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Microorganisms Jan 2024This study aimed to characterize 300 spp. strains isolated from 123 ornamental fish of 32 different species presenting with septicemia, skin lesions, and/or eye...
This study aimed to characterize 300 spp. strains isolated from 123 ornamental fish of 32 different species presenting with septicemia, skin lesions, and/or eye lesions. Within the 300 strains, 53.0% were identified as , 41.3% as , and 5.7% as . Among the six virulence genes investigated, the most frequent were (90.3%) and (79.3%). More than 50% of strains were positive for all the studied genes. A total of 30 virulence profiles were identified, with the five main profiles identified comprising 75% of strains. Only five strains were negative for all genes and were identified as and . The antimicrobial susceptibility profile was performed for 234 strains, with sulfonamides presenting more than 50% of the resistance rates. Susceptibility was observed mainly for cephalosporins, aminoglycosides, chloramphenicol and piperacillin-tazobactam. Multidrug resistance was detected in 82.5% of the studied strains, including with 100% multidrug resistance, and with 90.9% multidrug resistance. The SE-AFLP analysis resulted in 66 genotypes of , 118 genotypes of , and 14 genotypes of , demonstrating the greater heterogeneity of and A. . However, no direct correlation was observed between the genotypes and the strains' origins or virulence and resistance profiles.
PubMed: 38258002
DOI: 10.3390/microorganisms12010176 -
BMC Veterinary Research Jan 2024Aeromonas species are one of the most important etiologies of diseases in fish farms, leading to clinical manifestation and mortality and are associated with public...
BACKGROUND
Aeromonas species are one of the most important etiologies of diseases in fish farms, leading to clinical manifestation and mortality and are associated with public health risks. This study aimed to investigate the prevalence, phenotypic and molecular characteristics of Aeromonas species isolated from farmed Clarias gariepinus using 16 S rRNA sequencing. Additionally, their antibiogram and multiple antibiotic resistance index were determined using a disc diffusion test.
RESULTS
A total of 230 Aeromonas strains were isolated from Clarias gariepinus with 40.9% obtained from diseased fish, and 25% isolated from apparently healthy ones. Five different species including Aeromonas caviae, Aeromonas veronii, Aeromonas hydrophila, Aeromonas dhakensis and Aeromonas enteropelogenes were fully identified and genetically characterized. Based on the available literature, this is the first report of Aeromonas enteropelogenes from the study area. The phylogenetic analysis showed genetic heterogeneity and distance within the species and the reference strains. The multiple resistant Aeromonas species were susceptible to ciprofloxacin, gentamycin, and florfenicol. The Aeromonas species' multiple antibiotic resistance index values varied between 0.20 and 0.80 and were isolated from the farms where antibiotics were intensively used.
CONCLUSIONS
The diversity of multidrug-resistant Aeromonas species isolated from fish farms is a major threat to fish production giving us more understanding of epidemiology and the multidrug Aeromonas species with a MAR index of greater than 0.2 were isolated from farms where antibiotic use was widespread. As a result, a considerably increased danger of multiple antibiotic resistance spreading to the fish culture environment may impact aquaculture production. Hence there is a need for appropriate and monitored drug usage.
Topics: Animals; Catfishes; Phylogeny; Aeromonas; Drug Resistance, Microbial; Anti-Bacterial Agents
PubMed: 38184574
DOI: 10.1186/s12917-023-03860-5 -
Journal of Immunology (Baltimore, Md. :... Feb 2024Collectin is a crucial component of the innate immune system and plays a vital role in the initial line of defense against pathogen infection. In mammals, collectin...
Collectin is a crucial component of the innate immune system and plays a vital role in the initial line of defense against pathogen infection. In mammals, collectin kidney 1 (CL-K1) is a soluble collectin that has recently been identified to have significant functions in host defense. However, the evolutionary origins of immune defense of CL-K1 and its mechanism in clearance of pathogenic microorganisms remain unclear, especially in early vertebrates. In this study, the Oreochromis niloticus CL-K1 (OnCL-K1) protein was purified and identified, which was capable of binding to two important pathogens of tilapia, Streptococcus agalactiae and Aeromonas hydrophila. Interestingly, OnCL-K1 exhibited direct bactericidal activity by binding to lipoteichoic acid or LPS on cell walls, disrupting the permeability and integrity of the bacterial membrane in vitro. Upon bacterial challenge, OnCL-K1 significantly inhibited the proliferation of pathogenic bacteria, reduced the inflammatory response, and improved the survival of tilapia. Further research revealed that OnCL-K1 could associate with OnMASPs to initiate and regulate the lectin complement pathway. Additionally, OnCD93 reduced the complement-mediated hemolysis by competing with OnMASPs for binding to OnCL-K1. More importantly, OnCL-K1 could facilitate phagocytosis by collaborating with cell surface CD93 in a lectin pathway-independent manner. Moreover, OnCL-K1 also promoted the formation of phagolysosomes, which degraded and killed ingested bacteria. Therefore, this study reveals the antibacterial response mechanism of CL-K1 in primitive vertebrates, including promoting complement activation, enhancing opsonophagocytosis, and killing of macrophages, as well as its internal links, all of which provide (to our knowledge) new insights into the understanding of the evolutionary origins and regulatory roles of the collectins in innate immunity.
Topics: Animals; Opsonization; Macrophages; Complement Activation; Kidney; Vertebrates; Collectins; Fish Proteins; Mammals
PubMed: 38180157
DOI: 10.4049/jimmunol.2300457 -
Molecular Biology Reports Jan 2024Pollution with heavy metals (HMs) is time- and concentration-dependent. Lead and zinc pollute the aquatic environment, causing severe health issues in aquatic animals.
BACKGROUND
Pollution with heavy metals (HMs) is time- and concentration-dependent. Lead and zinc pollute the aquatic environment, causing severe health issues in aquatic animals.
MATERIALS AND METHODS
Nile tilapia, the predominant cultured fish in Egypt, were experimentally exposed to 10% of LC of lead nitrate (PbNO) and zinc sulfate (ZnSO). Samples were collected in three different periods, 4, 6, and 8 weeks, in addition to a trial to treat the experimental fish infected with Aeromonas hydrophila, with an antibiotic (florfenicol).
RESULTS
Liver enzymes were linearly upsurged in a time-dependent manner in response to HMs exposure. ALT was 92.1 IU/l and AST was 82.53 IU/l after eight weeks. In the eighth week of the HMs exposure, in the hepatic tissue, the levels of glutathione peroxidase (GPx), catalase (CAT), and metallothionein (MT) were increased to 117.8 U/mg prot, 72.2 U/mg prot, and 154.5 U/mg prot, respectively. On exposure to HMs, gene expressions of some cytokines were linearly downregulated in a time-dependent manner compared to the control. After four weeks of exposure to the HMs, the oxidative burst activity (OBA) of immune cells was decreased compared to the control 9.33 and 10.3 cells, respectively. Meanwhile, the serum bactericidal activity (SBA) significantly declined to 18.5% compared to the control 32.6% after eight weeks of exposure. Clinical signs of A. hydrophila infection were exaggerated in polluted fish, with a mortality rate (MR) of 100%. The re-isolation rate of A. hydrophila was decreased in fish treated with florfenicol regardless of the pollution impacts after eight weeks of HMs exposure.
CONCLUSION
It could be concluded that the immune suppression and oxidative stress resulting from exposure to HMs are time-dependent. Clinical signs and post-mortem lesions in polluted fish infected with A. hydrophila were prominent. Infected-Nile tilapia had weak responses to florfenicol treatment due to HMs exposure.
Topics: Animals; Lead; Zinc Sulfate; Cichlids; Nitrates; Aeromonas hydrophila
PubMed: 38175215
DOI: 10.1007/s11033-023-09033-9 -
BMC Research Notes Jan 2024This research aims to quantify antiquorum sensing and antibiofilm activity of f phyllosphere bacteria against biofilm formed by pathogenic fish bacteria such as...
OBJECTIVE
This research aims to quantify antiquorum sensing and antibiofilm activity of f phyllosphere bacteria against biofilm formed by pathogenic fish bacteria such as Aeromonas hydrophila, Streptococcus agalactiae, and Vibrio harveyi.
RESULTS
Antiquorum sensing assay using Chromobacter violaceum as indicator bacteria and antibiofilm assay showed six phyllosphere bacteria have antiquorum sensing and antibiofilm activities against tested bacteria. The highest inhibition and destruction activity was showed by metabolite of JB 3B and EJB 5 F against A. hydrophila, respectively. Determination using light microscope and scanning electron microscope performed decreaing in biomass of biofilm observed after treated with metabolite from phyllosphere bacteria.
Topics: Animals; Quorum Sensing; Biofilms; Fishes; Anti-Bacterial Agents
PubMed: 38167225
DOI: 10.1186/s13104-023-06657-9 -
Open Forum Infectious Diseases Dec 2023The genus is increasingly implicated in human infections, but knowledge of its clinical characteristics and antimicrobial resistance profiles has been limited owing to...
BACKGROUND
The genus is increasingly implicated in human infections, but knowledge of its clinical characteristics and antimicrobial resistance profiles has been limited owing to its complex taxonomy.
METHODS
We conducted a multicenter prospective cohort study of patients with infections at hospitals across Japan. Patients were eligible for inclusion if they had an spp. strain in a clinical culture and were considered infected at the culture site. Clinical data were collected, and isolates underwent susceptibility testing and whole-genome sequencing.
RESULTS
A total of 144 patients were included. Hepatobiliary infection accounted for a majority of infections (73% [105 of 144]), which mostly occurred in elderly patients with comorbid conditions, including hepatobiliary complications. The all-cause 30-day mortality rate was 10.0% (95% confidence interval, 4.9%-14.8%). By whole-genome sequencing, 141 strains (98%) belonged to 4 species, , , and with significant intraspecies diversity. was predominant in all infection sites except skin and soft tissue, for which was the prevailing species. The genes encoding chromosomally mediated class B, C, and D β-lactamases were harbored by 92%-100% of the isolates in a species-specific manner, but they often lacked association with resistance phenotypes. The activity of cefepime was reliable. All isolates of and carried an like colistin resistance gene and showed reduced susceptibility to colistin.
CONCLUSIONS
Hepatobiliary tract was the most common infection site of spp., with being the dominant causative species. The resistance genotype and phenotype were often incongruent for β-lactam agents.
PubMed: 38156048
DOI: 10.1093/ofid/ofad587 -
IL-6 Mutation Attenuates Liver Injury Caused by Infection by Reducing Oxidative Stress in Zebrafish.International Journal of Molecular... Dec 2023Interleukin-6 (IL-6), a pleiotropic cytokine, plays a crucial role in acute stress induced by bacterial infection and is strongly associated with reactive oxygen species...
Interleukin-6 (IL-6), a pleiotropic cytokine, plays a crucial role in acute stress induced by bacterial infection and is strongly associated with reactive oxygen species (ROS) production. However, the role of IL-6 in the liver of fish after infection remains unclear. Therefore, this study constructed a zebrafish () knockout line by CRISPR/Cas9 to investigate the function of IL-6 in the liver post bacterial infection. After infection with , pathological observation showed that zebrafish exhibited milder liver damage than wild-type (WT) zebrafish. Moreover, liver transcriptome sequencing revealed that 2432 genes were significantly up-regulated and 1706 genes were significantly down-regulated in fish compared with WT fish after infection. Further, gene ontology (GO) analysis showed that differentially expressed genes (DEGs) were significantly enriched in redox-related terms, including oxidoreductase activity, copper ion transport, etc. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that DEGs were significantly enriched in pathways such as the PPAR signaling pathway, suggesting that mutation has a significant effect on redox processes in the liver after infection. Additionally, zebrafish exhibited lower malondialdehyde (MDA) levels and higher superoxide dismutase (SOD) activities in the liver compared with WT zebrafish following infection, indicating that IL-6 deficiency mitigates oxidative stress induced by infection in the liver. These findings provide a basis for further studies on the role of IL-6 in regulating oxidative stress in response to bacterial infections.
Topics: Animals; Aeromonas hydrophila; Bacterial Infections; Gram-Negative Bacterial Infections; Interleukin-6; Liver; Mutation; Oxidation-Reduction; Oxidative Stress; Zebrafish; Zebrafish Proteins; Disease Models, Animal
PubMed: 38139043
DOI: 10.3390/ijms242417215 -
Biology Nov 2023The transcriptional regulators of the MarR family play an important role in diverse bacterial physiologic functions, whereas their effect and intrinsic regulatory...
The transcriptional regulators of the MarR family play an important role in diverse bacterial physiologic functions, whereas their effect and intrinsic regulatory mechanism on the aquatic pathogenic bacterium are, clearly, still unknown. In this study, we firstly constructed a deletion strain of (Δ) of a MarR family transcriptional regulator in ATCC 7966 (wild type), and found that the deletion of caused significantly enhanced hemolytic activity, extracellular protease activity, and motility when compared with the wild type. The differentially abundant proteins (DAPs) were compared by using data-independent acquisition (DIA), based on a quantitative proteomics technology, between the Δ strain and wild type, and there were 178 DAPs including 80 proteins up-regulated and 98 proteins down-regulated. The bioinformatics analysis showed that the deletion of gene led to some changes in the abundance of proteins related to multiple biological processes, such as translation, peptide transport, and oxidation and reduction. These results provided a theoretical basis for better exploring the regulatory mechanism of the MarR family transcriptional regulators of on bacterial physiological functions.
PubMed: 38132299
DOI: 10.3390/biology12121473 -
Heliyon Dec 2023The fish immune system, which consists of innate and adaptive immunologic processes, defends against viruses, bacteria, fungi, and parasites. The gut immunity is an...
The fish immune system, which consists of innate and adaptive immunologic processes, defends against viruses, bacteria, fungi, and parasites. The gut immunity is an integral part of the host immune system that controls immunological homeostasis, hosts' interactions with their microbiomes, and provides defence against a number of intestinal infections. , a facultative air-breathing fish, was experimentally infected with using intraperitoneal injection followed by bath challenge, and transcriptome data were used to examine the gut immune responses during disease progression and recovery from the diseased state without the use of medication. For the control or uninfected fish (FGC) and the infected fish that were kept for seven days (FGE1) and fifteen days (FGE2), separate water tanks were set up. Coding DNA sequences (CDS) for FGC and FGE1, FGC and FGE2, and FGE1 and FGE2 were analyzed for differential gene expression (DGE). The presence and expression of genes involved in the T cell receptor (TCR) signalling pathway, natural killer (NK) cell-mediated cytotoxicity pathway, and complement-mediated pathway, along with a large number of other immune-related proteins, and heat shock protein (HSPs) under various experimental conditions and its relationship to immune modulation of the fish gut was the primary focus of this study. Significant up-and-down regulation of these pathways shows that, in FGE1, the fish's innate immune system was engaged, whereas in FGE2, the majority of innate immune mechanisms were repressed, and adaptive immunity was activated. Expression of genes related to the immune system and heat-shock proteins was induced during this host's immunological response, and this information was then used to build a thorough network relating to immunity and the heat-shock response. This is the first study to examine the relationship between pathogenic bacterial infection, disease reversal, and modification of innate and adaptive immunity as well as heat shock response.
PubMed: 38130423
DOI: 10.1016/j.heliyon.2023.e22936 -
Fish and Shellfish Immunology Reports Dec 2023The skin mucus of fish is an important part of the innate immune system, which is poorly understood at the proteomic level. The study established a complete map of the...
The skin mucus of fish is an important part of the innate immune system, which is poorly understood at the proteomic level. The study established a complete map of the proteins in the skin mucus of () and discussed the Differentially Expressed Proteins (DEPs) after () infection. Using Label Free Liquid Chromatography-Mass Spectrometry (LC-MS/MS) analysis, a total of 126 proteins were identified as differentially expressed, 89 proteins of which were upregulated, and 37 proteins were downregulated. Functional annotations of DEPs showed that the upregulated proteins in the skin mucus of the treated group were mostly associated with complement system and cytoskeleton proteins, whereas downregulated proteins were associated with metabolism. The key upregulated immune proteins were transferrin variant C, lysozyme g, annexin A11, 26S proteasome non-ATPase regulatory subunit 8, hypothetical protein ROHU_000884, 60S ribosomal L7a, calpain-2 catalytic subunit-like protein, calpain-9-like protein, complement component C9, complement C3, cathepsin S, cathepsin Z, 14 kDa apolipo, heat shock protein and intelectin, whereas, leukocyte elastase inhibitor, annexin A11, C-factor-like protein, biotinidase isoform X1 and epidermal growth factor receptor substrate 15-like were the downregulated proteins. Moreover, we for the first-time report proteins such as coactosin, lamin-B2 and kelch 12, which were never reported in fish. Our study directly pointing out the possible immunological biomarkers in the skin mucus of after treatment. Each of the protein we report in this study could be used as base to establish their mechanism of action during bacterial infection that may contribute to the strategies against bacterial prevention and control in fishes.
PubMed: 38023345
DOI: 10.1016/j.fsirep.2023.100122