- September 22, 2025
- By Kimbra Cutlip
While urban farming is an increasingly important way to fight food insecurity and improve nutrition for underserved communities, soils in urban settings are often contaminated with the buildup of human waste products, including pathogens and bacteria that have developed resistance to antimicrobial products and medications.
University of Maryland research published Sunday in Frontiers in Plant Science describes the presence of antimicrobial-resistant genes in harmless soil microbes—genes that could also find their way into pathogens that can infect people. Antimicrobial resistance contributes to an estimated 2.8 million infections and over 35,000 deaths annually in the U.S.
The study was led by Ryan Blaustein, a University of Maryland assistant professor of food microbiology, with co-authors from the Department of Nutrition and Food Science including first author and Ph.D. student Erin Harrelson, Ph.D. student Qingyue Zeng, and Postdoctoral Associate Mairui Gao.
Blaustein and his colleagues also found a high level of resistance to multiple antibiotics in microbes from soils and leafy green vegetables taken from seven urban farms in the Washington, D.C., area. Multi-drug resistance is particularly concerning because pathogens with this trait can become difficult to treat with available medications.
Although the multi-drug-resistant bacteria that Blaustein and his team found in urban farm environments are not thought to pose direct threats to human health, they could serve as a reservoir for multi-drug-resistant genes that may one day jump into pathogenic bacteria in the food system, such as E. coli or salmonella.
“Overall, the food safety risk from antimicrobial resistance in urban agriculture is low,” Blaustein said. “But the potential for anti-resistance genes to move through the system represents an emerging concern that we and others need to be watching out for.”