Comparison of Minitek Anaerobe II, API An-Ident, and RapID ANA systems for identification of Clostridium difficile.

Three commercial anaerobic systems, Minitek (BBL Microbiology Systems, Cockeysville, MD), API An-Ident (Analytab Products, Plainview, NY), and RapID ANA (Innovative Diagnostic Systems, Decatur, GA) were evaluated for ability to identify 45 Clostridium difficile isolates accurately. Minitek correctly identified 66% of C. difficile isolates to species, 27% were incompletely identified, and 7% were misidentified. Most of the discrepancies with Minitek were due to false negative biochemical results. API An-Ident correctly identified 9% C. difficile isolates to species, 89% were incompletely identified, and 2% were misidentified. Most of the API An-Ident discrepancies were due to the data base, which distinguished poorly between C. difficile, Clostridium hastiforme, and Clostridium sporogenes. RapID ANA correctly identified 100% of C. difficile isolates.