Evaluation of quantitative antibiotic susceptibility testing by Vitek 2 as a routine method to predict strain relatedness of coagulase-negative staphylococci isolated from blood cultures.

To test the hypothesis that the strain relatedness of coagulase-negative staphylococci (CoNS) recovered from blood cultures can be inferred from automated antibiotic susceptibility testing (AST) results generated by Vitek 2, concordant or discordant AST results were compared with pulsed-field gel electrophoresis (PFGE) typing results for 119 CoNS blood culture isolate pairs. Concordant AST results were highly predictive of the strain relatedness of CoNS isolates.