Shigella

∞ generated and posted on 2016.02.16 ∞

Enteric cause of bacillary dysentery.

Enteric here is meant to imply that Shigella is a member of family Enterobacteriaceae. Shigella is also, unsurprisingly, associated with as well as a fraction of cases of .

Very funny, and instructional!, song about Shigella:

From :

Bacillary dysentery was first differentiated from in 1887 and an etiologic agent, Bacillus dysenteriae , was isolated and described by in 1898. The subsequent painstaking process of epidemiological, physiological, and serological characterization of related dysentery bacilli culminated with the recommendations of the 1950 Congress of the International Association of Microbiologists Shigella Commission that Shigella be adopted as the generic name and that be designated A (), B (), C (), and D (). The next was the characterization of the basic virulence mechanism of shigellosis. By the late 1950s, it had been shown that can infect the of (this is the basis of the ) and it was also known that organisms can be grown in cultured . Nonetheless, it was the prevailing view as late as 1960 that shigellae cause disease by elaborating endotoxin while adhering to the surface of the . In 1964, however, it was conclusively demonstrated that S. flexneri causes disease by penetrating the .

…shigellosis is an unusually contagious infection. Under experimental conditions, of as few as 10 organisms can cause disease in 10% of volunteers, and ingestion of 500 organisms routinely causes disease in 50% of these volunteers . The reason(s) for the low 50% infective dose of Shigella species is not readily apparent, but the relative resistance of shigellae to when compared with or may facilitate the of small numbers of ingested organisms and provide the opportunity for organisms to infect the intestinal mucosa . The clinical signs of shigellosis range from mild to severe with frequent passage of , , small-volume . such as , , severe , and are the most common of shigellosis . Shigella infections are usually , but bacillary dysentery can be life-threatening in as a result of or . is most often associated with S. sonnei infection, whereas S. flexneri and S. dysenteriae may have a of diarrhea but are usually characterized by dysentery .