• Journal of Aquaculture
• /
• v.10 no.4
• /
• pp.439-447
• /
• 1997

A specific disease syndrome, which led to massive mortality on the Korean mandarin fish fingerling (Sinperca scherzeri) at Chongpyong Inland Fisheries Institute was atudied. The causetive agent isolated from the diseased fish was identified as Aeromonas hydrophila on the basis of biochemical and physiological characteristics. Infection experiments in the Korean mandarin fish fingerling, weighting 3-4 g with A. hydrophila were conducted by immersion, oral administration, intramuscular injection, and injection of the soluble extracellular products secreted from it. Motality rate was higher virulence in intramuscular injection group than other experimental groups. In injection group of the soluble extracellular products, all fish treated with high concentration ($8{\times}10^9$ cfu/ml) were repidly killed into 3-6 hrs. There results show that the Korea mandarin fish fingerling has high susceptibility to A. hydrophila.

• Journal of Marine Life Science
• /
• v.7 no.2
• /
• pp.187-195
• /
• 2022

Crucian carp, Carassius carassius (Weight 28.1±3.7 g, Length 10.0±1.0 cm) were challenged with Aeromonas hydrophila at 0, 2.0×10⁴, 2.0×10⁵, 2.0×10⁶, 2.0×10⁷ CFU/ml for 2 weeks. The lethal concentration 50 (LC₅₀) at 2 weeks of C. carassius challenged with A. hydrophila was 19.776×10⁵ CFU/ml. In hematological parameters, the hemoglobin and RBC counts were significantly decreased by A. hydrophila challenge, whereas there was no significant change in hematocrit. The inorganic plasma components such as magnesium and calcium were significantly decreased. In organic plasma components, glucose and cholesterol were significantly increased by A. hydrophila challenge, whereas total protein was significantly decreased. In enzymatic plasma components, ALP (Alkaline phosphatase) were significantly increased by A. hydrophila challenge. The results of this study suggest that the A. hydrophila challenge to C. carassius induced the significant physiological changes in the hematological parameters and plasma components as deadly pathogenic bacteria.

• Animal cells and systems
• /
• v.11 no.1
• /
• pp.33-38
• /
• 2007

Liposome-entrapped atypical Aeromonas hydrophila antigen was prepared to investigate the potential protective efficacy for A. hydrophila infection. Carp (Cyprinus carpio) were immunized orally with liposome-entrapped A. hydrophila antigen. After immunization, significantly more antigen-specific antibodies were detected in serum, intestinal mucus and bile than non-immunized control group. The immunized carp were then challenged by immersion with $1{\times}10^{6}$ cfu/ml of A. hyrdophila for 60 min. Of the eight non-immunized carp, three carp died (62.5% survival), whereas five out of six (83.5%) of the immunized survived. Furthermore, development of skin ulcers was significantly inhibited in carp immunized with liposomes containing A. hydrophila antigen. These results suggest that liposomes containing A. hydrophila antigen have a potential for induction of protective immune responses against atypical A. hydrophila infection and also suggest the possibility of developing a vaccine that may ultimately be used for prevention of fish diseases.

• The Korean Journal of Food And Nutrition
• /
• v.13 no.6
• /
• pp.611-618
• /
• 2000

For the purpose of the isolation of microorganisms which have the capability of nitrification, we isolated the microorganisms in 6 samples collected from the stream of Kyonggi area. 60 strains were isolated. The selected strain were identified as a Aeromonas hydrophila based on the data obtained from the morphological, biochemical and cultural characteristics defined experiments. Among them Aeromonas hydrophila (AH-1), (AH-3) , (AH-4), (AH-6) showed the highest nitrification capability. All isolates were resistant to amoxillin, ampicillin, cephalothin and ticarcillin. Optimum culture conditions of isolates were 37$^{\circ}C$ and 1${\times}$10$\^$8/ cells/ml for 4 hours in the nitrate medium.

• Journal of Life Science
• /
• v.18 no.6
• /
• pp.878-883
• /
• 2008

Aeromonas hydrophila DA33 was isolated from cultivated soils as a bacteria having high abilities to solubilize inorganic phosphate. Glucose dehydrogenase gene (gdh) was cloned from Escherichia coli. The recombinant plasmid, pGHS containing glucose dehydrogenase gene was introduced into A. hydrophila DA33 in order to improve the activity of phosphate-solubilizing. The transformant harboring the gdh gene, A. hydrophila pGHS/DA33 increased enzyme activity. The strain also increased the gluconic acid generation that was effective for phosphate solubilization. It was possible that the strain containing pGHS produced higher solubilized phosphate with tri-calcium phosphate as the unique (P) source, in comparison with that of wild type without plasmid. These results suggest that the strain, A. hydrophila pGHS/DA33 is expected as effective biofertilizer for phosphate solubilization.

• Journal of environmental and Sanitary engineering
• /
• v.6 no.1
• /
• pp.31-46
• /
• 1991

Aeromonas hydrophila which bacause various diseases in human also infects fresh water fish, severly damaging the fishing industries. To prevent disease in humans and reduce damaging on the fishing industries, We have examined several characteristics of Aeromonas hydrophila and obtained the following results. All of the strains gave a posive voges-proskauer, methyl-red, salicin and esculin reaction. Seventeen(94.4%) A. hydrophila strains presented the phenotype SP-PAB- in autoagglut-ination test, but only strain AH 997 showed $SP^{+}PAB^{+}$. in autoagglut ination test, but only strain AH 997 $SP^{+}PAB^{+}$ All of the strains took up the censored to various degrees. Three of 18 strains showed positive reaction in crystal violet binding test. Hemolytic activity ranged from titers of 0 to 1/256. Seven of the 17(38.8%) A. hydrophila strains were positive in sucking mouse assay. Cytotoxin activity on vero and RK cells was displayed various titers.(1/2-1/1024)

• Journal of Microbiology and Biotechnology
• /
• v.10 no.5
• /
• pp.595-598
• /
• 2000

Aeromonas hydrophila is a pathogen to fish as well as human. It is a food-borne disease, and causes severe mortality in fish, and sometimes severe septicemia in human. In this study, a rapid detection method using latex agglutination has been developed for A. hydrophila. Polyclonal antibodies were raised against membrane and whole cells of three isolates from rainbow trout. Among these, latex particles coated with antibodies raised against whole cells of isolate No. 2 showed the best sensitivity. With latex particles coated with this antibody, we could detect $5{\times}10^4$ CFU of A. hydrophila in 5 min. The cross-reactivity with bacteria constituting the normal intestinal microflora and other pathogens for rainbow trout was insignificant. This latex agglutination assay method produced positive reaction with all clinical isolates of A. hydrophila which were identified by species-specific PCR for 16S rRNA in A. hydrophila.

• Journal of Life Science
• /
• v.25 no.2
• /
• pp.214-222
• /
• 2015

Aeromonas hydrophila is the most common water fish pathogen and cause diseases such as hemorrhagic septicemia, dropsy, ulceration and asymptomatic septicemia. A. hydrophila secretes many extracellular products (ECPs) which contribute to effective infection, wide distribution and great adaptability to environmental changes. Crude ECPs of A. hydrophila CK257, a strain used in this study, exhibits a toxic activity to the animals including mouse, rabbit and fish. Toxic symptoms were indicated by tissue damage and skin injuries in animal. When ECPs were subcutaneously injected to animals, skin damages were observed, appearing like necrosis. Preliminary research demonstrated that the active factors are protein component. The crude ECPs were collected after ammonium sulfate precipitation of cell-free culture supernatant. ECPs were fractionated with the use gel filtration chromatography. Five ECP fractions were obtained, of which one fraction was found to be toxic to goldfish. MALDI-TOF analyses provided two interesting proteases called M35 and M28. Both M35 and M28 are known as metalloprotease. Accordingly, proteins in an active fraction exhibited caseinolytic activity. These proteins were difference of caseinolytic activity under different metallic ions. Also active fraction has elastolytic activity. These results suggested that peptidase M28 and M35 may be a candidate factor for tissue necrosis activity about infection with A. hydrophila.

• Microbiology and Biotechnology Letters
• /
• v.25 no.2
• /
• pp.151-158
• /
• 1997

For the production of potent chitinolytic enzyme from bacteria, screening was carried out. Of 100 samples from soil, fresh water and sea water collected from the Kyung-gi area, 7 strains of chitinolytic bacteria were isolated. Among them, Aeromonas hydrophila 5-3K showed the highest chitinolytic activity. Culture conditions of Aeromonas hydrophila for the production of chitinolytic enzyme were inverstigated and lytic enzyme was fractionated by the use of ammonium sulfate and Sephadex G-100. Maximum production of chitinolytic enzyme was obtained at pH 7.0 and 30$\circ$C with chitin concentration between 0.2% and 1.0%. Conditions for the enzyme production were optimized including fermentor cultivation. The chitinolytic system of Aeromonas hydrophila 5-3K was composed of two enzymes, chitinase and chitobiase.

• Korean Journal of Veterinary Research
• /
• v.50 no.4
• /
• pp.331-333
• /
• 2010

Moribund albino catfish, Clarias sp., displayed from an indoor private commercial aquarium were submitted in the laboratory for diagnostic examination. Dense culture of bacteria was recovered from the kidney and was characterized using Vitek System 2 and showed 98% probability to Aeromonas (A.) hydrophila. PCR result showed positive using A. hydrophila extracellular hemolysin gene ahh1 (130 bp) and aerolysin gene aerA (309 bp). The 16S rRNA gene was identical and exhibited 97% sequence similarity with the other known isolates of A. hydrophila available in the GenBank. In this paper, we reported the isolation and molecular detection of A. hydrophila from an albino catfish.