Chonsin Kaknokrat, Matsuda Shigeaki, Theethakaew Chonchanok, Kodama Toshio, Junjhon Jiraphan, Suzuki Yasuhiko, Suthienkul Orasa, Iida Tetsuya
Department of Microbiology, Faculty of Public Health, Mahidol University, Bangkok 10400, Thailand.
Department of Bacterial Infections, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan.
FEMS Microbiol Lett. 2016 Jan;363(2):fnv222. doi: 10.1093/femsle/fnv222. Epub 2015 Nov 21.
Acute hepatopancreatic necrosis disease (AHPND) is an emerging shrimp disease that causes massive die-offs in farmed shrimps. Recent outbreaks of AHPND in Asia have been causing great losses for shrimp culture and have become a serious socioeconomic problem. The causative agent of AHPND is Vibrio parahaemolyticus, which is typically known to cause food-borne gastroenteritis in humans. However, there have been few reports of the epidemiology of V. parahaemolyticus AHPND strains, and the genetic relationship among AHPND strains is unclear. Here, we report the genetic characterization of V. parahaemolyticus strains isolated from AHPND outbreaks in Thailand. We found eight isolates from AHPND-suspected shrimps and pond water that were positive for AHPND markers AP1 and AP2. PCR analysis confirmed that none of these eight AP-positive AHPND strains possesses the genes for the conventional virulence factors affecting to humans, such as thermostable direct hemolysin (TDH), TDH-related hemolysin (TRH) and type III secretion system 2. Phylogenetic analysis by multilocus sequence typing showed that the AHPND strains are genetically diverse, suggesting that AHPND strains were not derived from a single genetic lineage. Our study represents the first report of molecular epidemiology of AHPND-causing V. parahaemolyticus strains using multilocus sequence typing, and provides an insight into their evolutionary mechanisms.
急性肝胰腺坏死病（AHPND）是一种新出现的虾类疾病，可导致养殖虾大量死亡。近期亚洲爆发的AHPND给对虾养殖业造成了巨大损失，并已成为一个严重的社会经济问题。AHPND的病原体是副溶血性弧菌，该菌通常会导致人类食源性肠胃炎。然而，关于副溶血性弧菌AHPND菌株的流行病学报道较少，且AHPND菌株之间的遗传关系尚不清楚。在此，我们报告了从泰国AHPND疫情中分离出的副溶血性弧菌菌株的遗传特征。我们从疑似感染AHPND的虾和池塘水中发现了8株分离株，它们的AHPND标记AP1和AP2呈阳性。PCR分析证实，这8株AP阳性的AHPND菌株均不具备影响人类的传统毒力因子基因，如耐热直接溶血素（TDH）、TDH相关溶血素（TRH）和III型分泌系统2。多位点序列分型的系统发育分析表明，AHPND菌株在遗传上具有多样性，这表明AHPND菌株并非源自单一的遗传谱系。我们的研究是首次使用多位点序列分型对引起AHPND的副溶血性弧菌菌株进行分子流行病学报道，并深入了解了它们的进化机制。
