About the method
Like an intricate puzzle
The Research Group for Genomic Epidemiology at DTU National Food Institute has developed and maintains one of the world’s most comprehensive resistance databases. It currently includes 3,134 known resistance genes.
The researchers have used the database to map resistance genes in the sewage samples in the new study.
The samples contain a very large number of microorganisms from different sources, including human faeces. The frozen sewage samples have been sent to DTU, where laboratory technicians extract all the bacteria from the thawed samples.
The bacteria are then broken up and their collective DNA is broken into smaller pieces, which state-of-the-art DNA sequencing equipment can read all at once.
A supercomputer can then compare the billions of recorded DNA sequences with known genes and construct larger pieces of the original genomes contained in the samples.
This process provides insight into several areas such as in which bacteria and genetic neighbourhoods the resistance genes are located.