The Centers for Disease Control and Prevention (CDC) estimates that CDI affects nearly 500,000 people in the U.S. annually. . Not all CDI cases are reported to local health departments, as mandated by individual states. The disease is currently underreported and under-diagnosed. The CDC recognizes CDI as an unmet medical need and an emerging global public health crisis.

According to data from the National Hospital Discharge Survey and the National Inpatient Sample, the number of CDI cases tripled between 1993 and 2000 and more than doubled between 2001 and 2005. In 2009, the American Journal of Infection Control published survey findings from the Association for Professionals in Infection Control and Epidemiology (APIC) showing that 13 in every 1,000 hospitalized patients have CDI, which was 20 times more than previous estimates. And according to a new analysis of infection rates in 28 hospitals from 2008-2009, rates of CDI were 25 percent higher than rates of methicillin-resistant Staphylococcus aureus infection (MRSA).

Twice as many patients contracted CDI in U.S. short-stay hospitals in 2003 as in 1996, according to a CDC study. Patients who stay in the hospital up to two weeks are 13% more likely to contract CDI. The rate is 50% higher if the stay is longer than four weeks.

Although CDI most often occurs in hospitals, CDI is also afflicting otherwise healthy people in community settings. In one study, it was reported that 30% of patients who visited a general practitioner for CDI in 2006 acquired the disease outside of a health care setting.

There is a new hypervirulent and more infectious strain (NAP1/BI/027) of C. difficile emerging that has been contributing to the CDI epidemic in the United States, Canada, and northern Europe. This NAP1/BI/027 does not respond to fluoroquinolone-class antibiotics (generally prescribed for bacterial infections i.e. ciprofloxacin and levofloxacin) and produces 16–23 times more toxin than other strains. Because of this, the NAP1 strain does not respond as well to the most commonly prescribed antibiotic, metronidazole, which can cause more serious infection.

In 2008 there were 5,931 death certificates that cited C. difficile, according to the UK Public Health Service, and highly virulent strains of C. difficile bacteria have been identified in virtually every country, including the U.S., Canada, the Netherlands, France, UK, Switzerland, and Japan.

CDI is caused by an overgrowth of C. difficile, a spore-forming bacterium that lives in the digestive tract of about 3% of healthy adults. Naturally occurring in this small minority of the population, CDI is most often acquired through contact with and ingestion of the bacterium’s spores. Because of their resistance to heat and many disinfectants, C. difficile spores can remain in soil, air, water, and on most surfaces in hospitals and long-term care facilities for months and are difficult to eradicate.

C. difficile remains quiet in the digestive system’s natural "gut flora," the population of microorganisms that normally live in the digestive tract. These digestive bacteria perform a number of useful functions, such as assisting with food digestion and nutrient absorption in the digestive system. Relatively harmless in small numbers, C. difficile becomes problematic when a disruption of the gut flora allows the bacteria to overgrow and colonize the intestinal tract.

The number one culprit for C. difficile overgrowth is the use of broad-spectrum antibiotics, which eradicate not only the bacteria responsible for the disease and the antibiotic which was prescribed in the first place, but also the beneficial bacteria found in the gut flora in the colon. High risk antibiotics commonly linked to CDI include ampicillin, amoxicillin, clindamycin, fluoroquinolones and cephalosporins, but almost all antibiotics can cause CDI.

Once overgrown, C. difficile produces harmful toxins that can cause a variety of complications including pseudo-membranous colitis, toxic megacolon, perforations of the colon, sepsis, and death.

The primary risk factors for developing CDI include:

Antibiotic therapy. CDI is most closely linked to antibiotic use. Broad-spectrum antibiotics strip the digestive system of natural bacteria (gut flora) and allow harmful overgrowth of C. difficile to inhabit the digestive tract. The risk of developing CDI more than doubles after three days of antibiotic therapy.

Those at highest risk for developing CDI are patients in the intensive care unit with bacterial infections such as pneumonia, and patients who recently received immunosuppressive therapy.

Age. The elderly are disproportionately affected by CDI. The CDC found that overall CDI rates were highest in persons over 65 years of age, and explained that increased exposure to health care facilities and weakened immune systems in persons of advanced age may increase the risk of developing CDI.

Multiple and severe underlying diseases. Underlying diseases greatly weaken a patient’s immune system and may increase their risk of developing CDI.

Other factors that may increase the risk of developing CDI include prolonged exposure to a nasogastric tube and the use of stomach acid-suppressing drugs such as proton pump inhibitors (PPIs).

If you are at high risk for CDI, it is important to be aware of prevention methods (/LINK) that may decrease your risks of developing the disease.

Recurrence. If you’ve been treated for CDI in the past, you may be at high risk for developing a C. difficile infection again. 20-30% of patients with CDI will have recurrent infection, and up to 5% of patients will have more than six recurrences.

CDI recurrence may be due to persistent C. difficile spores in the digestive tract that were not eradicated by previous treatments.

Signs and symptoms of CDI include:

• Profuse, watery diarrhea
• Up to 10 or more bowel movements a day
• Fever, often greater than 101 oF
• Abdominal pain
• Blood or pus in the stool
• Nausea
• Dehydration
• Weight loss

Most people develop signs of CDI during or shortly after antibiotic therapy. However, some people may not exhibit symptoms of CDI for weeks or even months after taking antibiotics. Left untreated, patients with CDI can develop colitis or pseudomembranous colitis, which are severe inflammations of the colon.

It is important to identify the signs and symptoms of CDI early in order to prevent potentially life-threatening complications. Speak with your doctor immediately if you begin experiencing any of the symptoms listed above. You may have CDI.

Your doctor may suspect CDI if you’ve developed diarrhea during or shortly after hospitalization or have taken antibiotics in the last two months. Tests to confirm the presence of C. difficile include:

Stool test. The diagnosis is generally based on the detection of one or both of two toxins, enterotoxin (toxin A) and cytotoxin (toxin B), in the stool. Detection of cytotoxin B in the stool with a tissue-culture cytotoxicity assay is regarded for for its high sensitivity, but the results may take up to 3 days. A test known as a toxin-specific enzyme-linked immunosorbent assay (ELISA) is most often used because of its lower cost and more rapid turnaround time. New, rapid molecular tests are now being used in hospitals for detection of infection in as little as an hour, providing results early enough to guide treatment decisions and prevent hospital outbreaks.

Colon examination. Your doctor may conduct a sigmoidoscopy or colonoscopy in order to confirm CDI. A colonoscopy examines the entire colon, while a sigmoidoscopy looks only at the last two feet of intestine. In both procedures, your doctor uses a long flexible tube with a camera on one end to look for inflammation and pseudomembranes, which could suggest CDI.

Imaging tests. You may have a computerized tomography scan, which provides your doctor with detailed images of your colon. The scan can show a thickening of the wall of your colon, a common symptom in pseudomembranous colitis.

One or more of these tests may be needed to confirm the presence of Clostridium difficile. If you suspect you’ve developed CDI, speak with your doctor immediately to schedule an appointment for diagnosis.

CDI costs patients and health providers time and money. As mortality rates rise and CDI becomes an even greater concern, treating the infection has become costly, requiring prolonged hospital stays.

A single occurrence of CDI adds about $3,700 to a hospital bill and can mean three or more additional nights in the hospital. CDI accounts for more than $7.0 billion in health care costs each year in the U.S. and Europe combined. Taking into account the likelihood of recurrent infections, additional hospital stays and treatment, the costs are much higher.

In 2005, the Pennsylvania Health Care Cost Containment Council (PHC4) monitored CDI-associated healthcare costs in nearly 21,000 hospitals in Pennsylvania. The PHC4 reported that patients with CDI were hospitalized two-and-a-half times longer and faced hospital bills more than twice as high as patients who were able to avoid CDI.