A FEW years ago, I participated in a speed meet event at the Sydney Science Festival where members of the public were invited to quiz scientists and science writers about any topic of their choosing.

At one point, I found myself facing an earnest young boy.

“Jane,” he said, “what should we do about antibiotic resistance?”

If a 10-year old can see the urgency of the question, it seems more than a bit puzzling that we adults have been willing for so long to squander the riches offered to us by antimicrobial drugs.

It’s not as though resistance is a new thing. The UK experienced repeated outbreaks of ampicillin-resistant Salmonella in the early 1960s, the first coming just one year after the drug was first released for human use.

New research suggests a possible explanation for the bacteria’s apparently speedy fightback against the new drug.

Gene sequencing of Salmonella bacteria collected in France and its former colonies before 1969 has found that resistant strains were in evidence before the release of ampicillin for human use.

How can that be? While the researchers stress that they have not proved a causal link, the most likely explanation would appear to be the widespread use of ampicillin in livestock feed during the late 1950s for both disease prevention and growth promotion.

Reducing the agriculture industry’s use of antibiotics is now one of the key focuses of the fight against antimicrobial resistance, alongside campaigns to reduce clinical prescribing in humans, though it’s been a long time coming.

Concerns that routine use of the drugs in livestock feed might be contributing to antimicrobial resistance go back to at least the 1960s, but the practice itself has proved somewhat resistant to change.

As recently as 2005, the US National Cattlemen’s Beef Association was claiming that “science has not found a link between the use of antibiotics in food animals and development of resistant bacteria that might compromise the efficacy of related antibiotics in human medicine”.

Those with vested interests have always tended to fall back on the “no scientific proof” argument, even when the overwhelming weight of evidence is against them.

Big Tobacco was the master at that game.

“A demand for scientific proof is always a formula for inaction and delay and usually the first reaction of the guilty,” an unnamed British–American tobacco scientist admitted privately back in 1980, according to a historical summary on the World Health Organization (WHO) website.

The WHO is in no doubt that non-therapeutic use of antimicrobials in livestock production is contributing to the growing crisis of antimicrobial resistance.

In November 2017, it called on the global agriculture industry to finally put an end to the practice.

“Scientific evidence demonstrates that overuse of antibiotics in animals can contribute to the emergence of antibiotic resistance,” a spokesperson said. “The volume of antibiotics used in animals is continuing to increase worldwide, driven by a growing demand for foods of animal origin, often produced through intensive animal husbandry.”

While wealthy nations, including to some extent Australia, are increasingly phasing out non-therapeutic use of the drugs in livestock production, the issue remains an enormous problem in low and middle-income countries.

In some countries, around 80% of antibiotic use is in animal husbandry, mostly as a growth promotion tool, the WHO says. This includes antimicrobials classified as critically important, last-resort treatments for human illness.

This is my last column for the year, so I’m putting an end to such practices on my Christmas list, along with a reduction in CO2 emissions and a compassionate approach to the millions of displaced people in our world.

Jane McCredie is a health and science writer based in Sydney.


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