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Shigella
1University of Texas Medical School, Houston.
Abstract:
Shigella strains capable of producing illness possess a 140 megadalton plasmid that determines its property of epithelial cell penetration. In the classic presentation, there is a descending intestinal tract infection beginning with the passage of small numbers of large-volume stools and progressing to the passage of many small-volume stools that contain blood and mucus. Shigellae are efficiently transmitted to contacts in person-to-person spread and only 200 viable cells are sufficient to produce illness in susceptible persons. Shigellosis should be suspected in persons with severe diarrhea, in those with fever, when bloody stools are passed, or when stool smears contain many leukocytes. The current treatment of choice is TMP-SMX or, in adults, a quinolone (norfloxacin or ciprofloxacin).
Insights
Shigella bacteria cause illness using a plasmid for cell invasion, leading to severe diarrhea. Prompt diagnosis and treatment with antibiotics like TMP-SMX are crucial for managing shigellosis.
Area of Science:
- Microbiology
- Infectious Diseases
- Gastroenterology
Background:
- Shigella strains harbor a 140-megadalton plasmid essential for epithelial cell penetration, a key virulence factor.
- Shigellosis presents as a descending intestinal infection, characterized by severe diarrhea, fever, and bloody, mucus-laden stools.
Purpose of the Study:
- To summarize the key characteristics of Shigella infection, including its pathogenesis, transmission, clinical presentation, and treatment.
Main Methods:
- Review of existing literature on Shigella pathogenesis and clinical management.
- Analysis of the role of the virulence plasmid in epithelial cell invasion.
Main Results:
- A 140-megadalton plasmid is critical for Shigella's ability to penetrate epithelial cells.
- Shigellosis is highly contagious, with as few as 200 cells causing infection.
- Clinical suspicion is raised by severe diarrhea, fever, bloody stools, and fecal leukocytes.
Conclusions:
- Effective treatment for shigellosis includes trimethoprim-sulfamethoxazole (TMP-SMX) or quinolones (norfloxacin, ciprofloxacin) in adults.
- Understanding the plasmid-mediated virulence is key to combating Shigella infections.