Soil harbors antibiotic resistance genes that threaten public health, and human activities influence their spread, mainly through bacteria such as listeria.
Soil plays a role much more important in the spread of antibiotic resistance than one might imagine.
Surprisingly, the soil beneath us is full of antibiotic resistance genes (ARGs) – little codes that allow bacteria to resist antibiotics.
Human activities, such as pollution and land use change, can disrupt soil ecosystems and facilitate the transfer of resistance genes from soil bacteria to humans.
In a new study, Jingqiu Liaoassistant professor of civil and environmental engineering at Virginia Tech, sought to understand how soil bacteria contribute to the growing global issue of antibiotic resistance.
The results, which were recently published in the journal Nature Communicationsshow that once bacteria acquire these resistant genes, they can be quickly transmitted to other specieswhich makes this a pressing threat to public health.
Understanding these patterns can help scientists find ways to control the spread of antibiotic resistanceprotecting human health and preserving the effectiveness of antibiotics for future generations.
Soil isn’t just dirt – it’s an ecosystem full of bacteria. Some of these bacteria naturally carry ARGs, which help them fight off antibiotics.
Although this may doesn’t seem like a big problem At first glance, it becomes dangerous when these ARGs turn into harmful bacteria that infect humans.
One of these bacteria is Listeria monocytogenes. This soil inhabitant can enter the food chain and cause serious illness called listeriosis. For people with weakened immune systems, listeriosis can be deadlywith mortality rates that can reach 20 to 30 percent.
Because of its ability to propagate ARGs and infect humans, listeria is an important model for studying how antibiotic resistance develops in soil and spreads to other environments.
“Soil is an important reservoir of resistant bacteriabecome ARGs”, explains Liao, from Virginia Tech. “You environmental factors can amplify ARGs by creating conditions that promote the survival, propagation and exchange of these genes between bacteria.”
“The ecological and evolutionary mechanisms underlying the dynamics of ARGs in soils continue to be insufficiently explored. In this study, we used listeria as a key model to understand the emergence and development of ARGs in soils”, adds the researcher.
In the course of their study, team members analyzed about 600 listeria genomes from soil samples that Liao had collected in a previous study, published in Nature Microbiologyand identified five major ARGs from across the United States.
The study also revealed how ARGs spread between bacteria. A process called transformation allows bacteria to take hold loose pieces of DNA containing ARGs of your surroundings.
Once a bacterium acquires these genes, you can pass them on to others — even to different species. This rapid sharing of resistance genes is one of the main reasons why antibiotic resistance is so difficult to combat.
Based on this research, Liao now hopes to find new strategies to control antibiotic resistance, so that antibiotics can continue to be effective in treating infections for years to come.
“Establishing a fundamental understanding of the ecological drivers of these bacteria in soil can help us better understand the emergence, evolution and spread of antibiotic resistance,” Liao said. “It’s about an urgent and global threat to public health“.
