부산대학교 도서관

•A higher frequency of fosfomycin heteroresistance among MDR E. coli UTI isolates compared with other studies was found.•Reduced intracellular fosfomycin in subpopulations indicated that mutations in transporter genes are related to the heteroresistant profile.•Half of the resistant subpopulations overexpressed murA, which can lead to fosfomycin resistance with a low fitness cost.•Several genes were over- or underexpressed in resistant subpopulations, showing the complexity of this phenotype.•Most of the mutations in fosfomycin transporter and/or regulatory genes did not lead to an increase in fitness cost.