The escalating emergence of AMR is a growing public health concern, and a result of the use and misuse of antibiotics since its introduction. To prevent the development of resistance and preserve the efficacy of antimicrobial agents, new treatment strategies is of utmost importance. One possible approach may be to take advantage of collateral sensitivity, a phenomenon where bacteria acquiring resistance to one antimicrobial drug simultaneously became more sensitive to others. Our aim in this project is to investigate the generality of collateral sensitivity in clinical urinary tract isolates of E. coli. In addition, we wanted to investigate effects of the mutations on biofilm forming ability of the resistant mutants