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Microbiology Spectrum Apr 2024, an aquatic pathogenic bacterium, has been found to infect many fish species and cause huge aquaculture losses. Antibiotics are the most common drugs used to treat...
, an aquatic pathogenic bacterium, has been found to infect many fish species and cause huge aquaculture losses. Antibiotics are the most common drugs used to treat these infections. However, antibiotic abuse can lead to the development of antibiotic resistance. Probiotics have the potential to replace antibiotics for preventing infections. Zebrafish () is a model organism used to study the innate immune system and host-pathogen interactions. Currently, there is little information on how the fish immune system responds to and probiotic treatment. To increase the understanding of the molecular mechanisms behind the zebrafish defense against and provide evidence that antibiotics can be replaced by probiotics, a transcriptome analysis of the zebrafish spleen was conducted 48 hours after infection by , as well as after treatment using KUST48 4 hours after infection. A total of 36,499 genes were obtained. There were 3,337 genes found to have significant differential expression between treatment and control groups. According to further annotation and enrichment analysis, differentially expressed genes (DEGs) were involved in signal transduction, endocrine system cancer, and the immune system. Insulin resistance disappeared in the zebrafish after treatment. Quantitative real-time PCR was performed to confirm the significant regulation of immune defense DEGs, the results of which were consistent with the RNA-sequencing data. These results could serve as a basis for future studies on the immune response to and provide suggestions for probiotic alternatives to antibiotics, which will be of great significance to aquaculture and environmental protection.IMPORTANCEIn recent years, the unreasonable use of antibiotics has led to the emergence of drug-resistant pathogenic bacteria, antibiotic residues, cross infection, toxic side effects, and so on, which has caused a serious threat to human food safety and life health. In recent years, many studies have demonstrated the potential of probiotics as a substitute for antibiotics, but there is still a lack of understanding of the molecular mechanisms underlying probiotic therapy. We conduct a research on the impact of KUST48 on the transcription profile of -infected zebrafish spleen. Mortality of zebrafish infected with was significantly reduced after treatment with KUST48. Our results can help to strengthen our understanding of the pathogenic mechanisms of zebrafish and provide a valuable reference for the molecular mechanisms of probiotic therapy.
Topics: Animals; Humans; Zebrafish; Aeromonas hydrophila; Lactococcus lactis; Spleen; Anti-Bacterial Agents; Gram-Negative Bacterial Infections; Fish Diseases
PubMed: 38441470
DOI: 10.1128/spectrum.03927-23 -
Antimicrobial Resistance and Infection... Mar 2024Aeromonas hydrophila infections can cause gastrointestinal symptoms such as diarrhea; however, deep infections are rarely reported. Outbreaks of A. hydrophila are...
BACKGROUND
Aeromonas hydrophila infections can cause gastrointestinal symptoms such as diarrhea; however, deep infections are rarely reported. Outbreaks of A. hydrophila are reported more frequently in fish, poultry, and snakes than in humans. This study aimed to track clonal relatedness of deep infections caused by A. hydrophila using whole genome sequencing (WGS).
METHODS
We collected three isolates of A. hydrophila in July 19 to August 29, 2019, from patients that underwent spine surgery. Accurate species identification was performed using whole-genome average nucleotide identity (ANI). Antimicrobial susceptibility testing was performed using a VITEK 2 automated AST-N334 Gram-negative susceptibility card system. Antimicrobial resistance and virulence genes were identified using the Comprehensive Antibiotic Resistance Database and Virulence Factor Database VFanalyzer.
RESULTS
All three isolates were identified as A. hydrophila based on ANI and multilocus sequence typing analysis revealed that A. hydrophila belonged to a novel sequence type (ST1172). All three isolates were susceptible to amikacin and levofloxacin; however, they were resistant to piperacillin/tazobactam, ceftriaxone, cefuroxime, cefoxitin, and imipenem. Isolate 19W05620 (patient 3) showed increased ceftazidime resistance (minimum inhibitory concentration ≥ 64 µg/mL). All three isolates possessed the same chromosomally encoded β-lactamases, including bla (β-lactamase), imiH (metallo-β-lactamase), and bla (AmpC) in plasmids.
CONCLUSIONS
Our study validated the transmission of a novel carbapenem-resistant A. hydrophila sequence type (ST1172) in patients that underwent spine surgery. Control measures should be developed to prevent dissemination of A. hydrophila in the hospital setting.
Topics: Animals; Humans; Aeromonas hydrophila; Amikacin; Carbapenems; beta-Lactamases; Anti-Infective Agents
PubMed: 38433212
DOI: 10.1186/s13756-023-01339-4 -
PloS One 2024The rapid and accurate detection of pathogenic bacteria is essential for food safety and public health. Conventional detection techniques, such as nucleic acid...
The rapid and accurate detection of pathogenic bacteria is essential for food safety and public health. Conventional detection techniques, such as nucleic acid sequence-based amplification and polymerase chain reaction, are time-consuming and require specialized equipment and trained personnel. Here, we present quick, disposable impedance sensors based on the novel hybrid MoS2 nanomaterial for detecting Escherichia coli DNA. Our results indicate that the proposed sensors operate linearly between 10- 20 and 10-15 M concentrations, achieving an impressive detection limit of 10-20 M with the highest sensitivity observed at a 0.325 nM probe concentration sensor. Furthermore, the electrochemical impedance spectroscopy biosensors exhibited potential selectivity for Escherichia coli DNA over Bacillus subtilis and Vibrio proteolyticus DNA sequences. The findings offer a promising avenue for efficient and precise DNA detection, with potential implications for broader biotechnology and medical diagnostics applications.
Topics: Electric Impedance; Molybdenum; Aeromonas hydrophila; DNA; Escherichia coli; Biosensing Techniques; Electrochemical Techniques
PubMed: 38422053
DOI: 10.1371/journal.pone.0299272 -
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 -
BMC Veterinary Research Jun 2024The liver-expressed antimicrobial peptide 2 (LEAP2) plays a pivotal role in the host's immune response against pathogenic microorganisms. Numerous such antimicrobial...
BACKGROUND
The liver-expressed antimicrobial peptide 2 (LEAP2) plays a pivotal role in the host's immune response against pathogenic microorganisms. Numerous such antimicrobial peptides have recently been shown to mitigate infection risk in fish, and studying those harboured by the economically important fish Acrossocheilus fasciatus is imperative for enhancing its immune responses against pathogenic microorganisms. In this study, we cloned and sequenced LEAP2 cDNA from A. fasciatus to examine its expression in immune tissues and investigate the structure-activity relationships of its intramolecular disulphide bonds.
RESULTS
The predicted amino acid sequence of A. fasciatus LEAP2 was found to include a signal peptide, pro-domain, and mature peptide. Sequence analysis indicated that A. fasciatus LEAP2 is a member of the fish LEAP2A cluster and is closely related to Cyprinus carpio LEAP2A. A. fasciatus LEAP2 transcripts were expressed in various tissues, with the head kidney exhibiting the highest mRNA levels. Upon exposure to Aeromonas hydrophila infection, LEAP2 expression was significantly upregulated in the liver, head kidney, and spleen. A mature peptide of A. fasciatus LEAP2, consisting of two disulphide bonds (Af-LEAP2-cys), and a linear form of the LEAP2 mature peptide (Af-LEAP2) were chemically synthesised. The circular dichroism spectroscopy result shows differences between the secondary structures of Af-LEAP2 and Af-LEAP2-cys, with a lower proportion of alpha helix and a higher proportion of random coil in Af-LEAP2. Af-LEAP2 exhibited potent antimicrobial activity against most tested bacteria, including Acinetobacter guillouiae, Pseudomonas aeruginosa, Staphylococcus saprophyticus, and Staphylococcus warneri. In contrast, Af-LEAP2-cys demonstrated weak or no antibacterial activity against the tested bacteria. Af-LEAP2 had a disruptive effect on bacterial cell membrane integrity, whereas Af-LEAP2-cys did not exhibit this effect. Additionally, neither Af-LEAP2 nor Af-LEAP2-cys displayed any observable ability to hydrolyse the genomic DNA of P. aeruginosa.
CONCLUSIONS
Our study provides clear evidence that linear LEAP2 exhibits better antibacterial activity than oxidised LEAP2, thereby confirming, for the first time, this phenomenon in fish.
Topics: Animals; Structure-Activity Relationship; Amino Acid Sequence; Fish Diseases; Antimicrobial Peptides; Fish Proteins; Disulfides; Phylogeny; Aeromonas hydrophila; Base Sequence
PubMed: 38835040
DOI: 10.1186/s12917-024-04106-8 -
Parasites & Vectors May 2024Culex pipiens pallens is a well-known mosquito vector for several diseases. Deltamethrin, a commonly used pyrethroid insecticide, has been frequently applied to manage...
BACKGROUND
Culex pipiens pallens is a well-known mosquito vector for several diseases. Deltamethrin, a commonly used pyrethroid insecticide, has been frequently applied to manage adult Cx. pipiens pallens. However, mosquitoes can develop resistance to these insecticides as a result of insecticide misuse and, therefore, it is crucial to identify novel methods to control insecticide resistance. The relationship between commensal bacteria and vector resistance has been recently recognized. Bacteriophages (= phages) are effective tools by which to control insect commensal bacteria, but there have as yet been no studies using phages on adult mosquitoes. In this study, we isolated an Aeromonas phage vB AhM-LH that specifically targets resistance-associated symbiotic bacteria in mosquitoes. We investigated the impact of Aeromonas phage vB AhM-LH in an abundance of Aeromonas hydrophila in the gut of Cx. pipiens pallens and its effect on the status of deltamethrin resistance.
METHODS
Phages were isolated on double-layer agar plates and their biological properties analyzed. Phage morphology was observed by transmission electron microscopy (TEM) after negative staining. The phage was then introduced into the mosquito intestines via oral feeding. The inhibitory effect of Aeromonas phage vB AhM-LH on Aeromonas hydrophila in mosquito intestines was assessed through quantitative real-time PCR analysis. Deltamethrin resistance of mosquitoes was assessed using WHO bottle bioassays.
RESULTS
An Aeromonas phage vB AhM-LH was isolated from sewage and identified as belonging to the Myoviridae family in the order Caudovirales using TEM. Based on biological characteristics analysis and in vitro antibacterial experiments, Aeromonas phage vB AhM-LH was observed to exhibit excellent stability and effective bactericidal activity. Sequencing revealed that the Aeromonas phage vB AhM-LH genome comprises 43,663 bp (51.6% CG content) with 81 predicted open reading frames. No integrase-related gene was detected in the vB AH-LH genome, which marked it as a potential biological antibacterial. Finally, we found that Aeromonas phage vB AhM-LH could significantly reduce deltamethrin resistance in Cx. pipiens pallens, in both the laboratory and field settings, by decreasing the abundance of Aeromonas hydrophila in their midgut.
CONCLUSIONS
Our findings demonstrate that Aeromonas phage vB AhM-LH could effectively modulate commensal bacteria Aeromonas hydrophila in adult mosquitoes, thus representing a promising strategy to mitigate mosquito vector resistance.
Topics: Animals; Aeromonas hydrophila; Culex; Bacteriophages; Insecticide Resistance; Pyrethrins; Nitriles; Insecticides; Mosquito Vectors; Female
PubMed: 38745242
DOI: 10.1186/s13071-024-06281-x -
BMC Veterinary Research May 2024Moringa oleifera, a well-known medicinal plant, has been used in aquafeed as a dietary supplement. Based on previous studies, insufficient research is available on the...
Immunomodulatory, antioxidant, and growth-promoting activities of dietary fermented Moringa oleifera in Nile tilapia (Oreochromus niloticus) with in-vivo protection against Aeromonas hydrophila.
BACKGROUND
Moringa oleifera, a well-known medicinal plant, has been used in aquafeed as a dietary supplement. Based on previous studies, insufficient research is available on the dietary supplementation of Nile tilapia with M. oleifera leaf and seed mixtures, specifically the fermented form. Therefore, this study aimed to investigate the efficacy of fermented (FMO) versus non-fermented M. oleifera (MO) leaf and seed mixtures on immunological parameters, antioxidant activity, growth performance, and resistance to A. hydrophila infection after a 30-day feeding trial on Nile tilapia.
METHODS
A total of 180 fingerlings were randomly divided into four groups in addition to the control group (36 fish each, in triplicate). Fish in the tested groups were fed on basal diet supplemented with MO5%, MO10%, FMO5%, and FMO10%, while those in control were fed on basal diet only. After the feeding trial, fish were challenged with A. hydrophila. The immunomodulatory activity of M. oleifera was evaluated in terms of phagocytic and lysozyme activities, immune-related cytokines and IgM gene expression. Antioxidants, and growth-promoting activities were also assessed.
RESULTS
The results revealed that fish supplemented FMO markedly in FMO10% group followed by FMO5%, exhibited significant (P < 0.05) improvement in the tested immunological, hepatic antioxidants, and growth performance parameters. Furthermore, the highest survival rate post-challenge with mild clinical symptoms, and the lowest A. hydrophila bacterial count were reported in these groups. Meanwhile, MO10%-supplementation exhibited the opposite trend.
CONCLUSIONS
The study' conclusion suggests that fermented M. oleifera leaf and seed mixture is a promising growth-promoting and immunostimulatory feed-additive candidate for Nile tilapia and could reduce the losses caused by A. hydrophila infection.
Topics: Animals; Moringa oleifera; Aeromonas hydrophila; Cichlids; Gram-Negative Bacterial Infections; Antioxidants; Animal Feed; Fish Diseases; Diet; Dietary Supplements; Plant Leaves; Fermentation; Seeds
PubMed: 38802892
DOI: 10.1186/s12917-024-04070-3 -
Scientific Reports Apr 2024This study was divided into two parts. The first part involved the isolation, and detection of the prevalence and antimicrobial resistance profile of Aeromonas...
This study was divided into two parts. The first part involved the isolation, and detection of the prevalence and antimicrobial resistance profile of Aeromonas hydrophila, Pseudomonas aeruginosa, and Vibrio species from Nile tilapia fish and marine aquatic water. One hundred freshly dead Nile tilapia fish were collected from freshwater aquaculture fish farms located in Al-Abbassah district, Sharkia Governorate, and 100 samples of marine aquatic water were collected from fish farms in Port Said. The second part of the study focused on determining the in vitro inhibitory effect of dual-combination of AgNPs-H2O2 on bacterial growth and its down regulatory effect on crucial virulence factors using RT-PCR. The highest levels of A. hydrophila and P. aeruginosa were detected in 43%, and 34% of Nile tilapia fish samples, respectively. Meanwhile, the highest level of Vibrio species was found in 37% of marine water samples. Additionally, most of the isolated A. hydrophila, P. aeruginosa and Vibrio species exhibited a multi-drug resistance profile. The MIC and MBC results indicated a bactericidal effect of AgNPs-H2O2. Furthermore, a transcriptional modulation effect of AgNPs-H2O2 on the virulence-associated genes resulted in a significant down-regulation of aerA, exoU, and trh genes in A. hydrophila, P. aeruginosa, and Vibrio spp., respectively. The findings of this study suggest the effectiveness of AgNPs-H2O2 against drug resistant pathogens related to aquaculture.
Topics: Animals; Hydrogen Peroxide; Silver; Fisheries; Metal Nanoparticles; Anti-Bacterial Agents; Cichlids; Pseudomonas aeruginosa; Water; Fish Diseases; Aeromonas hydrophila
PubMed: 38575637
DOI: 10.1038/s41598-024-58349-4 -
Fish Physiology and Biochemistry Aug 2023In this study, the effects of Coriandrum sativum to control Aeromonas veronii infection in Oreochromis niloticus were determined. Coriandrum sativum extract (CE) was...
Therapeutic efficacy of coriander (Coriandrum sativum) enriched diets in Oreochromis niloticus: effect on hepatic-renal functions, the antioxidant-immune response and resistance to Aeromonas veronii.
In this study, the effects of Coriandrum sativum to control Aeromonas veronii infection in Oreochromis niloticus were determined. Coriandrum sativum extract (CE) was tested in vitro against A. veronii by the disc diffusion assay. In in vivo, 150 O. niloticus (from El-Abbassa, Sharkia, Egypt, weighing 34.95 ± 1.98 g) was distributed in five groups (with three replications) in glass aquariums (80 × 40 × 30 cm). The first group (control) was intraperitoneally injected with 0.2 ml of sterilized tryptic soya broth. Groups 2-5 were intraperitoneally challenged with 0.2 ml of A. veronii (4.3 × 10). The five groups were administered a basal diet until clinical signs appeared, and then therapeutic feeding (15 days) was followed: the first (CONT) and second (AV) groups were administered a normal basal diet. The third (AV+CP) and fourth (AV+CE) groups were administered diets supplemented with C. sativum powder and extract, respectively, each at 30 mg/kg. The fifth group (AV+OT) was administered a diet supplemented with oxytetracycline at 500 mg/kg diet. The results of the in vitro experiment revealed that CE has a zone of inhibition of 43 mm against A. veronii. The in vivo results showed that fish administered a therapeutic diet supplemented with CE showed a significant improvement in hematological, biochemical, and immunological parameters, as well as antioxidant capacity (P < 0.05) and the pathological findings of the liver and kidney tissues. The current findings supported that the administration of a CE-enriched diet (30 mg/kg) is an eco-friendly strategy for controlling A. veronii in O. niloticus.
Topics: Animals; Antioxidants; Aeromonas veronii; Coriandrum; Cichlids; Diet; Dietary Supplements; Disease Resistance; Kidney; Fish Diseases; Animal Feed; Gram-Negative Bacterial Infections
PubMed: 37438674
DOI: 10.1007/s10695-023-01220-6 -
Open Veterinary Journal Jan 2024Organic selenium (Sel-Plex) supplementation holds considerable promise for improving the effectiveness of fish production.
Impact of Sel-Plex dietary supplementation on growth performance, physiological response, oxidative status, and immunity-linked gene expression in Nile tilapia () fingerlings challenged with .
BACKGROUND
Organic selenium (Sel-Plex) supplementation holds considerable promise for improving the effectiveness of fish production.
AIM
This experiment was accomplished to judge the potential benefits of Sel-Plex nutritional additive on growth outcomes, physiological response, oxidative status, and immunity-linked gene expression in Nile tilapia () fingerlings exposed to bacterial infection with .
METHODS
Utilizing a basal diet of 30% protein, four experimental diets were prepared, each of which contained Sel-Plex at concentrations of 0.0, 0.5, 1, and 2 mg/kg, respectively. Three replicates of 20 fish/treatment were used using 240 healthy Nile tilapia fingerlings. Fish were placed in 12 glass aquariums and separated into 4 groups at random. For the entire span of 8 weeks, diets were admitted to fish at a 3% rate of fish biomass/aquarium. After the feeding trial, pathogenic was intraperitoneally injected into fish of each treatment, and fish were observed for 15 days to track the survival rate (SR) after the challenge.
RESULTS
Growth performance, physiological response, immunological parameters (phagocytic activity, phagocytic index, and lysozyme), and antioxidant parameters [catalase, superoxide dismutase (SOD), malondialdehyde, and glutathione peroxidase (GPx)] were noticeably improved in Sel-Plex treated groups. Moreover, Sel-Plex increased gene expression linked with the immune system in the liver (tumor necrosis factor-alpha and interleukin 1β), to growth (insulin-like growth factor 1 and growth hormone receptor), and antioxidants (SOD and GPx). Under pathogen-challenge conditions, the employed dietary Sel-Plex supplementation could successfully lower fish oxidative stress, offering a potential preventive additive for Nile tilapia instead of antibiotics. On the other hand, Sel-Plex significantly enhanced each of three intestinal morphological measurements (villus width, villus length, and crypt depth), demonstrating the greatest influence on the improvement of intestinal structure overall. In the Nile tilapia control group, the infection with caused noticeable degenerative alterations in the gut, hepatopancreas, spleen, and posterior kidney. The severity of the lesion was significantly reduced and significantly improved with higher Sel-Plex concentrations. Sel-Plex supplemented groups had 100% SRs among the -challenged groups.
CONCLUSION
It could be advised to enrich the diets of Nile tilapia fingerlings with 1-2 mg.kg of Sel-Plex to enhance growth rate, physiological response, immunological reaction, and intestinal absorptive capacity.
Topics: Animals; Aeromonas hydrophila; Cichlids; Disease Resistance; Gram-Negative Bacterial Infections; Dietary Supplements; Antioxidants; Superoxide Dismutase; Oxidative Stress; Gene Expression
PubMed: 38633150
DOI: 10.5455/OVJ.2024.v14.i1.8