Routine culturing for Clostridium difficile?

In order to determine whether routine culturing for Clostridium difficile was warranted or whether culturing a selected group of patients was adequate, we conducted a prospective trial of culturing all stool specimens for C. difficile. A total of 408 specimens from 297 patients was studied. Two hundred and eighteen stool specimens from 169 patients were selected on the basis of fulfilling one or more of the following criteria; (i) the stools were loose or watery; (ii) leukocytes and/or red cells were seen on direct microscopic examination; (iii) there was a history of antibiotic therapy; (iv) there was a diagnosis or history of inflammatory bowel disease. Fifty-three stools from 33 (19.5%) of these patients either yielded C. difficile by culture or had C. difficile cytotoxin demonstrable in fecal extracts. C. difficile was cultured in only one of 190 stools from the remaining 128 patients. Hence routine culturing of all stool specimens does not appear warranted provided that an accurate clinical history can be obtained and a careful macroscopic and microscopic examination is carried out.