AUTHOR=He Yu-Zhang , Long Teng-Fei , He Bing , Li Xing-Ping , Li Gong , Chen Liang , Liao Xiao-Ping , Liu Ya-Hong , Sun Jian 

TITLE=ISEc69-Mediated Mobilization of the Colistin Resistance Gene mcr-2 in Escherichia coli

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 11 - 2020

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.564973

DOI=10.3389/fmicb.2020.564973

ISSN=1664-302X

ABSTRACT=Objectives: The emergence of mobile colistin resistance genes has compromised the efficacy of the last resort antibiotic, colistin, in clinical treatment. The mcr-2 gene was first identified in Belgium in association with the insertion sequence ISEc69. However, the molecular mechanisms of mcr-2 mobilization are not well understood.
Methods: To further explore the mobilization of mcr-2 gene via ISEc69, we constructed a conjugative plasmid that carries an intact composite transposon Tn7052. Transposition assays were performed by conjugation, the transposition sites were characterized by arbitrary primed PCR and DNA sequencing.
Results: In this study, we experimentally demonstrated that mcr-2 could be mobilized as a composite transposon Tn7052 and its transposition generated 8-bp AT-rich duplications in the host genome.
Conclusions: These results indicate that mcr-2 gene could be mobilizied by ISEc69, the current investigations provide mechanistic insights in the transposition of mcr-2.