This technology includes Escherichia coli isolate with MCR-1 gene which can be used in the development of diagnostic tests. The MCR-1 gene makes bacteria resistant to the antibiotic colistin, which is used as a last-resort drug to treat patients with multi-drug-resistant infections, including carbapenem-resistant Enterobacteriaceae (CRE). This gene exists on a plasmid, a small piece of DNA that is capable of moving from one bacterium to another, spreading antibiotic resistance among bacterial species.