Over the past several years nationwide, states have reported increased rates of C. difficile infection, noting more severe disease and an associated increase in mortality. CDI remains a disease mostly associated with healthcare (at least 80%). Patients most at risk remain the elderly, especially those using antibiotics. Although the elderly are still most affected, more disease has been reported in traditionally ‘low risk’ persons such as healthy person in the community, and peripartum women.
The increased rates and/or severity of disease may be caused by changes in antibiotic use, changes in infection control practices, or the emergence of the epidemic strain of CDI with increased virulence and/or antimicrobial resistance.
In 2004 the emergence of a new epidemic strain of C. difficile-associated disease causing hospital outbreaks in several states was reported by the Centers for Disease Control and Prevention (CDC) at scientific meetings.
The epidemic strain, identified in 2004 appears to be more virulent, with ability to produce greater quantities of toxins A and B. In addition, it is more resistant to the antibiotic group known as floroquinolones.
Like other strains of C. difficile, this new strain can be detected in the stool of infected patients by using laboratory tests that are commonly available in most hospitals. However, none of the FDA-approved tests differentiate between the various strains of C. difficile. Fortunately, because the control measures for outbreaks of any strain of C. difficile are similar, identification of the specific strain is not imperative for controlling outbreaks.