Air pollution has become one of the most worrisome health crises of our lifetime. According to the World Health Organization (WHO), 9 out of 10 people in the world live in areas where air pollution poses a significant health risk and 1 in 9 deaths worldwide can be attributed to unclean air. One recent study even found that industrial air pollutants can create the airborne equivalent of sulfuric acid, leading to such catastrophes as London’s “Great Smog” of 1952.
To make matters worse, a new study published in the journal Microbiome has found that air pollution can actually carry and transmit bacterial genes that lead to antibiotic resistance. According to the research, antibiotic resistance genes (ARGs) are found in air samples collected from both indoor and outdoor environments all over the world, but were highest in concentration in air samples collected in China’s perpetually-smoggy capital of Beijing:
Microbial communities from Beijing smog harboured the highest richness of known ARGs (64.4 different ARG types), as well as the highest bacterial richness of all environments. [...] The richness of ARGs was higher in Beijing smog than in the air samples from US cities with the exception of office indoor air samples. Notably, the Beijing smog metagenomes contained several resistance genes to carbapenems, a class of last resort antibiotics.
This research was conducted by the Centre for Antibiotic Resistance Research (CARe) at the University of Gothenburg. Joakim Larsson, director of CARe, stated in a press release that this means of gene transmission was a surprise to immunologists:
This may be a more important means of transmission than previously thought [...] Of particular concern is that we found a series of genes that provide resistance to carbapenems, a group of last resort antibiotics taken for infections caused by bacteria that are often very difficult to treat.
Human activity, naturally, is to blame. The evaporation of water from sewage treatment plants can lead to the bacteria genes entering ambient air. As more and more people take antibiotics, various human effluvia release those antibiotics into groundwater supplies where they can affect bacterial evolution. Climate change is also increasing the bacterial threat, as long-dormant colonies of deadly bacteria begin to awaken as the ground around them thaws.