Identification of gram-positive anaerobic cocci by use of systems for detecting pre-formed enzymes.

Two systems for detecting pre-formed enzymes, RapID ANA and a prototype system from API, were compared in a blind study for their ability to identify 69 gram-positive anaerobic cocci isolated from clinical specimens. Both systems were able to identify Peptostreptococcus anaerobius, Ps. asaccharolyticus and Ps. micros accurately without the need for further tests. The prototype API system identified all isolates of Ps. magnus correctly, but the RapId ANA system misidentified several isolates as Ps. micros. Numerous different enzyme patterns were found with the indole-negative, butyrate-producing cocci (Ps. prevotii and Ps. tetradius), suggesting that this group of organisms may be heterogeneous. We conclude that kits for detecting preformed enzymes are of considerable potential for the identification of gram-positive anaerobic cocci in clinical laboratories.