The combination of aztreonam with ceftazidime-avibactam is increasingly used for treatment of antimicrobial-resistant Gram-negative bacilli. Clinical laboratories are asked to perform susceptibility testing using this combination, but many laboratory directors have been unsure how to approach this. We discuss a recent paper in the Journal of Clinical Microbiology in which the investigators evaluated a promising method for testing this combination of two antimicrobials and a beta-lactamase inhibitor. We also discuss the rational for combining these agents, as well as what lab directors should consider before validating and offering this susceptibility testing. Guests: Dr. Trish Simner - Director of the Medical Bacteriology and Infectious Disease Sequencing Laboratories, Johns Hopkins Hospital Dr. Romney Humphries - Director of the Division of Laboratory Medicine and the Medical Director of the Microbiology Laboratory at Vanderbilt University Medical Center. Links: Multicenter Evaluation of an MIC-Based Aztreonam and Ceftazidime-Avibactam Broth Disk Elution Test This episode of Editors in Conversation is brought to you by the Journal of Clinical Microbiology and hosted by JCM Editor in Chief, Alex McAdam and Dr. Elli Theel. JCM is available at https://jcm.asm.org and on https://twitter.com/JClinMicro. Visit journals.asm.org/journal/jcm to read articles and/or submit a manuscript. Follow JCM on Twitter via @JClinMicro