Preformed enzyme profiles of reference strains of gram-positive anaerobic cocci.

The preformed (constitutive) enzyme profiles of 30 type strains and reference strains of gram-positive anaerobic cocci were determined with two commercial systems, RapID ANA and a prototype system from API. Both systems identified Peptostreptococcus anaerobius, Ps. asaccharolyticus, Ps. indolicus, Ps. magnus and Ps. micros accurately, except for one strain of Ps. magnus misidentified as Ps. micros by the RapID ANA system. The indole-negative, butyrate-producing cocci (classified at present as Ps. prevotii and Ps. tetradius) produced several different, unique patterns with the prototype API system, but the results with RapID ANA were often misleading. Eight strains of Hare group cocci produced previously described profiles. Four strains of streptococci produced profiles easily distinguished from those of the gram-positive anaerobic cocci. We conclude that most gram-positive anaerobic cocci can be identified rapidly and reliably to the species level by their preformed enzyme profiles, providing that their underlying classification is sound. Problems were encountered with the butyrate-producing cocci, which appear to be a more heterogeneous group of organisms than is currently acknowledged; further taxonomic studies on these organisms are required.