While it is true that bowel infections are a possibility from a colonscopy, the risks are rather low. A colonoscopy is not like another type of procedure or surgery, the colon is not a sterile environment. The colon usually contains stool, which as everyone knows, is full of bacteria. That is why feces smell so horrible. There is no way to make the colon sterile and you would not want to do it even if you could. The bacteria that live in the colon are an essential part of the function of the colon. Without the bacteria, the colon would not be able to process the stools and people would have a lot of other problems. Therefore the colonoscopy risks of a colon infection are rather low since there is really not a way to infect an area of the body that is already full of bacteria.
What can happen during the procedure is something like a colon perforation or biopsy infection. These types of colonscopy risks carry the possibility of a colon infection. This is because the layers of the colon have been penetrated, either on purpose or by accident. When this happens, there are going to be signs of infection and other problems because there are going to be bacteria in places that they are not supposed to be. It is fine for bacteria to live in the colon, it is not fine for them to exist outside of it.
In a colon perforation the thin walls of the colon develop a small hole and the contents of the colon enter the abdominal cavity. This can be caused by several different issues. The first is when the patient does not perform and adequate preparation and the colon is difficult to navigate. The presence of a lot of stool in the colon makes it very hard to figure out where the scope is located and what is normal versus abnormal tissue. This can lead the doctor to move the scope in ways that can be dangerous. They might be too vigorous with the scope and push it through the wall of the colon. Because there is air in the colon under pressure, the air then escapes through the holes and infects the belly.
Another common way to have an infection is to have a biopsy performed. If the biopsy gets too much tissue, it is also possible to have a perforation or get bacteria in places where they should not be going. This will give the signs of infection of fever, abdominal pain, and chills. While these bowel infections are rare, they are possible.