Methods: Clinical isolates of Escherichia coli and Klebsiella pneumoniae (n=50) were obtained from internal repositories and the FDA-CDC Antimicrobial Resistance Isolate Bank. Five minutes of hands on time was required and comprehensive results were returned in about one hour. This panel contained assays for twenty-two resistance determinants including extended-spectrum β-lactamases (CTX-M, TEM, SHV), plasmid-mediated AmpCs (CMY, DHA, FOX), carbapenamases (KPC, NDM, VIM, IMP, OXA), and quinolone resistance determinants (gyrA, parC, QnrA/B/S/D, QepA). Specific variants of gyrA, parC, TEM, and SHV were identified with genotyping assays. Detected resistance determinants not previously identified were confirmed with sequencing.
Results: The following resistance determinants were detected and were in 100% agreement with expected resistance: CTX-M, TEM, SHV, CMY, DHA, KPC, NDM, VIM, IMP, OXA-181. Genotyping assays detected variants of TEM (E104K, R164H/S, G238S, E240K), SHV (D179G/N, G238S, E240K), gyrA (S83L/F/I, D87A/N), and parC (S80I, E84G/K/V) and were 95% concordant with sequencing. Disagreements were due to similar missense mutations (e.g. the gyrA D87A assay detected D87G).
Conclusion: The FilmArray System is amenable to rapid identification and genotyping of antimicrobial resistance determinants in an easy-to-use format. Additional studies are required to evaluate the relationship between resistance determinant typing and standard susceptibility testing.
This abstract contains information regarding assays that have not been reviewed by regulatory agencies for in vitro diagnostic use.
BioFire Diagnostics, LLC:
A. Hemmert, BioFire Diagnostics, LLC: Employee , Salary
R. Crisp, BioFire Diagnostics, LLC: Employee , Salary