infectious diseases
Polypeptide Antibiotics: Bacitracin, Colistin, Polymyxin B
Resistance
Resistance to colistin andpolymyxin Bis typically acquired via modifications to the lipid A moiety of the lipopolysaccharide outer membrane; these modifications lead to a more positively charged cell surface, which lacks affinity for the positively charged polymyxins. Acquired resistance can be carried on mobile genetic elements (eg,mcr-1, 2, 3[mobilized colistin resistance] plasmid), increasing the risk of horizontal transfer. Cross-resistance between colistin andpolymyxin Bis nearly 100%. 