Distinct mechanisms of acquisition of mcr-1 -bearing plasmid by Salmonella strains recovered from animals and food samples

Mingquan Cui, Congming Wu, Jinfei Zhang, Chunping Zhang, Ruichao Li, Edward Wai-Chi Chan, Chenbin Wu, Sheng Chen

Research output: Journal article publicationJournal articleAcademic researchpeer-review

14 Citations (Scopus)


Since the report of its discovery in E. coli in late 2015, the plasmid-mediated colistin resistance gene, mcr-1, has been detected in various bacterial species in clinical setting and various environmental niches. However, the transmission mechanisms of this gene in Salmonella is less defined. In this study, we conducted a comprehensive study to characterize the genetic features of mcr-1-positive Salmonella strains isolated from animals and foods. Our data revealed that Salmonella recovered from animals and food specimens exhibited highly different PFGE patterns, and acquired mcr-1-encoding plasmids via different mechanism. Plasmids harboring mcr-1 in Salmonella food isolates were all conjugative and similar as plasmids reported in other species of Enterobacteriaceae, whereas mcr-1-bearing plasmids from animal Salmonella isolates were not conjugative, and belonged to the IncHI2 type. The lack of a region carrying the tra genes was found to account for the inability to undergo conjugation for various sizes of IncHI2 plasmids harbored by animal strains. These data suggest that transmission of mcr-1-positive Salmonella from animal to food might not be a common event and food isolates may have acquired mcr-1-bearing plasmids from other mcr-1-positive bacteria such as E. coli, which co-exist in food samples.
Original languageEnglish
Article number13199
JournalScientific Reports
Issue number1
Publication statusPublished - 1 Dec 2017

ASJC Scopus subject areas

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