An Approach to the Taxonomy of Gram-positive Anaerobic Cocci. 5. The Metabolism of Amino Acid

Abstract

This study showed that the metabolism of amino acids was useful in differentiating between the species of Gram-positive anaerobic cocci (GPAC). The best results were obtained from those whose taxonomic positions or biochemical reactions were in doubt. These include Peptococcus ( Pc.) asaccharolyticus, Pc. aerogenes,, Pc. magnus, Pc. anaerobius, Pc. variabilis, Pc. niger and Peptostreptococcus (Pst. micros. For these species which are easily recognized by carbohydrate fermentation amino acid utilization was less discriminatory. It should be noted, however, that the most frequently isolated GPAC from clinical materials are those which have a high capacity to utilize amino acids. This study has revealed that the carbohydrate fermenters are less commonly encountered in clinical specimens. This indicates that the species which are more active against amino-acids are more commonly pathogenic, and this phenomenon should therefore be exploited to identify and classify the GPAC.