Lai Hung-Chiao, Ng Tze Hann, Ando Masahiro, Lee Chung-Te, Chen I-Tung, Chuang Jie-Cheng, Mavichak Rapeepat, Chang Sheng-Hsiung, Yeh Mi-De, Chiang Yi-An, Takeyama Haruko, Hamaguchi Hiro-o, Lo Chu-Fang, Aoki Takashi, Wang Han-Ching
Institute of Biotechnology, National Cheng Kung University, 701, Taiwan, ROC.
Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, Tokyo 162-0041, Japan.
Fish Shellfish Immunol. 2015 Dec;47(2):1006-14. doi: 10.1016/j.fsi.2015.11.008. Epub 2015 Nov 6.
Acute hepatopancreatic necrosis disease (AHPND), also called early mortality syndrome (EMS), is a recently emergent shrimp bacterial disease that has resulted in substantial economic losses since 2009. AHPND is known to be caused by strains of Vibrio parahaemolyticus that contain a unique virulence plasmid, but the pathology of the disease is still unclear. In this study, we show that AHPND-causing strains of V. parahaemolyticus secrete the plasmid-encoded binary toxin PirAB(vp) into the culture medium. We further determined that, after shrimp were challenged with AHPND-causing bacteria, the bacteria initially colonized the stomach, where they started to produce PirAB(vp) toxin. At the same early time point (6 hpi), PirB(vp) toxin, but not PirA(vp) toxin, was detected in the hepatopancreas, and the characteristic histopathological signs of AHPND, including sloughing of the epithelial cells of the hepatopancreatic tubules, were also seen. Although some previous studies have found that both components of the binary PirAB(vp) toxin are necessary to induce a toxic effect, our present results are consistent with other studies which have suggested that PirB(vp) alone may be sufficient to cause cellular damage. At later time points, the bacteria and PirA(vp) and PirB(vp) toxins were all detected in the hepatopancreas. We also show that Raman spectroscopy "Whole organism fingerprints" were unable to distinguish between AHPND-causing and non-AHPND causing strains. Lastly, by using minimum inhibitory concentrations, we found that both virulent and non-virulent V. parahaemolyticus strains were resistant to several antibiotics, suggesting that the use of antibiotics in shrimp culture should be more strictly regulated.
急性肝胰腺坏死病（AHPND），也称为早期死亡综合征（EMS），是一种最近出现的虾类细菌性疾病，自2009年以来已造成重大经济损失。已知AHPND由含有独特毒力质粒的副溶血性弧菌菌株引起，但该病的病理仍不清楚。在本研究中，我们表明，导致AHPND的副溶血性弧菌菌株将质粒编码的二元毒素PirAB(vp)分泌到培养基中。我们进一步确定，在用导致AHPND的细菌攻击虾后，这些细菌最初定殖于胃中，并在那里开始产生PirAB(vp)毒素。在相同的早期时间点（感染后6小时），在肝胰腺中检测到PirB(vp)毒素，但未检测到PirA(vp)毒素，并且还观察到AHPND的特征性组织病理学迹象，包括肝胰腺小管上皮细胞的脱落。尽管先前的一些研究发现二元PirAB(vp)毒素的两个组分对于诱导毒性作用都是必需的，但我们目前的结果与其他研究一致，这些研究表明单独的PirB(vp)可能足以引起细胞损伤。在随后的时间点，在肝胰腺中检测到细菌以及PirA(vp)和PirB(vp)毒素。我们还表明，拉曼光谱“全生物体指纹”无法区分导致AHPND的菌株和不导致AHPND的菌株。最后，通过使用最小抑菌浓度，我们发现有毒和无毒的副溶血性弧菌菌株对几种抗生素均具有抗性，这表明在对虾养殖中抗生素的使用应受到更严格的监管。
