PROBLEM TO BE SOLVED : To provide an antibody directed against MDR strains of E. coli with improved specificity to be used for the prevention or treatment of E. coli infections caused by LPO O25b carrying strains. SOLUTION : The invention provides : an isolated antibody that specifically binds to O25b antigen of multi-drug resistant (MDR) E. coli strains; its medical and diagnostic use; and a method of preparing the antibody. The invention further includes an isolated nucleotide sequence, plasmids and host cells to be used in preparing the antibody; and an isolated epitope recognized by the specific antibody. SELECTED DRAWING : Figure 6 COPYRIGHT : (C)2019, JPO&INPIT