016; 4:4/3/e00503-16. [PMID: 27365345 PMCID: PMC4929508 DOI: 10.1128/genomea.00503-16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We report here the draft genome sequence of a rickettsia-like organism, isolated from a New Zealand Chinook salmon farm experiencing high mortality. The genome is approximately 3 Mb in size, has a G+C content of approximately 39.2%, and is predicted to contain 2,870 coding sequences.
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30
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Mandakovic D, Glasner B, Maldonado J, Aravena P, González M, Cambiazo V, Pulgar R. Genomic-Based Restriction Enzyme Selection for Specific Detection of Piscirickettsia salmonis by 16S rDNA PCR-RFLP. Front Microbiol 2016; 7:643. [PMID: 27242682 PMCID: PMC4860512 DOI: 10.3389/fmicb.2016.00643] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 04/18/2016] [Indexed: 12/24/2022] Open
Abstract
The gram negative facultative bacterium P. salmonis is the etiological agent of Salmonid Rickettsial Septicaemia (SRS), a severe disease that causes important economic losses in the global salmon farmer industry. Despite efforts to control this disease, the high frequency of new epizootic events indicate that the vaccine and antibiotics treatments have limited effectiveness, therefore the preventive and diagnostic approaches must be improved. A comparison of several methodologies for SRS diagnostic indicate differences in their specificity and its capacity to detect other bacteria coexisting with P. salmonis in culture media (contamination) and fish samples (coinfection), aspects relevant for research, vaccine development and clinical diagnostic. By computer-simulation analyses, we identified a group of restriction enzymes that generate unique P. salmonis 16S rDNA band patterns, distinguishable from all other bacteria. From this information, we designed and developed a PCR-RFLP (Polymerase Chain Reaction—Restriction Fragment Length Polymorphism) assay, which was validated using 16S rDNA universal primers and restriction enzyme PmaCI for the amplification and digestion, respectively. Experimental validation was performed by comparing the restriction pattern of P. salmonis with the restriction patterns generated by bacteria that cohabit with P. salmonis (fish bacterial isolates and culture media contaminants). Our results indicate that the restriction enzyme selection pipeline was suitable to design a more specific, sensible, faster and cheaper assay than the currently used P. salmonis detection methodologies.
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Affiliation(s)
- Dinka Mandakovic
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de ChileSantiago, Chile; Fondap Center for Genoma RegulationSantiago, Chile
| | - Benjamín Glasner
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile Santiago, Chile
| | - Jonathan Maldonado
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de ChileSantiago, Chile; Fondap Center for Genoma RegulationSantiago, Chile
| | - Pamela Aravena
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de ChileSantiago, Chile; Laboratorio de Genómica Aplicada, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de ChileSantiago, Chile
| | - Mauricio González
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de ChileSantiago, Chile; Fondap Center for Genoma RegulationSantiago, Chile; Laboratorio de Genómica Aplicada, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de ChileSantiago, Chile
| | - Verónica Cambiazo
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de ChileSantiago, Chile; Fondap Center for Genoma RegulationSantiago, Chile; Laboratorio de Genómica Aplicada, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de ChileSantiago, Chile
| | - Rodrigo Pulgar
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de ChileSantiago, Chile; Fondap Center for Genoma RegulationSantiago, Chile; Laboratorio de Genómica Aplicada, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de ChileSantiago, Chile
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31
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Labra Á, Arredondo-Zelada O, Flores-Herrera P, Marshall SH, Gómez FA. In sílico identification and characterization of putative Dot/Icm secreted virulence effectors in the fish pathogen Piscirickettsia salmonis. Microb Pathog 2015; 92:11-18. [PMID: 26706346 DOI: 10.1016/j.micpath.2015.12.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 11/26/2015] [Accepted: 12/01/2015] [Indexed: 11/25/2022]
Abstract
Piscirickettsia salmonis seriously affects the Chilean salmon industry. The bacterium is phylogenetically related to Legionella pneumophila and Coxiella burnetii, sharing a Dot/Icm secretion system with them. Although it is well documented that L. pneumophila and C. burnetii secrete different virulence effectors via this Dot/Icm system in order to attenuate host cell responses, to date there have been no reported virulence effectors secreted by the Dot/Icm system of P. salmonis. Using several annotations of P. salmonis genome, here we report an in silico analyses of 4 putative Dot/Icm effectors. Three of them contain ankyrin repeat domains and the typical conserved 3D structures of this protein family. The fourth one is highly similar to one of the Dot/Icm-dependent effectors of L. pneumophila. Additionally, all the potential P. salmonis effectors contain a classical Dot/Icm secretion signal in their C-terminus, consisting of: an E-Block, a hydrophobic residue in -3 or -4 and an electronegative charge. Finally, qPCR analysis demonstrated that these proteins are overexpressed early in infection, perhaps contributing to the generation of a replicative vacuole, a key step in the neutralizing strategy proposed for the Dot/Icm system. In summary, this report identifies four Dot/Icm-dependent effectors in P. salmonis.
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Affiliation(s)
- Álvaro Labra
- Laboratorio de Patógenos Acuícolas, Núcleo de Biotecnología Curauma, Pontificia Universidad Católica de Valparaíso, Chile; Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Av. Universidad 330, Curauma, Valparaíso, Chile.
| | - Oscar Arredondo-Zelada
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Av. Universidad 330, Curauma, Valparaíso, Chile.
| | - Patricio Flores-Herrera
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Av. Universidad 330, Curauma, Valparaíso, Chile.
| | - Sergio H Marshall
- Laboratorio de Patógenos Acuícolas, Núcleo de Biotecnología Curauma, Pontificia Universidad Católica de Valparaíso, Chile; Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Av. Universidad 330, Curauma, Valparaíso, Chile; Fraunhofer Chile Research Foundation, Center for Systems Biotechnology, Santiago, Chile.
| | - Fernando A Gómez
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Av. Universidad 330, Curauma, Valparaíso, Chile.
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