“…This is an important issue, since polymyxins are considered to be the last resort of antibacterial agents against MDR E. coli [146]. Several clones harbour chromosomal pmrA and pmrB mutations and plasmid-mediated colistin resistance determinants (mcr-1,-3,-5,-9) [7,[18][19][20]38,56,57,60,102,105,106,111,130,141,142]. In addition, apart from the most frequently detailed ExPEC clones (ST131, ST69, CC10, ST405, ST38, ST457, ST410, ST48, ST58, ST88), a huge number of currently less widely known strains carry mcr-genes, such as ST57, ST156, ST224, ST345, ST393, ST850, ST3024, ST8900, ST12657 (Tables 3 and 4, Figure 2).…”