CLOSTRIDIUM DIFFICILE

Description

Clostridium difficile, or C. difficile (a spore forming gram-positive anaerobic bacterium), is recognized as the major causative agent of colitis (inflammation of the colon) and diarrhea that may occur following antibiotic intake. C. difficile infection represents one of the most common hospital (nosocomial) infections around the world. In the United States alone, it causes approximately three million cases of diarrhea and colitis per year. This bacterium is primarily acquired in hospitals and chronic care facilities following antibiotic therapy covering a wide variety of bacteria (broad-spectrum) and is the most frequent cause of outbreaks of diarrhea in hospitalized patients. One of the main characteristics of C. difficile-associated colitis is severe inflammation in the colonic tissue (mucosa) associated with destruction of cells of the colon (colonocytes). The disease involves, initially, alterations of the beneficial bacteria, which are normally found in the colon, by antibiotic therapy. The alterations lead to colonization by C. difficile when this bacterium or its spores are present in the environment.

The most serious manifestation of C. difficile infection, fulminant colitis (severe sudden inflammation of the colon), is frequently associated with very serious complications. This can be a life-threatening form of C. difficile infection and occurs in 3% of patients; most are elderly and debilitated from other diseases. Patients with this form of the disease experience severe lower abdominal pain, diarrhea, high fever with chills, and rapid heart beat. Timely treatment of fulminant colitis is essential; this condition can be life threatening.

Where are they found?

The disease involves, initially, alterations of the beneficial bacteria in the gut, by antiobic therapy. The alterations lead to colonization by the organism when this bacterium or its spores are present in the environment. In hospitals or nursing home facilities where C. difficile is prevalent and patients frequently receive antibiotics, C. difficile infection is very common. In contrast, individuals treated with antibiotics as outpatients have a much smaller risk of developing C. difficile infection. Laboratory studies show that when C. difficile colonize the gut, they release two potent toxins, toxin A and toxin B, which bind to certain receptors in the lining of the colon and ultimately cause diarrhea and inflammation of the large intestine, or colon (colitis). Thus, the toxins are involved in the pathogenesis, or development of the disease.

How do we get infections?

An important characteristic of C. difficile-associated diarrhea and colitis is its high prevalence among hospitalized patients. Thus, C. difficile contributes significantly to hospital length of stay, and may be associated in some elderly adults with chronic diarrhea, and occasionally other serious or potentially life-threatening consequences. One study demonstrated that 20% of patients admitted to a hospital for various reasons were either positive for C. difficile on admission or acquired the microorganism during hospitalization. Interestingly, only one-third of these patients developed diarrhea while the remainder were asymptomatic carriers serving as a reservoir of C. difficile infection. The organism and its spores were also demonstrated in the hospital environment, including toilets, telephones, stethoscopes, and hands of healthcare personnel. Individuals with C. difficile-associated disease shed spores in the stool that can be spread from person to person.

Spores can survive up to 70 days in the environment and can be transported on the hands and equipment of healthcare personnel who have direct contact with infected patients or with environmental surfaces (floors, bed frames, bedpans, toilets, etc.) contaminated with C. difficile. It is for this reason that thorough, terminal housekeeping procedures along with isolation practices be used to help control the spread of this organism. While patient-to-patient spread and environmental contamination can be some of the reasons of cross-infection in C. difficile-associated diarrhea and colitis, antibiotic therapy is the major risk factor for this disease. Thus, antibiotic use only when necessary is the most effective measure of preventing C. difficile infection.

Incubation period

Most cases develop 4 to 9 days after the beginning of antibiotic intake. It should be noted, however, that some patients develop diarrhea after antibiotics are discontinued and this may lead to diagnostic confusion.

Treatment

Therapy of C. difficile is directed against eradication of the microorganism from the colonic micro flora. No therapy is required for asymptomatic carriers. In noncomplicated patients with mild diarrhea, no fever, and modest lower abdominal pain, discontinuation of antibiotics (if possible) is often enough to alleviate symptoms and stop diarrhea. When severe diarrhea is present and in cases of established colitis, the patients should receive the antibiotics, metronidazole or vancomycin, for 10 to 14 days. Several clinical trials have shown that these antibiotics are equally effective in cases of mild to moderate C. difficile infection and more than 95% of patients respond very well to this treatment. Diarrhea following treatment with either vancomycin or metronidazole is expected to improve after 1 to 4 days with complete resolution within 2 weeks. However, some patients do not respond despite aggressive medical therapy and require surgical intervention.

Therapy for relapsing C. difficile infection - Although C. difficile infection usually responds well to treatment with metronidazole or vancomycin, approximately 15 to 20% of patients will experience re-appearance of diarrhea and other symptoms weeks or even months after initial therapy has been discontinued. The usual therapy for relapse is to repeat the 10 to 14 day course of either metronidazole or vancomycin and this is successful in most patients.

Prevention

Strict adherence to handwashing techniques and the proper the use of personal protective equipment such as gloves and gowns and the proper handling of contaminated wastes when performing patient care are effective in preventing the spread of the disease. Frequent, thorough terminal decontamination practices of frequently touched environmental surfaces and floors with an EPA approved disinfectant also help provide significant control of the spread. Proper isolation when patients are having bouts of diarrhea.