Automated preparation for identification and antimicrobial susceptibility testing: evaluation of a research use only prototype, the BD Kiestra IdentifA/SusceptA system

Objective: The current BD Kiestra™ total laboratory automation (TLA) system automates specimen inoculation, incubation, and digital visualization of cultures prior to initiation of manual or semi-automated identification (ID) and antimicrobial susceptibility testing (AST). The current study aimed to compare the performance, in a clinical setting, of a fully automated research-use-only prototype, BD Kiestra™ IdentifA/SusceptA (automated system), to our current BD Kiestra™ TLA which utilizes manual or semi-automated IDs and ASTs (current system).

Methods: Clinical samples yielding significant growth after processing by the BD Kiestra™ TLA were tested in parallel for ID and AST by both systems. IDs and ASTs were determined by Bruker matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and BD Phoenix, respectively, with data stored and managed in the BD EpiCenter™. The automated system used a common inoculum preparation for both tests, whereas the current system used separate inocula. Results were compared to assess agreement between the systems.

Results: On initial testing, 89% of IDs (466/523) and 92.4% of IDs (484/523) for the automated and current ID systems, respectively, yielded acceptable MALDI-TOF log scores of ≥1.7. On repeat testing, the respective acceptable scores were 97.1% (508/523) and 98.1% (513/523). For initial ASTs, the automated and current systems yielded 97.5% categorical agreement for 7325 drug-organism tests. After omitting discrepant MICs that differed by only one dilution and categorical discrepancies that were not reproducible, 0.2% unresolved discrepancies remained thus (99.8% categorical agreement).

Conclusions: The automated prototype is suitable for development into technology that will provide clinical microbiology laboratories with significant advantages such as improved efficiency, standardization, reproducibility, reduced technical error and greater safety.