Antibiotic-resistant bacteria continue to spread worldwide. They cause difficult-to-treat diseases and, according to experts, could cause 10 million deaths annually by 2050*. Antibiotic resistance is believed to develop due to the extensive use of antibiotics through natural selection—mutant bacterial strains that have acquired resistance to antimicrobials gain an advantage in the struggle for survival. However, there is no doubt that other factors also influence the spread of drug resistance.

A team of scientists from the University of Toronto (Canada) and Harvard University (USA) analyzed** the role of climate change (air temperature changes) and other factors in the spread of antibiotic resistance in the United States. They examined data on the susceptibility of more than 1.6 million samples of Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus bacteria to most classes of antibiotics from 223 laboratories in 41 US states from 2013 to 2015. Key climate (temperature) indicators in these regions over the past 30 years were also carefully studied.

A 10°C local temperature increase was found to be associated with a 4.2%, 2.2%, and 2.7% increase in antibiotic resistance for E. coli, K. pneumoniae , and S. aureus , respectively (the correlation was most pronounced for average minimum temperatures). Furthermore, increased population density also accelerates the spread of antibiotic resistance in pathogenic bacteria in a given area.

Global warming is known to facilitate the spread of insect-borne infectious diseases, as well as intestinal infections. The authors of the study note that warming and population growth could accelerate the advent of a "post-antibiotic era," in which humanity loses control of infectious diseases.

* Global Action Plan on Antimicrobial Resistance (World Health Organization, 2015).

** MacFadden DR, McGough SF, Fisman D, Santillana M & Brownstein JS. Antibiotic resistance increases with local temperature // Nature Climate Change, 2018, 8:510–514. https://doi.org/10.1038/s41558-018-0161-6