Encyclopedia / S / Shigella



Shigellosis is an infection with shigella (a rod-shaped bacteria) that normally occurs in the digestive tract.


Shigella dysentery is a common disease, often self-limited and mild but occasionally serious, particularly in the first 3 years of life. Poor sanitary conditions promote the spread of shigella.

Shigella sonnei is the leading cause of this illness in the U.S., followed by shigella flexneri. Shigella dysenteriae causes the most serious form of this illness. Recently, there has been a rise in strains resistant to multiple antibiotics.


Shigella is transmitted primarily from person-to-person by the fecal-oral route. Outbreaks can occur in day-care centers. Occasionally, outbreaks can be caused by contamination of food by infected food handlers.


The usual symptoms are diarrhea associated with cramping, abdominal pain, chills, and malaise, headache, and fever. The diarrhea often contains blood and mucus. The patient may become progressively weaker and more dehydrated.


A stool sample will be analyzed for blood and white blood cells (mucus), and a culture may be done. Examination by sigmoidoscope (a tube inserted into the rectum to visualize the surface) reveals an inflamed, engorged mucosa (lining) with areas of ulceration.


Antimicrobial treatment may include Bactrim (trimethoprim-sulfamethoxazole) or Cipro (ciprofloxacin), usually for 7 to 10 days. Treatment of dehydration and hypotension (low blood pressure) is lifesaving in severe cases. Antispasmodics are helpful when cramps are severe.

Appropriate precautions should be taken both in the hospital and in the home to limit the spread of infection.


What tests are needed to diagnose this condition?

How long will this last?

What treatment will you be recommending?

Are there any side effects to this treatment?

How can this be prevented?

Shigella infection can be prevented by assuring that adequate hand washing technique is used by all involved in the preparation of food. If in doubt about the quality of food purchased in restaurants, delis or while traveling, stick to processed foods and bottled drinks.