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ETEST® Eravacycline for Antimicrobial Susceptibility Testing of Enterobacteriaceae and Enterococcus spp.: performance results from a multi-centre study

April 18 • P0293

L. Blanchard1, T. Armstrong2, G. Denys3, Y. Ying4, M. Kresken5/6, J. Carpenter3, V. Sauvonnet7, G. Zambardi7

1) bioMérieux, bioMérieux, Marcy-l’Étoile, France
2) bioMérieux Global Clinical Affairs, Marcy L’Étoile, France
3) Indiana University School of Medicine, Indianapolis, United States
4) med fusion, Lewisville, United States
5) Antiinfectives Intelligence GmbH, Rheinbach, Germany
6) Rheinische Fachhochschule Köln gGmbH, Cologne, Germany
7) R&D Microbiology, bioMérieux, La Balme-les-Grottes, France

Background: Eravacycline (XERAVA™) is a fluorocycline antibiotic developed by Tetraphase Pharmaceuticals Inc. for the treatment of complicated intra-abdominal infections. This study evaluated the performance of ETEST® Eravacycline (ERV), a new gradient diffusion strip, for determining the minimum inhibitory concentration (MIC) of Enterobacteriaceae, Enterococcus faecalis and Enterococcus faecium as compared to CLSI/ISO-20776-2 broth microdilution reference method (BMD).

Material/Methods: A set of 679 isolates including 542 Enterobacteriaceae and 137 Enterococci were tested at 4 clinical trial sites using ETEST® ERV and BMD. Results were analyzed for essential (EA) and category (CA) agreements, major (ME) and very major (VME) error rates using EUCAST breakpoints [E. coli: ≤ 0.5 (S), > 0.5 (R) mg/L, Enterococcus spp.: ≤ 0.125 (S), > 0.125 (R) mg/L) as well as FDA breakpoints (Enterobacteriaceae: ≤ 0.5 mg/L (S), Enterococcus faecium and Enterococcus faecalis: ≤ 0.064 mg/L (S)]. Results for Klebsiella pneumoniae were analyzed for EA only for EU claim as EUCAST breakpoints have not been established.

Results: Results are summarized in the table below. ETEST® ERV performance for Enterobacteriaceae and Enterococcus spp. met FDA and ISO acceptance criteria for EA (≥ 90%), CA (≥ 90%), ME (≤ 3%) and VME (≤ 2 or ≤ 3% respectively). A trend to overestimate E. coli, C. freundii and K. aerogenes MICs was observed.

Conclusions: Results of this study support the accuracy of ETEST® ERV for determining MICs of Enterobacteriaceae, and Enterococcus spp. As such, the ETEST® ERV is considered as substantially equivalent to BMD.

*In accordance with the FDA response to Susceptibility Testing Manufacturers Association (STMA) letter dated November 3, 2015, for drugs for which there is no intermediate breakpoint, the VME rate and/or the ME rate may be adjusted to exclude the VME results and/or the ME results that were within essential agreement (EA).

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