Evaluation of MicroScan Synergies plus Positive Combo 3 Panels for Identification and Antimicrobial Susceptibility Testing of Staphylococcus aureus and Enterococcus Species

Abstract

Background : Few studies have evaluated the performance of the recently introduced MicroScan Synergies plus Positive Combo 3 Panels (SIPC3) (Dade Behring Inc., USA). We evaluated the clinical efficacy of the panels in identification (ID) and antimicrobial susceptibility testing (AST) of Staphylococcus aureus and enterococci.Methods : To evaluate the panels' accuracy of identification, the results obtained using the test panels were compared with those obtained by using conventional biochemical tests in conjunction with VITEK 2 system (bio-Merieux, USA). In addition, the AST results obtained using the panels were compared with those obtained by performing CLSI broth microdilution.Results : The overall agreement between the approaches for the ID of S. aureus and enterococci was 100% and 96%, respectively. The categorical and essential agreements (CA and EA) for S. aureus were 98%, each. Very major errors (VME), major errors (ME), and minor error (mE) for S. aureus were 0.45%, 0.3%, and 4.2%, respectively. The majority of VMEs were for oxacillin (8.6%), penicillin (2.0%), erythromycin (7.9%), clindamycin (3.8%), and tetracycline (4.1%). For enterococci, the CA, EA, VME, ME, and mE were 88.8%, 93.7%, 4.4%, 0%, and 2.8%, respectively. The 80.5% (29/36) of Enterococcus faecium had concordant ID with the reference. Most of the categorical errors (3 VMEs and 14 mEs) were observed for quinupristin/dalfopristin (Synercid; Catalytica Pharmaceuticals Inc., USA).Conclusions : The panels compared favorably with conventional methods for the ID and AST of S. aureus. However, we expected a better performance for ID of E. faecium and AST using Synercid. (Korean J Lab Med 2010;30:373-80)