Carriage of colistin-resistant, extended-spectrum β-lactamase-producing Escherichia coli harboring the mcr-1 resistance gene after short-term international travel to Vietnam

Figures & data

Table 1 Detection of ESBL-producing Escherichia coli harboring mcr-1 before and after travel

Traveler	Traveling	Number of isolates
		Before travel		After travel^a
		ESBL^b	mcr-1^c	ESBL	mcr-1
1	November 2015
2	August 2016			3
3	August 2016			3
4	March 2016			6
	May 2016	3		6
5	May 2016			3
6	May 2016			2
7	February 2016
8	August 2015	3		3
	January 2016			1
9	August 2015			7
10	August 2015			7	1, B-1^d
11	September 2015	2		6
12	September 2015			7
13	June 2015	4		7
	September 2015	3		7
	December 2015	3		3
	January 2016	3		6
14	July 2015	3
	November 2015			5
15	July 2015			6
	November 2015			4
16	June 2015			6
	December 2015			3
17	July 2015			3
	September 2015			2
	November 2015			5
18	June 2015			6
	July 2015	3		7	1, A-1
	September 2015	3		5
	November 2015
	January 2016			3
19	September 2015			6	1, C-1
	January 2016	3		4
Total			*
19	34	33	0	142	3

Notes: ^aSpecimens were collected up to 2 weeks after traveling.

b Extended- spectrum β-lactamase-producing E. coli.

c mcr-1-positive E. coli.

d Strain name. *P<0.001.

Abbreviation: ESBL, extended-spectrum β-lactamase.

Table 2 Characteristics of travelers carrying ESBL-producing Escherichia coli isolates harboring mcr-1

Variable	Traveler	A	B	C
Travelers	Age (years)	38	35	33
	Sex	Male	Male	Male
	Travel sites in Vietnam	Hanoi, Nha Trang	Ho Chi Minh City	Can Tho, Ho Chi Minh City
	Travel term	July 2015	August 20l5	September 2015
	Length of stay in Vietnam	4 days	l2 days	5 days
	Day of fecal sampling after returning to Japan	1 day	3 days	6 days
	Duration of carriage of mcr-1 after returning to Japan	< 17 days	<20 days	< 19 days
Bacteria	Isolates	A-1	B-l	C-l
	Phylogenetic group	B2	B2	D
	Antibiotic resistance^a	AMP, CTX, CHL, TET, GEN, KAN	AMP, CTX, SXT, TET	AMP, CTX, NAL, CHL, SXT, TET, STR
	ESBL CTX-M gene	blaCTX-M-l4	blaCTX-M-55	blaCTX-M-l4
	Colistin resistance gene	mcr-1	mcr-1	mcr-1
	Colistin MIC (pg/mL)	1.0	3.0	4.0

Note: ^aAntibiotic resistance was determined by the Clinical & Laboratory Standards Institute guidelines: AMP, CTX, NAL, CHL, SXT, TET, GEN, KAN, and STR.

Abbreviations: AMP, ampicillin; CHL, chloramphenicol; CTX, cefotaxime; ESBL, extended-spectrum b-lactamase; GEN, gentamycin; KAN, kanamycin; MIC, minimum inhibitory concentration; NAL, nalidixic acid; STR, streptomycin; SXT, sulfa/trimethoprim; TET, tetracycline.