| Summary: | We report the presence of the <i>mcr-1</i> gene among 880 <i>Escherichia coli</i> clinical isolates collected in 13 hospitals from 12 Colombian cities between 2016 and 2019. Seven (0.8%) isolates were colistin resistant (MIC ≥ 4 µg/mL). These colistin-resistant isolates were screened for the presence of the <i>mcr-1</i> gene; five carried the gene. These five isolates were subjected to whole genome sequencing (WGS) to identify additional resistomes and their ST. In addition, antimicrobial susceptibility testing revealed that all <i>E. coli</i> isolates carrying <i>mcr-1</i> were susceptible to third generation-cephalosporin and carbapenems, except one, which carried an extended-spectrum β-lactamase (CTX-M-55), along with the fosfomycin resistance encoding gene, <i>fosA</i>. WGS indicated that these isolates belonged to four distinct sequence types (ST58, ST46, ST393, and a newly described ST14315) and to phylogroups B1, A, and D. In this geographic region, the spread of <i>mcr-1</i> in <i>E. coli</i> is low and has not been inserted into high-risk clones such as ST131, which has been present in the country longer.
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