Clinical blood samples are collected from patients suspected of having sepsis attending the Infectious Disease ER at the University Hospital of Örebro. In addition to the standard 4 blood culture flasks drawn per patient for routine diagnostics, an extra flask is taken for the present study. Of the approximately 500 clinical samples collected, so far 28 identified as positive in normal clinical routine diagnostics, were selected and are presented in this study. Pathogen ID was performed in a prototype ASTrID® system, directly from patient without waiting for a positive blood culture. The identification achieved sensitivity of 97% and specificity of 99.6%, compared to conventional analysis on positive blood cultures.
A pre-clinical study is currently performed in collaboration with the University Hospital of Örebro, Sweden. This study is one of several ongoing pre-clinical collaborations with Scandinavian hospitals.
AST results directly from blood
AST analysis on clinical isolates (E.coli) spiked in blood (inoculum consistent with 10 CFU/ml) was performed in a prototype ASTrID system, and results compared with broth microdilution according to ISO 20776. The AST results showed 99% essential agreement and 99% categorical agreement. The results are highly correlated with EUCAST guidelines.
AST results from positive blood cultures
AST analysis was performed in a prototype ASTrID system on bacteria isolated from positive blood cultures. Two clinical isolates in ten replicates of each species (P. aeruginosa, E. coli, K. pneumoniae, S. aureus, E. faecalis) were spiked into blood culture flasks and incubated until signaled positive. The phenotypic AST results obtained after six hours using showed 96% essential agreement and 95% categorical agreement compared to reference broth microdilution, of 476 bacteria-antimicrobial agent combinations tested.