RT Journal Article SR Electronic T1 Analysis of beta-lactam heteroresistance in CRE suggests a stage in the spectrum of antibiotic resistance JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.09.19.304873 DO 10.1101/2020.09.19.304873 A1 Victor I. Band A1 David S. Weiss YR 2020 UL http://biorxiv.org/content/early/2020/09/19/2020.09.19.304873.abstract AB Antibiotic resistance is a growing crisis that threatens many aspects of modern healthcare. Dogma is that resistance often develops due to acquisition of a resistance gene or mutation, and that when this occurs, all the cells in the bacterial population are phenotypically resistant which we term “homogenous resistance”. In contrast, heteroresistance (HR) is a form of antibiotic resistance where only a subset of cells within a bacterial population are resistant to a given drug. These resistant cells can rapidly replicate in the presence of the antibiotic and cause treatment failures. If and how HR and homogenous resistance are related is unclear. Using carbapenem-resistant Enterobacterales (CRE), we show that HR to beta-lactams develops over years of antibiotic usage and that it is gradually supplanted by homogenous resistance. This suggests the possibility that HR may often develop before homogenous resistance and frequently be a stage in its progression, representing a major shift in our understanding of the evolution of antibiotic resistance.Competing Interest StatementThe authors have declared no competing interest.