Fecal Matters: It All Starts with a Stool Sample
By Molly Freeman, PhD, and Andrea Stokfisz, MPH
Imagine you go to your doctor’s office or an emergency room with more than just an upset stomach. Your doctor asks you questions, such as, “How long have you been sick?” and “Do you feel like you have a fever?” After more questions, and given your symptoms, your doctor considers that you might have a foodborne illness. Each year, foodborne illnesses, commonly known as food poisoning, affects about 1 in 6 (or 48 million) people in the United States. It can happen anywhere, to anyone, and from foods we might not expect.
Why Does Your Stool Sample Matter?
Your doctor may ask for a sample of “poop,” (or in doctor terms: your feces, or stool). But, only about one in five people already at their doctor’s office with diarrhea will give a stool sample. And, they are more likely to give one if the diarrhea is bloody or has lasted more than three days.
Testing the stool sample is important to track the “who, what, when, where, and why” of foodborne disease. Other people may also be ill with the same germ that you have, because they also ate the same tainted food. It is important that our public health system links people with similar laboratory results. These results can help you, your family, community, and even people in other states. When two or more people become sick from the same contaminated food or drink, the event is called a foodborne outbreak.
What Happens to your Stool Sample?
After you provide a stool sample, your doctor will test it for bacteria in a laboratory. Sometimes testing happens in your doctor’s office or in a commercial lab; or, if an outbreak is suspected, in a public health laboratory.
It can take up to three days to find out why you are sick and even longer for scientists to determine if your illness is part of an outbreak (see graphic).
Scientists in the lab, add your stool sample to a petri dish to start the testing. If bacteria grow--for instance, Salmonella (as shown in the petri dish below)--then the diagnosis is confirmed as positive, or in laboratory-terms, “culture confirmed.” Further lab testing can show which antibiotic medicines can kill it.
Additional testing at a public health lab, reveals the DNA “fingerprint”—the unique genetic code--of the bacteria. It is important for your doctor to know the specific details of the germ that made you sick.
These differences influence how your doctor treats your illness and how bad it might get-. These differences also provide essential information to scientists in public health laboratories. By tracking and finding similar DNA fingerprints of bacteria from sick people, “disease detectives”, or epidemiologists, can connect related-illnesses that could signal an outbreak.
Why is testing the stool sample and tracking foodborne illness important? The 1,000 or more reported outbreaks that happen each year reveal familiar culprits—like Salmonella and other common germs.
Other persons visiting the doctor may also feel sick from tainted food, making it important that our public health system reliably links people with similar lab results. Testing the stool sample is important for the patient, doctor, and public health officials to know if your sickness is connected to other illnesses. Tracking illnesses and investigating outbreaks helps to show how food can be made safer. Even though most people get better without visiting a doctor, CDC estimates that each year 48 million people get sick, 128,000 are hospitalized, and 3,000 die of foodborne diseases.
Testing, detection, and prevention matter. Do the stool sample. It could save your life; and, those of others.
* There are new tests that can be performed right in the doctor’s office, please check back for a later blog post on the pros and cons of these tests.