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Fish & Shellfish Immunology Jun 2024Mucosal tissues appear to be more important in fish than in mammals due to living in a microbial-rich aquatic milieu, yet the complex interaction between the immune and...
Sea water acclimation of rainbow trout (Oncorhynchus mykiss) modulates the mucosal transcript immune response induced by Vibrio anguillarum and Aeromonas salmonicida vaccine, and prevents further transcription of stress-immune genes in response to acute stress.
Mucosal tissues appear to be more important in fish than in mammals due to living in a microbial-rich aquatic milieu, yet the complex interaction between the immune and the neuroendocrine system in these tissues remains elusive. The aim of this work was to investigate the mucosal immune response in immunized rainbow trout vaccinated with Alpha ject vaccine (bivalent), kept in fresh water (FW) or transferred to seawater (SW), and to evaluate their response to acute stress (chasing). Acute stress resulted in higher levels of plasma cortisol (Sham+Stress and Vaccine+Stress). A similar response was observed in skin mucus, but it was lower in Vaccine+Stress compared with stressed fish. With a few exceptions, minimal alterations were detected in the transcriptomic profile of stress-immune gene in the skin of vaccinated and stressed fish in both FW and SW. In the gills, the stress elicited activation of key stress-immune components (gr1, mr, β-ar, hsp70, c3, lysozyme, α-enolase, nadph oxidase, il1β, il6, tnfα, il10 and tgfβ1) in FW, but fewer immune changes were induced by the vaccine (nadph oxidase, il6, tnfα, il10 and igt) in both SW and FW. In the intestine, an array of immune genes was activated by the vaccine particularly those related with B cells (igm, igt) and T cells (cd8α) in FW with no stimulation observed in SW. Therefore, our survey on the transcriptomic mucosal response demonstrates that the immune protection conferred by the vaccine to the intestine is modulated in SW. Overall, our results showed: i) plasma and skin mucus cortisol showed no additional stress effect induced by prolonged SW acclimation, ii) the stress and immune response were different among mucosal tissues which indicates a tissue-specific response to specific antigens/stressor. Further, the results suggest that the systemic immune organs may be more implicated in infectious events in SW (as few changes were observed in the mucosal barriers of immunized fish in SW) than in FW.
PubMed: 38944251
DOI: 10.1016/j.fsi.2024.109733 -
Journal of Water and Health Jun 2024The misuse of antibiotics and the emergence of antimicrobial resistance (AMR) is a concern in the aquaculture industry because it contributes to global health risks and...
The misuse of antibiotics and the emergence of antimicrobial resistance (AMR) is a concern in the aquaculture industry because it contributes to global health risks and impacts the environment. This study analyzed the AMR of sentinel bacteria associated with striped catfish () and giant snakehead (), the two main fish species reared in the pond culture in Cambodia. Phenotypic and genotypic characterization of the recovered isolates from fish, water, and sediment samples revealed the presence of bacteria, such as 22 species belonging to families , , and . Among 48 isolates, (n = 2), (n = 2), (n = 1), (n = 4) were detected. and are known as fish pathogens that occur worldwide in both fresh and marine water aquaculture. Antibiotic susceptibility testing revealed antibiotic resistance patterns of 24 (50 %) isolates among 48 isolates with higher multiple antibiotic resistance index (> 0.2). All the isolates of were susceptible to ciprofloxacin. Ciprofloxacin is a frontline antibiotic that is not recommended to use in aquaculture. Therefore, its use has to be strictly controlled. This study expands our knowledge of the AMR status in aquaculture farms which is very limited in Cambodia.
Topics: Aquaculture; Cambodia; Drug Resistance, Bacterial; Catfishes; Water Microbiology; Sentinel Species; Phenotype; Genotype; Aeromonadaceae; Enterobacteriaceae; Pseudomonadaceae; Aeromonas caviae; Aeromonas hydrophila; Ciprofloxacin; Anti-Bacterial Agents; Fish Diseases; Gram-Negative Bacterial Infections; Environmental Monitoring
PubMed: 38935454
DOI: 10.2166/wh.2024.101 -
Microorganisms May 2024is sensitive to most antibiotics and the sole species of this genus susceptible to ampicillin. This susceptibility profile could be related to its inability to acquire...
is sensitive to most antibiotics and the sole species of this genus susceptible to ampicillin. This susceptibility profile could be related to its inability to acquire exogenous DNA. In this study, isolates were analyzed to establish their capacity to incorporate foreign DNA. Fourteen strains were identified as by multilocus phylogenetic analysis (MLPA). Minimal inhibitory concentrations of antibiotics (MIC) were assessed, confirming the susceptibility to most antibiotics tested. To explore their capacity to be transformed, strains were used as recipients in different horizontal transfer assays. Results showed that around fifty percent of strains were able to incorporate pBAMD1-2 and pBBR1MCS-3 plasmids after conjugal transfer. In all instances, conjugation frequencies were very low. Interestingly, several isoforms of plasmid pBBR1MCS-3 were observed in transconjugants. Strains could not receive pAr-32, a native plasmid from . strains were unable to receive DNA by means of electroporation, natural transformation or vesiduction. These results confirm that species are extremely refractory to horizontal gene transfer, which could be associated to plasmid instability resulting from oligomerization or to the presence of defense systems against exogenous genetic material in their genomes. To explain the poor results of horizontal gene transfer (HGT), selected genomes were sequenced and analyzed, revealing the presence of defense systems, which could prevent the stable incorporation of exogenous DNA in .
PubMed: 38930473
DOI: 10.3390/microorganisms12061091 -
Pathogens (Basel, Switzerland) May 2024The genus includes well-known pathogenic species for fishes and humans that are widely distributed in the aquatic environment and foods. Nowadays, one of the main...
The genus includes well-known pathogenic species for fishes and humans that are widely distributed in the aquatic environment and foods. Nowadays, one of the main issues related to wild isolates is their identification at the species level, which is challenging using classical microbiological and biomolecular methods. This study aims to test MALDI-TOF MS technology in the identification of strains isolated from n. 60 retail sushi and sashimi boxes using an implemented version of the SARAMIS software V4.12. A total of 43 certified strains were used to implement the SARAMIS database by importing the spectra obtained from their identification. The original SARAMIS version (V4.12) failed to recognize 62.79% of the certified strains, while the herein-implemented version (V4.12) allowed the identification of all the certified strains at least to the genus level with a match of no less than 85%. Regarding the sushi and sashimi samples, spp. was detected in n. 18 (30%) boxes. A total of 127 colonies were identified at the species level, with detected as the most prevalent species, followed by and . Based on the results of the present study, we could speculate that MALDI-TOF technology could be a useful tool both for the food industry to monitor product contamination and for clinical purposes to make diagnoses effectively and quickly.
PubMed: 38921730
DOI: 10.3390/pathogens13060432 -
Infection and Immunity Jun 2024Cold shock proteins (Csp) are pivotal nucleic acid binding proteins known for their crucial roles in the physiology and virulence of various bacterial pathogens...
Cold shock proteins (Csp) are pivotal nucleic acid binding proteins known for their crucial roles in the physiology and virulence of various bacterial pathogens affecting plant, insect, and mammalian hosts. However, their significance in bacterial pathogens of teleost fish remains unexplored. subsp. (hereafter ) is a psychrotrophic pathogen and the causative agent of furunculosis in marine and freshwater fish. Four genes (, and ) have been identified in the genome of J223 (wild type). Here, we evaluated the role of DNA binding proteins, CspB and CspD, in physiology and virulence in lumpfish (). Δ, Δ, and the double ΔΔ mutants were constructed and characterized. Δ and ΔΔ mutants showed a faster growth at 28°C, and reduced virulence in lumpfish. Δ showed a slower growth at 28°C, biofilm formation, lower survival in low temperatures and freezing conditions (-20°C, 0°C, and 4°C), deficient in lipopolysaccharide synthesis, and low virulence in lumpfish. Additionally, ΔΔ mutants showed less survival in the presence of bile compared to the wild type. Transcriptome analysis revealed that 200, 37, and 921 genes were differentially expressed in Δ, Δ, and ΔΔ respectively. In Δ and ΔΔ virulence genes in the chromosome and virulence plasmid were downregulated. Our analysis indicates that CspB and CspD mostly act as a transcriptional activator, influencing cell division (e.g., ), virulence factors (e.g., ), and ultimately virulence.
PubMed: 38920386
DOI: 10.1128/iai.00011-24 -
Fish & Shellfish Immunology Jun 2024Aeromonas salmonicida is one of the most prevalent pathogens that causes huge economic losses to aquaculture. Effective vaccination is the first choice for preventing...
Aeromonas salmonicida is one of the most prevalent pathogens that causes huge economic losses to aquaculture. Effective vaccination is the first choice for preventing infection. Bacterial ghost (BG), an empty bacterial shell devoid of cytoplasm, is a promising vaccine antigen with distinct advantages. Herein, we established strategies for producing a substantial yield of A. salmonicida ghost (ASG) and investigated the immune-protective properties of it. As a result, 2.84 mg/ml NaOH was discovered to be capable of inducing considerable amounts of ASG. Furthermore, the ASG vaccine elicited adaptive immunity in turbots after rapid activation of innate immunity. Even though formalin-killed cells (FKC) produced a few more antibodies than ASG, ASG ultimately provided a much stronger immune protection effect because it strengthened cellular immunity, with a relative percentage survival (RPS) of 50.1 % compared to FKC. These findings demonstrated that ASG effectively activated cell-mediated immunity, which helped get rid of microorganisms inside cells. Therefore, this study presented novel perspectives for future research on furunculosis vaccine products based on ASG as an antigen.
PubMed: 38901685
DOI: 10.1016/j.fsi.2024.109711 -
Aquatic Toxicology (Amsterdam,... Jul 2024The increasing release of engineered nanoparticles (ENPs) in aquatic ecosystems stresses the need for stringent investigations of nanoparticle mixture toxicity towards...
The increasing release of engineered nanoparticles (ENPs) in aquatic ecosystems stresses the need for stringent investigations of nanoparticle mixture toxicity towards aquatic organisms. Here, the individual and combined immunotoxicity of two of the most consumed ENPs, the ZnO and the TiO ones, was investigated on rainbow trout juveniles (Oncorhynchus mykiss). Fish were exposed to environmentally realistic concentrations (21 and 210 µg L for the ZnO and 210 µg L for the TiO) for 28 days, and then challenged with the pathogenic bacterium, Aeromonas salmonicida achromogenes. Antioxidant and innate immune markers were assessed before and after the bacterial infection. None of the experimental conditions affected the basal activity of the studied innate immune markers and the redox balance. However, following the bacterial infection, the expression of genes coding for pro and anti-inflammatory cytokines (il1β and il10), as well as innate immune compounds (mpo) were significantly reduced in fish exposed to the mixture. Conversely, exposure to ZnO NPs alone seemed to stimulate the immune response by enhancing the expression of the IgM and c3 genes for instance. Overall, our results suggest that even though the tested ENPs at their environmental concentration do not strongly affect basal immune functions, their mixture may alter the development of the immune response when the organism is exposed to a pathogen by interfering with the inflammatory response.
Topics: Animals; Aeromonas salmonicida; Zinc Oxide; Oncorhynchus mykiss; Titanium; Water Pollutants, Chemical; Gram-Negative Bacterial Infections; Immunity, Innate; Nanoparticles; Fish Diseases; Metal Nanoparticles; Cytokines
PubMed: 38843740
DOI: 10.1016/j.aquatox.2024.106981 -
Scientific Reports May 2024The immunomodulatory effects of omega-3 and omega-6 fatty acids are a crucial subject of investigation for sustainable fish aquaculture, as fish oil is increasingly...
The immunomodulatory effects of omega-3 and omega-6 fatty acids are a crucial subject of investigation for sustainable fish aquaculture, as fish oil is increasingly replaced by terrestrial vegetable oils in aquafeeds. Unlike previous research focusing on fish oil replacement with vegetable alternatives, our study explored how the omega-6 to omega-3 polyunsaturated fatty acid (PUFA) ratio in low-fish oil aquafeeds influences Atlantic salmon's antiviral and antibacterial immune responses. Atlantic salmon were fed aquafeeds rich in soy oil (high in omega-6) or linseed oil (high in omega-3) for 12 weeks and then challenged with bacterial (formalin-killed Aeromonas salmonicida) or viral-like (polyriboinosinic polyribocytidylic acid) antigens. The head kidneys of salmon fed high dietary omega-3 levels exhibited a more anti-inflammatory fatty acid profile and a restrained induction of pro-inflammatory and neutrophil-related genes during the immune challenges. The high-omega-3 diet also promoted a higher expression of genes associated with the interferon-mediated signaling pathway, potentially enhancing antiviral immunity. This research highlights the capacity of vegetable oils with different omega-6 to omega-3 PUFA ratios to modulate specific components of fish immune responses, offering insights for future research on the intricate lipid nutrition-immunity interplay and the development of novel sustainable low-fish oil clinical aquaculture feeds.
Topics: Animals; Salmo salar; Fatty Acids, Omega-6; Fatty Acids, Omega-3; Aeromonas salmonicida; Fish Diseases; Head Kidney; Animal Feed; Soybean Oil; Fish Oils; Aquaculture
PubMed: 38740811
DOI: 10.1038/s41598-024-61144-w -
Pathogens and Disease Feb 2024The development of sustainable alternatives to conventional antimicrobials is needed to address bacterial virulence while avoiding selecting resistant strains in a...
The development of sustainable alternatives to conventional antimicrobials is needed to address bacterial virulence while avoiding selecting resistant strains in a variety of fields, including human, animal, and plant health. Quorum sensing (QS), a bacterial communication system involved in noxious bacterial phenotypes such as virulence, motility, and biofilm formation, is of utmost interest. In this study, we harnessed the potential of the lactonase SsoPox to disrupt QS of human, fish, and plant pathogens. Lactonase treatment significantly alters phenotypes including biofilm formation, motility, and infection capacity. In plant pathogens, SsoPox decreased the production of plant cell wall degrading enzymes in Pectobacterium carotovorum and reduced the maceration of onions infected by Burkholderia glumae. In human pathogens, lactonase treatment significantly reduced biofilm formation in Acinetobacter baumannii, Burkholderia cepacia, and Pseudomonas aeruginosa, with the cytotoxicity of the latter being reduced by SsoPox treatment. In fish pathogens, lactonase treatment inhibited biofilm formation and bioluminescence in Vibrio harveyi and affected QS regulation in Aeromonas salmonicida. QS inhibition can thus be used to largely impact the virulence of bacterial pathogens and would constitute a global and sustainable approach for public, crop, and livestock health in line with the expectations of the One Health initiative.
Topics: Quorum Sensing; Animals; Humans; Virulence; Biofilms; Bacteria; Plant Diseases; Anti-Bacterial Agents
PubMed: 38724459
DOI: 10.1093/femspd/ftae009 -
Amino Acids Apr 2024In the face of increasing antimicrobial resistance in aquaculture, researchers are exploring novel substitutes to customary antibiotics. One potential solution is the...
In the face of increasing antimicrobial resistance in aquaculture, researchers are exploring novel substitutes to customary antibiotics. One potential solution is the use of antimicrobial peptides (AMPs). We aimed to design and evaluate a novel, short, and compositionally simple AMP with potent activity against various bacterial pathogens in aquaculture. The resulting peptide, KK12YW, has an amphipathic nature and net charge of + 7. Molecular docking experiments disclosed that KK12YW has a strong affinity for aerolysin, a virulence protein produced by the bacterial pathogen Aeromonas sobria. KK12YW was synthesized using Fmoc chemistry and tested against a range of bacterial pathogens, including A. sobria, A. salmonicida, A. hydrophila, Edwardsiella tarda, Vibrio parahaemolyticus, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis, and methicillin-resistant S. aureus. The AMP showed promising antibacterial activity, with MIC and MBC values ranging from 0.89 to 917.1 µgmL and 3.67 to 1100.52 µgmL, respectively. In addition, KK12YW exhibited resistance to high temperatures and remained effective even in the presence of serum and salt, indicating its stability. The peptide also demonstrated minimal hemolysis toward fish RBCs, even at higher concentrations. Taken together, these findings indicate that KK12YW could be a highly promising and viable substitute for conventional antibiotics to combat microbial infections in aquaculture.
Topics: Animals; Methicillin-Resistant Staphylococcus aureus; Molecular Docking Simulation; Antimicrobial Cationic Peptides; Anti-Bacterial Agents; Escherichia coli; Fishes; Microbial Sensitivity Tests
PubMed: 38578302
DOI: 10.1007/s00726-024-03388-4