2131. Multicenter Evaluation of Meropenem/Vaborbactam MIC Results for Enterobacteriaceae Using MicroScan Dried Gram-Negative MIC Panels

BACKGROUND: A multicenter study was performed to evaluate the accuracy of meropenem/vaborbactam on a MicroScan Dried Gram-negative MIC (MSDGN) Panel when compared with a frozen CLSI broth microdilution reference panel. METHODS: For efficacy, an evaluation was conducted at three US sites by comparing MIC values obtained using the MSDGN to MICs using a CLSI broth microdilution reference panel. A total of 560 Enterobacteriaceae clinical isolates were tested using the turbidity and Prompt(®*) methods of inoculation. For challenge, 95 Enterobacteriaceae isolates were tested on MSDGN panels at one site. For reproducibility, a subset of 14 organisms was tested on MSDGN panels at each site. MSDGN panels were incubated at 35 ± 2°C and read on the WalkAway System, the autoSCAN-4 instrument, and read visually. Read times for the MSDGN panels were at 16–20 hours. Frozen reference panels, prepared according to CLSI/ISO methodology, were inoculated using the turbidity inoculation method. All frozen reference panels were incubated at 35 ± 2°C and read visually. Frozen reference panels were read at 16–20 hours. FDA/CLSI breakpoints (µg/ml) used for interpretation of MIC results were: Enterobacteriaceae ≤ 4/8 S, 8/8 I, and ≥ 16/8 R. RESULTS: When compared with frozen reference panel results, essential and categorical agreements for isolates tested in the Efficacy and Challenge are as follows (see table). Reproducibility among the three sites were greater than 95% for all read methods for both the turbidity and Prompt* inoculation methods. CONCLUSION: This multicenter study showed that meropenem/vaborbactam MIC results for Enterobacteriaceae obtained with the MSDGN panel correlate well with MICs obtained using frozen reference panels using FDA/CLSI interpretive criteria. * PROMPT(®) is a registered trademark of 3M Company, St. Paul, MN, USA. Beckman Coulter, the stylized logo and the Beckman Coulter product and service marks mentioned herein are trademarks or registered trademarks of Beckman Coulter, Inc. in the United States and other countries. Vabomere(®) (Meropenem/Vaborbactam) is a registered trademark of Melinta Therapeutics, Inc. [Image: see text] DISCLOSURES: All authors: No reported disclosures.