A groundbreaking study has revealed that latent antimicrobial resistance is more widespread globally than previously understood. Conducted by a team of researchers and published in Nature Communications, the study calls for enhanced surveillance of resistance in wastewater to uncover potentially problematic genes hidden in the extensive reservoir of latent resistance genes.
The research, coordinated by the DTU National Food Institute in Denmark, analyzed 1,240 wastewater samples from 351 cities across 111 countries. The findings indicate that bacterial latent antimicrobial resistance is prevalent on all continents. While these resistance genes do not currently pose a significant risk, researchers warn that some may become problematic in the future, emphasizing the need for broader surveillance efforts.
Understanding Latent vs. Acquired Resistance
According to the study, latent resistance genes have a far wider geographical distribution than acquired resistance genes. Hannah-Marie Martiny, a researcher involved in the study, stated,
“The research shows that we have a latent reservoir of antimicrobial resistance that is far more widespread around the world than we had expected.”
Martiny, along with Associate Professor Patrick Munk, recommends that routine surveillance of antimicrobial resistance in wastewater should include both acquired and latent resistance genes to address future challenges.
Consistent with previous studies, the research highlights that acquired resistance genes are more prevalent in sub-Saharan Africa, South Asia, and the Middle East and North Africa (MENA) regions than in other parts of the world. However, globally, latent resistance genes outnumber acquired ones, except in sub-Saharan Africa, where the numbers are equal.
The Implications of Widespread Latent Resistance
The World Health Organization (WHO) has already termed antimicrobial resistance (AMR) a pandemic, driven by the widespread use of antibiotics and other environmental pressures. Researchers typically focus on resistance genes that can jump between bacterial hosts, posing a significant challenge to treating infections in humans and animals.
Martiny explains that expanded surveillance could help map the ecology of resistance genes, providing insights into where and how antimicrobial resistance arises and spreads.
“By tracking both acquired and latent antimicrobial resistance genes, we can gain a broad overview of how they develop, change hosts, and spread in our environment,”
she says.
Functional Metagenomics: Mapping Latent Resistance
To identify latent resistance genes, researchers use a method called functional metagenomics. This involves extracting DNA from samples and testing random DNA fragments for antimicrobial resistance. Although this method can identify resistance, it does not confirm whether these genes can naturally transfer between bacteria in the environment.
Patrick Munk highlights the concern that some latent resistance genes could become acquired resistance genes, gaining the ability to jump between bacterial hosts in the environment.
“Our concern is that some latent resistance genes will become acquired resistance genes and thus become able to jump to different bacterial hosts out in the environment,”
he explains.
Future Directions and Global Health Implications
The study’s findings underscore the importance of including latent resistance genes in surveillance programs to prevent future public health crises. The DTU National Food Institute maintains a comprehensive collection of resistance genes, aiding doctors and researchers worldwide in identifying antimicrobial-resistant bacteria.
Environmental factors play a crucial role in determining which bacteria survive and multiply, influencing the spread of resistance. When antibiotics are present, susceptible bacteria die first, allowing resistant strains to thrive. Understanding these dynamics is essential for developing strategies to combat antimicrobial resistance.
As the world grapples with the growing threat of antimicrobial resistance, the study offers hope that by expanding surveillance efforts, researchers can better predict and mitigate future challenges. The findings emphasize the need for a proactive approach to monitoring and addressing both latent and acquired resistance genes to safeguard global health.
