Antibiotic resistance is endemic, not an epidemic — UNSW study

According to a new study from UNSW, antimicrobial resistance (AMR) is not itself an epidemic. Rather, it has the potential to worsen pandemics or seasonal influenza epidemics, and should be kept in perspective.

AMR happens when microorganisms (such as bacteria) change when they are exposed to antimicrobial drugs (such as antibiotics), and make medicines ineffective. It is gradually increasing, driven by patterns of antibiotic use in animals and humans.

AMR is sometimes called an ‘epidemic’, with some experts predicting it will cause 10 million deaths by 2050. Yet while the World Health Organization recognises AMR is an increasing concern globally, it does not feature among its list of leading causes of death and disability. In fact, since 2008, non-communicable diseases have overtaken infections as the leading cause of disease burden.

Furthermore, while respiratory infections, TB, malaria and HIV remain in the top 10 causes of death, many of these cases occur in countries where antibiotics are uncommon. Less than 4% of TB is multidrug resistant, and HIV drug resistance is falling in many countries, including Australia.

Study authors Professor Raina MacIntyre and research assistant Dr Chau Bui thus disagree with the assessment of AMR as an epidemic, as they explain in the journal Archives of Public Health.

“When we examine the pattern, AMR is a chronic, endemic problem,” said Professor MacIntyre. “It is not an epidemic condition itself, but may complicate epidemics, which are characterised by sudden societal impact due to rapid rise in cases over a short timescale.

“Influenza, which causes direct viral effects, or secondary bacterial complications, is the most likely cause of an epidemic where AMR may be a problem,” Professor MacIntyre said. AMR could also pose a problem in a pandemic caused by re-emergent smallpox, as well as genetically engineered or modified organisms.

Professor MacIntyre has now developed a risk analysis method for assessing the impact of AMR in a pandemic, which could be used to rapidly assess the risk. Furthermore, the technology now exists to create viruses or bacteria in a lab or modify existing ones, and to insert or remove certain characteristics — including drug resistance.

“Understanding the epidemiology of AMR is key to successfully addressing the problem,” Professor MacIntyre said.

“AMR is a chronic, endemic condition which requires long-term strategies to mitigate.”

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