Abstract：Investigation on the prevalence of virulence genes among Shigella spp. from Fujian is helpful to determine the distribution and circulating mode of virulence genes from different groups and serotypes, evaluating their hazards and providing scientific laboratory evidence for shigellosis control and prevention. In this study, virulence genes, i.e, ipaH,set1（set1A and set1B）,sen and ial, in 104 Shigella isolates from Fujian,2005-2010,were detected by PCR. The positive rates of these genes and their distribution modes were analyzed. It was revealed that positive rates for ipaH、set1、sen and ial genes were 100%,36.54%, 66.35% and 64.42%，respectively. Notably, the positive rates of set1 were 85% and 6.25% for S. flexneri and S. sonnei,respectively. Based on their virulence gene distribution mode, the 104 Shigella strains were divided into 8 groups.Group IV was the dominant mode（67.5%）for S. flexneri, while Group VI was the dominant mode（39.06%）for S. sonnei. Meanwhile,the distribution modes of Group I, VII and V were relatively common in S. sonnei. These results indicated that ipaH could be used as a target gene for identification of Shigella spp., and that set1 was the mainly harbored virulence gene in S. flexneri. The observation that Group IV was the unique dominant circulating mode in S. flexneri and there were more relatively clustered modes in S. sonnei, suggested that the evolution process of Shigella spp. involved complicated differentiation, and that insertion and deletion of virulence genes was associated with variation and differentiation of Shigella spp.
2012, Vol. 28 
