confers_resistance_to_antibiotic confers_resistance_to_drug_class confers_resistance_to_antibiotic confers_resistance_to_drug_class peptide antibiotic colistin A colistin B phosphoethanolamine transferase conferring colistin resistance MCR phosphoethanolamine transferase ARO:3004268 antibiotic_resistance A group of mobile colistin resistance genes encode the MCR family of phosphoethanolamine transferases, which catalyze the addition of phosphoethanolamine onto lipid A, thus interfering with the binding of colistin to the cell membrane.