Serotypes and virulence genes of Shigella in Yuyao, Zhejiang, 2009-2014

Objective To understand the serotypes and virulence gene carriage of Shigella in Yuyao, Zhejiang province. Methods Serotyping was conducted for 82 Shigella strains isolated from diarrhea patients during 2009-2014, and 6 pairs of primers (ipaH, ial, set1A, set1B, sen and virA) were designed for the detection of Shigella virulence genes. Results Among the 82 Shigella strains, Shigella sonnei accounted for 42.5% and Shigella flexneri accounted for 57.5%. The carriage rates of IpaH, ial gene were 100%, and the carriage rates of set1A, set1B, Sen, virA genes were 79.3%, 76.8%, 96.3% and 91.4%, respectively. The positive rate of Set1 gene in Shigella flexneri was significantly higher than that in Shigella sonnei. Conclusion Predominant Shigella serotype varied with year, and differences in virulence gene carriage were found among the Shigella strains with different serotypes in Yuyao.