Shigella infection is easily spread by faecal-oral contact or by contaminated water or food. It usually presents as a mild, self-limiting diarrhoeal illness.
S dysenteriae is more common in developing countries and causes a more severe illness with dysentery. S dysenteriae type 1 is a cause of haemolytic uraemic syndrome owing to its production of Shiga toxin.
Treatment is usually supportive in mild cases. Antibiotics may be useful to shorten the course of the illness and reduce shedding of the organism in stool.
Empirical antibiotics are recommended for children and adults with severe disease, for older adults, for malnourished or chronically ill patients, and to reduce spread (e.g., in institutions).
Prevention is paramount, including basic hygiene measures such as hand-washing, access to clean water, and cooking, especially in institutions and camps during natural disasters. Immunisations are in developmental stages.
Shigellosis is an important cause of diarrhoeal disease worldwide, most commonly affecting children <5 years old. However, about 40% of patients are adults.Shigella is a genus of the Enterobacteriaceae family, consisting of 4 species of aerobic, non-motile, non-lactose-fermenting gram-negative rods: S sonnei, S flexneri, S boydii, and S dysenteriae.
Shigellosis may spread from person to person (by faecal-oral contact), and via contaminated water and food. Outbreaks occur in institutions and in overcrowded areas where sanitation is poor. Although not equivalent, the term 'bloody diarrhoea' is sometimes used interchangeably by clinical practitioners.
History and exam
Key diagnostic factors
- presence of risk factors
- cramping abdominal pain
- features of haemolytic uraemic syndrome
Other diagnostic factors
- abdominal pain or tenderness
- signs of volume depletion
- increased bowel sounds
- febrile seizures
- delirium or somnolence
- exposure to contaminated water or food or direct faecal-oral contact
- age <5 years
- age >50 years
- poor hygiene and cramped conditions
- chronic illness or immunocompromise
- travel to endemic areas
- men who have sex with men
1st investigations to order
- stool microscopy, culture, and sensitivity
- serum urea and creatinine
Investigations to consider
- Shigella serotyping
- peripheral blood smear
- abdominal x-ray
- flexible sigmoidoscopy
suspected or confirmed shigellosis
Ashley Barnabas, MRCP
Consultant Hepatologist and Gastroenterologist
St Mark's and Northwick Park Hospitals
AB declares that he has no competing interests.
Dr Ashley Barnabas would like to gratefully acknowledge Dr Satish Keshav, Dr Gehanjali D.A. Amarasinghe, and Dr Richard Pollok, the previous contributors to this topic. Unfortunately, we have been made aware that Dr Satish Keshav has passed away.
GDAA and RP declare that they have no competing interests.
David Acheson, MD
Chief Medical Officer
Director of Food Safety and Security
US Food and Drug Administration
DA declares that he has no competing interests.
Franz Allerberger, MD, MPH
Professor of Clinical Microbiology
Austrian Agency for Health and Food Safety (AGES)
FA declares that he has no competing interests.
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