Existence of virulence genes in clinical Shigella sonnei isolates from Jiangsu Province of China: a multicenter study

Bing Gu, Wenting Fan, Tingting Qin, Xiaoxiao Kong, Chen Dong, Zhongming Tan, Ying Chen, Nana Xu, Ping Ma, Chang-Jun Bao, Huimin Qian


Background: The ability of Shigella to invade, colonizes, and eventually kill host cells is influenced by many virulence factors. The aims of this study were to assess the presence of 11 virulence genes of S. sonnei strains isolated in this country.
Methods: A total of 166 S. sonnei was collected from 13 cities of Jiangsu province through the provincial Centers for Disease Control (CDC) from 2010 to 2015 and then the distribution of virulence genes was detected by polymerase chain reaction (PCR) technology.
Results: Invasive virulence genes included ipaH and ial, in which the positive rate of ipaH was 100% while the positive rate of ial was 15.1% in S. sonnei. The classic pathway of regulating expression of Shigella virulence gene involved virF and virB gene, which positive rates were 33.7% and 24.1% respectively. The most common serine protease autotransporters of Enterobacteriaceae among S. sonnei were sigA (100%), followed by sepA (3.0%), sat (3.0%), pic (1.2%). Shigella enterotoxin genes include sen, set1A, set1B were found in 16.3%, 6.0% and 1.8% of the isolates, respectively.
Conclusions: This study provides baseline information on the distribution of virulence genes in clinical S. sonnei trains in Jiangsu province in China, which will be important for implementation of effective control strategies.