Comparative Evaluation of a Commercial System for Identification of Gram-Positive Cocci

Abstract

 The performance of a new commercial system for the identification of different groups of gram-positive cocci [BBL Crystal Gram-Positive (GP) Identification System; Becton Dickinson Microbiology Systems, Germany] was evaluated in comparison with two currently used commercial systems, the API Staph and the API Strep (bioMérieux Diagnostic, Germany). A total of 191 strains from seven different gram-positive genera comprising 32 different species were tested. For the BBL Crystal GP system, the correct identification rate without additional tests was 89.5% at the species level and 97.9% at the genus level. The findings suggest that the newly introduced BBL Crystal GP ID system provides an accurate method for the identification of gram-positive cocci, with an overall rate of correct species identification of about 90%, similar to that of the established API systems. Its major advantage is the extended spectrum of taxa included in a single test panel in contrast to the two different API test kits. Furthermore, the simplicity of use and the safe and rapid handling in a closed system conveniently accommodate existing laboratory workflow.