Introduction
In order to identify the types of bacteria in the Gastrointestinal tract, a fecal culture is a laboratory test. There are several bacterial species that can cause disease or infection. A healthcare provider can determine what kinds of germs are present by testing one’s waste or feces. This can assist them in determining the reason for digestive difficulties and the best course of action. The examination is short, painless, and comparatively simple. A stool culture or an enteric pathogens culture were its previous names.
Why Is a Fecal Culture Test Conducted?
A fecal culture test is performed when individuals experience chronic and persistent digestive issues, as stated by the American Association for Clinical Chemistry. Common symptoms associated with these problems include:
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Cramping.
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Vomiting.
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Presence of blood or mucus in the stool.
Before prescribing the test, the doctor will inquire about the possibility of a food-borne illness causing the symptoms. For instance, consuming raw eggs or improperly processed foods can lead to similar reactions. Additionally, the doctor will inquire about any recent travel outside, as individuals who have visited developing nations may be at a higher risk of food contamination.
Typically, individuals with healthy immune systems recover naturally from minor digestive infections without complications. However, those with weakened immune systems, such as infants, older adults, or individuals with specific conditions like HIV or AIDS, may require antibiotics to combat infections.
In some cases, the doctor may order multiple stool tests over a period of time to monitor the effectiveness of treatments or to determine if the infection is worsening.
How Is the Test Conducted?
In order to perform the fecal culture test, a stool sample is required, and there are various methods of collection. One can collect the sample in the following ways:
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Using Plastic Wrap: Place the plastic wrap loosely over the toilet bowl, securing it with the toilet seat. Carefully deposit the sample into a clean container provided by the healthcare provider.
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Using a Test Kit With Special Toilet Tissue: Some test kits include special toilet tissue for sample collection. Place the collected sample into a clean container provided by the healthcare provider.
It is important not to mix urine, water, or toilet tissue with the stool sample. For infants and young children wearing diapers, the following steps should be followed:
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Line the diaper with plastic wrap to prevent the mixing of urine and stool, ensuring a better sample.
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Send the sample back to the lab as soon as possible. Exclude toilet paper or urine from the specimen.
Once the sample reaches the laboratory, a technician places a portion of the specimen in a specialized dish. The dish is then filled with a gel that promotes the growth of bacteria or other microorganisms. If there is growth, the specific germs causing the infection are identified. The lab technician may also conduct additional tests to determine the most effective treatment approach.
How Does the Test Work?
Upon receiving the specimen in the laboratory, the first step is to visually inspect the specimen for its consistency and the presence of blood or mucus.
Microscopy is then conducted to examine the specimen for the presence of red and white blood cells, as well as to screen for the presence of ova, cysts, and parasites. If a parasitic infection is suspected, a comprehensive examination specifically targeting ova, cysts, and parasites should be requested, as these specimens require specific processing methods.
Some laboratories may also perform a lactoferrin test to detect the presence of fecal leukocytes. Lactoferrin, an iron-binding glycoprotein found in leukocyte granules, serves as a marker for leukocytes in the stool.
Culture is conducted by inoculating the fecal material onto various agar culture plates. These plates are made up of differential and selective media that are intended to isolate and initially identify particular organisms. Suspected pathogens are then formally identified at the species level using a combination of manual and automated methods.
Salmonella, Shigella, and Campylobacter species are routinely cultured in laboratories. However, testing for other pathogens, such as Yersinia enterocolitica or Shiga-toxin-producing Escherichia coli (E. coli) and Clostridium difficile, requires specialized laboratory techniques.
For organisms that are known to cause more serious illnesses and frequently need antibiotic treatment, such as Shigella and the Salmonella enterica serovars Typhi and Paratyphi, antibiotic susceptibility testing is typically carried out and reported. For public health reasons, Salmonella isolates are sent to a reference lab for serotyping.
What Are the Next Steps if the Test Is Positive?
In most cases of bacterial diarrhea, the condition is self-limiting, and management primarily focuses on supportive care. However, it is important to note that a positive stool culture result should not automatically trigger antibiotic therapy.
In many jurisdictions, certain enteric pathogens that cause diarrhea are required to be reported to public health authorities. It is the responsibility of the healthcare provider who requested the test to notify the appropriate authorities upon receiving the laboratory result. The notification requirements for specific infections should be outlined at the conclusion of the laboratory report.
What if the Result Is Negative?
If stool cultures yield negative results and diarrhea persists, it is important to consider re-evaluating the clinical condition and potentially conducting further investigations for nonbacterial causes (for example, parasites, viruses) and noninfectious causes of diarrhea (for example, inflammatory bowel disease or adverse effects of medication). For example, blood tests (such as complete blood counts with peripheral blood eosinophilia, parasite serology, and serum chemistry), endoscopies, antigen detection tests, nucleic acid amplification assays, and stool inspection for ova, cysts, and parasites may all be required. Consultation with a clinical microbiologist or an infectious diseases specialist may be necessary when an infectious cause is suspected, but conventional laboratory testing is unable to detect a pathogen, especially when thinking about additional testing or experimental therapy options.
Are There Risks Associated With Stool Culture?
A stool culture test has no known hazards or negative effects. The test is primarily painless, safe, and relatively private because the participant typically uses the restroom by themselves. If people are experiencing constipation, try eating a dinner heavy in fiber the night before to ensure a smooth stool flow the following morning. The feces sample may include infectious diseases that can transmit to other people, so make sure to properly wash one’s hands with soap and water after handling it.
Conclusion
The bacteria in the gastrointestinal tract can be identified by the doctor using a straightforward, risk-free method called a fecal culture. Some bacterial species can lead to illnesses and infections. Consult a physician if someone has chronic digestive issues, including nausea, vomiting, or diarrhea.
