A recent study published in the journal Science of The Total Environment has revealed that antibiotic-resistant bacteria can spread through the clouds. The study, conducted by researchers from Quebec and France, took samples from clouds at the Puy de Dôme summit in central France. The team found that the concentration of antibiotic-resistant genes in the clouds was comparable to that found in other natural environments. The bacteria were found to be aerosolized by wind or human activities, and some of them rise into the atmosphere and contribute to the formation of clouds.
According to the World Health Organization, the rise of antibiotic-resistant bacteria has made it increasingly difficult to treat a range of bacterial infections. Antibiotic resistance occurs when bacteria are exposed to antibiotics and develop immunity to the drugs. This study highlights the importance of controlling the emission sources resulting from human activities to limit the dispersal of these genes.
The study found that oceanic clouds and continental clouds each have their signature of antibiotic resistance genes. Continental clouds were found to contain more antibiotic resistance genes used in animal production. The average concentration of 29 subtypes of antibiotic-resistant genes in cloud water was 20,800 copies per millilitre.
Lead author Florent Rossi of the Université Laval commented on the findings, stating that «our study shows that clouds are an important pathway for antibiotic-resistance genes spreading over short and long ranges.» The study suggests that the spread of antibiotic-resistant bacteria poses a major threat to global health and food security as the use of antibiotics continues to grow.