The study came from The National Food Institute at the Technical University of Denmark, and Statens Serum Institut, which were able to quickly create an overview of the situation in Denmark because many bacteria have had their DNA-profile mapped with the help of whole genome sequencing.

The new resistance gene, mcr-1, leads to resistance to colistin - antimicrobials of the type polymyxin, which are the last available option to treat infections with multiresistant so-called gram negative bacteria such as fx E-coli and klebsiella.

Since 2009 the National Food Institute and DTU Systems Biology have built up computer facilities which are able to quickly map a bacteria’s DNA and compare the results with bacterial findings from around the world. Many bacterial findings in Denmark have had their DNA profile mapped with the help of whole genome sequencing.

When the resistance gene, mcr-1, was made available to Danish researchers on 23 November 2015, they were able to quickly create an overview of the situation in Denmark for the Danish authorities.

Unlike previously when it was necessary to collect bacterial samples, set up new detection methods and carry out analysis, researchers can these days get an overview of the situation within hours by using the existing database, thereby saving months of work.

Approximately 3000 gram negative coli or salmonella bacteria, which have previously been mapped using whole genome sequencing, have been re-examined to see whether mcr-1 is present.

Results show that mcr-1 was found in one patient, who suffered from a blood infection in 2015 and in five food samples that have been imported from 2012-2014. All these bacteria found are multiresistant ESBL bacteria containing the mcr-1 gene, which can further complicate treatment.