Genomic characterization of colistin heteroresistance in <i>Acinetobacter baumannii</i> : Evidence for <i>lpxD</i> deletion and collateral sensitivity

This study demonstrates a high prevalence of both colistin resistance and CHR among A. baumannii bloodstream isolates. The identification of a partial lpxD deletion in the resistant subpopulation of the colistin-heteroresistant isolate suggests a potential contributory role of LPS-related alterations in CHR. Inverse antimicrobial activity profiles between populations highlight distinct resistance mechanisms potentially shaped by evolutionary trade-offs and collateral sensitivity.