S ince the first description of the plasmid-mediated colistin resistance gene (mcr-1), over 30 follow-up reports have proved the worldwide geographical distribution of this gene (1, 2). The overall picture indicates a very low prevalence in animals, human beings, and retail food, with two exceptions, the first in China, where mcr-1 carriage was observed in 21% and 15% of the animals and raw meat samples, and the second in France, where 21% of the extended-spectrum-␤-lactamase (ESBL)-producing Escherichia coli isolates from calves were mcr-1 positive (1, 3).