Efficient generation of complete sequences of MDR-encoding plasmids by rapid assembly of MinION barcoding sequencing data

Background

Multidrug resistance (MDR)-encoding plasmids are considered major molecular vehicles responsible for transmission of antibiotic resistance genes among bacteria of the same or different species. Delineating the complete sequences of such plasmids could provide valuable insight into the evolution and transmission mechanisms underlying bacterial antibiotic resistance development. However, due to the presence of multiple repeats of mobile elements, complete sequencing of MDR plasmids remains technically complicated, expensive and time-consuming.

Results

Here, we demonstrate a rapid and efficient approach to obtain multiple MDR plasmid sequences through the use of the MinION nanopore sequencing platform, which is incorporated in a portable device. By assembling the long sequencing reads generated by a single MinION run according to a rapid barcoding sequencing protocol, we obtained the complete sequences of twenty plasmids harbored by multiple bacterial strains. Importantly, single long reads covering a plasmid end-to-end were recorded, indicating that de novo assembly may be unnecessary if the single reads exhibit high accuracy.

Conclusions

This workflow represents a convenient and cost-effective approach for systematic assessment of MDR plasmids responsible for treatment failure of bacterial infections, offering the opportunity to perform detailed molecular epidemiological studies to probe the evolutionary and transmission mechanisms of MDR-encoding elements.