Walking On Volume 3, Issue 8, September 2016 | Page 8

For the Health of It

Mcr-1 and Other New Resistance Genes:
What is the Threat to Horses?
Reprinted with permission from the July 2016 edition of Equine Disease Quarterly.

Recent identification of the mcr-1 resistance gene in
bacteria from humans and animals has focused attention on the emerging epidemic of multidrug resistance.
Multidrug resistant Gram-negative bacteria, particularly those of the Enterobacteriaceae family (e.g. E.
coli, Klebsiella, Enterobacter), are not new, as serial
waves of resistance mediated by a wide range of genes
have been encountered. Yet, emergence of mcr-1 is of
concern because it confers resistance to colistin, an antimicrobial that can be the only option for some hig