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

Abstract

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.

Virulence factors and molecular characteristics of Shigella flexneri isolated from calves with diarrhea

“…In agreement with previous studies, our study showed that set1A and set1B were only detected in the S. flexneri 2a strain. The plasmid encoding ShET-2 (encoded by sen) is known to be an enterotoxin hemolysin that elicits an inflammatory response during Shigella invasion [12,30]. As reported, both sen and set enterotoxins…”

“…are significantly associated with bloody diarrhea [30]. However, unlike ShET-1, ShET-2 could be harbored by different species of Shigella.…”

Virulence factors and molecular characteristics of Shigella flexneri isolated from calves with diarrhea

“…In agreement with previous studies, our study showed that set1A and set1B were only detected in the S. flexneri 2a strain. The plasmid encoding ShET-2 (encoded by sen) is known to be an enterotoxin hemolysin that elicits an inflammatory response during Shigella invasion [12,30]. As reported, both sen and set enterotoxins are significantly associated with bloody diarrhea [30].…”

“…Shigella, as an important invasive enteric infectious pathogen, may appear in different sporadic, epidemic, and pandemic forms [3], which remains the hallmark etiology of inflammatory diarrhea and dysentery and presents a serious challenge to public health, especially in developing countries and regions with substandard hygiene and poor quality water supplies [30]. All four species of Shigella can cause shigellosis, but S. flexneri is the most prevalent bacterial agent in shigellosis [31].…”

“…The Shigella enterotoxins ShET-1 and ShET-2 can alter electrolyte and water transport in the small intestine, which can cause diarrhea and dehydration [30]. ShET-1 is located on chromosomes and encodes the set1 (A and B subunit) gene, which is almost exclusively found in several S. flexneri serotype 2 isolates and is rarely found in other serotypes [38].…”