CHO Cell Elongation Factor Found in Limp Lobster Disease Vibrio fluvialis Isolates     Ben D. Tall1, Mahendra H. Kothary1, Marion Periera1, Moraima Ramos-Valle1, Nancy Flores1, Aminat Johnson1, Sherill K. Curtis1, Venugopal Sathyamoorthy1, Robert H. Hall1, Sukadev Lavu1, Barbara McCardell1, and Robert C. Bayer2   1U.S. FDA, Washington, D.C. and 2University of Maine, Orono, ME               Recent studies in this laboratory have shown that Vibrio fluvialis isolates causing limp lobster disease possess a number of virulence factors found in other pathogenic Vibrio species. For example, they express a hemagglutinin whose N-terminal sequence shows significant homology to that of the mannose-sensitive hemagglutinin expressed by Vibrio cholerae. Further analysis of the V. fluvialis isolates revealed that they produced a factor that elongates(Chinese hamster ovary(CHO) cells. PCR analysis using primers specific for the cef gene, recently shown to encode the CHO cell elongation factor in V. cholerae, revealed that 4 of 19 isolates gave a strong PCR reaction product, while the remaining isolates produced a weak reaction product. Characterization and testing of the V. fluvialis isolates using a sealed suckling mouse assays revealed that the organisms caused fluid accumulation comparable to that produced by V. cholerae or Vibrio parahaemolyticus. The fluid accumulation was dose dependent, but no microorganisms were recovered from the intestinal contents. Thus, the elongation of CHO cells and the positive fluid accumulation response in sealed suckling mouse assays observed in the present study might be attributable at least in part to the expression of the cef gene in V. fluvialis. However, other yet-to-be characterized enterotoxins may also be produced.