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Microbial Genomics May 2024spp. are commonly found in the aquatic environment and have been responsible for motile septicemia (MAS) in striped catfish, resulting in significant economic loss....
spp. are commonly found in the aquatic environment and have been responsible for motile septicemia (MAS) in striped catfish, resulting in significant economic loss. These organisms also cause a range of opportunistic infections in humans with compromised immune systems. Here, we conducted a genomic investigation of 87 isolates derived from diseased catfish, healthy catfish and environmental water in catfish farms affected by MAS outbreaks in eight provinces in Mekong Delta (years: 2012-2022), together with 25 isolates from humans with bloodstream infections (years: 2010-2020). Genomics-based typing method precisely delineated species while traditional methods such as PCR and MALDI-TOF were unable identify was found to be more prevalent than in both diseased catfish and human infections. sequence type (ST) 656 followed by ST251 were the predominant virulent species-lineages in diseased catfish (43.7 and 20.7 %, respectively), while diverse STs were found in humans with bloodstream infections. There was evidence of widespread transmission of ST656 and ST251 on striped catfish in the Mekong Delta region. ST656 and ST251 isolates carried a significantly higher number of acquired antimicrobial resistance (AMR) genes and virulence factors in comparison to other STs. They, however, exhibited several distinctions in key virulence factors (i.e. lack of type IV pili and enterotoxin in ), AMR genes (i.e. presence of carbapenemase in ), and accessory gene content. To uncover potential conserved proteins of spp. for vaccine development, pangenome analysis has unveiled 2202 core genes between ST656 and ST251, of which 78 proteins were in either outer membrane or extracellular proteins. Our study represents one of the first genomic investigations of the species distribution, genetic landscape, and epidemiology of in diseased catfish and human infections in Vietnam. The emergence of antimicrobial resistant and virulent strains underscores the needs of enhanced genomic surveillance and strengthening vaccine research and development in preventing diseases in catfish and humans, and the search for potential vaccine candidates could focus on core genes encoded for membrane and secreted proteins.
Topics: Animals; Catfishes; Vietnam; Aeromonas; Gram-Negative Bacterial Infections; Humans; Sepsis; Fish Diseases; Phylogeny; Genomics; Genome, Bacterial; Virulence Factors; Anti-Bacterial Agents
PubMed: 38739115
DOI: 10.1099/mgen.0.001248 -
International Journal of Molecular... May 2024C-type lectins in organisms play an important role in the process of innate immunity. In this study, a C-type lectin belonging to the DC-SIGN class of was identified....
C-type lectins in organisms play an important role in the process of innate immunity. In this study, a C-type lectin belonging to the DC-SIGN class of was identified. MsDC-SIGN is classified as a type II transmembrane protein. The extracellular segment of MsDC-SIGN possesses a coiled-coil region and a carbohydrate recognition domain (CRD). The key amino acid motifs of the extracellular CRD of MsDC-SIGN in Ca-binding site 2 were EPN (Glu-Pro-Asn) and WYD (Trp-Tyr-Asp). MsDC-SIGN-CRD can bind to four pathogen-associated molecular patterns (PAMPs), including lipopolysaccharide (LPS), glucan, peptidoglycan (PGN), and mannan. Moreover, it can also bind to Gram-positive, Gram-negative bacteria, and fungi. Its CRD can agglutinate microbes and displays D-mannose and D-galactose binding specificity. MsDC-SIGN was distributed in seven tissues of the largemouth bass, among which the highest expression was observed in the liver, followed by the spleen and intestine. Additionally, MsDC-SIGN was present on the membrane of . leukocytes, thereby augmenting the phagocytic activity against bacteria. In a subsequent investigation, the expression patterns of the MsDC-SIGN gene and key genes associated with the TLR signaling pathway (TLR4, NF-κB, and IL10) exhibited an up-regulated expression response to the stimulation of . Furthermore, through RNA interference of MsDC-SIGN, the expression level of the DC-SIGN signaling pathway-related gene (RAF1) and key genes associated with the TLR signaling pathway (TLR4, NF-κB, and IL10) was decreased. Therefore, MsDC-SIGN plays a pivotal role in the immune defense against . by modulating the TLR signaling pathway.
Topics: Animals; Aeromonas hydrophila; Bass; Cell Adhesion Molecules; Fish Diseases; Fish Proteins; Gram-Negative Bacterial Infections; Immunity, Innate; Lectins, C-Type; Pathogen-Associated Molecular Pattern Molecules; Receptors, Cell Surface; Signal Transduction; Toll-Like Receptors
PubMed: 38732232
DOI: 10.3390/ijms25095013 -
Letters in Applied Microbiology Jul 2024Aeromonas dhakensis is reported as an emerging pathogenic species within the genus Aeromonas and is widely distributed in tropical coastal areas. This study provided a...
Aeromonas dhakensis is reported as an emerging pathogenic species within the genus Aeromonas and is widely distributed in tropical coastal areas. This study provided a detailed description and characterization of a strain of A. dhakensis (202108B1) isolated from diseased Ancherythroculter nigrocauda in an inland region of China. Biochemical tests identified the isolate at the genus level, and the further molecular analysis of concatenated housekeeping gene sequences revealed that the strain belonged to the species A. dhakensis. The isolated A. dhakensis strain was resistant to five antibiotics, namely, penicillin, ampicillin, clindamycin, cephalexin, and imipenem, while it was susceptible to or showed intermediate resistance to most of the other 15 tested antibiotics. The isolated strain of A. dhakensis caused acute hemorrhagic septicemia and tissue damage in artificially infected A. nigrocauda, with a median lethal dose of 7.76 × 104 CFU/fish. The genome size of strain 202108B1 was 5 043 286 bp, including 1 chromosome and 4 plasmids. This is the first detailed report of the occurrence of infection caused by an A. dhakensis strain causing infection in an aquaculture system in inland China, providing important epidemiological data on this potential pathogenic species.
Topics: China; Aeromonas; Animals; Anti-Bacterial Agents; Fish Diseases; Gram-Negative Bacterial Infections; Fishes; Phylogeny; Microbial Sensitivity Tests; Aquaculture; Genome, Bacterial; RNA, Ribosomal, 16S; Plasmids
PubMed: 38719546
DOI: 10.1093/lambio/ovae046 -
Fish & Shellfish Immunology Jun 2024Curcumin (Cur) exhibits diverse natural pharmacological activities, despite its limited water solubility (hydrophobicity) and low bioavailability. In this investigation,...
Curcumin (Cur) exhibits diverse natural pharmacological activities, despite its limited water solubility (hydrophobicity) and low bioavailability. In this investigation, a valine-curcumin conjugate (Val-Cur) was synthesized through amino acid side chain modification, and its solubility increased to 1.78 mg/mL. In vitro experimental findings demonstrated that the antibacterial activity of Val-Cur against Escherichia coli, Staphylococcus aureus, Aeromonas hydrophila, and Vibrio parahaemolyticus was significantly superior to that of Cur. The inhibition rate of Val-Cur against HepG2 (human hepatocellular carcinoma) cells was higher than that of Cur at low concentrations (below 25 μmol/L), although the IC value of Val-Cur did not differ significantly from that of Cur. In vivo biological effects of Val-Cur were assessed by adding it into the feed (150 mg/kg) of American eels (Anguilla rostrata). Val-Cur significantly improved the growth performance (↑weight gain rate, ↑specific growth rate, and ↓feed conversion rate) and activities of intestinal digestive enzymes (amylase and lipase) and antioxidant enzymes (superoxide dismutase) in American eels. Additionally, Val-Cur significantly improved serum biochemical indices (↑high-density lipoprotein cholesterol, ↓low-density lipoprotein cholesterol, ↓aspartate and alanine aminotransferases). Furthermore, Val-Cur increased intestinal microbial diversity, reduced the abundance of potentially pathogenic bacteria (Spiroplasma, Clostridium, and Pseudomonas), and elevated the abundance of beneficial digestion-promoting bacteria (Romboutsia, Phyllobacterium, Romboutsia sedimentorum, and Clostridium butyricum) conducive to glucose metabolism (P < 0.05). To the best of our knowledge, this study is the first to explore water-soluble curcumin in aquaculture, and the findings will lay the groundwork for the potential application of water-soluble curcumin in the field of aquaculture.
Topics: Animals; Curcumin; Anti-Bacterial Agents; Anguilla; Antineoplastic Agents; Valine; Animal Feed; Diet; Humans; Dietary Supplements; Vibrio parahaemolyticus; Staphylococcus aureus; Hep G2 Cells; Aeromonas hydrophila
PubMed: 38719095
DOI: 10.1016/j.fsi.2024.109615 -
Comparative Biochemistry and... Jun 2024A comprehensive bioinformatics analysis was conducted to elucidate the innate immune response of Charybdis japonica following exposure to Aeromonas hydrophila. This...
A comprehensive bioinformatics analysis was conducted to elucidate the innate immune response of Charybdis japonica following exposure to Aeromonas hydrophila. This study integrated metabolomics, 16S rRNA sequencing, and enzymatic activity data to dissect the immune mechanisms activated in response to infection. Infection with A. hydrophila resulted in an increased abundance of beneficial intestinal genera such as Photobacterium spp., Rhodobacter spp., Polaribacter spp., Psychrilyobacter spp., and Mesoflavibacter spp. These probiotics appear to suppress A. hydrophila colonization by competitively dominating the intestinal microbiota. Key metabolic pathways affected included fatty acid biosynthesis, galactose metabolism, and nitrogen metabolism, highlighting their role in the crab's intestinal response. Enzymatic analysis revealed a decrease in activities of hexokinase, phosphofructokinase, and pyruvate kinase, which are essential for energy homeostasis and ATP production necessary for stress responses. Additionally, reductions were observed in the activities of acetyl-CoA carboxylase and fatty acid synthase. Gene expression analysis showed downregulation in Peroxiredoxin 1 (PRDX1), Peroxiredoxin 2 (PRDX2), glutathione-S-transferase (GST), catalase (CAT), and glutathione (GSH), with concurrent increases in malondialdehyde (MDA) levels, indicating severe oxidative stress. This study provides insights into the molecular strategies employed by marine crabs to counteract bacterial invasions in their natural habitat.
Topics: Aeromonas hydrophila; Animals; Immunity, Innate; Brachyura; Gram-Negative Bacterial Infections; Metabolomics; Gastrointestinal Microbiome; Microbiota
PubMed: 38718732
DOI: 10.1016/j.cbd.2024.101240 -
Aquatic Toxicology (Amsterdam,... Jun 2024Excessive antibiotic use has led to the spread of antibiotic resistance genes (ARGs), impacting gut microbiota and host health. However, the effects of antibiotics on...
Metagenomic and transcriptomic analysis revealing the impact of oxytetracycline and ciprofloxacin on gut microbiota and gene expression in the Chinese giant salamander (Andrias davidianus).
Excessive antibiotic use has led to the spread of antibiotic resistance genes (ARGs), impacting gut microbiota and host health. However, the effects of antibiotics on amphibian populations remain unclear. We investigated the impact of oxytetracycline (OTC) and ciprofloxacin (CIP) on Chinese giant salamanders (Andrias davidianus), focusing on gut microbiota, ARGs, and gene expression by performing metagenome and transcriptome sequencing. A. davidianus were given OTC (20 or 40 mg/kg) or CIP (50 or 100 mg/kg) orally for 7 days. The results revealed that oral administration of OTC and CIP led to distinct changes in microbial composition and functional potential, with CIP treatment having a greater impact than OTC. Antibiotic treatment also influenced the abundance of ARGs, with an increase in fluoroquinolone and multi-drug resistance genes observed post-treatment. The construction of metagenome-assembled genomes (MAGs) accurately validated that CIP intervention enriched fish-associated potential pathogens Aeromonas hydrophila carrying an increased number of ARGs. Additionally, mobile genetic elements (MGEs), such as phages and plasmids, were implicated in the dissemination of ARGs. Transcriptomic analysis of the gut revealed significant alterations in gene expression, particularly in immune-related pathways, with differential effects observed between OTC and CIP treatments. Integration of metagenomic and transcriptomic data highlighted potential correlations between gut gene expression and microbial composition, suggesting complex interactions between the host gut and its gut microbiota in response to antibiotic exposure. These findings underscore the importance of understanding the impact of antibiotic intervention on the gut microbiome and host health in amphibians, particularly in the context of antibiotic resistance and immune function.
Topics: Animals; Oxytetracycline; Gastrointestinal Microbiome; Ciprofloxacin; Urodela; Anti-Bacterial Agents; Transcriptome; Metagenome; Metagenomics; Gene Expression Profiling; Water Pollutants, Chemical; Aeromonas hydrophila; Gene Expression Regulation
PubMed: 38718521
DOI: 10.1016/j.aquatox.2024.106925 -
Microbial Ecology May 2024Aeromonas hydrophila is an opportunistic motile pathogen with a broad host range, infecting both terrestrial and aquatic animals. Environmental and geographical...
Aeromonas hydrophila is an opportunistic motile pathogen with a broad host range, infecting both terrestrial and aquatic animals. Environmental and geographical conditions exert selective pressure on both geno- and phenotypes of pathogens. Flagellin, directly exposed to external environments and containing important immunogenic epitopes, may display significant variability in response to external conditions. In this study, we conducted a comparative analysis of ~ 150 A. hydrophila genomes, leading to the identification of six subunits of the flagellin gene (fla-1 to fla-4, flaA, and flaB). Individual strains harbored different composition of flagellin subunits and copies. The composition of subunits showed distinct patterns depending on environmental sources. Strains from aquatic environments were mainly comprised of fla-1 to fla-4 subunits, while terrestrial strains predominated in groups harboring flaA and flaB subunits. Each flagellin showed varying levels of expression, with flaA and flaB demonstrating significantly higher expression compared to others. One of the chemotaxis pathways that control flagellin movement through a two-component system was significantly upregulated in flaA(+ 1)/flaB(+ 1) group, whereas flaA and flaB showed different transcriptomic expressions. The genes positively correlated with flaA expression were relevant to biofilm formation and bacterial chemotaxis, but flaB showed a negative correlation with the genes in ABC transporters and quorum sensing pathway. However, the expression patterns of fla-2 to fla-4 were identical. This suggests various types of flagellin subunits may have different biological functions. The composition and expression levels of flagellin subunits could provide valuable insights into the adaptation of A. hydrophila and the differences among strains in response to various external environments.
Topics: Flagellin; Aeromonas hydrophila; Transcriptome; Phylogeography; Adaptation, Physiological; Phylogeny; Biofilms
PubMed: 38695873
DOI: 10.1007/s00248-024-02373-4 -
Journal of Microbiology and... Jun 2024The environment has been identified as an origin, reservoir, and transmission route of antibiotic resistance genes (ARGs). Among diverse environments, freshwater...
The environment has been identified as an origin, reservoir, and transmission route of antibiotic resistance genes (ARGs). Among diverse environments, freshwater environments have been recognized as pivotal in the transmission of ARGs between opportunistic pathogens and autochthonous bacteria such as spp. In this study, five environmental strains of spp. exhibiting multidrug resistance (MDR) were selected for whole-genome sequencing to ascertain their taxonomic assignment at the species-level and to delineate their ARG repertoires. Analyses of their genomes revealed the presence of one protein almost identical to AhQnr ( Qnr protein) and four novel proteins similar to AhQnr. To scrutinize the classification and taxonomic distribution of these proteins, all genomes deposited in the NCBI RefSeq genome database (1,222 genomes) were investigated. This revealed that these Qnr (AQnr) proteins are conserved intrinsic resistance determinants of the genus, exhibiting species-specific diversity. Additionally, structure prediction and analysis of contribution to quinolone resistance by AQnr proteins of the isolates, confirmed their functionality as quinolone resistance determinants. Given the origin of mobile genes from aquatic bacteria and the crucial role of spp. in ARG dissemination in aquatic environments, a thorough understanding and strict surveillance of AQnr families prior to the clinical emergence are imperative. In this study, using comparative genome analyses and functional characterization of AQnr proteins in the genus , novel ARGs requiring surveillance has suggested.
Topics: Aeromonas; Quinolones; Bacterial Proteins; Anti-Bacterial Agents; Whole Genome Sequencing; Phylogeny; Genome, Bacterial; Microbial Sensitivity Tests; Drug Resistance, Multiple, Bacterial; Drug Resistance, Bacterial
PubMed: 38693047
DOI: 10.4014/jmb.2403.03043 -
Open Veterinary Journal Mar 2024() is a bacterium with zoonotic potential and is multidrug-resistant. It utilizes hemolysin and aerolysin to spread infection. Black soldier flies (BSFs) can be...
BACKGROUND
() is a bacterium with zoonotic potential and is multidrug-resistant. It utilizes hemolysin and aerolysin to spread infection. Black soldier flies (BSFs) can be antibacterial because of the fatty acids it contains.
AIMS
This study aimed to investigate and compare the fatty acid profiles of BSF prepupae grown in fermented and nonfermented media using bioinformatics tools and assess their potential as antibacterial agents against .
METHODS
The study used BSF prepupae reared on various organic substrates. BSF prepupae grown in fermented or nonfermented substrate were observed against fatty acid. The fatty acid analysis was performed using GC-MS. Fatty acids were analyzed statistically using the one-way ANOVA test with a 95% confidence level. Fatty acid bioactivity was predicted using the online PASS-two-way drug program. Molecular docking on BSF fatty acid compounds was analyzed with PyMol 2.2 and discovery Studio version 21.1.1.
RESULTS
The molecular docking test showed the strongest bond was oleic acid with aerolysin and linoleic acid with hemolysin. BSF prepupae grown on fermented media showed higher crude fat and saturated fatty acids (SFAs) but lower unsaturated fatty acids than nonfermented media.
CONCLUSION
Black soldier fly prepupae, particularly those grown on fermented media, possess antibacterial activity against through potential fatty acid-mediated inhibition of crucial virulence factors.
Topics: Aeromonas hydrophila; Animals; Fatty Acids; Fermentation; Computational Biology; Anti-Bacterial Agents; Diptera; Hemolysin Proteins; Larva; Molecular Docking Simulation
PubMed: 38682129
DOI: 10.5455/OVJ.2024.v14.i3.18 -
Microbiological Research Jul 2024Aeromonas veronii, a significant pathogen in aquatic environments, poses a substantial threat to both human and animal health, particularly in aquaculture. In this...
Complete genome sequence and genome-wide transposon mutagenesis enable the determination of genes required for sodium hypochlorite tolerance and drug resistance in pathogen Aeromonas veronii GD2019.
Aeromonas veronii, a significant pathogen in aquatic environments, poses a substantial threat to both human and animal health, particularly in aquaculture. In this study, we isolated A. veronii strain GD2019 from diseased largemouth bass (Micropterus salmoides) during a severe outbreak of aeromonad septicemia in Guangdong Province, China. The complete genome sequence of A. veronii GD2019 revealed that GD2019 contains a single chromosome of 4703,168 bp with an average G+C content of 58.3%. Phylogenetic analyses indicated that GD2019 forms a separate sub-branch in A. veronii and comparative genomic analyses identified the existence of an intact Type III secretion system. Moreover, to investigate the genes that are required for the conditional fitness of A. veronii under various stresses, a high-density transposon insertion library in GD2019 was generated by a Tn5-based transposon and covers 6311 genomic loci including 4155 genes and 2156 intergenic regions. Leveraging this library, 630 genes were classified as essential genes for growth in rich-nutrient LB medium. Furthermore, the genes GE001863/NtrC and GE002550 were found to confer tolerance to sodium hypochlorite in A. veronii. GE002562 and GE002614 were associated with the resistance to carbenicillin. Collectively, our results provide abundant genetic information on A. veronii, shedding light on the pathogenetic mechanisms of Aeromonas.
Topics: Aeromonas veronii; DNA Transposable Elements; Genome, Bacterial; Animals; Phylogeny; Whole Genome Sequencing; Sodium Hypochlorite; Drug Resistance, Bacterial; Fish Diseases; China; Gram-Negative Bacterial Infections; Bass; Anti-Bacterial Agents; Base Composition; Mutagenesis, Insertional
PubMed: 38653011
DOI: 10.1016/j.micres.2024.127731