Inducible colistin resistance via a disrupted plasmid-borne mcr-1 gene in a 2008 Vietnamese Shigella sonnei isolate

Duy Pham Thanh, Ha Thanh Tuyen, To Nguyen Thi Nguyen, Hao Chung The, Ryan R. Wick, Guy E. Thwaites, Stephen Baker, Kathryn E. Holt

Research output: Contribution to journalArticleResearchpeer-review

54 Citations (Scopus)


Objectives: The objective of this study was to assess the presence of mcr-1 in Shigella sonnei isolated in Vietnam. Methods: WGS data were analysed for the presence of the mcr-1 gene sequence. The association of mcr-1 with a plasmid was assessed by PCR and by conjugation. Results: Through genome sequencing we identified a plasmid-associated inactive form of mcr-1 in a 2008 Vietnamese isolate of Shigella sonnei. The plasmid was conjugated into Escherichia coli and mcr-1 was activated upon exposure to colistin, resulting in highly colistin-resistant transconjugants. Conclusions: This is the first description of the mcr-1 gene in Shigella, which is atypical given that colistin is not ordinarily used to treat diarrhoea. Our data suggest the mcr-1 gene has been circulating in human-restricted pathogens for some time but likely carries a selective fitness cost.

Original languageEnglish
Pages (from-to)2314-2317
Number of pages4
JournalJournal of Antimicrobial Chemotherapy
Issue number8
Publication statusPublished - 1 Aug 2016
Externally publishedYes

Cite this