目的　探讨O139霍乱弧菌肠毒素 (CTX)核苷酸与O1群霍乱CTX毒素核苷酸序列异同。方法　用聚合酶链反应、DNA序列分析测定 2株O139群、2株O1群古典型、2株O1群ElTor型霍乱弧菌CTXA2 B亚单位核苷酸。结果　 2株O139群霍乱弧菌均含有CTXA2 B亚单位基因 ,O139群与O1群CTXA2 B核苷酸同源性为 97.1%～ 98.9%。结论　O139群与O1群霍乱弧菌CTXA2 B核苷酸基本同源。进一步证实两者CTX核苷酸序列一致。 Objective To investigate the similarities and differences between CTX toxin nucleotide sequences of O139 cholera toxin (CTX) nucleotide and O1 cholera virus. Methods Two strains of O139, two strains of classical O1 and CT2A2 B subunits of two O1 strains of ElTor Vibrio cholerae were sequenced by polymerase chain reaction and DNA sequence analysis. Results The two strains of Vibrio cholerae O139 contained CTXA2 B subunit gene. The nucleotide homology of CTXA2 B between O139 group and O1 group was 97.1% -98.9%. Conclusion O139 and O1 Vibrio cholerae CTXA2 B nucleotide homology. Further confirmed that both CTX nucleotide sequence consistent.