ABSTRACT:
Conventionally, susceptibility testing and pharmacokinetic/pharmacodynamic relationships are determined using standard inoculum (i.e., 10
5
–10
6
CFU). These may be poorly predictive of efficacy for high-inoculum infections, especially amongst β-lactamase-producing organisms. A. J. Kunz-Coyne, R. Gray, E. May, H. Curry, et al. (Antimicrob Agents Chemother 69:e01170-25, 2025,
https://doi.org/10.1128/aac.01170-25
) used a 96-h simulated endocardial vegetation model to describe pharmacodynamic efficacy, resistance emergence, and β-lactamase expression that resulted after clinically relevant exposures of antibiotics against three
Enterobacter cloacae
complex isolates, demonstrating that MIC values were often poorly predictive of efficacy in the model.