Colistin resistance in Gram-negative bacteria analysed by five phenotypic assays and inference of the underlying genomic mechanisms

Table 3 Mutations in associated colistin-resistance proteins in E. coli, K. pneumoniae and A. bereziniae resistant isolates

Species	Isolate	MIC (mg/L)^a	Amino acid change						Plasmid mediated resistance
Species	Isolate	MIC (mg/L)^a	MgrB	PmrB	PmrA	PmrC	PhoP	PhoQ	*mcr*
*K. pneumoniae*	404,507-16	≥64	D31N	L213M	A41T			S288N
	4,002,006-2	32	K3*
	16,003,084	32	C28S		A217V	G25S
	20,038,016	32	C39Y
	808,927-16	32	L8*			R152H
	808,927-16	32	L8*			D477N
	26,048,671	32	I41* (ISKpn26)^b
	800,138-16	32	I41* (ISEcp1)^b
	401,433-14	16	Q30*
	802,208-17	16	L4*		D149E
	187,701,876	16	C39G
	19,852,760	8			A217V	G25S
	809,156-16	4			D149E
*E. coli*	721,296-16	16		P97L		C27Y
	700,455-17	16		L197D		N12D
	709,006-16	16		E169K
	705,963-16	16		P97A
	700,099-17	8							mcr 1.1
	706,090-16	8			R81H	Q479E
	NCTC-13846	8						L467M	mcr 1.1
	KP-37-MCR-2-18	8				C27Y			mcr 2
	KP-37-MCR-2-18	8				L74I			mcr 2
	707,671-17	8				C27Y
	719,645-16	8							mcr 1.1
	705,498-12	4							mcr 1.1
*A. bereziniae*	502,814-14	≥64		Q242R

^aMIC values obtained by the reference broth microdilution method
^bNucleotide sequence interrupted by insertion sequence. * indicates premature stop codons or termination in the amino acid sequence indicates premature stop codons or termination in the amino acid sequence

ISSN: 1471-2180