Clostridium difficile – associated disease (CDAD)
Press release
11/08 - Statement by Gina Pugliese, RN, MS, and vice president of Premier Safety Institute, on the APIC C. difficile study
Recent studies point to changing epidemiology
Clues to possible factors - but uncertainty continues as to complete prevention & control
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In this module:
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Overview
Diarrhea caused by Clostridium difficile has been a hot topic in both the popular press and the scientific literature of late. There are increasing calls for including CDAD as a reportable disease to local public health. The Ohio Department of Health has responded to this changing epidemiology and added this disease to its reportable disease list as of January 2006. Most recently, McDonald and colleagues studied the National Hospital Discharge Survey (NHDS), a sample of almost 500 U.S., acute care hospitals in which over 300,000 patient records per year are abstracted, for incidence of Clostridium difficile–associated disease (CDAD) as coded in discharge records.(1) They found the incidence of CDAD rose from 31/100,000 population in 1996 to 61/100,000 in 2003. Among those 65 or older the incidence was over five fold higher (228/100,000), and geographic analysis revealed the Midwest and south had a statistically significant increase between 2000-2003, but overall rate in the northeast was highest. One caveat to remember is that ICD-9CM codes (medical record coding) are imprecise in that some studies demonstrate overestimated frequency of almost 32 percent compared to laboratory confirmed cases whereas others find coding underestimates cases by 50 percent. Another multi-center study by Sohn and others, using a combination of clinical and laboratory parameters for defining CDAD, did not find an increased rate at any of the participating hospitals.(2)
These differences point to the need for clear definitions. Up to eight percent of healthy adults carry C. difficile in their gastrointestinal (GI) tracts and experience no symptoms. For those hospitalized, this carriage increases as high as 40 percent; however there is new information that CDAD has emerged in persons considered "low-risk" for this disease, e.g., children or obstetrical patients.(3) Therefore distinguishing community-associated from healthcare-associated infection (HAI) is becoming less clear. This issue is particularly evident given that onset of symptoms of CDAD begins, on average, 5-10 days after receipt of antibiotics, but the range of onset can be as short as one day to 10 weeks.(4)
Clostridium difficile is an anaerobic, spore-forming, gram-positive bacillus that produces two important exotoxins: toxin A, an enterotoxin, and toxin B, which is primarily a cytotoxin. Any quick scan of the literature will reveal a wide range of terms such as Clostridium difficile –associated diarrhea, antibiotic-associated colitis (AAC), etc. In addition to definitions, however there is emerging consensus that CDAD is a broad term that recognizes the spectrum of illness caused by this microorganism and can extend from asymptomatic carriage (especially in neonates – as high as 70 percent) to life threatening toxic megacolon – dilation of the lower gastrointestinal tract due to presence of toxin produced by C. difficile.