Methods:The epf gene fragment was amplified by PCR from ZYH24 and cloned into prokaryotic expression plasmid pGEX4T-2 to form pGEX4T-2-epf.

• 方法根据GenBank S.；suis2epf基因序列设计引物；克隆ZYH24株epf基因片段并进行序列分析;