FS-15A also undergone about 20kb deletion in large plasmid, no invasive gene deletion was found in FS-15A and Fs-15V. Ipa ABCD was expressed on the surfaces of FS-15A and FS-15V. FS-15A was avirulent, while FS-15V was virulent.

• FS-15A与FS-15V侵袭基因完整,但Tn5插入位点的不同可能是它们毒力表型不同的原因。