The mobile colistin resistance gene, mcr-1, and its variants have been detected among humans and domestic animals worldwide. Since its first detection in 2017, mcr-3 has been reported in Asia, Europe and North America. Here, we describe the presence of mcr-3 in diverse plasmids and the chromosome in Escherichia coli from diseased swine, and the co-occurrence of plasmid-located mcr-1. E. coli isolates from humans, retail meat, and diseased swine (n= 7942, 537, and 645, respectively) were subjected to reference broth microdilution method. A part of human and meat isolates have been published for the prevalence of mcr-1 [1] (please see Supplementary methods for the details). PCR targeting mcr-1 to mcr-8 was performed on colistin-resistant isolates. Only mcr-1 was detected in 58 and 41 isolates from humans and meat, respectively. Among isolates from diseased swine, 330 were positive for mcr-1 only, seven were positive for mcr-3 only and three were concomitantly positive for mcr-1 and mcr-3. The 10 mcr-3-positive isolates were multi-drug resistant but the co-occurrence of mcr-1 and mcr-3 did not increase colistin MICs (Supplementary Table S1).
Date:
2020-07
Relation:
International Journal of Antimicrobial Agents. 2020 Jul;56(1):Article number 105996.
