Authors’ contributions AM participated in the study design, conducted the experimental work, analyzed and interpreted data, and wrote the manuscript. LS conducted the selleck chemicals statistical analysis. KN and LA conceived the study, participated in the study design process and reviewed the manuscript. All authors read and approved the final manuscript.”
“Background The Gram-negative bacterium Shigella dysenteriae serotype 1 (SD1) is among the most virulent serotypes of the four Shigella (S.) species (S. dysenteriae, S. flexneri, Selleckchem CUDC-907 S. sonnei and S. boydii). SD1 is a causative agent of shigellosis, a severe form of epidemic bacillary dysentery in humans and primates
[1, 2]. Shigellosis is most prevalent in underdeveloped countries, with a mortality rate of 10-15% when untreated, killing about 1.1 million people of the roughly 120 million cases each year http://www.who.int/vaccine_research/diseases/diarrhoeal/en/index6.html. SD1 has an extremely low infectious dose of 10-100 organisms which has contributed to causing pandemic Shiga dysentery in several continents including Asia, Africa and Central America [2]. In addition to having a low infectious dose, multi-drug antibiotic resistance to more than six types https://www.selleckchem.com/products/sgc-cbp30.html of antibiotics (tetracycline, streptomycin,
chloramphenicol, etc.) has developed in several Shigella serotypes [3]. S. dysenteriae is also very closely related to Escherichia (E.) coli, with certain strains of E. coli (Shiga toxin-producing E. coli, or STEC) producing the potent Shiga toxins (Stx) of which Stx1 is produced by SD1 as well [4]. Shiga toxin causes cell death primarily in the microvascular endothelium. A vaccine that is protective against Shigella serotypes is of utmost importance, and several attenuated vaccines are currently being developed and tested in human volunteers. Components of the Type Three Secretion
System (TTSS) encoded by a virulence plasmid are also involved in the pathogenesis of shigellosis [5]. Also called the Mxi-Spa system in Shigella, the TTSS is responsible for triggering entry into host epithelial cells and apoptosis in macrophages [6, 7]. The TTSS is activated upon contact Pregnenolone with host cells, leading to the integration of translocators in the host cell membranes which then promotes transit of effectors into host cells [8]. The TTSS and effector proteins thereby play an important role in infection and intra- and inter-cellular spreading of bacterial cells in the host intestinal epithelium [9]. O-antigens present in the cell surface lipopolysaccharide (LPS) of Shigella also contribute to its virulence [2]. The Shigella O-antigen comprises of a toxic lipid A moiety embedded in the bacterial outer membrane, a core sugar region and an exposed terminal O-polysaccharide. In SD1, the O-polysaccharide consists of tetrasaccharide repeats that contain repeat units of three rhamnose residues and one N-acetylglucosamine [2].