Researchers at the National Food Institute of the Technical University of Denmark (DTU) have now mapped out where places in the world the appearance of genes is greater resistance to antibiotics, how they are located and in what types of bacteria they are found.
They have created it by analysis of wastewater samples received by DTU from 243 cities in 101 countries between 2016 and 2019. The results of the new metagenomic study -which have just been published in ‘Nature Communications‘- have surprised researchers. In fact, the map shows that genes have appeared in many genetic contexts and different types of bacteria, indicating greater transmission than the researchers expected.
“We have found similar resistance genes in very different types of bacteria. We find it worrying when genes can be passed from a very broad group of bacteria to a completely different group to which there is no resemblance. It is rare for these gene transmissions to occur over such long distances.. It’s a bit like very different animal species have offspring,” explains Adjunct Professor Patrick Munk.
If the genes are found in bacteria that don’t usually make people sick—such as lactic acid bacteria—it’s less of a concern. However, if resistance genes are found in bacteria important to human health, such as salmonella, the story is completely different.
“This makes it bacteria are much more likely to kill people, for example in a hospital, because there is no treatment available,” stresses Munk.
Transmission Hot Spots
In different locations in sub-Saharan Africa, researchers have found the same resistance gene in several different bacteria. “We interpret this to mean that we may be quite close to a transmission hot spot, where there is a transmission of the gene from one to another to a third bacterium. That’s why we see the gene in so many different contexts right there,” explains Munk.
He adds that many of the surprising transmissions appear to be in sub-Saharan Africa. They are also countries with the least developed resistance control programswhich means that there is very little data on the situation of the resistance.
“We risk missing important trends because we don’t have data,” he suggests, stressing that what is needed is solid data to develop effective counter-resistance strategies.
“Right now, we have a great insight into how resistance behaves in the West and, based on that knowledge, we plan how to combat it. Now it turns out that if we look at some new places, the genes for resistance can behave very differently, probably because have more favorable transmission conditions. Therefore, the way to combat resistance must also be adjusted and adapted to local conditions,” says Munk.
The successor
The global wastewater project – which is supported by the Novo Nordisk Foundation and the VEO research project – concludes in 2023. The researchers believe it has proven to be a good complement to existing monitoring initiatives, which operate mainly nationally or regional and measure the resistance in the bacteria of the patients.
Therefore, they hope that a successor to the project will appear, so that the world can continue to benefit from the important knowledge generated by the surveillance program. this toon Applies to countries with robust surveillance programs and control strategies.
“There are many analogies with climate change, where what happens on the other side of the globe is not unimportant to you. One day or another, the problem will turn against usas we have seen time and time again,” says Munk.
Genomic analysis of wastewater is fast and quite cheap in relation to the number of people it can cover. Wastewater analysis does not require ethical approval, as sample material cannot be linked to individuals.