Laboratory Diagnosis, Treatment and Prevention of Shigella dysenteriae


The most common specimen for the laboratory diagnosis of Shigella dysenteriae is stool. Stool samples should be collected as soon as possible after the onset of symptoms, preferably within 48 hours. The samples should be transported to the laboratory under refrigeration or in a transport medium such as Cary-Blair or buffered glycerol saline. Stool samples should be processed within 2 hours of collection or stored at 4°C until processing.

Other specimens that can be used for the diagnosis of Shigella dysenteriae include rectal swabs, sigmoidoscopy or colonoscopy specimens, and blood cultures. Rectal swabs are less sensitive than stool samples and should be avoided if possible. Sigmoidoscopy or colonoscopy specimens can provide direct visualization of the colonic mucosa and allow for the collection of biopsy material or pus. Blood cultures can be positive in severe cases of shigellosis, especially in children and immunocompromised patients.

The quality and quantity of the specimens are important for the accurate identification of Shigella dysenteriae. The specimens should be representative of the infection and contain sufficient material for microscopic examination and culture. The specimens should also be free of contaminants such as urine, water, soil, or food particles. The specimens should be labeled with the patient`s name, date and time of collection, and type of specimen. The specimens should be accompanied by a request form that includes relevant clinical information such as age, sex, travel history, symptoms, duration of illness, and antibiotic treatment.