Stool culture is a laboratory test to isolate and identify organisms in the stools (faeces) that may cause gastrointestinal symptoms and overt disease. Normally, many organisms are present in the faeces, but some can act as pathogens (disease causing organisms). Some bacteria cause symptoms because of the toxins they produce.
Why is the test done?
The test is performed when gastrointestinal distress is present and an infection is suspected as a cause of the distress. It may be performed if severe, persistent, or recurrent diarrhoea of unknown cause is present. It may also be performed when long-term antibiotic therapy has been used.
How is it done?
There are many ways to collect the samples. You can catch the stool on a plastic sheet that is loosely placed over the toilet bowl and held in place by the toilet seat. Then put the sample in a clean container and send to the laboratory for testing. The stool sample is placed in culture media to encourage the growth of bacteria. The culture is observed for growth at regular intervals in the laboratory. When growth is observed, the organisms are identified. Further tests to determine sensitivity of the organisms to antimicrobial therapy may also be carried out.
How to prepare?
A collection container will be provided for the stool specimen. Return the sample to the laboratory as soon as possible.
What are the normal results?
Normal faecal organisms are present.
What are the abnormal results?
Abnormal results may indicate a bacterial infection. The common bacteria which can be isolated are Salmonella species (cause typhoid and paratyphoid), Shigella species (cause dysentery) and Vibrio cholerae (causes Cholera).