Emergence of the mcr-1 colistin resistance gene in extended-spectrum β-lactamase-producing Klebsiella pneumoniae in Taiwan

• Main Authors: Yu-Chi Lin, Makoto Kuroda, Satowa Suzuki, Jung-Jung Mu
• Format: Article
• Language: English
• Published: Elsevier 2021-03-01
• Series: Journal of Global Antimicrobial Resistance
• Subjects: mcr-1; Colistin; Klebsiella pneumonia; ISApl1
• Online Access: http://www.sciencedirect.com/science/article/pii/S2213716521000096

Objectives: The resistance ofmcr-1-carrying Enterobacteriaceae to polymyxins, which are last-resort antibiotics, has raised great concern worldwide. In this study, four mcr-1-carrying plasmids isolated from Klebsiella pneumoniae clinical isolates were completely sequenced and the genome composition of the mcr-1-carrying plasmids was analysed. Methods: Antimicrobial resistance genes and antimicrobial susceptibility of fourmcr-1-carrying K. pneumoniae isolates were characterised. Comparison of mcr-1-carrying plasmids with closely related plasmids and analysis of the mcr-1 gene cassette were performed. Results: The genome composition of the fourmcr-1-carrying plasmids revealed the Tn6330 and Tn6390 cassettes embedded in two IncHI1-type plasmids, ΔTn6330 in an IncHI2-type plasmid, and mcr-1–pap2 in an IncX4-type plasmid. We also predicted the intermediate structures of the Tn6330 and Tn6390 cassettes. Conclusion: Dissemination of the colistin resistant genemcr-1 in Taiwan could have been driven by various plasmids and mobile gene cassettes. Evolution of the genetic environment has led to diversity in the mcr-1 gene among plasmids. This work sheds light on the urgent need for continued surveillance of the worldwide distribution of mcr-1 and evaluates the public-health risk of colistin resistance.