C. difficile in the hospital: Time to quit counting?

One of my IPs is assigned the task of looking at each inpatient with C. difficile and trying to determine whether the case should be classified as nosocomial. She says it drives her crazy. There's a new review in Clinical Infectious Diseases that looks at contamination of retail foods, primarily ground meat products, with C. difficile. The authors seem cautious in claiming that contamination of food leads to disease in humans, but given that we are increasingly seeing patients with C. difficile infection who have not had contact with healthcare facilities, it seems highly plausible. The editorial points out that new strains of C. difficile are constantly being imported into the hospital from the community. So when an inpatient who has never before been hospitalized develops C. difficile diarrhea on hospital day 12 is this from nosocomial acquisition or from the hamburger he ate a week before admission? Maybe I should quit driving my IP crazy.