[Sequence analysis of housekeeping genes recA, dnaE, and mdh in different serogroups or biotypes of Vibrio cholerae isolated from China].

Objective: To analyze sequences of the housekeeping genes including recA, dnaE, and mdh in different serogroups or different biotypes of Vibrio cholerae (VC) strains isolated from China.

Methods And Results: recA, dnaE, and mdh genes of Vibrio cholerae were obtained by PCR, sequenced and analyzed. Forty-four variable bases were identified in the 500 bases of recA gene of 18 VC strains, and the mutation of only 3 variable bases could result in changes of 2 amino acids. In the 600 bases of dnaE genes of 18 strains, 32 variable bases were found and only 1 contributed to an amino acid change. In the 367 bases of mdh genes of 18 strains, only 1 variable base was identified whose mutation involved an amino acid convertion. Toxic EI Tor biotype (EVC) strains and toxic O139 serogroup strains were closely related. Non-toxic strains of different serogroups or types were lowly related. Non-toxic and toxic strains of different serogroups or types were lowly related.

Conclusion: Toxic EVC and toxic O139 serogroup strains isolated from different areas of China may evolve from a common original strain, and toxic O139 VC strains may come from toxic EVC strains.