Sequence analysis of important toxic genes and housekeeping genes of Vibrio cholerae strains isolated from Guangdong province

  Objective   To analyse the sequences of important toxic genes and housekeeping genes of Vibrio cholerae strains isolated from Guangdong province.

  Methods   Toxic genes(ctxAB and tcpA), and housekeeping genes(dna E, hlyA, mdh and recA)of Vibrio cholerae were obtained by PCR, sequenced and analysed.

  Results   Toxic genes of 2 toxic EVC strains and 1 toxic O139 VC strain were analysed with those reported by others.The identities of ctxA and CtxA were 99.7%~100% and 98.8%~100%.The identities of ctxB and CtxB were 98.8%~100% and 96.8%~100%.The identity of tcpA of 3 toxic strains was 100%, and sequences of tcpA were the same as that of international standard EVC(N16961).The identities of dna E, hlyA, mdh, and recA of 3 toxic VC strains were 99.8%~100%, 100%, 99.5%~99.8%, and 100%.The identities of Dna E, HlyA, Mdh, and RecA of 3 toxic VC strains were 100%, 100%, 98.5%~99.3%, and 100%.The identities of dna E, hlyA, mdh, and recA of 3 toxic VC strains and 1 non-toxic O139 VC strain were 97.0%~97.2%, 91.8%, 94.1%~94.4%, and 96.9%.The identities of Dna E, HlyA, Mdh, and RecA of 3 toxic VC strains and 1 non-toxic O139 VC strain were 100%, 94.6%, 94.3%~98.5%, and 99.7%.

  Conclusion   Toxic EVC strains and toxic O139 VC strain isolated from Guangdong province are very closely related and there has been a high of recombination in their evolution.