Study shows: Unregulated use of antibiotics in animal experiments probably contributes to drug resistance in humans | Antibiotics

The chronic and unregulated use and disposal of antibiotics in animal testing facilities is contributing to the emergence of drug-resistant superbugs that could pose a threat to human health, according to new research.

A study published in the journal Plos One concludes that widespread and excessive use of antibiotics, unregulated access to essential medicines, and disposal practices in rodent laboratories likely contribute to the global health problem of antimicrobial resistance.

The survey of 95 laboratories in Australia and New Zealand found that 71% routinely used antimicrobial drugs, including antibiotics. Common practices included adding antibiotics to rodents' drinking water and improper disposal of medicated water and feed.

Lead author Dr Rebbecca Wilcox, a laboratory animal veterinarian at RMIT and infectious disease researcher, said animal laboratories had unregulated access to antibiotics from veterinary wholesalers and chemical suppliers and there were none of the necessary oversight mechanisms in place for doctors or veterinarians who prescribe these antibiotics.

Responses to the survey from laboratory veterinarians and farm managers showed they use antibiotics that “are not used in other animal settings” and “are considered drugs of last resort,” she said. “We use them in ways that we can often avoid.”

The World Health Organization has described antimicrobial resistance as one of the greatest threats to global public health.

Wilcox said antibiotic resistance is “an impending pandemic.”

“This means that routine procedures such as hip and knee replacements, caesarean sections, cancer surgery and chemotherapy will no longer be possible. They will be life-threatening,” she said.

While the issue of antibiotic use and antibiotic resistance in human health and agriculture has already been extensively studied, the Australian-led study is the first global publication of empirical evidence on practices in rodent laboratory facilities.

Most facilities (81%) reported flushing the rodents' medicated drinking water untreated down the drain. Wilcox said this is concerning because wastewater from hospitals and health care facilities is known to contribute to antibiotic resistance in the environment.

“There is a lot of documented evidence that wildlife such as seagulls, birds, rats and mice that frequent sewage treatment plants can carry and spread these resistant bacteria,” she said.

Sanjaya Senanayake, an infectious disease specialist at ANU who was not involved in the study, said deaths from antimicrobial resistance would rise to 10 million a year by 2050, surpassing deaths from cancer. “In a country like the US, there are already about 3 million antimicrobial-resistant infections and about 30,000 deaths every year,” he said.

He said the systemic problem has many causes that go beyond the health system. “It's not just a doctor in the hospital or a GP who prescribes an antibiotic when he shouldn't,” Senanayake said. “Most of the antibiotics used are not for us, they are used on animals.”

Prof Mark Blaskovich, who researches the development of new antibiotics and the detection of resistant bacteria at the University of Queensland, said that while the volumes of antibiotics used and discarded in rodent labs are unlikely to be on the same scale as those used in hospitals or by antibiotic manufacturers, the facilities provided an interesting “microcosm of the bigger picture”.

“Despite all the controls in these rodent facilities, antibodies are still not being used properly,” he said. “When people, veterinarians and farmers use antibiotics, very similar things happen, just on a much larger scale, and that really helps drive the evolution of these resistant bacteria.”

Wilcox said if animals contract an untreatable bacterial infection, it would be “catastrophic” from an animal welfare perspective, and potential exposure to resistant bacteria also poses a health and safety risk to people who work with the animals.

The study found that there was particular concern in cases where a laboratory was located adjacent to a hospital or in part of a hospital, as this could lead to biosecurity breaches.

Wilcox expressed hope that the findings would lead to greater awareness and improved practices in the research community, animal ethics committees and policy makers.

“Now that we have some confidence in the actual statistics on this, we can make some recommendations on the responsible use of antibiotics,” she said.