Validation of Aztreonam-Avibactam Susceptibility Testing Using Digitally Dispensed Custom Panels
Eric M. Ransom, Amelia Bhatnagar, Jean B. Patel, María-José Machado, Sandra Boyd, Natashia Reese, Joseph D. Lutgring, David Lonsway, Karen Anderson, Allison C. Brown, Christopher A. Elkins, J. Kamile Rasheed, Maria Karlsson
Abstract
antimicrobial susceptibility testing (AST) of aztreonam-avibactam is not commercially available; thus, most clinicians receive no laboratory-based guidance that can support consideration of aztreonam-avibactam for serious CPE infections. Here, we report our internal validation for aztreonam-avibactam AST by reference broth microdilution (BMD) according to Clinical and Laboratory Standards Institute (CLSI) guidelines. The validation was performed using custom frozen reference BMD panels prepared in-house at the Centers for Disease Control and Prevention (CDC). In addition, we took this opportunity to evaluate a new panel-making method using a digital dispenser, the Hewlett Packard (HP) D300e. Our studies demonstrate that the performance characteristics of digitally dispensed panels were equivalent to those of conventionally prepared frozen reference BMD panels for a number of drugs, including aztreonam-avibactam. We found the HP D300e digital dispenser to be easy to use and to provide the capacity to prepare complex drug panels. Our findings will help other clinical and public health laboratories implement susceptibility testing for aztreonam-avibactam.