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Microorganisms Mar 2024is widespread in aquatic environments and is responsible for infecting various aquatic animals. In this study, a dominant strain was isolated from the hepatopancreas of...
is widespread in aquatic environments and is responsible for infecting various aquatic animals. In this study, a dominant strain was isolated from the hepatopancreas of diseased and was named JDM1-1. According to its morphological, physiological, and biochemical characteristics and molecular identification, isolate JDM1-1 was identified as . The results of artificial challenge showed isolate JDM1-1 had high pathogenicity to with an LD value of 8.35 × 10 CFU/mL during the challenge test. Histopathological analysis revealed severe damage in the hepatopancreas and gills of the diseased prawns, characterized by the enlargement of the hepatic tubule lumen and gaps between the tubules as well as clubbing and degeneration observed at the distal end of the gill filament. Eight virulence-related genes, namely , , , , , , , and , were screened by PCR assay. In addition, virulence factor detection showed that the JDM1-1 isolate produced lipase, lecithinase, gelatinase, and hemolysin. Furthermore, the mRNA expression profiles of immune-related genes of following infection, including , , , and were assessed, and the results revealed a significant upregulation in the hepatopancreas and intestines at different hours post infection. This study demonstrates that is a causative agent associated with massive die-offs of and contributes valuable insights into the pathogenesis and host defense mechanisms of invasion.
PubMed: 38674638
DOI: 10.3390/microorganisms12040694 -
Journal of Applied Microbiology Mar 2023Aeromonas species are bacterial pathogens that cause significant economic losses in the aquaculture industry worldwide. They are widely distributed in aquatic... (Review)
Review
Aeromonas species are bacterial pathogens that cause significant economic losses in the aquaculture industry worldwide. They are widely distributed in aquatic environments and cause several diseases in both humans and aquatic animals. The presence of various virulent Aeromonas spp. in aquatic environments predisposes infections in aquatic animals and humans. Concern about the transfer of pathogens from fish to humans also increased with the substantial increase in seafood consumption. Aeromonas spp. are also primary human pathogens that cause local and systemic infections, both in immunologically compromised and immunologically competent hosts. The most common Aeromonas spp. causing infections in aquatic animals and humans are A. hydrophila, A. salmonicida, A. caviae, and A. veronii biotype sobria. The ability of Aeromonas spp. to produce a variety of virulence factors enhances their pathogenic ability. Literature has supplied evidence for the presence of various virulence factors, including proteases, enterotoxins, hemolysin, and toxin genes of Aeromonas spp. in aquatic environments. The high prevalence of Aeromonas spp. in the aquatic environment is also a threat to public health. Because the Aeromonas spp. infections in humans are generally the result of ingestion or exposure to contaminated food and water. This review summarizes the recently published information on various virulence factors and virulence genes of Aeromonas spp. isolated from various aquatic environments, including seawater, freshwater, wastewater, and drinking water. It is also intended to highlight the risks associated with Aeromonas species' virulence properties for both aquaculture and public health.
Topics: Animals; Humans; Aeromonas; Virulence; Virulence Factors; Fishes; Enterotoxins
PubMed: 36809788
DOI: 10.1093/jambio/lxad031 -
Microbial Pathogenesis Apr 2020Aeromonas veronii is an important zoonotic pathogen that causes significant economic losses in the aquaculture industry. The use of probiotics in aquaculture is a...
Aeromonas veronii is an important zoonotic pathogen that causes significant economic losses in the aquaculture industry. The use of probiotics in aquaculture is a practical alternative to antibiotics to promote animal health and aid in disease prevention. In the present study, we aimed to construct a recombinant Lactobacillus casei(surface-displayed or secretory) strain containing Malt from A. veronii TH0426 and assess its potential as an oral vaccine. A 1314-bp Malt gene fragment was successfully amplified and cloned into a prokaryotic protein expression system. Protein expression in resulting recombinant strains Lc-MCS-Malt (surface-displayed) and Lc-pPG-Malt (secretory) was then verified by Western blotting and indirect immunofluorescence. A single band was observed on the Western blots, with the molecular weight of the corresponding protein shown to be 48 kDa. Furthermore, a fluorescent signal for Lc-MCS-Malt was observed by fluorescence microscopy. At 0, 7, 16, 25, and 34 days post-immunization, tissue and blood samples were collected from common carp orally administered with the recombinant L. casei strains for immune-related index analyses. Treatment of common carp with the recombinant vaccine candidate stimulated high serum or skin mucus specific antibody titers and induced a higher lysozyme, ACP, SOD activity, while fish fed with Lc-pPG or PBS had no detectable immobilizing immune responses. Expression of IL-10, IL-1β, TNF-α, and IFN-γ genes in the group immunized with recombinant L. casei were significantly (P < 0.05) up regulated as compared with control groups, indicating that inflammatory response and cell immune response were triggered. Results also showed that recombinant L. casei could stimulate the mucosa through colonization of the intestine, resulting in increased transcription of IL-10, IL-1β, TNF-α, and IFN-γ. Immunity and colonization assays also showed that after 34 days of fasting, recombinant L. casei were still present in the intestines of the immunized fish. Common carp that received Lc-MCS-Malt(53.3%) and Lc-pPG-Malt (46.7%) exhibited higher survival rates than the controls after challenge with the pathogen A. veronii. Our findings suggested that recombinant L. casei can adequately protect fish and improve immunity, providing a theoretical basis for the future development of an oral Lactobacillus vaccine for use in aquaculture.
Topics: Aeromonas veronii; Animals; Bacterial Proteins; Bacterial Vaccines; Cloning, Molecular; Cytokines; Fish Diseases; Gene Expression; Immunity, Humoral; Immunization; Lacticaseibacillus casei; Leukocytes; Organ Specificity; Phagocytosis; Plasmids; Recombinant Proteins
PubMed: 31935441
DOI: 10.1016/j.micpath.2019.103918 -
Frontiers in Microbiology 2019species often cause disease in farmed fish. In the present study, dominant bacteria were isolated from diseased crucian carp (). Based on this, a bacterial isolate was...
species often cause disease in farmed fish. In the present study, dominant bacteria were isolated from diseased crucian carp (). Based on this, a bacterial isolate was tentatively named CFJY-623. This isolate was identified as based on analysis of its morphological, physiological, and biochemical features, as well as 16S rRNA and gene sequences. Six virulence genes related to pathogenicity including aerolysin, cytotonic enterotoxins, elastase, glycerophospholipid: cholesterol acyltransferase, lipase, and serine protease were identified in this isolate. The median lethal dosage (LD50) of the CFJY-623 isolate for crucian carp was determined as 1.31 × 10 CFU/mL. Artificial experimental infection showed that the CFJY-623 isolate caused considerable histological lesions in the fish, including tissue cell degeneration, necrosis, and inflammatory cell infiltrating. Drug sensitivity testing showed that the isolate was susceptible to aminoglycosides, carbapenemes, and nitrofurans. Exploring its growing features showed that this isolate exhibited a high level of environmental adaptability. These results provided a scientific basis for the identification of and treatment for fish infected by this pathogen.
PubMed: 32038507
DOI: 10.3389/fmicb.2019.02742 -
Antonie Van Leeuwenhoek Dec 2020In the study, Aeromonas strains (n = 12) were isolated from moribund grass carp fry reared in the cage culture unit from the Central Himalayan region of India. They...
Characterization and pathogenicity of Aeromonas veronii associated with mortality in cage farmed grass carp, Ctenopharyngodon idella (Valenciennes, 1844) from the Central Himalayan region of India.
In the study, Aeromonas strains (n = 12) were isolated from moribund grass carp fry reared in the cage culture unit from the Central Himalayan region of India. They were identified as Aeromonas veronii, by biochemically and 16S rRNA analysis. The experimental bath infection of grass carp fry was performed using A. veronii GCAFBLC 228, one of the 12 isolates at cell concentrations 10 and 10 CFU mL. The infected fry showed varied behavioural characteristics followed by tail rot, black pigmentation and hemorrhage in the body 48-96 h post infection. The post bath challenged demonstrated maximum mortality (23%) at cell concentration 10 CFU mL during 10 and 12th day. Histopathology revealed hypertrophy, hyperplasia, fusion of gill lamellae, detachment and epithelial cell detachment in gill, swelling of hepatocytes, granular deposition in liver and tubular degeneration and yellow pigmented macrophage aggregates in the kidney. The in vitro assays for virulence traits recorded that A. veronii GCAFBLC 228 was β-haemolytic having strong cell surface hydrophobicity (CHS) characteristic (> 50%), precipitated after boiling, produced slime, non-suicidal and bound to crystal violet. The antibiogram showed that the strain was susceptible to ciprofloxacin (5 μg), cefotaxime (30 μg), ceftazidime (30 μg), cefoxitin (30 μg), ceftriaxone (30 μg), chloramphenicol (30 μg) and tetracycline (30 μg). Negative staining transmission electron microscopy revealed presence of the lateral flagellum-like structure and cell adherence possibly could be correlated with the pathogenicity of A. veronii GCAFBLC 228. The further investigation is warranted to study the transmission, pathogenesis and epidemiology of A. veronii GCAFBLC 228 to develop the best health management practice for cage farmed fish.
Topics: Aeromonas; Aeromonas veronii; Animals; Carps; Fish Diseases; Gram-Negative Bacterial Infections; RNA, Ribosomal, 16S; Virulence
PubMed: 33125625
DOI: 10.1007/s10482-020-01478-3 -
Microbial Cell Factories Jun 2020The gut microbiota is a complex ecosystem, which is essential for the metabolism, health and immunity of host. Many diseases have been shown to be closely related to the...
BACKGROUND
The gut microbiota is a complex ecosystem, which is essential for the metabolism, health and immunity of host. Many diseases have been shown to be closely related to the alteration of intestinal flora. Aeromonas veronii as a conditioned pathogen can cause disease in Yangtze finless porpoise through intestinal infections. However, it is not clear whether the disease caused by Aeromonas veronii is related to changes of intestinal flora. In the current study, the diversity and composition of gut microbiota in the healthy and Aeromonas veronii-infected Yangtze finless porpoise were evaluated by high-throughput sequencing to further investigate the potential association between intestinal flora alteration and pathogen invasion.
RESULTS
A total of 127,3276 high-quality sequences were achieved and 2465 operational taxonomic units (OTUs) were in common among all samples. The results of alpha diversity showed that there was no obvious difference in richness and diversity between healthy and Aeromonas veronii-infected Yangtze finless porpoise. Firmicutes, Bacteroidetes and Proteobacteria were the most dominant phyla in all samples. In addition, the healthy Yangtze finless porpoise exhibited higher abundance of Firmicutes and Fusobacteria than Aeromonas veronii-infected Yangtze finless porpoise, while, the level of Proteobacteria was decreased. At the genus level, Paeniclostridium and Paraclostridium were the predominant bacteria genera in the CK (healthy Yangtze finless porpoise) group. In the DIS (Aeromonas veronii-infected Yangtze finless porpoise) group, Lactobacillus and unidentified_Enterobacteriaceae were the dominant bacteria genera and the proportion of Paeniclostridium, Paraclostridium, Terrisporobacter, Cetobacterium, Candidatus Arthromitus, Terrabacter and Dechloromonas were reduced.
CONCLUSIONS
In conclusion, our results showed that Aeromonas veronii infection can alter the gut microbiota of the Yangtze finless porpoise by affecting the number of harmful bacteria and beneficial bacteria.
Topics: Aeromonas veronii; Animals; Bacteria; China; Gastrointestinal Microbiome; Gram-Negative Bacterial Infections; Porpoises
PubMed: 32503532
DOI: 10.1186/s12934-020-01383-4 -
Applied and Environmental Microbiology Nov 2019The present study aimed to isolate from fish sold in the markets as well as in sushi and seafood shops and compare their virulence factors and antimicrobial...
The present study aimed to isolate from fish sold in the markets as well as in sushi and seafood shops and compare their virulence factors and antimicrobial characteristics with those of clinical isolates. Among the 128 fish isolates and 47 clinical isolates, , , and were the principal species. isolates carried at least 5 virulence genes, more than other species. The predominant genotype of virulence genes was in both and isolates, in isolates, and in isolates. , , and isolates more often exhibited hemolytic and proteolytic activity and showed greater virulence than isolates in and the C2C12 cell line. However, the link between the genotypes and phenotypes of the studied virulence genes in species was not evident. Among the four major clinical species, nearly all (99.0%) , , and isolates harbored , which encodes a carbapenemase, but only a minority (6.7%, 7/104) were nonsusceptible to carbapenem. Regarding AmpC β-lactamase genes, was exclusively found in isolates, and was found only in isolates, but only 7.6% ( = 6) of the 79 isolates carrying or exhibited a cefotaxime resistance phenotype. In conclusion, fish isolates carry a variety of combinations of virulence and β-lactamase resistance genes and exhibit virulence phenotypes and antimicrobial resistance profiles similar to those of clinical isolates. species can cause severe infections in immunocompromised individuals upon exposure to virulent pathogens in the environment, but the characteristics of environmental species remain unclear. Our study showed that several pathogenic species possessing virulence traits and antimicrobial resistance similar to those of isolates causing clinical diseases were present in fish intended for human consumption in Tainan City, Taiwan.
Topics: Aeromonas; Aged; Aged, 80 and over; Animals; Anti-Bacterial Agents; Bacterial Proteins; Caenorhabditis elegans; Cell Line; Female; Fishes; Genotype; Gram-Negative Bacterial Infections; Humans; Male; Microbial Sensitivity Tests; Phenotype; Prevalence; Seafood; Taiwan; Virulence; Virulence Factors; beta-Lactam Resistance; beta-Lactamases
PubMed: 31420346
DOI: 10.1128/AEM.01360-19 -
Microbial Pathogenesis Jul 2021Despite advancements in diagnosis and control, Aeromonas infections are considered the leading cause of economic aquaculture loss. In this study, to enhance DNA vaccine...
Despite advancements in diagnosis and control, Aeromonas infections are considered the leading cause of economic aquaculture loss. In this study, to enhance DNA vaccine efficacy against Aeromonas infections, a fused DNA fragment (1504 bp) of the OmpAI gene from Aeromonas veronii (A. veronii) combined with the C5-I gene from the common carp was generated with splicing by overlapping PCR (SOE-PCR) and expressed in Lactobacillus casei strain CC16. Protein C5-I served as a molecular adjuvant for the antigen OmpAI. Two types of fusion antigens were developed (anchored and secretory). Generally, anchored-type antigens are more effective in inducing immune responses in fish than secretory antigens. Western blot analysis showed that the bands of both antigens were present at 58 kDa. After oral immunization, both DNA vaccines enhanced the serum levels of AKP, ACP, SOD and LZM in immunized carp; the genes IL-10, IL-1β, TNF-α, and IFN-γ in the heart, liver, spleen, head kidney, and intestinal tract were upregulated; and a stronger phagocytic response was triggered in immunized fish. In addition, common carp administered the fused antigens were more protected from Aeromonas challenge (60-73.3% protection). Recombinant Lactobacillus bacteria expressing the fused protein showed a greater propensity for colonization in the intestinal tract in immunized fish than in controls. Here, we provide a promising approach to improve DNA vaccine immunogenicity for protecting common carp from A. veronii infections.
Topics: Aeromonas veronii; Animals; Bacterial Vaccines; Carps; Fish Diseases; Gram-Negative Bacterial Infections; Lacticaseibacillus casei
PubMed: 33892129
DOI: 10.1016/j.micpath.2021.104827 -
International Journal of Food... Oct 2022Aeromonas spp. are opportunistic and ubiquitous bacteria considered emerging pathogens that can cause infections in animals, especially fish, as well as humans. In...
Aeromonas spp. are opportunistic and ubiquitous bacteria considered emerging pathogens that can cause infections in animals, especially fish, as well as humans. In humans, these bacteria are associated with gastroenteritis but can also be related to extraintestinal diseases. Its main infection route is through water, but it has been increasingly associated with foods. Their association with ready-to-eat foods may be a concern, especially because these products are for immediate consumption. This study aimed to investigate the prevalence of Aeromonas spp. in ready-to-eat foods (temakis, cheeses and minimally processed fruits) and to characterize the virulence profile and antimicrobial resistance of the isolates. The species A. hydrophila, A. caviae and A. veronii were identified using polymerase chain reaction (PCR), which was later compared with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS). The performance of two isolation selective agars (starch-ampicillin agar-SAA and Aeromonas agar-AA) was also evaluated. Aeromonas spp. was isolated in 66.67 % (20/30) of temaki, 3.23 % (1/31) of fruits and none (0/30) of cheeses, observing high microorganism counts from <10 to 2.6 × 10 CFU/g. A. caviae (26.39 %) was the most prevalent species, followed by A. hydrophila (20.83 %) and A. veronii (8.34 %), and 44.44 % were classified as Aeromonas sp. The performance analysis between PCR and MALDI-TOF/MS for Aeromonas identification was not statistically significant, and the Kappa index showed moderate agreement (p < 0.01 and Kappa = 0.718). The SAA selective medium performed better than AA. We identified seventeen virulence profiles, and 59.72 % of the isolates had some of the genes studied. The aerA gene (47.2 %) was the most abundant, followed by act (41.7 %), hlyA and alt (38.9 %), and ast (18.1 %). A. hydrophila was the species most associated with these genes. The antimicrobial susceptibility test showed that 90 % of the isolates were resistant to amoxicillin-clavulanic acid, 17 % to tetracycline, 10 % to imipenem and 3 % to aztreonam. The results showed that temakis are carriers of potentially pathogenic Aeromonas spp. and therefore should be avoided by children, elderly individuals, pregnant women, and immunocompromised people. We also found strains resistant to antimicrobials, meaning that these microorganisms need constant monitoring.
Topics: Aeromonas; Agar; Aged; Animals; Anti-Bacterial Agents; Child; Drug Resistance, Bacterial; Female; Humans; Incidence; Pregnancy
PubMed: 35963079
DOI: 10.1016/j.ijfoodmicro.2022.109862 -
Antibiotics (Basel, Switzerland) Mar 2022The emergence of antimicrobial-resistant bacteria is an enormous challenge to public health. and are opportunistic pathogens in fish. They exert tremendous adverse...
The emergence of antimicrobial-resistant bacteria is an enormous challenge to public health. and are opportunistic pathogens in fish. They exert tremendous adverse effects on aquaculture production, owing to their acquired antibiotic resistance. A few Clinical and Laboratory Standards Institute (CLSI) epidemiological cut-off values (ECVs) against spp. are available. We evaluated antimicrobial susceptibility by establishing 8 ECVs using two analytical methods, normalized resistance interpretation and ECOFFinder. We detected antimicrobial resistance genes in two motile spp. isolated from aquatic animals. Results showed that 89.2% of and 75.8% of isolates were non-wild types according to the oxytetracycline ECV and ECV, respectively. The antimicrobial resistance genes included , , , , , , , , , , and . The most common gene in spp. isolates was , followed by . Some strains carried more than one gene, with - and - found in ; however, was not detected in any of the strains. Furthermore, 18.6% of and 24.2% of isolates showed presumptive multidrug-resistant phenotypes. The emergence of multidrug resistance among aquatic aeromonads suggests the spread of drug resistance and difficult to treat bacterial infections.
PubMed: 35326806
DOI: 10.3390/antibiotics11030343