A coproculture is a stool examination which consists in looking for the presence of bacteria. It allows to find the cause of acute bacterial diarrhea and better target antibiotic treatment.

Un parasitological examination of the stool can also be done to check for the presence of parasites.

La coproculture is prescribed for acute diarrhea suggestive of bacterial infection, in case of:

• at least three loose or watery stools per day for more than 24 hours and less than 14 days
• fever greater than or equal to 40 ° C,
• presence of mucus or blood in the stool,
• abdominal pain,
• returning from a trip to a country where bacterial diarrhea is frequent (endemic area)
• diarrhea occurring in a hospitalized patient (risk of nosocomial diarrhea due to Clostridium difficile)
• toxi-infection alimentaire collective (TIAC)

It should be remembered, however, that most acute gastroenteritis is of viral origin; rotaviruses being responsible for more than 50% of cases, especially in infants. Stool culture has no interest in these cases.

In the event of chronic diarrhea, stool culture is also unnecessary.

The examination consists of taking a small sample (approximately 10 to 20 g) of stool.

The procedures may differ according to the analysis laboratories, and the sample can be taken on site or at home. Most often, the patient is provided with a sterile container, and a small spatula for sampling. The saddle should be issued on a clean garbage bag placed over the toilet bowl or in a special basin. Gloves are usually provided: it is then sufficient to take a small quantity, insert it into the pot (s) provided and evacuate the rest of the stool in the toilet.

The sample should be stored in the fridge and brought to the laboratory as quickly as possible (if it is not collected on site).

In infants or children, stools are collected with a swab.

In the laboratory, the stools will be analyzed (cultured) to look for around ten bacteria responsible for infectious diarrhea, including salmonella (Salmonella), Shigella, Campylobacter, etc.

Note that Salmonella is the most common cause of acute bacterial food-borne diarrhea. Depending on the result, the doctor will suggest an appropriate treatment.

The stool culture is only positive in 0,5 to 14% of cases, because many diarrhea is viral but also because the examination is not always easy to perform and interpret.