Ki Cheol Song

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.

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.

Distribution and Antimicrobial Resistance of Vibrio parahaemolyticus Isolated from Korean Shellfish

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

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.

Defecation of Norovirus from the Oyster Crassostrea gigas by Depuration Following Translocation of the Growing Area

이매패류(이하 패류)는 분변-경구 감염 환을 통한 세균성 및 바이러스성 장관계 질환의 주요 전파 매개체로 간주되고 있다 (Butt et al., 2004). 이는 지역사회에서 장관계 질환이 유행하게 되면 해당 병원체가 하수 및 오수를 통하여 담수 및 기수 환경 으로 배출되게 되고(Da Silva et al., 2007; Iwai et al., 2009), 패 류는 여과섭식 작용을 통해 서식해역에 존재하는 미생물을 체 내에 농축하여 사람이 섭취하는 경우 재감염을 유발하기 때문 이다(Lees, 2000). 또한 전통적으로 패류를 생식하거나 살짝 익 혀먹는 식습관 때문에 오염된 패류에 의한 재감염의 위험성이 사라지지 않고 있다(Lees, 2000). 더욱이 70년대 이후 패류 냉 동가공품이 국제적으로 유통되면서 오염된 제품에 의한 감염 의 시공간적 범위가 확대되고 있다(Pinto et al., 2009; Polo et al., 2010). 이러한 패류에 의한 감염증 발생을 예방하고자 유럽 및 북미 대부분 국가와 남미 및 아시아 일부 국가에서는 엄격한 패류 위생 규정을 마련하였으며 유럽과 북미의 경우 그 역사가 백 여년에 이르고 있다(Lees, 2000). 동 규정에는 패류 생산해역 의 분변계 대장균 (fecal coliform) 농도 또는 패육 중의 대장균 (Escherichia coli) 농도를 기준으로 패류 생산해역의 등급을 구 분하고 그 등급에 따라 패류의 수확 전후 관리조건을 명시하고 있다(European Commission, 2004; US FDA, 2014). 그러나 이러한 노력에도 불구하고 패류 생식과 관련된 감염증이 지속 적으로 발생하고 있으며(Butt et al., 2004), 특히 노로바이러스 에 오염된 굴 섭취에 따른 장관계 질환이 세계적으로 유행하고 있다(Kroneman et al., 2008; Scallan et al., 2011). 오염된 활 패류 중 미생물의 농도를 저감화할 수 있는 방법 중 시설 내 정화 및 자연정화가 현재 상업적 이용되고 있는 대표적 인 것들이다(Lees, 2000; Dore et al., 2010). 시설 내 정화는 패 자연정화에 의한 양식굴(Crassostrea gigas) 중 노로바이러스 저감화 유홍식*·박용수·안세라·박큰바위·심길보·송기철·이태식

The Bacteriological Quality of Seawater in Kamak Bay, Korea

From 1998 to 2008, the bacteriological quality of seawater in Kamak Bay, Korea, was monitored. The total and fecal coliforms in seawater were monitored as bacterial indicators, and the level of fecal coliform contamination was used to evaluate seawater quality. In the southern shellfish growing area of Kamak Bay, the observed fecal coliform geometric mean (GM) and estimated 90th percentile did not exceed the quality standards for fecal coliforms in seawater in Korea and th USA (GM

Virulence Factors and Antimicrobial Susceptibility of Vibrio parahaemolyticus isolated from the Oyster Crassostrea gigas

장염비브리오균(Vibrio parahaemolyticus)은 그람음성, 무포 자, 호염성 간균으로 기수와 해양환경에 널리 분포하는 자연상 재 세균으로 부적절하게 취급된 수산물을 생식하거나 덜 익혀 섭취하여 발생하는 급성 장염의 주요 원인균이다(Su and Liu, 2007; Gode-Potratz et al., 2011; Ceccarelli et al., 2013; Zarei et al., 2012; Zhang and Orth, 2013; KFDA, 2016). 과거에는 표현형과 생화학적 특성을 바탕으로 장염비브리오균을 동정하 였으며 수산물과 해양환경에서 분리된 장염비브리오균 총 균 수를 근거로 잠재적 위해를 추정하였다(Malcolm et al., 2015). 그러나 PCR과 같은 분자생물학적 기법을 발달로 장염비브리 오균에서 병원성과 관련된 독소 유전자가 확인이 가능하게 되 었는데, 이 독소 유전자는 thermostable direct hemolysin (tdh) gene과 TDH related hemolysin (trh) gene이며 숙주 세포에 대 한 용혈과 세포독성을 유발하는 것으로 밝혀졌다(Broberg et al., 2011; Zhang and Orth, 2013; Letchumanan et al., 2015). 그래서 수산물에서 장염비브리오균 위해평가를 실시하거나 기 준규격을 설정하는 경우 특정 수산물에서 독소 유전자 보유 장 염비브리오균 출현 빈도를 고려하고 있다. 일반적으로 비브리오균은 대부분의 임상용 항균제에 감수성 이 큰 것으로 알려져 있다(Shaw et al., 2014; Yu et al., 2014). 양식 굴(Crassostrea gigas)에서 분리된 장염비브리오균의 독소 유전자 보유 및 항균제 감수성 김수경·안세라·박보미·오은경·송기철·김정완·유홍식*

Negative Correlation between the Prevalence of Norovirus and High Bacterial Loads of Escherichia coli in Oysters Crassostrea gigas

Seasonal variation in the prevalence of norovirus in oysters Crassostrea gigas was investigated and compared to levels of Escherichia coli, a fecal indicator in oysters. Oysters were collected from Iwon-myeon, Taean-gun, Korea, a primary production area for European Union export of oysters between 2013 and 2014. We observed seasonality in the prevalence of norovirus in oysters, with a higher prevalence and viral load detected during winter months. Oysters taken from production areas that complied with the European Union standard for raw consumption ( 230 MPN/100 g of E. coli). These results indicated that there is a negative correlation between the prevalence of norovirus and high levels of E. coli in oysters. Therefore, our results suggest that current food safety guidelines using only a bacterial fecal contamination indicator, E. coli, may not adequately assess shellfish production areas for viral and bacterial contamination.

Antimicrobial Resistance in Escherichia coli Isolated from Shellfish Farms on the West Coast of Korea

우리나라에서 패류는 연간 400천 톤 이상이 생산되고, 총 수산물 생산량의 14.3%를 차지하고 있으며 수천 년 동안 균들이인류에게 없어서는 안 될 중요한 동물성 영향을단백질 공급원이며 식량자원이다(MOF, 2013). 연안해역에 주로 서식하는 (Chae et al., 2005; Lee et al., 2005; Jeong et al., 2010). 패류는 육상과 인접해 있어 배수유역으로부터 유입되는 오염물질의 영향을 쉽게 받을 수 있으며 , 또한 이동성이 거의 없고, 여과섭이 활동을 통하여 먹이를 항균제가섭취하는 특성 때문에 패류는 해수 중에 부유하는 병원성 70% 세균, 바이러스 등을 체내에 쉽게 축적하게 된다(Grimes, 1991; Feldhusen, 2000). 최근 인구의 증가와 산업화로 인하여 일부 생활폐수, 산업폐수 내에그리고 사람이나 가축으로부터 배설된 분변 등의 오염원이 하수구나 있기하천을 통하여 해상으로 유입됨으로써 연안 해역의 수질에 악 내성균을영향을 미치고 있다(Hill et al., 2006; Lee et al., 2010). 또한, 기후변화의 영향으로 있다폭우의 빈도와 성에태풍의 강도 증가는 많은 강우를 발생시켜 분변성 오염물질들이 일시에 패류생산해역으로 유입되어 병원성세균 및 바이러스에 의해 쉽게 오염될 수 있다(Park et al., 2011; Park et al., 2012). 이러한분변성오염물질중에는항균제내성함유되어있어패류의위생학적안전성뿐만아니라해양상재세균의항균제내성획득에 미칠수있을것이다특히항균제를투여한 축산 동물이나 사람의 분변으로부터약제내성균이자연환경으로방출되기도하며사람이나동물에게투여한 완전히소화흡수되지않고섭취된항균제의경우약 정도가성분이변하지않은상태로배설된다는보고도있다(Kummerer, 2009). 한편, 대장균은사람이나동물의장상재하는정상세균총으로빈번하게투여되는항균제에노출되어 때문에항균제에의한내성획득과정을이해하고 모니터링함에있어매우유용한세균으로알려져(Levin et al., 1997). 이미국내에서도대장균의항균제내관한모니터링및연구가많이이루어지고있다(Chae et