• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.5
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• pp.293-299
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• 2007

The distribution of hemolytic Vibrio sp. from sea water of three main beaches located in Busan (Gwangan(G), Haeundae(H) and Songjeong(S) beaches) was investigated from June to September 2006 ; this is mid-summer and the main season for bathing. The monthly detection ratio from each beach was 29.2% (7 of 24 samples, G), 33.3% (8 of 24 samples, H), and 16.7% (4 of 24 samples, S). The most probable number(MPN) of strains detected ranged from 1.8-36(G), 1.8-180(H) and 1.8-18(S) MPN/100mL. Of the isolated strains, 24 strains showed definite hemolytic activity. These 24 strains were identified as Vibrio fluvialis, Vibrio vulnificus, Aeromonas hydrophila, Actinobacillus ureae and Eikenella corrodens. Vibrio fluvialis was detected from all three beaches investigated. Vibrio vulnificus was detected from Haeundae and Gwangan beaches. Gwangan beach had a higher detection ratio of Vibrio sp. than Haeundae and Songjeong beaches. These results suggest that seafood harvested from the vicinity of theses beaches may cause food poisoning and risk management to prevent Vibrio septicemia is required, especially for Haeundae and Gwangan beaches.

• Fisheries and Aquatic Sciences
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• v.6 no.3
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• pp.105-109
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• 2003

Fifty four strains of pathogenic vibrios were isolated from the Gwangan Beach from May to October, 2002. The isolated vibrios were composed of 7 different species: Vibrio parahaemolyticus, V. cholerae non-O1, V. alginolyticus, V. vulnificus, V. hollisae, V. fluvialis, ane V. mimicus. In the detection rate, V. parahaemolyticus was most predominant as $46\%$(25/54). From the isolated strains, only 25 strains have hemolytic activity or 25 strains only proteolytic activity on agar plates. Eleven strains showed both hemolytic and proteolytic activity. No strains showed urease activity. All strains of V parahaemolyticus did not show hemolytic activity, while V. cholerae non-O1 strains showed $\beta$ hemolytic activity. Kanagawa phenomena of pathogenic vibrios did not accord with hemolytic activity of the culture supernatant at the late log phase. Some strains showed high hemolytic activity despite having proteolytic activity, but some weak hemolytic activities despite having no proteolytic activity.

• Fisheries and Aquatic Sciences
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• v.5 no.3
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• pp.178-182
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• 2002

The authors identified 68 Vibrio strains from Gwangan beach seawater from June to October in 2001. We identified them as 19 strains of Vibrio alginolyticus, 15 strains of V. vulnificus, 15 strains of V. parahaemolyticus, 11 strains of V. cholerae non O1, 7 strains of V. fluvialis and just one strain of V. hollisae. They showed their typical biochemical characteristics by API 20E kit (bioMerieux), respectively. It was examined whether their cultural supernatants had enzymatic activities such as hemolysin, protease or urease. The 46 strains showed hemolytic activities and/or protease activities. But we could not find any strain which had urease activity. All isolates of V. cholerae non O1 showed $\beta$ hemolysis. The others showed $\alpha$ hemolysis or did not show clear zones on sheep blood agar plates. These results of Kanagawa phenomenon were not always correspondant with hemolytic activities of cultural supernatants at late log phase. Some strains had higher hemolytic activities despite of showing protease activities on skim milk agar plates and in litmus milk media. On the other hand, some strains showed protease activities but did not show hemolytic activities. Therefore we could guess that there were the relationships between hemolysins and proteases produced by pathogenic vibrios.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.2
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• pp.222-227
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• 2001

The members of the genus Vibrio include harmless aquatic strain as well as strains capable of causing infections in human and fish. Pathogenic mechanisms are only understood for Vibrio cholerae O1 and O139 and not for the majority of Vibrio species. Twelve clinical and nonclinical strains were examined by in vitro and in vivo experiments for the importance of extracellular enzymes as a virulence determinant of Vibrio species. In vivo cytotoxicity assay was performed by injecting approximately $10^{8}$ cells/mL into mice (BALB/c). V. harvyi and V. vulnificus showed 100% lethality within 3hr after bacterial injection. V. fluvialis and four strains of V. parahaemolyticus showed 50% lethality within 4hr. V. mimicus, V. alginolyticus and V. furnissii revealed 30% lethality within 9hr. Nonclinical strains, V. campbellii and V. ordalii, did not show any lethality. In vitro protease and hemolytic activities were also good indicators for clinical and nonclinical strains of Vibrio species. The clinical strains showed much higher activities than nonclinical strains. The activity of some clinical strains of re-isolates was evidently increased. Most clinical strains had $\beta$ hemolytic activity. The results demonstrate that the prevalent distribution of extracellular proteases in pathogenic Vibrio sp. implies their importance as a virulence determinant.

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.1021-1026
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• 2003

Numerous secreted and cell-associated virulence factors have been proposed to account for the fulminating and destructive nature of Vibrio vulnificus infections. Among the putative virulence factors are an elastase, elastolytic protease, and a cytolytic hemolysin. Effects of the elastase on the hemolysin were assessed by evaluating changes of hemolytic activities either in the presence or absence of the protease. Although hemolytic activity in the culture supernatant was lowered by the purified elastase added in vitro, the cellular level of hemolytic activity was unaffected by the mutation of vvpE encoding the elastase. Growth kinetic studies revealed that hemolysin reached its maximum level in the exponential phase of growth, and the elastase appeared at the onset of the stationary phase. These results have provided insight into the regulation of virulence factors: temporally coordinate regulation of virulence factors is essential for the overall success of the pathogen during pathogenesis.

• Journal of Food Hygiene and Safety
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• v.15 no.2
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• pp.173-175
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• 2000

Nine strains of pathogenic Vibrio sp. of clinical and environmental origin were examined for the degradation of gelatin, casein and hemolysin which is important to the virulence of this bacterium. Culture filtrates of all nine strains of Vibrio exhibited proteolytic activities. Especially, four strains of V. parahaemolyticus and one V. alginolyticus showed strong gelatin-degrading activity. In terms of hemolytic activity, three V. parahaemolyticus and V. mimicus showed strong $\beta$-hemolysis whereas those of strains of V. alginolyticus, V. fluvialis, V. vulnificus examined lacked this activity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.4
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• pp.243-247
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• 2008

The hemolysin of Vibrio cholerae non-O1 CT isolated from sea water was purified and characterized. The purified hemolysin displayed an optimum at $37^{\circ}C$ and exhibited more than 70% of residual hemolytic activity after incubation at $45^{\circ}C$ for 120 min. However, the activity dropped dramatically at temperature above $55^{\circ}C$. The purified protein showed the highest hemolytic activity at pH 7.0, while the activity was completely lost outside of the pH ranges of 5.0 and 10.0. The activity of hemolysin was inactivated by addition of divalent cations, such as $Cu^{2+},\;Fe^{2+},\;Hg^{2+},\;Mn^{2+},\;and\;Zn^{2+}$, however, the activity was not completely inhibited by additions of $Ca^{2+},\;Mg^{2+},\;K^+,\;Na^+,\;and\;Li^+$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.4
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• pp.556-561
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• 1997

Vibrio cholerae non-O1 FM-3 was isolated from sea water, and it showed the same bacteriological characteristics as Vibrio cholerae non-O1 ATCC 25872. V. cholerae non-O1 FM-3 presented the highest hemolytic activity at stationary phase of its growth. The hemolytic activity was decreased in accordance with increasing of pretense activity of its cultural supernatant. The characteristics of the hemolysin produced by V. cholerae non-O1 FM-3 were investigated after partial purification with a Sephadex G-100 chromatography. The hemolytic activity of purified protein was stable at $4^{\circ}C$ while it was completely lost by heating at $60^{\circ}C$ for 30 min. The activity of hemolysin was increased by addition of divalent cations such as $Ca^{2+},\;Mg^{2+},\;and\;Mn^{2+}$ while it was inhibited by additions of $Zn^{2+}$. When the hemolysin was incubated with suspensions of erythrocytes at $4^{\circ}C$ and $37^{\circ}C$, respectively, hemolysis was not observed at $4^{\circ}C$ but at $37^{\circ}C$. It means that hemolysis by purified hemolysin was temperature-dependent while its binding step of hemolysin to cell membrane was temperature-independent.

• Journal of Food Hygiene and Safety
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• v.12 no.1
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• pp.9-14
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• 1997

Vibrio mimicus is a closely related species with V. cholerae, and has been reported to be associated with gastrointestinal infections. Although extraintestinal infections of these vibrios have also been reported in Japan and Southeast Asia. But little research papers on V. mimicus was reported in Korea. Therefore, we tried to isolate V. mimicus from the environmental sea water from April to July in Pusan, Korea. Among the isolated strains, we selected the strongest hemolytic strain and then named V. mimicus SM-9. In this paper, we checked the antibiotic susceptibility and psychrotrophic characteristics of the isolated strain. Hemolytic activity of the hemolysin produced by the isolated strain was also measured. V. mimicus was not detected from the sea water samples in April and May, but its detection rate was relatively high in June and July in Pusan, Korea. The bacteriological characteristics of V. mimicus SM-9 were Gram-negative rods, motile, oxidase positive, Voges-Proskauer negative and sucrose negative. In 23 kinds of antibiotics susceptibility test, V. mimicus SM-9 showed susceptibility to the most of antibiotics submitted while it was resistive against lincomycin, oxacillin, rifampin and vancomycin. Hemolytic activity of the hemolysin produced by V. mimicus SM-9 was highest in stationary phase of the growth curve in BHI broth at 37$^{\circ}C$ and its activity was reached 18 HU per $m\ell$ of culture supernatant. For checking the psychrotrophic property of V. mimicus SM-9, the decreasing rate of the strain in phosphate buffer solution and yellowtail flesh homogenate was examined during the storage at 4, 0, -4 and -2$0^{\circ}C$. The decreasing rates of the selected strain stored in phosphate buffer solution were greater than those in fish homogenate. Decreasing rates of V. mimicus SM-9 stored in phosphate buffer solution were not significantly different by the storage temperatures. The viable cell counts of the strain were decreased as 5 log cycles after 120 hours at all the tested temperatures. While decreasing numbers of the strain in fish homogenates were 2*4 log cycles after 120 hours. The decreasing pattern of the strain numbers were very slow after 200 hours at all the stored temperatures.

• Journal of fish pathology
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• v.20 no.1
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• pp.71-81
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• 2007

Photobacterium damselae subsp. damselae and 4 Vibrio spp.(V. anguillarum, V. splendidus, V. harveyi and V. ordalii) were isolated from the diseased olive flounders, Paralichthys olivaceus. The isolates were tested on the pathogenicity in vitro. The properties of extracellular products(ECPs) were investigated with enzymatic activities, hemolytic activities toward the sheep and olive flounder erythrocytes, and cytotoxicity activities on the cell-line. And potential signal transduction pathways of the bacterial internalization were detected by using signal transduction inhibitors. P. damselae was high in phospholipase activity, hemolytic activity to olive flounder erythrocytes and cytotoxicity activity. And P. damselae had diversified internalizing pathways as compared to isolated vibrios. Therefore, these activities may be related with pathogenicity of P. damselae.