• Fisheries and Aquatic Sciences
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• v.25 no.8
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• pp.429-440
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• 2022

This study assessed the effects of oxygen and ozone nanobubbles on gill morphology, weight gain, and mortality of Pacific white shrimp (Penaeus vannamei), as well as the level of Vibrio parahaemolyticus and water quality of shrimp culture tanks under lab conditions. Two experiments were carried out with oxygen macrobubble, ozone macrobubble, oxygen nanobubble, ozone nanobubble, and control treatments (air-stone macrobubble). Experiments were done in triplicate in 100 L tanks with 15‰ saline water, and 20 shrimp per tank. Tanks in Experiment 1 were not inoculated with bacteria; tanks in Experiment 2 were inoculated with V. parahaemolyticus at a concentration of 10⁶ CFU/mL. The results revealed that short treatments with ozone nanobubbles had minimal impact on shrimp gills, mortality, and growth rates, reduced V. parahaemolyticus concentration in water compared to the other groups, and improve water quality. These laboratory results indicate that ozone nanobubble treatment may be useful for controlling V. parahaemolyticus. More work is needed to find the best protocol to apply the technology on a commercial scale.

• Fisheries and Aquatic Sciences
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• v.7 no.2
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• pp.58-63
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• 2004

Five urease-positive Vibrio parahaemolyticus strains were isolated from Kamak Bay in Yeosu in 2002 and 2003. V. parahaemolyticus YKB4 and YKB14 were isolated from seawater, YFB20 from black rockfish (Sebastes schlegeli), and YFO2l and YFO22 from olive flounder (Paralichthys olivaceus). The five urease-positive strains (YKB4, YKB14, YFB20, YFO21, and YFO22) did not show hemolysin and protease activity, while they did alter in color (to red) as the bacteria grew in the urea broth medium. All samples showed identical biochemical characteristics as a reference strain, V. parahaemolyticus KCTC2471, except in urease production. The five urease-positive strains showed urease activities at a mid stationary phase, and their activity was maximal in the late stationary phase of their culture supernatant. The addition of urea to the Luria-Bertani (LB) broth medium significantly affected the initial production of urease of V. parahaemolyticus isolates. Mortality by urease-positive V. parahaemolyticus YKB4, YKB14, YFO2l, and YFO22 was significantly high, being$60-80\%$, while YFB20 only reflected a rate of $20\%$. Protease-positive V. parahaemolyticus FM39 and FM50 showed a $40\%$ and $60\%$ mortality rate, respectively. However, hemolysin-positive V. parahaemolyticus had no mortality, like the non-pathogenic V. parahaemolyticus KCTC2471, while V. vulnificus resulted in a $40\%$ mortality rate. Injection with urease-positive V. parahaemolyticus strains showed mortality within 12 hrs in mice, and the strains could be isolated from the dead mice.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.1
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• pp.27-34
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• 2019

The seasonal and spatial variation of pathogenic Vibrio species, such as V. parahaemolyticus, V. vulnificus, V. alginolyticus, and V. cholerae were investigated in seawater and in bivalves off the Gyeongnam coast of Korea, which is an important area for shellfish production, during the period 2013-2016. V. parahaemolyticus, V. vulnificus, V. alginolyticus, and V. cholerae were detected in 12.1%, 5.2%, 15.4%, and 0.9% of seawater samples, respectively. V. parahaemolyticus, V. vulnificus, V. alginolyticus, and V. cholera were detected in 21.9%, 7.1%, 12.2%, and 0.0% of shellfish samples, respectively. The Vibrio spp. in seawater and bivalve samples were detected at high levels during the summer to early autumn; however, the levels were low during the winter. Therefore, their occurrence was seasonally dependent and correlated with high water temperature, which is also the biggest factor contributing to foodborne outbreaks associated with Vibrio. Relatively high detection rates of the strains were also found in the sea area that was continually exposed to inland wastewater. Our findings show that continuous monitoring is needed to reveal the patterns of occurrence of these pathogens from marine samples collected off the Korean coast, to reduce seafood-borne outbreaks caused by Vibrio.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.508-515
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• 2014

The contamination status of Vibrio parahaemolyticus in commercially valuable shellfish from the south and west coasts of Korea and the antimicrobial resistance patterns of isolated V. parahaemolyticus were investigated from July through October, 2011. The range of V. parahaemolyticus concentrations in oysters Crassostrea gigas and short neck clams Venerupis philippinarum was <30~290 MPN/100 g and <30~46,000 MPN/100 g, respectively, and greater than 10,000 MPN/100 g of V. parahaemolyticus was detected from 7 of 40 short neck clams. During the survey period, 436 strains of V. parahaemolyticus were isolated (129 from oysters and 307 from short-neck clams) and the antimicrobial resistance patterns of all of the isolates were examined. Antimicrobial resistance against at least one antibiotic was seen in 79.8% of the oyster isolates (103 strains) and 63.8% of the short neck clam isolates (196 strains). The antimicrobial resistance patterns were relatively simple because the antimicrobial resistance of the isolates was simply due to resistance to ampicillin. Only one oyster isolate and three short neck clam isolates showed multiple antibiotic resistance, i.e., resistance against more than four antibiotics.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.4
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• pp.460-466
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• 2016

From 2013 through 2015, we investigated the contamination status and antimicrobial resistance patterns of pathogenic Vibrio parahaemolyticus in commercially valuable seawater and shellfish (Oyster Crassostrea gigas, short-neck clam Venerupis philippinarum, ark shell Scapharca broughtonii and mussel Mytilus galloprovinciallis) from the southern coast of Korea. The detection rate of V. parahaemolyticus was highest in short-neck clams (23.7%), followed by ark shells (19.2%), oysters (15.9%), mussels (13.6%), and seawater (8.6%). The following percentages of PCR assays of shellfish were positive for the thermostable direct hemolysin-related hemolysin gene (trh) : oysters (12.8%), short-neck clams(11.8%), and ark shells (3.4%). Similar assays for the thermostable direct hemolysin gene (tdh) resulted in positive results for short-neck clams (5.9%) and ark shells (3.4%). Antimicrobial resistance was present in 100% of 8 tdh (+) and 2 trh (+) V. parahaemolyticus isolates challenged with ampicillin. However, all pathogenic V. parahaemolyticus were sensitive to 14 other antibiotics. To ensure the safety of shellfish consumption, the continuous monitoring of the prevalence and distribution of virulence factors of V. parahaemolyticus in shellfish farms is needed.

• Fisheries and Aquatic Sciences
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• v.21 no.2
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• pp.3.1-3.10
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• 2018

Background: Vibrio parahaemolyticus is one of the most common causes of seafood-borne illnesses in Korea, either directly or indirectly, by consuming infected seafood. Many studies have demonstrated the antibiotic susceptibility profile of V. parahaemolyticus. This strain has developed multiple antibiotic resistance, which has raised serious public health and economic concerns. This article reviews the food-borne outbreaks, distributions, virulence, and antibiotic resistance profiles of V. parahaemolyticus in Korea during 2003-2016. Main body: V. parahaemolyticus infections appeared to be seasonally dependent, because 69.7% of patient infections occurred in both August and September during 2003-2016. In addition, the occurrence of V. parahaemolyticus in marine environments varies seasonally but is particularly high in July, August, and September. V. parahaemolyticus isolated from aquaculture sources on the Korean coast varied in association with virulence genes, some did not possess either the tdh (thermostable direct hemolysin) or trh (tdh-related hemolysin) genes, and a few were positive for only the trh gene or both genes. The high percentage of ampicillin resistance against V. parahaemolyticus in the aquatic environment suggests that ampicillin cannot be used to effectively treat infections caused by this organism. Short conclusion: This study shows that the observed high percentage of multiple antibiotic resistance to V. parahaemolyticus is due to conventionally used antibiotics. Therefore, monitoring the antimicrobial resistance patterns at a national level and other solutions are needed to control aquaculture infections, ensure seafood safety, and avoid threats to public health caused by massive misuse of antibiotics.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.11 no.1
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• pp.19-24
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• 1978

The differences in Vibrio parahaemolyticus detection ratio were compared between the isolation methods, the Most Probable Number technique and single dilution tube method. During the period from February to October in 1976, 298 samples of sea water, 112 of bottom deposit, 169 of shellfish, and 80 of fish samples collected along the south coastal area of Korea were examined to determine the detection ratio of Vibrio parahaemolyticus. It was often observed that Vibrio parahaemolyticus was detected in higher diluted samples even through negative in lower dilution. Three hundred and forty three samples out of 659 samples submitted to the test by MPN procedure appeared positive for Vibrio parahaemolyticus showing $52\%$ detection ratio. Whereas only 149 samples, corresponding $22.5\%$, were positive for Vibrio parahaemolyticus in the lowest dilution grade. The positive result was $24.5\%$ in the lowest dilution grade and $50\%$ by MPN Procedure in sea water samples, $28.6\%$ and $65.2\%$ in bottom deposit, $22.5\%$ and $56.2\%$ in shellfish and $7.5\%$ and $32.5\%$ fish samples. When tested by triplicate tubes, $61.7\%$ of 149 Vibrio parahaemolyticus positive samples appeared positive in one tube, $28.9\%$ of them were positive in two tubes and $9.4\%$ of them were positive in all three tubes. The detection ratio determined by MPN procedure was more than two times higher than that of single dilution in triplicate tubes.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.330-336
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• 2004

Fifty-two pathogenic Vibrio parahaemolyticus strains were isolated from the environments of Busan and Yeosu, Korea. Forty-three of these strains showed protease activities, whereas 4 strains showed $\alpha / \beta$ hemolysin activities and 6 strains had urease activities. Their pathogenic factors were not overlapping except one strain, which had both protease and hemolysin activities. The 6 urease-positive strains (V. parahaemolyticus YKB4, YKB14, S25, YFB20, YFO21, and YFO22) showed the same biochemical characteristics as a reference strain [V. parahaemolyticus KCTC 2471 (urease-negative)], except for urease production. The 6 urease-positive strains showed different urease activities in their culture supernatant during the growth. The urease activity of S25 increased sharply at the late exponential phase, and was the highest at the initial stationary phase and was kept until the late stationary phase. The other 5 isolates, except C25, showed urease activities at the mid-stationary phase and increased steadily until the late stationary phase, when the urease activity was maximal. To compare the degree of virulence of V. parahaemolyticus with different pathogenic factors, hemolysin, protease, or urease-positive strains were injected into groups of 10 each of ICR mice (7- to l0-week-old males). The lethal rates of urease-positive V. parahaemolyticus, YKB14, YKB4, and S25, were significantly high, being 50, 70, and 80%, respectively. Protease-positive V. parahaemolyticus strains FM39 and FM50 showed 40% and 60% of lethal rate, respectively. Hemolysin-positive V. parahaemolyticus strains S34 and S72 had no mortality, similar to nonpathogenic V. parahaemolyticus FM12.

• Journal of fish pathology
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• v.35 no.1
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• pp.57-63
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• 2022

Vibrio parahaemolyticus and V. vulnificus are known to be infected to human via fisheries products. Therefore, food safety of fisheries products is important for public health and fish industry. This paper was conducted to know how well these human isolates can survive in olive flounder (Paralichthys olivaceus). The growth of V. parahaemolyticus and V. vulnificus showed about 50~60% reduced rates at 25℃ than at 37℃ and did not show any differences according to NaCl concentration of media except the increasing in the growth of V. vulnificus in medium containing 3% NaCl. Artificial infection of 1×10⁶ CFU/fish was carried out to confirm the sensitivity of olive flounder against V. parahaemolyticus and V. vulnificus. After 1 week from injection, no fish was dead. To evaluate nonspecific defense of olive flounder against V. parahaemolyticus and V. vulnificus, the antibacterial potency of serum and epidermal mucus were tested. The number of the vibrios exposed to serum obtained from olive flounder significantly decreased after 3 hours, and epidermal mucus showed decrease of the bacteria over than 90% until 12 hours from exposure. Phagocytosis of head kidney leucocytes of healthy olive flounder against V. parahaemolyticus and V. vulnificus showed in over 70% of leucocytes at the 2 hours. Therefore, cultured olive flounder only as vehicle for human pathogen in environmental water is well developed its antibacterial potency against human pathogens, so the viability of V. parahaemolyticus and V. vulnificus in cultured olive flounder was considered very low.

• The Korea Journal of Herbology
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• v.25 no.3
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• pp.111-116
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• 2010

Objectives : This experimental study was performed to investigate the antibacterial effect of Caesalpinia sappan and Coptis chinensis extract against B. cereus and V. parahaemolyticus. Methods : Methanol extracts of C. sappan and C. chinensis was tested against B. cereus and V. parahaemolyticus by paper disc method. Results : The growth of B. cereus and V. parahaemolyticus was inhibited by C. sappan and C. chinensis extract among 6 kinds of medicinal plant extracts. The extract of C. sappan and C. chinensis extract inhibited the growth of V. parahaemolyticus and B. cereus, respectively. The growth of B. cereus and V. parahaemolyticus had a tendency to increase depend on the concentration of the extract. EtOEt and EtOAc fractions and EtOEt and BuOH fractions of the C. sappan extract had a high antibacterial activity against B. cereus and V. parahaemolyticus, respectively. And, BuOH and $H_2O$ fractions of the C. chinensis extract showed antibacterial activity against B. cereus highly. Conclusions : C. sappan and C. chinensis extract efficiently inhibited the growth of B. cereus and V. parahaemolyticus.