Bacillary dysentery

Bacillary dysentery is a type of dysentery, and is a severe form of shigellosis. Bacillary dysentery is a type of dysentery, and is a severe form of shigellosis. Bacillary dysentery is associated with species of bacteria from the family Enterobacteriaceae. The term is usually restricted to Shigella infections. Shigellosis is caused by one of several types of Shigella bacteria. Three species are associated with bacillary dysentery: Shigella sonnei, Shigella flexneri and Shigella dysenteriae. A study in China indicated that Shigella flexneri 2a was the most common serotype. Salmonellosis caused by Salmonella enterica (serovar Typhimurium) has also been described as a cause of bacillary dysentery, though this definition is less common. It is sometimes listed as an explicit differential diagnosis of bacillary dysentery, as opposed to a cause. Bacillary dysentery should not be confused with diarrhea caused by other bacterial infections. One characteristic of bacillary dysentery is blood in stool, which is the result of invasion of the mucosa by the pathogen. Transmission is fecal-oral and is remarkable for the small number of organisms that may cause disease (10 ingested organisms cause illness in 10% of volunteers, and 500 organisms cause disease in 50% of volunteers). Shigella bacteria invade the intestinal mucosal cells but do not usually go beyond the lamina propria. Dysentery is caused when the bacteria escape the epithelial cell phagolysosome, multiply within the cytoplasm, and destroy host cells. Shiga toxin causes hemorrhagic colitis and hemolytic-uremic syndrome by damaging endothelial cells in the microvasculature of the colon and the glomeruli, respectively. In addition, chronic arthritis secondary to S. flexneri infection, called reactive arthritis, may be caused by a bacterial antigen; the occurrence of this syndrome is strongly linked to HLA-B27 genotype, but the immunologic basis of this reaction is not understood.