1
|
Xie H, Huang Y, Wang S, Che J, Luo T, Li L, Bao B. Deletion of speA and aroC genes impacts the pathogenicity of Vibrio anguillarum in spotted sea bass. Microb Pathog 2024; 189:106597. [PMID: 38395316 DOI: 10.1016/j.micpath.2024.106597] [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: 12/21/2023] [Revised: 02/20/2024] [Accepted: 02/20/2024] [Indexed: 02/25/2024]
Abstract
Vibrio anguillarum is one of the major pathogens responsible for bacterial infections in marine environments, causing significant impacts on the aquaculture industry. The misuse of antibiotics leads to bacteria developing multiple drug resistances, which is detrimental to the development of the fisheries industry. In contrast, live attenuated vaccines are gradually gaining acceptance and widespread recognition. In this study, we constructed a double-knockout attenuated strain, V. anguillarum ΔspeA-aroC, to assess its potential for preparing a live attenuated vaccine. The research results indicate a significant downregulation of virulence-related genes, including Type VI secretion system, Type II secretion system, biofilm synthesis, iron uptake system, and other related genes, in the mutant strain. Furthermore, the strain lacking the genes exhibited a 67.47% reduction in biofilm formation ability and increased sensitivity to antibiotics. The mutant strain exhibited significantly reduced capability in evading host immune system defenses and causing in vivo infections in spotted sea bass (Lateolabrax maculatus), with an LD50 that was 13.93 times higher than that of the wild-type V. anguillarum. Additionally, RT-qPCR analysis of immune-related gene expression in spotted sea bass head kidney and spleen showed a weakened immune response triggered by the knockout strain. Compared to the wild-type V. anguillarum, the mutant strain caused reduced levels of tissue damage. The results demonstrate that the deletion of speA and aroC significantly reduces the biosynthesis of biofilms in V. anguillarum, leading to a decrease in its pathogenicity. This suggests a crucial role of biofilms in the survival and invasive capabilities of V. anguillarum.
Collapse
Affiliation(s)
- Haisheng Xie
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Yajuan Huang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Shengming Wang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Jingyuan Che
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Tuyan Luo
- Institute of Quality Standards and Testing Technology for Agro-Products, Fujian Academy of Agricultural Sciences, Fuzhou, 350003, China
| | - Lekang Li
- Jiujiang Academy of Fishery Sciences, Jiujiang, 332000, China.
| | - Baolong Bao
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China; Marine Biomedical Science and Technology Innovation Platform of Lin-gang Special Area, Shanghai, 201306, China.
| |
Collapse
|
2
|
Oliver C, Ruiz P, Vidal JM, Carrasco C, Escalona CE, Barros J, Sepúlveda D, Urrutia H, Romero A. Effect of florfenicol on Piscirickettsia salmonis biofilm formed in materials used in salmonid nets, nylon and high-density polyethylene. JOURNAL OF FISH DISEASES 2024; 47:e13862. [PMID: 37776076 DOI: 10.1111/jfd.13862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 08/29/2023] [Accepted: 09/05/2023] [Indexed: 10/01/2023]
Abstract
Piscirickettsiosis is the most prevalent bacterial disease affecting seawater salmon in Chilean salmon industry. Antibiotic therapy is the first alternative to counteract infections caused by Piscirickettsia salmonis. The presence of bacterial biofilms on materials commonly used in salmon farming may be critical for understanding the bacterial persistence in the environment. In the present study, the CDC Biofilm Reactor® was used to investigate the effect of sub- and over-MIC of florfenicol on both the pre-formed biofilm and the biofilm formation by P. salmonis under the antibiotic stimuli on Nylon and high-density polyethylene (HDPE) surfaces. This study demonstrated that FLO, at sub- and over-MIC doses, decreases biofilm-embedded live bacteria in the P. salmonis isolates evaluated. However, it was shown that in the P. salmonis Ps007 strain the presence of sub-MIC of FLO reduced its biofilm formation on HDPE surfaces; however, biofilm persists on Nylon surfaces. These results demonstrated that P. salmonis isolates behave differently against FLO and also, depending on the surface materials. Therefore, it remains a challenge to find an effective strategy to control the biofilm formation of P. salmonis, and certainly other marine pathogens that affect the sustainability of the Chilean salmon industry.
Collapse
Affiliation(s)
- Cristian Oliver
- Laboratorio de Inmunología y Estrés de Organismos Acuáticos, Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - Pamela Ruiz
- Laboratorio de Biopelículas y Microbiología Ambiental, Centro de Biotecnología, Universidad de Concepción, Concepción, Chile
- Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andres Bello, Talcahuano, Chile
| | - José Miguel Vidal
- Laboratorio de Biopelículas y Microbiología Ambiental, Centro de Biotecnología, Universidad de Concepción, Concepción, Chile
- Departamento de Investigación y Desarrollo, Ecombio Limitada, Concepción, Chile
| | - Carlos Carrasco
- Laboratorio de Biopelículas y Microbiología Ambiental, Centro de Biotecnología, Universidad de Concepción, Concepción, Chile
| | - Carla Estefanía Escalona
- Laboratorio de Inmunología y Estrés de Organismos Acuáticos, Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - Javier Barros
- Departamento de Investigación y Desarrollo, Micbiotech Spa, Concepción, Chile
| | - Daniela Sepúlveda
- Laboratorio de Biopelículas y Microbiología Ambiental, Centro de Biotecnología, Universidad de Concepción, Concepción, Chile
| | - Homero Urrutia
- Laboratorio de Biopelículas y Microbiología Ambiental, Centro de Biotecnología, Universidad de Concepción, Concepción, Chile
- Departamento de Microbiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Alex Romero
- Laboratorio de Inmunología y Estrés de Organismos Acuáticos, Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
- Interdisciplinary Center for Aquaculture Research, (INCAR), Concepción, Chile
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
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.
Collapse
|