Rectal culture is a laboratory test to isolate and identify organisms in the rectum that can cause gastrointestinal symptoms and disease. Normally, many organisms are present in the lower gastrointestinal (GI) tract, but some can act as pathogens (disease-causing organisms) in the bowel.
A cotton swab is inserted into the rectum, rotated gently, and withdrawn. A smear of the swab is placed in culture media to encourage the growth of microorganisms. The culture is observed for growth at regular intervals in the laboratory. When growth is observed, the organisms can be identified. Further tests to determine sensitivity of the organisms to antimicrobial therapy may also be carried out (see sensitivity analysis).
A rectal examination is done by the health care provider.
There may be pressure as the swab is inserted into the rectum, but the test is usually not painful.
The test is performed when gastrointestinal distress is present and infection is suspected as a cause of the distress. It may be performed when a gonorrhea infection is suspected. It may be performed as an alternative to a fecal culture if it is not possible to obtain a feces specimen.
It may also be performed in a hospital or nursing home setting to see if someone carries vancomycin-resistant enterococcus (VRE) in their intestine, which can be spread to other patients. Patients with VRE are often maintained on isolation precautions.
The presence of organisms that are usually found in the body is normal.
Abnormal results may indicate an infection, such as bacterial or parasitic enterocolitis or gonorrhea. Sometimes culture shows the presence of vancomycin-resistant enterococcus, which means the patient is a carrier, but does not necessarily have an infection.
There are no risks.
Reviewed By: Kenneth Wener, M.D., Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, MA. Review provided by VeriMed Healthcare Network.