This phenomenon threatens one of the 20th century's most significant medical achievements: antibiotics, which have dramatically reduced mortality from bacterial infections and extended human life spans.
The emergence of bacteria resistant to multiple antibiotics, including "last resort" antibiotics, poses a growing threat.
The mass use of antibiotics in humans and animals has led to the emergence and spread of resistant strains.
In 2019, antibiotic resistance was responsible for the deaths of 4.95 million people worldwide, including nearly a million children.
The study's authors, including Prof. Piotr Rzymski from the Department of Environmental Medicine at the Poznań University of Medical Sciences in western Poland and Prof. Andrzej Fal, head of the Polish Society of Public Health, have emphasized that public health and environmental protection goals go hand in hand and must be addressed together.
They warn that antibiotic resistance and environmental changes are among the 21st century's greatest challenges, and require a coordinated approach.
Apart from the overuse and misuse of antibiotics, environmental changes such as global warming, pesticide emissions, heavy metal pollution, microplastic pollution, and changes in microbial diversity are contributing to the spread of resistance.
Global warming could lead to more frequent bacterial infections and food poisoning, driving up antibiotic use.
Additionally, higher temperatures facilitate horizontal gene transfer, a process by which genetic information is shared between bacteria, including resistance genes.
Extreme weather events, a consequence of climate change, can damage sewage infrastructure, releasing untreated sewage that contains antibiotics and resistant bacteria into the environment.
This situation is exacerbated in regions with lower economic development, where access to safe drinking water is increasingly compromised, potentially increasing antibiotic use and exposing people to contaminated water.
It is also present in countries such as the United Kingdom where insufficient safeguards are in place to prevent effluent combined with rainwater being released into the river system or directly into the sea.
Microplastic pollution is also implicated in promoting antibiotic resistance. Its hydrophobic surface provides a conducive environment for bacterial growth and facilitates the horizontal gene transfer between different bacteria.
Moreover, microplastics can adsorb antibiotics and transport them along with resistant bacteria over long distances, especially in aquatic environments.
"Resistance genes were found on the surface of microplastics present in both freshwater and marine ecosystems, leachates from landfills and dumps, as well as in agricultural soil," explained Rzymski.
The study, published in the journal Environmental Pollution, also indicates that exposure to pesticides and heavy metals can induce mechanisms in bacteria that reduce the toxicity of these chemicals.
This effect is significant given the annual emission of heavy metals such as mercury, cadmium and lead, which can persist in soil and water and accumulate in living organisms, while in 2020 alone, global pesticide use in agriculture reached 2.7 million tons of active ingredients.
The researchers have also highlighted the critical role of high microbial diversity in limiting the spread of antibiotic resistance.
A diverse microbiological community forms a biotic barrier that utilizes nutrients efficiently and includes organisms that can control the growth of resistant bacteria. Low diversity, however, facilitates the invasion and spread of antibiotic-resistant bacteria.
(rt/gs)
Source: naukawpolsce.pl