An 85-year-old woman with dementia is admitted to the hospital with worsening confusion, new urinary incontinence and constipation. These symptoms suggest a urinary tract infection, but the treating physician has a dilemma because the symptoms also suggest that dementia may be worsening or that she has simple constipation. Sending a sample to a laboratory for analysis can confirm the presence of bacteria in the urine, but obtaining a result takes days, so the doctor decides to act safely and prescribe antibiotics.
Scenes such as this are repeated every day in hospitals around the world and are leading to excessive and often unnecessary use of antibiotics. The inevitable consequence is the evolution of resistant bacterial strains. Bacterial genes undergo continuous mutation. When a colony of bacteria is exposed to an antibiotic, a mutation may eventually occur in a single member of the colony, making it immune to the antibiotic. This lucky mutant will then reproduce rapidly as its mutation spreads through the entire colony – as the video below illustrates.
Antibiotic resistance is a global problem that can make existing drugs ineffective against life-threatening bacterial infections. As such, doctors are being advised to prescribe antibiotics more judiciously. However, our most recent research suggests that this is unlikely to happen unless special measures are introduced to address the problem.
What we have proven is that antibiotic prescribing supports the idea that resources that do not belong clearly to an individual or group are probably overexploited (known as "the tragedy of the commons"). In fact, health professionals have suspected this for some time, but have not been rigorously proven so far.
What this implies is that if doctors act in the best interest of their own patients, prescribing antibiotics whenever there is a suspicion of bacterial infection is always the preferred treatment regardless of whether other doctors are doing the same. What makes it a common tragedy is that if all doctors adopt this strategy, the outcome will be worse for themselves and their patients than if they had all been restrained.
Like players in a prisoner's dilemma game, they know the outcome would be better if they all behaved differently, but prescribing antibiotics whenever a bacterial infection looks possible remains their best strategy. We have also shown that the antibiotic prescription rate will likely increase until antibiotics become useless unless steps are taken to alter the results of this potentially life-threatening game.
We come to these conclusions using the theory of evolutionary games and the dynamics of replicators (a mathematical model). The basic idea behind this type of analysis is straightforward. We begin with an assumption about the preferences of the players – in this case, physicians invariably prefer to act in the best interest of their own patients. We then take into account established facts about the effect of prescription rates on antibiotic resistance, and mathematically elaborate the implications for what will happen over time.
It's no use merely calling on doctors to change their prescription behavior, but that does not mean that nothing can be done about it. Based on a detailed review of the literature, we have recently suggested how to mitigate the problem.
Steps to take
Several steps must be taken. Clearly defined antibiotic regulations and access rights need to be established, and the visibility and urgency of the problem need to be intensified. Collective or team-based, rather than individual, decisions should be encouraged, and the prescription should be carefully monitored. In addition, incentives and social and reputational sanctions to encourage responsible prescribing should be introduced. Finally, perverse incentives that stimulate prescription should be removed.
In the long run, it is unlikely that the problem of antibiotic resistance can be completely eliminated, but the steps we suggest may slow down the process.
Eventually, radically new methods of dealing with bacterial infections will be needed. But if nothing is done immediately, then dangerous pandemics may be just around the corner.
New study finds very high rate of unnecessary antibiotic prescription in AS
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Antibiotics: Why asking doctors to prescribe less is futile (2019, April 29)
recovered on April 29, 2019
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