TABLE 2.

Amino acid alterations of PmrAB and PhoPQ.^a

E. coli strain	PmrA		PmrB											PhoP	PhoQ
	31	144	2	14	94	108	123	133–136	138	159	283	351	358	44	101	138	386
K-12 MG1655	T	G	H	L	P	D	E	VSRL	S	A	D	V	Y	I	D	S	V
CL-S
E015		S									G			L
E139	S						D					I		L
E154											G			L
CL-IR
E015R		S						DELb			G			L
E139R	S				L		D					I		L
E154R										V	G			L
CL-chrR
QIA18															E		L
QIA24											G			L
QIA32			R	Q					N		G			L		T
QIA33			R	Q					N		G			L		T
CL-mcrR
EC006													N
EC019		S				N							N
EC111			R			N			N							T

^aAmino acid alterations found only in colistin-resistant strains are indicated in bold. ^bDEL, deletion.