DePaola Angelo, Nordstrom Jessica L, Dalsgaard Anders, Forslund Anita, Oliver James, Bates Tonya, Bourdage Keri L, Gulig Paul A
Gulf Coast Seafood Laboratory, U.S. Food and Drug Administration, Dauphin Island, AL 36528, USA.
Appl Environ Microbiol. 2003 Jul;69(7):4006-11. doi: 10.1128/AEM.69.7.4006-4011.2003.
Representative encapsulated strains of Vibrio vulnificus from market oysters and oyster-associated primary septicemia cases (25 isolates each) were tested in a blinded fashion for potential virulence markers that may distinguish strains from these two sources. These isolates were analyzed for plasmid content, for the presence of a 460-bp amplicon by randomly amplified polymorphic DNA PCR, and for virulence in subcutaneously (s.c.) inoculated, iron-dextran-treated mice. Similar percentages of market oyster and clinical isolates possessed detectable plasmids (24 and 36%, respectively), produced the 460-bp amplicon (45 and 50%, respectively), and were judged to be virulent in the mouse s.c. inoculation-iron-dextran model (88% for each). Therefore, it appears that nearly all V. vulnificus strains in oysters are virulent and that genetic tests for plasmids and specific PCR size amplicons cannot distinguish between fully virulent and less virulent strains or between clinical and environmental isolates. The inability of these methods to distinguish food and clinical V. vulnificus isolates demonstrates the need for alternative subtyping approaches and virulence assays.
对从市售牡蛎和与牡蛎相关的原发性败血症病例中分离出的代表性创伤弧菌菌株（各25株）进行了盲法检测，以寻找可能区分这两种来源菌株的潜在毒力标志物。分析了这些分离株的质粒含量、通过随机扩增多态性DNA聚合酶链反应检测460碱基对扩增子的存在情况，以及在皮下接种右旋糖酐铁处理小鼠中的毒力。市售牡蛎分离株和临床分离株中具有可检测质粒的比例相似（分别为24%和36%），产生460碱基对扩增子的比例相似（分别为45%和50%），并且在小鼠皮下接种右旋糖酐铁模型中被判定为有毒力的比例相似（各为88%）。因此，看来牡蛎中的几乎所有创伤弧菌菌株都具有毒力，而且针对质粒和特定PCR大小扩增子的基因检测无法区分完全有毒力和毒力较弱的菌株，也无法区分临床分离株和环境分离株。这些方法无法区分食品来源和临床来源的创伤弧菌分离株，这表明需要采用其他分型方法和毒力测定方法。
