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| Photo Credit: Nana K. |
New research has shown, for the first time, how mixtures of commonly used medications which end up in our waterways and natural environments might increase the development of antibiotic-resistant bacteria.
When humans or animals take medications, as much as 90 percent can pass through the body and into natural environments, via waste-water, or run-off from fields, ending up in the ocean.
In the environment, this build-up of antibiotic medicines can accumulate to a strength sufficient to kill the bacteria that live there; this can result in bacteria evolving defenses that help them to survive these concentrations, which can mean they are also resistant to antibiotics used to treat them if they later infect humans. However, less is known about how build-up of other medicines also affects bacteria, and until now, scientists have largely investigated the effect of these medications on triggering this antibiotic resistance one-at-a-time.
Now, new research led by the University of Exeter and published in the journal ISME Communications, has revealed that regular drugs used for pain relief, diabetes medication, and hormone replacement can increase the tendency for bacteria to develop the genes needed to resist antibiotic treatments, when combined with a common antibiotic as happens in the environment.
In laboratory tests, the team exposed a community of wastewater bacteria to mixtures of the commonly-used antibiotic ciprofloxacin and one other non-antibiotic medication at low concentrations that are typical in the environment. They chose ciprofloxacin because it is often found in high concentrations in freshwater sources across the world.
The medications did not increase the ability of a bacteria to survive antibiotic treatments when they were tested on their own. However, when combined with ciprofloxacin, they were more likely to lead to an increase in specific antibiotic resistance genes – compared to when these bacteria were exposed to the antibiotic alone.
Dr April Hayes, postdoctoral research fellow and microbiologist at the University of Exeter, led the research and said:
“We’ve found that the kind of common medications that many people might routinely take can form a pharmaceutical cocktail in the environment and our waterways that promotes antibiotic resistance. This poses a potential threat to human health, because if we then ingest these bacteria and are infected, we may not be able to easily treat them, as antibiotics are more likely to fail. Antimicrobial resistance is a growing global problem – and these mixtures might form an important contribution to that problem.”
BBSRC Associate Director of Research Strategy and Programmes and Programme Lead for UKRI’s for Tackling Infections theme, Dr Jef Grainger, said:
“UKRI has identified tackling infections as one of its five strategic themes, with antimicrobial resistance (AMR) recognized as a flagship challenge.
“This research deepens our understanding of how resistance develops, not just through antibiotics, but through combinations of drugs commonly found in the environment.
“These findings highlight the urgent need to consider pharmaceutical mixtures in AMR research and policy, helping to shape more effective interventions.”
Funding: The research was funded by NERC with research support by AstraZeneca, with equipment support from the Biotechnology and Biological Services Research Council (BBSRC) and Wellcome.
Published in journal: ISME Communications
Authors: April Hayes, Lihong Zhang, Jason Snape, Edward Feil, Barbara Kasprzyk-Hordern, William H Gaze, and Aimee K Murray
Source/Credit: University of Exeter | Louise Vennells
Reference Number: env101425_01
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