Evaluation of the Cobasbact system for rapid antimicrobial susceptibility testing of positive blood culture broths.

The automated Cobasbact system was adapted for direct antimicrobial susceptibility testing of positive blood culture broths and its performance compared with that of the conventional Kirby-Bauer agar disc diffusion method using 278 positive blood samples. Overall, 1746 antibiotic-organism combinations were tested. Full agreement was 86.9% and essential agreement (i.e. including minor discrepancies) was 91.8%. The system would seem to produce acceptable susceptibility results within five hours after detection of a positive blood culture broth.