Ka Jeong Lee

Geographical and annual variation in lipophilic shellfish toxins from oysters and mussels along the south coast of Korea.

To better understand critical aspects of diarrhetic shellfish poisoning (DSP) occurrence in a chief producing region of bivalves in Korea, the geographical and annual variation of DSP toxins and other lipophilic toxins in mussels (Mytilus galloprovincialis) and oysters (Crassostrea gigas) were investigated by liquid chromatography-tandem mass spectrometry in an area on the south coast of Korea from 2007 to 2009. The total lipophilic shellfish toxin (LST) levels in bivalves showed geographical and annual variations. LSTs were detected mostly in the hepatopancreas of mussels from Jinhae Bay throughout the entire year, except in November and December of 2007, but were almost undetectable in all samples during the entire year in 2009. The peak DSP toxin (okadaic acid plus dinophysistoxin 1) levels in the hepatopancreas of mussels from Jinhae Bay and the Tongyeong region were 945.3 and 37.6 ng/g, respectively. The DSP toxin content was about 10 times higher in mussels than in oysters collected from the same region. The major toxins in bivalves were okadaic acid and dinophysistoxin 1; however, pectenotoxin 2 or yessotoxin was occasionally detected as a major component. The results of a quantitative analysis of phytoplankton showed that Dinophysis acuminata was the most probable source of the LSTs, with the exception of yessotoxin. When the highest DSP toxin level was measured (945.3 ng/g in the hepatopancreas of mussels from Jinhae Bay), the toxin concentration in whole mussel tissue was calculated to be 114.0 ng/g. The calculated highest DSP toxin level in whole oyster tissue from both regions was 15.0 ng/g. The calculated maximum toxicities in whole mussel and oyster tissues were lower than the regulatory limit (160 to 200 ng/g) in Korea, the European Union, and the United States. Korean oysters (242 samples) and mussels (214 samples) were thus deemed safe for consumption. But because such variation was detected in a relatively small area of the coast, it is possible that at some locations or during a specific period LST levels could exceed the standard and a few consumers could be at risk of experiencing DSP.

Seasonal Variability of Lipophilic Shellfish Toxins in Bivalves and Waters, and Abundance of Dinophysis spp. in Jinhae Bay, Korea

ABSTRACT Lipophilic shellfish toxins (LSTs) produced by dinoflagellates, including Dinophysis spp., can accumulate in bivalves. The seasonal variability of LSTs in bivalves and waters, and the abundance of Dinophysis spp. were investigated in Jinhae Bay, Republic of Korea, in 2007. Diarrhetic shellfish poisoning (DSP) such as okadaic acid and dinophysistoxin-1, and other lipophilic toxins such as pectenotoxin-2 (PTX2) and yessotoxin were analyzed by liquid chromatography—tandem mass spectrometry (LC-MS/MS). The toxin concentration in size-fractionated plankton material (20–100 µm in size) concentrated from a specific volume of water was converted into the toxin contents per unit volume of water. Among the genus Dinophysis, only D. acuminata was observed. The seasonal variability of okadaic acid, dinophysistoxin-1, and PTX2 per unit volume of water paralleled that of the abundance of D. acuminata. The cellular content and profile of toxins in D. acuminata varied, but PTX2 was mostly the dominant toxin. The toxins in the hepatopancreas of mussels (Mytilus galloprovincialis) were found from spring to autumn, and relatively high levels of toxins were detected in summer (June to August). Variation of the toxins in the hepatopancreas of mussels was remarkably consistent with both abundance of D. acuminata and toxin concentration in the water. Our results suggest that LC-MS/MS analysis of toxin in plankton concentrates has the possibility of becoming an alternative to or complement of the conventional microscopic method in toxic phytoplankton monitoring.

The first detection of okadaic acid and its derivatives in Korean bivalves by liquid chromatography-mass spectrometry

Lipophilic toxin profiles associated with diarrhetic shellfish poisoning in Korean bivalves were investigated by liquid chromatography-mass spectrometry (LC-MS). Okadaic acid (OA), dinophysistoxins (DTX), pectenotoxins (PTX) and yessotoxin (YTX) in bivalves were quantified by LC-MS. Thirty-eight bivalve samples were collected from five different areas on the south coast of Korea during January to June 2006. Dinophysistoxin-1 (DTX1) and OA were found in some samples of both mussel Mytilus edulis and oyster Crassostrea gigas. The levels of DTX1 and OA found in the hepatopancreas of the samples were 0.04–0.23 μg/g and 0.03–0.08 μg/g, respectively. Dinophysistoxin-3 was found in the hepatopancreas of the short-necked clam Ruditapes philippinarum at a concentration of 0.06 μg/g. PTX and YTX were not detected from all of the samples examined. This is the first report of the unambiguous identification of OA and its derivatives, by LC-MS, in Korean bivalves.

First detection and seasonal variation of lipophilic toxins okadaic acid, dinophysistoxin-1, and yessotoxin in Korean gastropods.

Okadaic acid (OA), dinophysistoxin-1 (DTX1), pectenotoxin-2, and yessotoxin (YTX) are classes of lipophilic toxins found in marine animals. OA and DTX1 accumulation causes diarrhetic shellfish poisoning, a worldwide public health problem. Diarrhetic shellfish poisoning has not previously been reported in gastropods, which are widely consumed in Korea. Seasonal variation in marine lipophilic toxins in gastropods was investigated using liquid chromatography-tandem mass spectrometry. Eighty specimens of Neptunea cumingii, 65 specimens of Rapana venosa, and 95 specimens of Batillus cornutus were collected at the Tongyeong fish market on the southern coast of Korea between May 2009 and December 2010. OA, DTX1, and YTX were detected in meat and digestive glands in all gastropod species studied. Pectenotoxin-2 was not found in any sample tested. Lipophilic toxins were detected in the digestive glands of gastropods; no lipophilic toxin was detected in the salivary glands of the carnivorous gastropods, N. cumingii and R. venosa. The highest concentrations of OA (21.5 ng/g) and DTX1 (8.4 ng/g) were detected in the digestive glands of R. venosa, and the maximum concentration of YTX (13.7 ng/g) was found in the digestive glands of N. cumingii. The maximum toxicities in gastropod tissues were lower than the European standard for acceptable levels. The concentrations of lipophilic toxins in carnivorous gastropods showed a high degree of seasonal variation; lipophilic toxins in carnivorous gastropods were found predominantly in spring and summer. This is the first report of the occurrence of lipophilic toxins in Korean gastropods.

Bacteriological quality evaluation of seawater and oysters from the Jaranman-Saryangdo area, a designated shellfish growing area in Korea: Impact of inland pollution sources

From 2011 to 2013, we conducted a full sanitary survey of pollution sources in proximity to a designated shellfish growing area in Korea, and their impact on the sea area therein. From this area, 836 seawater samples and 93 oyster samples were examined to evaluate their bacteriological quality. There were 483 potential pollution sources in the drainage area of the Jaranman-Saryangdo area, including 38 sources discharging water. It demonstrates that while many pollution sources have been identified, no significant impact occurred within the designated shellfish growing area. Variations in fecal coliform (FC) levels in seawater were closely related to rainfall. The FC levels of seawater and oysters from the designated area met the regulation limits set by various countries. Our study indicates that the oysters produced in this area are apparently safe for raw consumption based on their bacterial quality.

Identification of tetramine, a toxin in whelks, as the cause of a poisoning incident in Korea and the distribution of tetramine in fresh and boiled whelk (Neptunea intersculpta).

An investigation was conducted into the clinical symptoms and causative agent associated with a whelk poisoning incident that occurred in March 2005 in Korea. The whelk consumed in the poisoning incident was identified as Neptunea intersculpta. All of the 17 patients suffered from eyeball pain, headache, dizziness, abdominal pain, and nausea but no diarrhea. The causative agent was identified as tetramine, based on results from liquid chromatography-tandem mass spectrometry. Based on the tetramine concentration in the leftover whelk meat and the amount of meat consumed, the amount of tetramine ingested by the patients was estimated to be > or = 10 mg. This is the first report of the identification of tetramine as the causative agent in whelk poisoning in Korea. The anatomical distribution of tetramine in fresh and boiled N. intersculpta was examined. The toxin concentration in the meat was higher in specimens boiled in the shell than in fresh specimens collected on the same date. In meat boiled separately after removing the shell, the salivary gland, and the midgut gland, the tetramine concentration was much lower than that in fresh specimens or those boiled in the shell. This result suggests that boiling the meat after removing the salivary gland is a suitable way to prevent tetramine poisoning.

First Report of Contamination of the Abalone Haliotis discus hannai by Okadaic Acid and Yessotoxin

ABSTRACT The presence of the lipophilic toxins okadaic acid (OA), dinophysistoxin-1, pectenotoxin-2, and yesso toxin (YTX) in the abalone Haliotis discus hannai collected between March 2009 and May 2010 was analyzed via liquid chromatographytandem mass spectrometry (LC-MS/MS) and the mouse bioassay. Thirty abalone samples collected from 2 sites, Geumdang and Chungdo on the southwest coast of Korea, were submitted for toxin analysis. Lipophilic toxins OA and YTX were detected in the digestive gland of the abalone by LC-MS/MS, but no toxins were detected in the foot muscle. The highest toxin concentrations in the digestive glands of the abalone were 4.7 ng/g OA and 1.3 ng/g YTX. Okadaic acid and YTX were detected mainly during winter and spring. However, dinophysistoxin-1 and pectenotoxin-2 were not detected in any of the samples by LC-MS/MS. Diarrhetic shellfish poisoning toxins were not detected in the digestive gland or the foot muscle by mouse bioassay. Although low levels of toxins were detected, this is the first report identifying lipophilic toxins in abalone.

Distribution and antimicrobial susceptibility of Vibrio species associated with zooplankton in coastal area of Korea

Vibrio parahaemolyticus and V. vulnificus are the most common pathogens causing seafood-borne illnesses in Korea. This study determines the abundance and antimicrobial resistance of pathogenic Vibrio species in seawater and zooplankton samples from the Geoje Island coast in Korea, which is an important area for coastal fisheries, the fishing industry, and tourism. The two Vibrio species were detected more in mesozooplankton samples than in seawater samples. V. parahaemolyticus isolates showed greater resistance than those of V. vulnificus for antimicrobials. Of V. parahaemolyticus isolates, 93.3% exhibited resistance to three or more antimicrobial agents. Conversely, more than 80% of V. vulnificus isolates showed susceptibility to all antimicrobials examined, with the exception of rifampicin. Our findings show that strong antimicrobial resistance of V. parahaemolyticus in the surveyed area was exposed to conventionally used antibiotics, therefore necessitating proper surveillance programs for the monitoring of antimicrobial resistance patterns in seawater bodies and aquatic animals.

Spatial and seasonal variation of pollution sources in proximity of the Jaranman-Saryangdo area in Korea

We aimed to compare the spatial and seasonal distributions of fecal coliforms (FCs) and other physiochemical factors in the drainage basin of the Jaranman-Saryangdo area. Among the pollution sources, the mean daily loads and half-circle radii of FCs were the highest in June. However, the pollutants did not reach the boundary line of the designated area due to an existing buffer zone. The value of the FC geometric mean at station 1 was highest in August during periods of heavy rainfall; however, this value was lower than the regulation limit. The highest daily loads of chemical oxygen demand (COD) and chlorophyll-a (Chl-a) in seawater were in the surface layer in August; however, dissolved oxygen (DO) in the bottom water layer was at its lowest in August. This study demonstrated that season and rainfall have significant effects on the FC, COD, DO, and Chl-a concentrations in seawater.

Antimicrobial Resistance of Escherichia coli Isolates from Mussel Mytilus galloprovincialis Farms and Inland Pollution Sources in the Changseon Area, Korea

우리나라는 최근 5년간 패류를 매년 140만톤 이상 생산하고 있고, 그 중 지중해담치(Mytilus galloprovincialis)는 5만 6천 톤(총 패류 생산량의 3.8%)을 차지 하고 있다(Kosis, 2016). 패 류는 육상과 인접한 연안에 주로 서식하므로 육상으로부터 유 입되는 오염물질의 영향을 쉽게 받을 수 있으며, 패류는 이동성 이 거의 없고, 여과 섭이를 통하여 먹이를 섭취하므로 해수 중 에 존재하는 병원성 미생물을 먹이와 함께 체내에 축적하게 된 다(Grimmes, 1991; Feldhusen, 2000). 육상의 생활폐수 및 산 업폐수 그리고 사람이나 가축의 분변 등의 오염물질은 하수나 하천을 통하여 연안해역으로 유입되어 바다의 수질을 악화시 킬 수 있다(Hill et al., 2006; Lee et al., 2010; Mok et al., 2016a, 2016b). 또한 이러한 오염원에는 병원성 미생물은 물론 항생제 내성균이 존재할 가능성이 높아 패류의 위생학적 안전성을 위 협하는 요인이 될 수 있다(Park et al., 2013). 최근 5년간 국내에서 총 항생제의 판매 실적을 보면 2011년 87톤, 2012년 85톤, 2013년 76톤, 2014년 84톤 및 2015년에는 86톤으로 매년 80톤 가량 사용하고 있으며, 그 중 수산에서 항 생제 사용량은 2011년 23톤, 2012년 22톤, 2013년 21톤, 2014 년 24톤 및 2015년 20톤으로 매년 20톤 이상 사용되고 있다 (KMFDS, 2016). 최근 세균에 대한 항생제 내성은 세계적으로 문제가 되고 있으며, 이들 내성균의 대부분은 여러 가지 항생제 에 동시에 내성을 지니고 있어 사람에게 적절한 치료제의 부재 로 인한 사회적인 문제로 대두되고 있다(Frieden et al., 1993; Beam and Buckley, 2006). 특히 항생제를 투여한 축산 동물이 창선 해역의 지중해담치(Mytilus galloprovincialis) 양식장 및 육상오염원에서 분리한 대장균(Escherichia coli)의 항생제 내성