Shigella sonnei (S. sonnei)

Shigella sonnei is a Gram-negative, rod-shaped, nonmotile, non-spore-forming bacterium and a species within the Shigella genus, responsible for approximately 90% of shigellosis cases alongside Shigella flexneri. It causes shigellosis, an acute infectious diarrheal disease transmitted via the fecal-oral route through contaminated food, water, or direct person-to-person contact, with symptoms including watery or bloody diarrhea, abdominal cramps, fever, and tenesmus appearing 1-7 days post-exposure. The bacterium invades the colonic epithelium, polymerizes host cell actin for intracellular spread, triggers cytokine-mediated inflammation, and leads to colitis with bloody, mucoid stools. While often self-limiting, untreated infections can result in complications like dehydration, seizures (especially in children), hemolytic-uremic syndrome, toxic megacolon, rectal prolapse, reactive arthritis, or bloodstream infections in immunocompromised individuals. Antibiotic resistance is increasingly reported, complicating treatment, and S. sonnei is the predominant cause of shigellosis in developed countries, originating from a clonal European ancestor around 1500 AD and now widespread globally.

Other names

Shigella sonnei bacteriumGroup D Shigella