Copro-culture, or stool culture, may be requested by a doctor when a person complains of complaints (symptoms) such as diarrhea, abdominal cramps, nausea and / or vomiting that are severe or last for several days.
Copro-culture is used to identify the presence, inside the intestine, of microorganisms other than those normally present (bacterial flora) because they are capable of causing disease (pathogenic germs).
To perform the test, a fresh stool sample is required, brought to the laboratory within 2 hours of collection and no special preparation is required.
The causes of gastrointestinal infection are many and not only caused by bacteria: co-culture, therefore, may be required in combination with other tests to simultaneously examine viruses, bacteria, fungi (fungi) and parasites, common causes of gastrointestinal infections.
In many cases the infections resolve spontaneously, without the need for any specific treatment; in other cases, it is necessary to carry out coproculture to identify the cause and choose the most suitable treatment to eliminate the microorganism responsible for the disturbances.
The bacteria responsible for diseases (pathogenic bacteria) can be introduced into our body through the consumption of contaminated food or drinks. Examples of sources that can be infected include:
- raw or undercooked poultry and meat
- unpasteurized milk
- water not adequately controlled or made potable from water courses or aqueducts
Travel, particularly if made to developing nations, can also increase the risk of suffering from gastrointestinal infections. Some bacteria, which live in equilibrium with the organism of the local inhabitants and do not cause them diseases, can cause violent gastrointestinal disturbances in the organism of the tourist who is not used to dealing with them. When traveling to these areas, it is a good idea to avoid drinking tap water, not using ice cubes, and not eating raw foods such as salads or fruit.
The most common signs of a bacterial infection are: prolonged diarrhea, presence of mucus or blood in the stool, abdominal pain and nausea. If diarrhea persists over time it can cause dehydration and electrolyte imbalance, dangerous situations especially for children and the elderly. Dehydration can cause ailments (symptoms) such as fever, dry skin, tiredness and lightheadedness.
In severe cases, hospitalization may be required to reintroduce lost fluids and electrolytes.The test
Stool culture is an examination (test) that allows to distinguish the bacteria that cause diseases (pathogens) in the lower intestinal tract from those that, on the other hand, are normally found in the digestive tract (normal flora) and do not cause disturbances.
The bacteria present in the feces of healthy people make up what is commonly called normal intestinal flora. These are microorganisms that play an important role in the digestion of food and exert control over the growth of pathogenic bacteria, limiting it.
The balance of the normal intestinal flora can be altered by the administration of broad-spectrum antibiotics as they inhibit their growth thus facilitating the development and proliferation of pathogenic bacteria such as, for example, Clostridium difficile, a germ resistant to antibiotics that causes diarrhea and pain abdominal.
The collection of feces
The stools to be analyzed must be collected no more than two hours before taking them to the laboratory in a special sterile container equipped with a scoop. They must not be contaminated with urine or water. If it is not possible to bring them to the laboratory within two hours of collection, they can be transferred to a vial containing a specific preservative and delivered to the laboratory as soon as possible. In children, stool is usually swab directly from the rectum.
Bacteria researched with coproculture
Generally, the bacteria searched for with stool analysis are:
- Campylobacter spp
- Salmonella spp
- Shigella spp
Based on the story of the person's health over time (medical history) and / or the locations to which he or she traveled, the doctor may include in the analysis (extended co-culture), or request separately, specific tests (tests) for other germs capable of causing (pathogenic) diseases:
- Yersinia enterocolitica
- Vibrio spp
In some cases the disease is not caused directly by the presence of bacteria but by their production of toxins. Although these types of germs can also be searched (by observing their growth in specific media), the tests used to detect them are aimed at the direct search for their toxins using the glutamate dehydrogenase (GDH) test. Examples of bacteria that produce toxins include:
- Escherichia coli O157: H7
- Clostridium difficile
There hemolytic-uremic syndrome, due in some cases to infection caused by a toxin-producing strain of the bacterium Escherichia coli, is a serious complication characterized by the destruction of red blood cells and kidney failure. Children, the elderly and people with weakened immune systems are the most affected by this disease.Results
The test is used to identify bacteria in the faeces that are not included in the normal intestinal flora. If the result of the examination shows their presence, an antibiogram should be performed, that is, an analysis that indicates the antibiotics to which the germs detected are most sensitive and allows the doctor to prescribe the most effective treatment.
Since copro culture looks for the presence of bacteria, if there is gastroenteritis not caused by this type of microorganism, the results will be negative. If the disturbances persist, it will be up to the treating physician to decide whether to continue investigating the cause by prescribing the search for parasites and / or viruses in the stool.