Clostridioides difficile, also known as C. diff, is a bacterium that causes diarrhea and colitis. A 2015 CDC study found that it caused almost half a million infections among patients in the United States in a single year. An estimated 29,000 deaths are directly attributable to C. diff infections, making it a substantial cause of infectious disease death in the United States.
The Standardized Infection Ratio (SIR) is a statistic used to track healthcare associated infections (HAIs) over time, at a national, state, and facility level. The SIR compares the actual number of HAIs at each hospital, to the predicted number of infections.