Oligopeptidase activity of gram-positive anaerobic cocci used for rapid identification.

Abstract

The amidase and oligopeptidase activities of peptostreptococci, peptococci and anaerobic strains of streptococci were studied. Most of the asaccharolytic species of the Genus Peptostreptococcus, which include Peptostreptococcus micros, Peptostreptococcus magnus, Peptostreptococcus asaccharolyticus, Peptostreptococcus indolicus, and Peptostreptococcus prevotii, had very strong peptidase activities. Peptostreptococcus productus and Peptostreptococcus anaerobius, which are strongly or weakly saccharolytic species, had very weak peptidase activities.Most of the anaerobic strains of streptococci were strongly saccharolytic but their peptidase activities were divided into two groups: a high activity group and a low activity group. The former group includes Streptococcus intermedius, Streptococcus pleomorphus, Streptococcus constellatus, and Streptococcus morbillorum. The latter group includes Streptococcus hansenii and Streptococcus parvulus.Anaerobic cocci were grouped into 7 phenons according to the analysis of their lower fatty acids as metabolic end products, and the indole and nitrate reduction tests. Several amidase and oligopeptidase tests, which are useful for differentiation at the species level in each phenon, were selected to prepare a new scheme for a rapid identification system of anaerobic cocci.