Diagnosis of Shigellosis

History of diarrhea with eating in crowded places or on the street may give a clue about the possibility of Shigellosis. Laboratory tests are required to confirm the diagnosis.

A. Stool Examination

Stool (Fecal) examination is the most preferred diagnostic method.

Fresh, unstained samples of faeces are examined under a microscope.

Majority of the laboratories do not carry out specialized examinations unless instructed to do so. These special tests, however, will help to distinguish the subtypes of the bacteria involved. This in turn helps to treat the infection effectively.

B. Cultured Test

Feces are inoculated into the culture media that enhance the growth of the bacteria and confirmation of the bacterial presence is based on its characteristic growth in the media.

Deoxycholate Agar (DCA) or MacConkey Agar media is used.

C. Antigen Antibody Test

Serological investigation with species-specific sera helps to confirm characteristic bacterial colonies. This test is then carried out with type -specific sera.