Low levels of antibiotics in the environment do not actually help superbugs spread as much as we once thought.
April 29, 2026
Original Paper
Correcting the on-plate conjugation artifact reveals negligible antibiotic stimulation of plasmid dissemination
SSRN · 6660648
The Takeaway
It has long been a standard belief that the tiny amounts of antibiotics found in wastewater act as a training ground for drug-resistant bacteria. This study found that when the laboratory tests are corrected for a common technical error, the effect mostly disappears. The antibiotics do not significantly speed up the process of bacteria sharing their resistance genes with each other. This means that focusing on these low-level traces might not be the most effective way to stop the rise of superbugs. It suggests that our current strategies for managing antibiotic waste in the environment may need to be entirely rethought. This finding challenges one of the core pillars of environmental microbiology.
From the abstract
The global spread of antibiotic-resistant bacteria (ARB) poses a major threat to public health, with wastewater frequently regarded as a hotspot for conjugation-mediated horizontal gene transfer. In this study, we employed a conjugation model and hybrid whole-genome sequencing to characterize the transfer of plasmid pRK2013 between Escherichia coli strains. Our results indicate that conjugation frequently resulted in partial plasmid acquisition and chromosomal integration rather than stable epis