How do people get Clostridium difficile? What are the symptoms? What are the precautions? How long after starting treatment is a person contagious?

E.I.

Clostridium difficile is a bacterium that causes colitis (inflammation of the colon, or large bowel) and diarrhea. This infection is most common in a hospital setting, and it typically appears after a person has been treated with antibiotics for some other infection. The antibiotic alters the normal "flora" of microorganisms that live in the colon. This kills off helpful organisms that normally keep C. difficile in check. The C. difficile are then able to multiply and produce a toxin that causes the disease.

Where does the C. difficile come from? In some people, it is a part of the normal flora of the colon. In addition, the bacterium can be easily transmitted to hospitalized patients. It can be found in the hospital environment: in sinks, on bedrails, on plumbing, etc. Once a patient is infected with the bacterium, if he or she is put on antibiotics, conditions in the colon may allow the organism to cause disease.

Symptoms usually develop two or three weeks after antibiotics are started. Colon problems can range from mild diarrhea to a severe illness with fever, bloody diarrhea, abdominal pain and whole-body infection. The bowel can perforate, requiring surgery. Since the range of illness can be quite broad, it is difficult to definitively diagnose the disease based on symptoms and signs. The best way to prove the diagnosis is by testing the stool for the C. difficile toxin. If these tests are negative, but the clinician still suspects the disease, he or she may perform a sigmoidoscopy. In this procedure, a small, flexible fiberoptic scope is inserted into the patient's rectum. Typical findings, including so-called "pseudomembranes," tend to confirm the diagnosis. Also, sometimes it is only through sigmoidoscopy that the toxin can be found.

The most important part of treatment is stopping the offending antibiotic. If this cannot be done, or if the patient is very ill, then the doctor may prescribe antibiotics directed against C. difficile. Metronidazole (trade name Flagyl), taken orally, is the drug of choice. If this agent cannot be used, then vancomycin (Vancocin), also taken orally, is very effective. Once the patient is treated, he or she will usually respond well. There is about a 10 percent chance of relapse, but retreatment is usually effective. The patient may harbor the C. difficile bacterium for quite a long time, thus possibly spreading it to others. However, it is rather uncommon for a person to develop colitis after contact with someone harboring this organism. Remember that the second person would also have to be placed on antibiotics to allow replication of the bacterium in the colon.