Rectal Culture - An Overview

Introduction:

Rectal culture is the procedure for identifying bacteria or any other microorganism responsible for any condition related to the gastrointestinal tract, like food poisoning or gonorrhea. This is done to confirm the presence of an infection and identify the type of bacteria or microorganism responsible for its cause. The doctor suggests the rectal culture test when the relevant symptoms of infection of the digestive tract are visible. Rectal culture results are beneficial for the doctor when deciding the type of treatment.

How Is Rectal Culture Performed?

The rectal culture procedure is performed by placing a cotton swab in the rectum, which is rotated smoothly and removed. The sample collected is now sent to the laboratory, where the smear on the swab is placed in the culture media. After that, the sample is placed under the microscope to identify the type of germ or bacteria.

Let's have a look at what exactly a culture medium is, as it plays a really important role in the process of rectal culture or any other culture. A culture medium is a liquid or gel medium that, under favorable conditions, provides an environment for the microorganism to grow and multiply with the required essential nutrients and minerals in the laboratory setup. The culture of microorganisms is important for many reasons, like the identification of microbial species, diagnosis of infectious diseases, development of serological assays for vaccines, genetic studies, and obtaining antigens.

Why Is Rectal Culture Performed?

There could be multiple reasons why rectal culture is performed, such as:

• When the doctor suspects infection of the rectum or gastrointestinal tract after witnessing symptoms like gonorrhea. Gonorrhea is a sexually transmitted disease caused by bacteria, and one of the symptoms of this disease is rectal bleeding.

• When a person is hospitalized for any surgical procedure, they are screened for antibiotic-resistant organisms. This screening involves a method that requires samples from the nose and rectum, and hence, rectal culture is required.

• It is also done to check for vancomycin-resistant enterococcus (VRE) in the intestines of patients admitted to hospitals or nursing homes, as this microorganism can spread to other people.

• Rectal culture is also indicated in cases where fecal culture is not possible or getting feces samples is not possible.

Why Might a Doctor Order a Rectal Swab Culture and Sensitivity Test?

A rectal culture is done to know about gastrointestinal infection, while monitoring for any antibiotic-resistant bacteria, testing for sexually transmitted infections (STIs), and selecting the antibiotics to be administered. It is done to know about any infection present in the rectum, like gonorrhea and chlamydia. Sometimes, it can be performed instead of fecal culture due to the nonavailability of feces specimens.

What Types of Infections Can Be Diagnosed Using a Rectal Swab?

Rectal swabs can be used to detect infections of the rectum, which are known as proctitis. These infections include:

Inflammatory Bowel Disease (IBD): Diseases like Crohn’s disease, and ulcerative colitis tend to cause inflammation in many parts of the bowel, including rectum inflammation.

Sexually Transmitted Infections (STIs): STIs can enter the rectum through the anus. Many viral and bacterial infections can be observed in the rectum. These include:

• Gonorrhea.

• Chlamydia.

• Herpes simplex 2.

• Syphilis.

• Human papilloma virus (HPV).

Gastrointestinal Infections: Bacterial infections that cause food poisoning may cause infection of the rectum. These bacteria include:

• Salmonella.

• Shigella.

• Campylobacter.

If an individual has recently taken an antibiotic course, the bacteria Clostridioides difficile (C.diff) may infect the intestines and rectum.

Infant Food Protein Allergies: Infants may tolerate certain food proteins like dairy, milk or soy. This may lead to the development of inflammation in the intestines or rectum.

Infections Caused Due to Radiation Therapy: Radiation mucositis in the gastrointestinal tract may be caused by radiation therapy given for cancers. Radiation enteritis and radiation colitis are found to be common during targeted radiation given to the lower and upper abdomen. Radiation proctitis may be caused when radiation is given to the pelvic area.

What Are the Results of Rectal Culture?

Finding the normal range of microorganisms commonly present in the digestive tract is considered a normal result, indicating the absence of any infection. Abnormal results indicate the presence of an infection.

The infection can be:

• Enterocolitis - It is the inflammation of the gastrointestinal tract caused by parasites, fungi, bacteria, viruses, or other causes. It also involves enteritis of the small intestine and colitis of the large intestine.

• Bacterial Infections - Bacteria such as E. coli, Salmonella, Shigella, Clostridium, and Campylobacter cause gastrointestinal tract infections.

• Gonorrhea - Already explained in the previous section.

• Helicobacter Pylori Infection - H. pylori is a bacteria that infects the gastrointestinal tract. It causes inflammation and painful sores in the upper gastrointestinal tract.

• Proctitis - It is the inflammation and infection of the lining of the rectum.

There are results that show that the patient does not have an infection but is a carrier.

How to Prevent Infections That May Be Detected by a Rectal Swab?

Infections in the rectum are known as proctitis. This health issue can be prevented by:

• Screening partners before having sex to avoid sexually transmitted infections (STIs).

• Making use of condoms during sex may help protect against STIs.

• Dental dams can be used to avoid infections that spread orally.

• Being cautious about what to eat and observing safe food handling practices help avoid gastrointestinal infections from food poisoning. These should be practiced while traveling abroad. There are no measures available to prevent inflammatory bowel disease or radiation proctitis.

Conclusion:

Rectal culture is a safe test done for the identification of microorganisms responsible for the infection. Sample collection for rectal culture can be done by a professional or at home using the safe kits available. It is usually painless, but there may be pressure as the swab is inserted into the rectum. It is a safe procedure, and there is no risk to the patient's health.