Heteroresistance in Enterobacter cloacae complex caused by variation in transient gene amplification events.

ABSTRACT: Heteroresistance (HR) in bacteria describes a subpopulational phenomenon of antibiotic resistant cells of a generally susceptible population. Here, we investigated the molecular mechanisms and phenotypic characteristics underlying HR to ceftazidime (CAZ) in a clinical Enterobacter cloacae complex strain (ECC). We identified a plasmid-borne gene duplication-amplification (GDA) event of a region harbouring an ampC gene encoding a β-lactamase bla_DHA-1 as the key determinant of HR. Individual colonies exhibited variations in the copy number of the genes resulting in resistance level variation which correlated with growth onset (lag times) and growth rates in the presence of CAZ. GDA copy number heterogeneity occurred within single resistant colonies, demonstrating heterogeneity of G

SUBMITTER: Kupke J 

PROVIDER: S-EPMC11846870 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature