Of forty eight isolates carrying virulence genes, 38( 79.2%) had SLT 2, eaeA and hly genes, taking the dominate virulence gene pattern, 8( 16.6%) had all of the four virulence genes 2( 4.2%)had both SLT 2 and hly genes respectively.

• 菌株毒力基因图谱以SLT2 +eaeA +hly为主 ；占 79.；2%25；其次为SLT2 +SLT1+eaeA +hly和SLT2 +hly；分别占 16