Comparison of physiologic tests used to identify non-beta-hemolytic aerococci, enterococci, and streptococci

Twenty-one reference strains and 88 clinical isolates of Aerococcus, Enterococcus, and Streptococcus species were tested for reactions in the Rapid Strep (RS) and modified conventional tests. We conclude that some but not all of the tests in the RS system could be used to substitute for conventional tests. RS tests for hydrolysis of arginine, esculin, L-pyrrolidonyl-naphthylamide, production of acetyl methyl carbinol (Voges-Proskauer), and fermentation of arabinose, lactose, mannitol, raffinose, and sorbitol were satisfactory substitutes for conventional tests. However, the RS tests for hydrolysis of hippurate and starch and fermentation of inulin were not satisfactory substitutes for conventional tests. We also conclude that, of the five test tube Voges-Proskauer tests, the Coblentz modification is the most discriminatory.