Final answer:
Shigella targets intestinal epithelial cells, leading to shigellosis with symptoms like severe diarrhea and potential complications like HUS. The bacteria employ effector proteins to enter cells, and certain strains produce Shiga toxin, aggravating the infection.
Step-by-step explanation:
Shigella bacteria primarily invade the intestinal epithelial cells of the human body. This invasive process causes a severe bacterial infection known as shigellosis or bacillary dysentery.
Upon ingestion, Shigella enters the intestine and begins its pathogenic journey by penetrating the mucosal barrier through M cells. The bacteria induce their uptake using effector proteins that trigger membrane ruffling, which is a process enabling their entry into the host cells. Once inside, Shigella can escape from the phagosome and replicate within the cytoplasm. As the bacteria multiply, they can move to adjacent cells, exacerbating the infection which can lead to ulceration of the mucosa, stomach cramps, fever, and severe diarrhea.
This disease can present with a range of complications including dehydration, rectal bleeding, and in more extreme cases, could potentially result in conditions like hemolytic uremic syndrome (HUS) or reactive arthritis. Moreover, S. dysenteriae type 1 produces Shiga toxin, which exacerbates the condition by targeting vital cellular mechanisms in endothelial cells. While the illness is often self-limiting, supportive therapy can be necessary to manage symptoms.