Detection of the mcr-1 Colistin Resistance Gene in Carbapenem-Resistant Enterobacteriaceae from Different Hospitals in China

DOI: 10.1128/AAC.00440-16

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FIG 1
Chromosomal integration of mcr-1 gene. Arrows denote open reading frames (ORF), with red, gray, yellow, and white arrows denoting mcr-1, pap2, ISApl1, and neighboring chromosomal genes (illustrated by locus_tag in ST156 strain SE11 [GenBank accession no. AP009240]), respectively. The small black arrows adjacent to ISApl1 denote the inverted reverse repeats (IRR). The 2-bp putative target duplicated sequences for TnApl1 are underlined.

TABLE 1

Characteristics of MCR-1-producing E. coli strains and their E. coli J53 transconjugants^a

E. coli strain	ST	β-Lactamase(s)	Plasmid	MIC (μg/ml)^b
E. coli strain	ST	β-Lactamase(s)	Plasmid	SAM	AMC	CFZ	CAZ	CTX	FEP	ATM	IMP	MEM	AMK	GEN	CIP	LVX	MXF	TZP	SXT	TET	CHL	COL
CDA6	167	NDM-5, CMY-2, TEM-1	ND	>16/8	>16/8	>16	>16	>32	>16	≤2	>8	>8	≤8	<1	>2	>8	>4	>64/4	>2/38	≤2	8	>2
BJ10	156	NDM-5, TEM-1	ND	>16/8	>16/8	>16	>16	>32	>16	>16	>8	>8	≤8	>8	>2	>8	>4	>64/4	>2/38	>8	>16	>2
BJ13	457	CTX-M-14, CMY-2, TEM-1	ND	>16/8	>16/8	>16	>16	>32	>16	16	>8	4	≤8	>8	>2	>8	>4	>64/4	≤0.5/9	>8	8	>2
CDA6-mcr-T	ND	—	IncX4	≤4/2	≤8/4	≤4	≤1	≤1	≤2	≤2	≤1	≤1	≤8	≤2	≤0.5	≤1	≤1	≤4/2	≤0.5/9	≤2	≤4	>2
BJ13-mcr-T	ND	—	IncI2	≤4/2	≤8/4	≤4	≤1	≤1	≤2	≤2	≤1	≤1	≤8	≤2	≤0.5	≤1	≤1	≤4/2	≤0.5/9	≤2	≤4	>2
CDA6-NDM-T	ND	NDM-5	IncX3	>16/8	>16/8	>16	>16	>32	>16	≤2	>8	>8	≤8	≤2	≤0.5	≤1	≤1	>64/4	≤0.5/9	≤2	≤4	≤0.5
BJ10-NDM-T	ND	NDM-5	IncX3	>16/8	>16/8	>16	>16	>32	>16	≤2	>8	>8	≤8	≤2	≤0.5	≤1	≤1	64/4	≤0.5/9	≤2	≤4	≤0.5

↵a CDA6-mcr-T and BJ13-mcr-T, mcr-1 E. coli J53 transconjugants; CDA6-NDM-T and BJ10-NDM-T, bla_NDM-5 E. coli J53 transconjugants. No mcr-1 transconjugant was obtained from BJ10. ND, not determined; —, negative by PCR.
↵b MICs were determined using a MicroScan WalkAway Plus system. SAM, ampicillin-sulbactam; AMC, amoxicillin-clavulanic acid; CFZ, cefazolin; CAZ, ceftazidime; CTX, cefotaxime; FEP, cefepime; ATM, aztreonam; IMP, imipenem; MEM, meropenem; AMK, amikacin, GEN, gentamicin; CIP, ciprofloxacin; LVX, levofloxacin; MXF, moxifloxacin; TZP, piperacillin-tazobactam; SXT, trimethoprim-sulfamethoxazole; TET, tetracycline; CHL, Chloramphenicol; COL, colistin.