Study on biological characteristics of five vibrio cholerae O139 strains

  Objective   To investigate the biological characteristics of five vibrio O139 strains isolated from patients and seafood.

  Methods   The basic biological characteristics, including growth properties, bio chemical characteristics, serological responses, drug sensitivities, were detected according to the routine methods recommended by "A manual of prevention and treatment for cholera". Multiplex PCR was used to detect the toxin genes, including ctxA、zot、ace、tcpA、tcpI、hlyA、rtxA、rtxC、ompU、toxR.The vero cell cytotoxicty assay was applied in testing the level of CT production of ctxA⁺ strains.

  Results   The biological characteristics and serological responses of 5 strains were similar to positive control strain Mo45.In 2 strains isolated from the heavy patients and 1 strain isolated from seafood. All of 11 toxin genes were found in the 3 strains, of which CT titers reached 1B160.In the other 2 strains isolated from light patients only 4 toxin genes were found.

  Conclusion   In the determinant of pathogenicity related gene in vibrio cholerae O139 strains there were others genes besides ctxA、ace、cep、zot toxin genes.