Signs and symptoms

Some people who are infected with C. difficile never become sick, though they can still spread the infection. Others have bouts of watery diarrhea, often with nausea and abdominal pain and cramping. And an increasing number of people develop colitis or pseudomembranous colitis — severe inflammations of the colon. Signs and symptoms of these potentially life-threatening illnesses include:

• Profuse, watery diarrhea — 10 or more bowel movements a day
• Fever, often greater than 101 F
• Abdominal pain, which may be severe
• Blood or pus in the stool
• Nausea
• Dehydration
• Weight loss

Most people develop C. difficile infection during or shortly after a course of antibiotics, but signs and symptoms may not appear for weeks or even months after treatment has stopped.

Causes

Your intestinal tract contains hundreds of kinds of bacteria (intestinal flora). Many are essential, helping to synthesize certain vitamins and stimulating the immune system. And some play a key role in suppressing the growth of harmful organisms. But when you take an antibiotic to treat an infection, it often destroys these beneficial bacteria as well as the bacteria that's causing your illness. Without enough healthy bacteria, dangerous pathogens such as C. difficile can quickly grow out of control.

Once it takes hold, C. difficile can produce two virulent toxins that attack the lining of the intestine. The toxins destroy cells and produce pseudomembranes — telltale patches (plaques) of inflammatory cells and decaying cellular debris on the interior surface of the colon.

Almost any antibiotic can cause harmful bacteria to proliferate in the intestine, but ampicillin, amoxicillin, clindamycin, fluoroquinolones and cephalosporins are most often implicated in C. difficile infections. The use of broad-spectrum drugs that target a wide range of bacteria and the taking of antibiotics for a prolonged period increase the chance of infection. Other antimicrobials, including antiviral and antifungal drugs, and chemotherapy medications also can lead to an increased risk of infection with C. difficile.

How C. difficile spreads
Although a small number of people naturally have C. difficile in their intestinal tract, most people pick up C. difficile from the environment. The bacteria are eliminated in feces and spread to food, surfaces and objects when people who are infected don't wash their hands thoroughly. Although you can develop a C. difficile infection anywhere, the majority of cases occur in healthcare settings, where germs spread easily, antibiotics are common and people are especially vulnerable to infection.

In hospitals and nursing homes, C. difficile travels from patient to patient mainly on the hands of caregivers, but also on cart handles, bedrails, bedpans, toilets, bathing tubs, stethoscopes, thermometers — even telephones and remote controls. What's more, the bacteria produce hardy spores that can persist in a room for weeks or months.