Identification and characterization of plasmids carrying the mobile colistin resistance gene mcr-1 using optical DNA mapping
Artikel i vetenskaplig tidskrift, 2023

Objectives Colistin is a last-resort antibiotic, but there has been a rapid increase in colistin resistance, threatening its use in the treatment of infections with carbapenem-resistant Enterobacterales (CRE). Plasmid-mediated colistin resistance, in particular the mcr-1 gene, has been identified and WGS is the go-to method in identifying plasmids carrying mcr-1 genes. The goal of this study is to demonstrate the use of optical DNA mapping (ODM), a fast, efficient and amplification-free technique, to characterize plasmids carrying mcr-1. Methods ODM is a single-molecule technique, which we have demonstrated can be used for identifying plasmids harbouring antibiotic resistance genes. We here applied the technique to plasmids isolated from 12 clinical Enterobacterales isolates from patients at a major hospital in Thailand and verified our results using Nanopore long-read sequencing. Results We successfully identified plasmids encoding the mcr-1 gene and, for the first time, demonstrated the ability of ODM to identify resistance gene sites in small (similar to 30 kb) plasmids. We further identified bla(CTX-M) genes in different plasmids than the ones encoding mcr-1 in three of the isolates studied. Finally, we propose a cut-and-stretch assay, based on similar principles, but performed using surface-functionalized cover slips for DNA immobilization and an inexpensive microscope with basic functionalities, to identify the mcr-1 gene in a plasmid sample. Conclusions Both ODM and the cut-and-stretch assay developed could be very useful in identifying plasmids encoding antibiotic resistance in hospitals and healthcare facilities. The cut-and-stretch assay is particularly useful in low- and middle-income countries, where existing techniques are limited.


Sriram Kesarimangalam

Chalmers, Life sciences, Kemisk biologi

Moa Wranne

Chalmers, Life sciences, Kemisk biologi

Tsegaye Sewunet

Karolinska Institutet

Elina Ekedahl

Chalmers, Life sciences, Kemisk biologi

Maarten Coorens

Karolinska universitetssjukhuset

Teerawit Tangkoskul

Mahidol University

Visanu Thamlikitkul

Mahidol University

Christian G. Giske

Karolinska universitetssjukhuset

Karolinska Institutet

Fredrik Westerlund

Chalmers, Life sciences, Kemisk biologi

JAC-Antimicrobial Resistance

2632-1823 (eISSN)

Vol. 5 1 dlad004


Nanovetenskap och nanoteknik

Hälsa och teknik




Mikrobiologi inom det medicinska området





Mer information

Senast uppdaterat