​Infectious Diseases and Microbiology - Bacillary Dysentery ( Shingella)

​Infectious Diseases and Microbiology - Bacillary Dysentery ( Shingella) 
Bacillary dysentery, also known as shigellosis, is caused by a group of bacteria called Shigella. Shigella is a type of Gram-negative rod-shaped bacterium, and there are four species of Shigella: S. dysenteriae, S. flexneri, S. boydii, and S. sonnei.

The primary mode of transmission is typically by the ingestion of fecal matter. Infection can occur when a small quantity of organisms (100-200) are consumed.

Shigella induces diarrhea, which exhibits clinical similarities to dysentery produced by enteroinvasive E coli (EIEC). The symptoms consist of fever, abdominal cramps, and the presence of blood and mucus in stools during episodes of diarrhea. S dysenteriae also secretes Shiga toxin, which is linked to more severe illness and the occurrence of hemolytic uremic syndrome (HUS).

Shigella possesses various virulence factors, including as genes necessary for invasion, endotoxin production, and Shiga toxin production. Similar to Salmonella, Shigella infiltrates the body by penetrating intestinal M cells. Subsequently, it evades the endosomes, duplicates in the cytoplasm, and extends horizontally to neighboring enterocytes. Cellular breakdown triggers an immune response in the host. Shiga toxin is unnecessary for the occurrence of dysentery. Shiga toxin causes the cleavage of 28S RNA, leading to the death of endothelial cells in a way that is exactly the same as that of enterohemorrhagic E. coli.
 Similar to Salmonella, Shigella bacteria do not digest lactose and can be identified in stool cultures using several selective and differential diagnosis media. Shigella bacteria, unlike Salmonella, do not generate hydrogen sulfide (H2S) and are unable to move.

Therapeutic intervention Mild cases of the condition can typically be managed with fluid and electrolyte replacement alone, while more severe cases may require the administration of antibiotics such as ceftriaxone, ciprofloxacin, or trimethoprim-sulfamethoxazole for treatment. Prevention entails the implementation of appropriate sanitation practices and the maintenance of good personal hygiene.