Evaluation of antimicrobial susceptibility of bacteria containing the qnr gene and FOX-5 β-lactamase by four automated systems


Corresponding author and reprint requests: M. C. Conejo, Microbiology, Faculty of Medicine, University of Seville, Seville, Spain
E-mail: cconejo@us.es


The accuracy and performance of four automated instruments (BD Phoenix, MicroScan WalkAway, VITEK-2 and Wider) were evaluated for susceptibility testing of fluoroquinolones and β-lactams with four clinical isolates of Klebsiella pneumoniae and the corresponding Escherichia coli transconjugants containing a plasmid carrying the qnr gene and coding for FOX-5 production. No major or very major errors were detected with the MicroScan system. Many of the minor errors for both quinolones and β-lactams clustered around the intermediate breakpoints.