Clostridium difficile is a species of bacteria.  It is often called C. diff (pronounced "see diff").  It is a gram-positive bacteria which belongs to the genus Clostridium. 

C. diff can live in the human colon (the large intestine) without causing any problems.  About 2-5% of adults have C. diff living in their colons. However, in some people, C. diff causes serious illness.  In these people, C. diff bacteria grow out of control in the colon.   The bacteria attack the lining of the intestines.  This causes a problem called C. diff colitis.  Colitis is inflammation (swelling) of the colon.

C. diff infection is getting more and more common in hospitals, nursing homes, and other health care facilities.    It kills about 14,000 people a year just in the United States.

C. diff infection 
The most common symptom of C. diff infection is severe diarrhea.  C. diff infection can also cause fever, belly pain, loss of appetite (not wanting to eat), and nausea. 

Some cases of C. diff infection are not very serious.  In other cases, people get very sick and even die. When people experience severe diarrhea from C. diff infection, they may become badly dehydrated (not have enough fluid in their bodies).  This can damage the kidneys leading to renal failure.  C. diff bacteria can also eat a hole in the intestines (perforation), which is very dangerous.

Once a person has C. diff infection, they can spread the infection to other people.  C. diff can live for a long time on surfaces like doorknobs, sheets, and medical equipment.  If a person with C. diff infection does not clean their hands, they can spread the bacteria to other people on their hands.

Who gets C. diff infection? 
C. diff infection usually happens in people who are taking antibiotic medicine.   Usually, the intestines are filled with good, healthy bacteria.  These healthy bacteria keep C. diff bacteria under control.  If antibiotic medicines kill the healthy bacteria, C. diff bacteria can grow out of control.

C. diff infection is also more common in:
 People in hospitals, nursing homes, and other health care facilities
 People who are 65 years old or older
 People with weak immune systems (in the body, the immune system is in charge of fighting disease)
 People who have just had surgery on their intestines
 People with colon problems, like inflammatory bowel disease or colon cancer
 People who take antacid medicines called proton pump inhibitors.  (These medicines cause the stomach to make less acid.  Normally, stomach acid helps keep bacteria like C. diff under control.)

How is C. diff infection treated? 
C. diff infection can be treated with some antibiotic medicines.  However, C. diff is an antibiotic-resistant bacteria.  This means that many antibiotic medicines cannot kill C. diff.  This can make C. diff infection very difficult to treat.  Many people with C. diff infection have relapses (they get better for a while, but then get sick again).  This happens to about one in every five people with C. diff infection. 

Usually, doctors try an antibiotic called metronidazole as the first treatment for C. diff infection. About three in every four people with C. diff infection get better after taking metronidazole for ten days.  When metronidazole does not work, doctors give other antibiotics, usually vancomycin or fidoxamacin.

In severe cases of C. diff infection which do not get better with antibiotics, doctors may do surgery to remove parts of the colon.

Fecal transplantation, especially for those with recurrent C. diff infections, has been shown to be more effective than oral vancomycin.

How can C. diff infection be prevented? 
Usually, C. diff infection can be prevented.  Hand-washing is one of the best ways to prevent C. diff infection.  If a person has C. diff bacteria on their hands, they can kill the bacteria by washing their hands with soap and water.   C. diff bacteria on surfaces (like doorknobs and medical equipment) can be killed with bleach.  Many hospitals and other health care facilities have special bleach wipes which kill C. diff.  Washing sheets and clothes with bleach and detergent also kills C. diff.

Alcohol does not kill C. diff, so instant hand sanitizer and alcohol wipes will not keep C. diff bacteria from spreading.

Hospitals and other health care facilities can also use "C. diff precautions" to prevent C. diff from spreading.   (Precautions are ways of being careful.)  When a patient has C. diff, health care workers can keep the bacteria from spreading by:
 Using gloves and then washing their hands every time they touch the patient, the patient's things, or anything in the patient's room
 Cleaning medical equipment with special bleach wipes every time they use it
 Cleaning the patient's things and the patient's room with bleach
 Giving patients with C. diff infection private rooms, or putting them only with other patients who have C. diff infection

References

Clostridium