Evaluation of a commercial enzyme immunoassay kit for the detection of Clostridium difficile toxin A.

A new enzyme immunoassay (EIA) kit developed for the rapid detection of Clostridium difficile toxin A in faecal specimens, Premier (Meridian Diagnostics), was evaluated using 101 faecal specimens. Sixty-nine specimens were positive for Clostridium difficile by isolation of the organism and by cytotoxicity in tissue culture. The EIA for toxin A was positive in 49 of these 69 cases. No specimen that was negative for cytotoxicity was positive by EIA. Eight of the 32 specimens negative by both EIA and cytotoxicity assay yielded Clostridium difficile by culture. In five of these cases the cytotoxigenic status of the isolate was determined, and four were positive. There was no direct relationship between cytotoxin titre and EIA reading.