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AMR: social and economic factors involved

by
01 January 2015, at 12:00am

JOHN BONNER reports on a meeting called to try to identify practical solutions to the problems of maintaining the efficacy of antimicrobial agents against infective diseases in both humans and animals

WILL the 2028 centenary of the discovery of penicillin be an occasion to celebrate the positive impact of antimicrobial agents on human and animal health – or to mourn their demise after being killed off by waves of drug-resistant bacteria?

Professor Neil Woodford, head of the NHS antibiotic reference laboratory, Colindale, posed the question to a joint meeting of medical and veterinary scientists at the Royal Society of Medicine in London in October.

The event, organised by the RSM in collaboration with the Bella Moss Foundation, was intended to identify practical solutions to the problems of maintaining the efficacy of these drugs against infective diseases in both human and animal patients.

Yet while speakers recognised the significant role that GPs and veterinary practitioners will need to play in tackling antimicrobial resistance, there was a realisation that broader social and economic factors were involved, and that input from other professional groups would be crucial.

Social scientists would play a particularly important part in the process, the audience was told. That is because they will be needed to understand the reasons why antimicrobial drugs are often used inappropriately and how it may be possible to alter such behaviour.

Professor Tony Barnett, a behavioural scientist at the London School of Hygiene and Tropical Medicine, has studied the reasons why people will often ignore the advice they are given by health professionals.

Gallantly, he cited his own wife’s response to finding that an elderly member of their flock of backyard poultry was seriously ill. She refused his offer to deal with the bird himself and took it to their veterinary practice to be euthanased at a cost of £28, plus travel expenses.

“You do need to understand the rationale rather than assuming the rationality of anthropogenic activity. So you must find out what is the meaning of that animal or that event to the person acting in that particular situation,” he explained.

Ignoring warnings in favour of other concerns

In some situations, people may be aware that their behaviour is potentially dangerous for their health but they will choose to ignore the warnings because they have other, more immediate concerns.

Prof. Barnett used the example of a woman in Uganda interviewed as part of a study on AIDS control. She was willing to sleep with a long-distance lorry driver who passed through her village, in spite of the risks, to earn a little extra money to help feed her children, he said.

Another problem arose when people did not believe the health advice that they were given. Those who campaigned against the use of the MMR vaccine in children are a good example of this issue, he said. Such people cannot be dismissed as irrational as they often had well-argued reasons for their strongly held but erroneous beliefs.

Orthodox scientists will need to engage in a debate with those people and attempt to change their hearts and minds as they can form an articulate and extremely vocal lobby group with the power to undermine important public health initiatives, he said.

Persuasion alone may not be enough to change human behaviour and, in this instance, discourage them from seeking out antimicrobial therapy when it is unnecessary, or using those drugs inappropriately when they are medically useful.

The tactics used by the marketing departments of major companies should be studied carefully rather than dismissed out of hand, he believed.

“Their methods focus on the creation of needs and desires in their customers and they are very good at it. They are able to convince people of their desire to have a new mobile phone that is roughly the same as the one that they paid £400 for six months ago. We need to understand and to use those techniques,” he said.

Social scientists, however, are not the only group of non-medical professionals that need to be recruited to help fight the emergence of antimicrobial resistance.

Professor Malcolm Bennett, a veterinary epidemiologist at Liverpool University, highlighted the shortcomings in current knowledge of the way resistance genes circulate in the environment.

Collaborations with environmental scientists will be necessary to estimate the potential risks and devise appropriate strategies to control them, he said.

Resistance genes naturally present

Prof. Bennett produced evidence to show that resistance genes are naturally present in bacteria in the environment. However, the use of antibiotic drugs in human and veterinary medicine will certainly affect their frequency and the ability that bacteria show to acquire resistance genes from each other.

A study by researchers at Liverpool has isolated bacterial strains that are resistant to many front-line antimicrobial agents in the guts of voles found on uninhabited islands off the Scottish coast.

There is no evidence to suggest that drugs used to control disease in farmed salmon can explain those findings, he said. Moreover, there are even traces of resistant bacteria in sediment samples that have lain undisturbed for more than 30,000 years, he pointed out.

The natural environment is therefore a key battleground in the fight against bacterial resistance. So medics and veterinarians must do all they can to reduce the environmental load.

It was worrying that around 80% of the antibiotic dose in many treatments was excreted from the patient’s body without being metabolised, and these drugs will often have a long half-life that allows them to persist for long periods in the environment.

So Prof. Bennett suggested that sewage works are likely to provide an important breeding ground for novel antimicrobial resistant strains.