Antibiotic resistant genes in the clouds? This is the astonishing discovery made by a team of Quebec and French researchers, which makes it possible to better document a worrying public health phenomenon that is claiming more and more victims.

Antibiotic resistance is a serious public health problem and could even become one of the leading causes of death worldwide by 2050. The growing use of antibiotics in various spheres of activity, including the treatment of infections and animal production, is obviously at the origin of the phenomenon, which “is now reaching dangerously high levels in all regions of the world”, estimates the World Health Organization (WHO).

Like the microplastics that are now found everywhere in the environment, even at the top of Everest, antibiotic-resistant genes are multiplying in the oceans, in rivers and in soils. We now know that there are some in the clouds, thanks to the work of a team of researchers from Laval University and Clermont Auvergne University in France.

“This is the first study that demonstrates that clouds harbor antibiotic resistance genes,” explains Florent Rossi, the study’s first author and postdoc who is part of the research team of Professor Caroline Duchaine of the Laval University. The study was published in the journal Science of the Total Environment.

“These genes are found in bacteria which are found on the surface of the Earth or in the oceans. We wanted to check if there were also some in the clouds, ”says the researcher in an interview with La Presse.

The scientists took cloud samples from an atmospheric research station located 1465m above sea level on the top of Puy de Dôme, a dormant volcano in France’s Massif Central. Analyzes determined that there were an average of 8,000 bacteria per milliliter of cloud water.

By pushing the analyzes further, it was also possible to establish that the clouds contained an average of 20,800 copies of genes resistant to antibiotics per milliliter of water. It should be noted that more genes used in animal production are found in continental clouds than in oceanic clouds. The study measured the concentration of 29 antibiotic-resistant gene subtypes.

Can these genes survive in the clouds? As the clouds move, can these genes then pass on and escalate the problem of antibiotic intolerance?

These issues will need to be addressed, says Rossi. The team would also like to be able to identify the sources of emission of these genes in order to possibly better limit their dissemination.

“This subject was not documented before. The good news is that we will now have a point of comparison in the future to determine if it will increase. »

Remember that every year, tens of thousands of tons of antibiotics are used to treat and prevent human, animal and plant diseases, according to WHO estimates. Due to greater resistance to antibiotics, it is becoming more difficult to treat many infectious diseases.