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Animals : An Open Access Journal From... Mar 2024is a pathogen that severely affects aquatic animals, including the snakehead, . Lytic bacteriophages have been recognized as effective alternatives to antibiotics for...
is a pathogen that severely affects aquatic animals, including the snakehead, . Lytic bacteriophages have been recognized as effective alternatives to antibiotics for controlling bacterial infections. However, there have been no reports of phages as far as we know. In this study, a lytic bacteriophage SD04, which could effectively infect , was isolated from pond water cultured with diseased snakehead. The SD04 phage formed small, round plaques on Petri dishes. Electron microscopy revealed a hexagonal head and a contractile tail. Based on its morphology, it may belong to the Myoviridae family. Two major protein bands with molecular weights of 50 and 38 kilodaltons were observed after the phage was subjected to SDS-PAGE. The phage showed a large average burst size, high specificity, and a broad host range. When stored at 4 °C, phage SD04 had high stability over 12 months and showed almost no variation within the first six months. All fish were healthy after both intraperitoneal injection and immersion administration of SD04, indicating the safety of the phage. After treatment with SD04, in both phage therapy groups and prevention groups showed high survival rates (i.e., 83.3 ± 3.3% and 100 ± 1.3%, respectively). Phage therapy inhibits bacterial growth in the liver, the target organ of the infected . The experimental results indicate the potential use of phage SD04 for preventing infection in .
PubMed: 38540055
DOI: 10.3390/ani14060957 -
Frontiers in Immunology 2022β-glucan is widely used in aquaculture due to its immunostimulatory effects, but the specific effect and potential regulatory mechanism on largemouth bass () are still...
β-glucan is widely used in aquaculture due to its immunostimulatory effects, but the specific effect and potential regulatory mechanism on largemouth bass () are still unclear. Here, we evaluated the effects of β-glucan on growth, resistance to , intestinal health, and transcriptome of largemouth bass to reveal the potential regulators, metabolic pathways, and altered differential microbiota. Four experimental diets were designed with β-glucan supplementation levels of 0 (control), 100 (LA-100), 200 (MA-200), and 300 (HA-300) mg kg, and each diet was fed to largemouth bass (79.30 ± 0.50 g) in triplicate for 70 days, followed by a 3-day challenge experiment. Results showed that different β-glucan supplementations had no significant effects on growth performance and whole-body composition. Fish fed a diet with 300 mg kg β-glucan significantly increased the activity of lysozyme than those fed diets with 0 and 100 mg kg β-glucan. In addition, the survival rate of largemouth bass in β-glucan supplementation groups was significantly higher than the control group at 12- and 24-h challenge by . Transcriptome analysis showed that a total of 1,245 genes were differentially expressed [|log(fold change)| ≥1, -value ≤0.05], including 109 immune-related differentially expressed genes (DEGs). Further analysis revealed that significantly upregulated and downregulated DEGs associated with immunity were mapped into 12 and 24 pathways, respectively. Results of intestinal microflora indicated that fish fed a diet with 300 mg kg β-glucan had higher bacterial richness and diversity as evaluated by Sobs, Chao, Ace, and Simpson indices, but no significant differences were found in the comparison groups. Furthermore, 300 mg kg β-glucan significantly increased the relative abundance of and decreased (mainly and ) and in largemouth bass intestinal microflora. The findings of this study provided new insights that will be valuable in future studies to elucidate the mechanism of immunity enhancement by β-glucan.
Topics: Animals; Transcriptome; Bass; Diet; Gene Expression Profiling
PubMed: 36591266
DOI: 10.3389/fimmu.2022.1086103 -
Veterinary World Jan 2022Antibiotic resistance has been a progressively documented problem, resulting in treatment failure in humans and animals. This study aimed to investigate the...
BACKGROUND AND AIM
Antibiotic resistance has been a progressively documented problem, resulting in treatment failure in humans and animals. This study aimed to investigate the antimicrobial susceptibility and virulence of extensively drug-resistant (XDR) spp. in wild and its surrounding seawater along the coastal road of Port Said, Egypt.
MATERIALS AND METHODS
Specimens were examined bacteriologically, confirmed biochemically, and tested for their sensitivity against 11 antimicrobial agents. Molecular confirmation of the obtained isolates by was performed, followed by the detection of antimicrobial resistance and virulence genes.
RESULTS
spp. was recovered from fish (44%) and water samples (36%). was the most prevalent identified strain, followed by , , and . Moreover, 90% of the tested isolates were multidrug-resistant (MDR), while 26.67% were XDR. Tested isolates were resistant to b-lactams and sulfonamides (100%), oxytetracycline (90%), and streptomycin (62.22%) but completely susceptible to cefotaxime. XDR isolates successfully amplified resistance genes (, and ()) but not the () gene, although there was phenotypic resistance to streptomycin on plates. All XDR isolates carry the cytotoxic enterotoxin gene (), but gene was detected in only one isolate (12.5%).
CONCLUSION
Data in this study provide a recent update and highlight the role of wild mullet and seawater as reservoirs for MDR and XDR spp. that may pose a risk to humans as food-borne infection or following direct contact.
PubMed: 35369605
DOI: 10.14202/vetworld.2022.55-64 -
Microbiology Resource Announcements Jan 2022Aeromonas schubertii is a Gram-negative, rod-shaped bacterium. It is a rare species that has been reported in humans and aquatic animals. Here, we report the genome...
Aeromonas schubertii is a Gram-negative, rod-shaped bacterium. It is a rare species that has been reported in humans and aquatic animals. Here, we report the genome sequences of A. schubertii strains isolated from two mass mortality events in central Thailand that were associated with aquaculture of Asian seabass.
PubMed: 34989613
DOI: 10.1128/mra.01007-21 -
Pathogens (Basel, Switzerland) Aug 2021is the etiological pathogen of internal organ nodules in snakehead fish. Infections with produce a significant economic loss in aquaculture. Therefore, it is important...
is the etiological pathogen of internal organ nodules in snakehead fish. Infections with produce a significant economic loss in aquaculture. Therefore, it is important to examine the immune mechanisms by which snakeheads defend against infection. In this study, we established a hybrid snakehead infection model by intraperitoneal injection of that produced internal organ nodules. The splenic immune response of infected fish was examined at the transcriptome level by Illumina-seq analysis. Results showed 14,796 differentially expressed genes (DEGs) following infection, including 4441 up-regulated unigenes and 10,355 down-regulated unigenes. KEGG analysis showed 2084 DEGs to be involved in 192 pathways, 14 of which were immune-related. Twelve DEGs were used to validate quantitative real-time PCR results with RNA-seq data. Time-course expression analysis of six genes demonstrated modulation of the snakehead immune response by Furthermore, transcriptome analysis identified a substantial number of DEGs that were involved in the apoptosis signaling pathway. TUNEL analysis of infected spleens confirmed the presence of apoptotic cells. This study provided new information for a further understanding of the pathogenesis of in snakeheads, which can be used to prevent and possibly treat infections.
PubMed: 34451461
DOI: 10.3390/pathogens10080997 -
Frontiers in Public Health 2021Aeromonads are aquatic bacteria associated with frequent outbreaks of diarrhea in coastal Bangladesh, but their potential risks from environmental sources have remained...
Aeromonads are aquatic bacteria associated with frequent outbreaks of diarrhea in coastal Bangladesh, but their potential risks from environmental sources have remained largely unexplored. This study, over 2 years, examined homestead pond waters in the region for monthly dynamics and diversity of spp. The bacterial counts showed bi-modal annual growth peak, pre- and post-monsoon, strongly correlating ( < 0.0005) with temperature. Of 200 isolates characterized, bv. sobria (27%) was predominant among co-existent (20%), (17%), (13%), and three more. PCR screening of virulence-related genes identified 15 genotypes (I to XV), however, enterotoxigenicity in animal model was observed for five genotypes, ca. 18% (nine of 50) strains, prevalent in bv. sobria, , and . Pathogenic strains were distinguishable by possessing at least three of the major virulence genes: , and , together with accessory virulence factors. PFGE of I-digested genomic DNA revealed high genetic diversity and distant lineage of potentially toxigenic clones. Therefore, along with increased global warming, spp. having multi-factorial virulence potential in coastal ponds that serve as drinking water sources pose a potential health risk, and underscores the need for routine monitoring.
Topics: Aeromonas; Animals; Bangladesh; Ponds; Virulence; Water
PubMed: 34307285
DOI: 10.3389/fpubh.2021.692166 -
Genome Announcements Feb 2016We sequenced the complete genome of the type strain of Aeromonas schubertii, ATCC 43700. The full genome sequence of A. schubertii ATCC 43700 is 4,356,858 bp, which...
We sequenced the complete genome of the type strain of Aeromonas schubertii, ATCC 43700. The full genome sequence of A. schubertii ATCC 43700 is 4,356,858 bp, which encodes 3,842 proteins and contains 110 predicted RNA genes.
PubMed: 26893413
DOI: 10.1128/genomeA.00012-16 -
Genome Announcements Jan 2016We sequenced the complete genome of the highly virulent Aeromonas schubertii strain WL1483, which was isolated from diseased snakehead fish (Channa argus) in China. The...
We sequenced the complete genome of the highly virulent Aeromonas schubertii strain WL1483, which was isolated from diseased snakehead fish (Channa argus) in China. The full genome sequence of A. schubertii WL1483 is 4,400,034 bp, which encodes 4,376 proteins and contains 195 predicted RNA genes.
PubMed: 26798095
DOI: 10.1128/genomeA.01567-15