An Evaluation of the API-20 Strep System (Rapid-Strep System)

Summary The API-20 strep (API System S.A., La-Balme-les-Grottes, France), which is identical to the Rapid-STREP system, marketed in the U.S. (API system S.A., Moutalieu-Vercieu, France), was compared with conventional biochemical and serological methods for the identification of streptococci. Ten strains of each of 27 species were tested. When the API-20 strep was read after 4 h incubation there was a 39.4% agreement with conventional methods. When the galleries were read after 24 h this figure rose to 78.8%. Of the remaining strains, 17% could not be identified because the profiles were not in the data base and 4.2% were identified differently from the identification obtained by conventional methods. The API-20 strep system was easy to perform and results were obtained in 24 h. The use of the system in combination with serological grouping reduces the misidentification of Streptococcus sanguis and Streptococcus salivarius , which can be differentiated by testing for levan and/or dextran production.