Ecology, more than antibiotics consumption, is the major predictor for the global distribution of aminoglycoside-modifying enzymes

Publication Summary

Antibiotic use in any sector can drive the development of antibiotic resistance. Multiple factors, including but not limited to antibiotic use, play a role in the persistence and spread of antibiotic resistance. Using publicly available information on aminoglycoside resistance as an example, this study analyzed the temporal, spatial, and ecological distribution patterns of aminoglycoside resistance genes (looking specifically at genes for aminoglycoside-modifying enzymes or AME genes). The authors found that the exchange of antibiotic resistance genes (e.g., AME genes) between ecosystems plays a significant role in understanding the similarities and differences of resistance found in different ecosystems. Results suggest that antibiotic stewardship interventions would be more impactful if they both targeted reducing antibiotic use and controlling the exchange of resistance genes between ecosystems.

Who this is for

• Microbiologists
• Public health workers and agencies
• Policymakers

Key findings

• While many confounding variables exist, and are noted within the publication, the results of this study indicate that, while necessary, interventional strategies based on prudent uses of aminoglycosides for humans, animals, and plants alone are an insufficient way to control and limit the spread of aminoglycoside resistance.
• AME genes were found in all biomes considered and from all continents (except Antarctica) although distribution varied. In this dataset, AME prevalence increased between the 1940s and the 1980s, and plateaued since the 1990s, with the increase likely explained by the discovery and marketing for clinical use of most aminoglycosides. In Europe, aminoglycoside use has stabilized and/or decreased (since 1997).
• The authors found clusters of homologous genes to coexist over long time periods and to be unevenly distributed across space, suggesting an impact from a combination of different local dynamics. However, they also found that while local distributions of AME genes are driven by local parameters, local resistomes also appear to be connected at the global scale since two very distant regions (e.g., Europe and Southern Asia and Oceania) can display the same time trends with regard to specific genes.
• Using multiple modeling techniques to address variations between biomes, the authors considered the contributions of aminoglycoside use and its interaction with ecology on the prevalence of resistance genes. They found that prevalence is shaped not only by antibiotic use but also, and in fact more so, by ecology and human exchanges (e.g., trade and migration).
• The authors conclude that understanding the big picture of antibiotic resistance will require a stronger sampling effort in natural ecosystems and since resistomes tend to cluster by ecology rather than by geography, emphasis should be put on monitoring the resistome of all biomes with equal intensity (not only on clinical and farm samples).