Evaluation of the Accelerate Pheno™ system to identify bacteria and determine antimicrobial susceptibility in positive blood cultures

Abstract

Introduction. New platforms have recently been developed to reduce response time of identification and antimicrobial susceptibility of bacterial isolates in positive blood cultures from patients with bloodstream infections. The Accelerate Pheno TM system (Accelerate Diagnostics, Inc.) provides information on pathogen identification and antibiotic susceptibility in approximately 1.5 and 7 hours, respectively. Methods. In this study we compared the Accelerate Pheno TM system with the standard procedure used in our laboratory. A total of 41 blood cultures were prospectively analysed with the Accelerate Pheno TM system and our standard methods, which include identification by MALDI-TOF mass spectrometry and antibiotic susceptibility testing (AST) by BD Phoenix system and E-test. Results. The correlation between the two methods using Cohen's kappa coefficient was 0.82; mean (sd) time of identification for MALDI-TOF MS was 0.7 (0.22) hours and 1.43 (0.14) hours for the Accelerate PhenoTM system. The mean (sd) time of AST with the BD Phoenix system was 15.85 (2.57) hours and with the Accelerate Pheno TM system 6.7 (0.12) hours. AST results showed an overall essential agreement of 92% for the minimal inhibitory concentrations (MIC) and an overall category agreement of 96%. Among Gram positive isolates, essential and category agreements of 100% were observed. In Gram negative isolates 10 discrepancies were detected, which were classified as 7 major and 3 minor errors. Discrepancies in the Accelerate Pheno TM system were observed particularly for P. aeruginosa. Conclusion. The Accelerate Pheno TM system can improve turnaround time in the management of patients with bloodstream infections. Sepsis | Accelerate Pheno TM | Microbiology| Blood cultures | DiagnosticsCorrespondence: ccasals@clinic.cat