A recent study by Michigan State University (MSU) and international collaborators has uncovered significant findings regarding antibiotic resistance genes in livestock manure. The research, spanning 14 years, analyzed over 4,000 manure samples from pigs, chickens, and cattle across 26 countries. It represents the most comprehensive survey of its kind to date.
The study reveals that livestock manure contains a high concentration of antibiotic resistance genes that pose potential threats to human health. These genes can transfer to bacteria that infect humans through various channels such as contaminated water or food. “This research shows that what happens on farms doesn’t stay on farms,” stated James Tiedje, an MSU Distinguished Professor and one of the study’s authors.
To assess the risk further, researchers created a global map indicating regions where dangerous antibiotic resistance genes are prevalent. They also developed a system to rank these genes based on their threat level to human health.
Xun “Shawn” Qian from Northwest Agriculture and Forestry University in China emphasized the importance of monitoring these genes in major livestock-producing countries. He noted higher levels of antibiotic resistance in cattle manure in the United States and swine manure in China compared to other nations.
Antimicrobial resistance is considered an urgent public health threat globally. According to the World Health Organization, it was responsible for at least 1.27 million deaths worldwide in 2019 alone.
While antibiotics remain crucial for animal health when used correctly, their overuse contributes significantly to resistance issues. “We need antibiotics to control disease,” said Tiedje. However, he stressed the importance of preserving their effectiveness.
Encouraging trends were noted where policies reducing farm antibiotic use have been implemented successfully. Countries like Denmark led with bans on growth-promotion antibiotics years ago, resulting in lower resistance levels.
The findings provide essential data for countries formulating national action plans against antibiotic resistance. “By identifying the riskiest genes and the countries where they’re most likely to spread, we can start to better target surveillance and policy,” Qian remarked.
The research paper has been published in Science Advances.
