TABLE 1.

Characteristics of colistin-resistant Escherichia coli strains carrying the mcr-1 gene from Brazil

Characteristica	ICBEC2AM	ICBEC3AM	ICBEC13AM	ICBEC7P	ICBEC72H
Source	Seawater	Seawater	Seawater	Infected migratory penguin	Human infection
Location	−23.974697S, −46.395060W	−23.974995S, −46.371613W	−23.986450S, −46.309086W	−23.986306S, −46.308361W	−5.779257S, −35.200916W
Isolation date	September 2016	September 2016	September 2016	June 2013	March 2016
NaCl tolerance (%)	10	10	10	10	10
Serotype	ONT:H55	O9:H4	O54:H32	ONT:H32	ONT:H9
ST/CC	1638	46/46	10/10	10/10	101/43
Virulence genes	Not detected	iss, gad, mchF	gad	gad	iroN, mcmA, mchB, mchC, mchF, lpfA, iss
Phylogroup	B1	B1	B1	A	B1
Resistance	AMO, AMP, CAZ, CEF, CRO, CTF, CTX, DOX, NAL, SUL, TET	AMO, CEF, CLO, NAL, SUL, SXT	AMO, AMP, ATM, CAZ, CEF, CRO, CTX, DOX, NAL, SUL, SXT, TET	AMK, AMO, AMP, ATM, CAZ, CEF, CIP, CTF, CTX, ENR, FEP, GEN, NAL, SXT, TET	AMO, AMP, ATM, CEF, CTX, FEP
Colistin/polymyxin MIC (μg/ml)	4/4	4/4	4/4	8/8	4/4
Resistance genotype	mcr-1, blaCTX-M-8, qnrB19, aadA2, strA, strB, sul2	mcr-1, blaTEM-1B, qnrB19, catA1, aadA1, strA, strB, sul1, sul2, tetA, dfrA1, dfrA8	mcr-1, blaCTX-M-1, aadA1, sul2, tetA, tetB	mcr-1, blaCTX-M-1, aadA1, sul2, tetA, tetB	mcr-1, blaCTX-M-8
Plasmids (Inc)b	I1, ColRNAI, X4	FIB, Q1, X4	HI2, I1, N, X4	FIN, HI2, HI2A, I1, N, X4	I1, X4

^aE. coli isolates ICBEC2AM, ICBEC3AM, and ICBEC13AM were analyzed in this study. Data for E. coli ICBEC7P and ICBEC72H were obtained from earlier studies by our group (5, 7). ST, sequence type; CC, clonal complex; AMK, amikacin; AMO, amoxicillin; AMP, ampicillin; ATM, aztreonam; CAZ, ceftazidime; CEF, cephalothin; CIP, ciprofloxacin; CLO, chloramphenicol; CRO, ceftriaxone; CTF, ceftiofur; CTX, cefotaxime; DOX, doxycycline; ENR, enrofloxacin; FEP, cefepime; GEN, gentamicin; NAL, nalidixic acid; SUL, sulfonamide; SXT, trimethoprim-sulfamethoxazole; TET, tetracycline.

^bThe replicon types of plasmids carrying the mcr-1 gene are in bold.