The performance of the BD Phoenix Automated Microbiology System (BD Diagnostic Systems, Sparks, Md.) was assessed for identification (ID) and antimicrobial susceptibility testing (AST) for the majority of clinically encountered bacterial isolates in a European collaborative two-center trial. A total of 469 bacterial isolates of the genera Staphylococcus (275 isolates), Enterococcus (179 isolates), and Streptococcus (15 isolates, for ID only) were investigated; of these, 367 were single patient isolates, and 102 were challenge strains tested at one center. Sixty-four antimicrobial drugs were tested, including the following drug classes: aminoglycosides, beta-lactam antibiotics, beta-lactam-beta-lactamase inhibitors, carbapenems, cephems, folate antagonists, quinolones, glycopeptides, macrolides-lincosamides-streptogramin B (MLS), and others. Phoenix ID results were compared to those of the laboratories' routine ID systems (API 32 Staph, API 32 Strep, and VITEK 2 [bioMérieux, Marcy l'Etoile, France]); Phoenix AST results were compared to those of frozen standard broth microdilution (SBM) panels according to NCCLS guidelines (NCCLS document M 100-S 9, approved standard M 7-A 4). Discrepant results were repeated in duplicate. Concordant IDs of 97.1, 98.9, and 100% were observed for staphylococci, enterococci, and streptococci, respectively. For AST results the overall essential agreement was 93.3%; the category agreement was 97.3%; and the very major error rate, major error rate, and minor error rate were 1.2, 1.9, and 1.3%, respectively. In conclusion, the Phoenix ID results showed high agreement with results of the systems to which they were being compared; the AST performance was highly equivalent to that of the SBM reference method.The clinical microbiology laboratory is confronted with an alarming increase of antimicrobial resistance on a global scale (7,8,9,13). Furthermore, the emergence of bacterial isolates with special resistance mechanisms such as oxacillin-resistant staphylococci or vancomycin-resistant enterococci constitutes a major problem, especially in intensive care units (1, 4). Both accurate and rapid diagnosis of oxacillin-resistant staphylococci and vancomycin-resistant enterococci has therefore become essential in the current health care environment.The BD Phoenix Automated Microbiology System (BD Diagnostic Systems, Sparks, Md.[BD]) is a newly developed instrument for the reliable and accurate identification and susceptibility testing for the majority of clinically encountered strains. The system is comprised of disposable panels, which combine both identification testing (ID) and antimicrobial susceptibility testing (AST), and an instrument which performs automatic reading at 20-min intervals during incubation. The system claims to provide accurate and rapid susceptibility results with easy workflow for the laboratory worker.We report on the ability of the Phoenix system to accurately perform ID and AST of clinical and challenge isolates in a large collaborative two-center trial involving th...