Antibacterial Mechanisms of Polymyxin and Bacterial Resistance

Table 1

The structural differences between polymyxin B and polymyxin E.

Polymyxin	Fatty acid^a	R6^b
Polymyxin B1	MOA	D-Phe
Polymyxin B2	IOA	D-Phe
Polymyxin E1 (colistin A)	MOA	D-Leu
Polymyxin E2 (colistin B)	IOA	D-Leu

MOA: 6-methyloctanoic acid; IOA: isooctanoic acid; Phe: phenylalanine; Leu: leucine.
^bR6 means amino acid residue at position 6 on polymyxin.