Antimicrobial resistance (AMR) is a growing threat to global health security that transcends national boundaries, socioeconomic divisions and affects human, animal and environmental health. For the scientific community, the increasing alarm around the proliferation of resistant bugs is matched only by the awe and wonder over the intricate biomolecular mechanisms that drive it. This week the Lancet Infectious Diseases journal has brought AMR into sharp focus in a new report describing strains of a common bacterial species, Enterobacteriaceae, taken from pigs and humans in China, that are now resistant to Colistin and polymixins – a class of antibiotics that represents one of the last lines of defence in a rapidly depleting armoury.
Of particular worry is the emergence of a gene that not only makes the bacteria resistant to polymixins, but that can also be readily transferred to other bacteria that cause serious infections in people. This is a new development that has not been previously described. The report represents another example of both the frightening adaptive power of these ancient life-forms and the systemic weakness of human efforts to kill and control them.
Ironically, the use of Colistin, an antibiotic first approved for use in the 1950s, had largely stopped in humans by the 1970s because of worries about its toxicity. In the absence of viable new alternatives, its use in humans was reintroduced during the late 2000s for treating serious multi-drug resistant bacterial infections. Despite this critical role as an antibiotic of last resort in humans, Colistin use in the animal and livestock sector has continued to increase over the years. An estimated 12,000 tonnes of it will be used in agriculture worldwide this year – its widespread use in pigs and poultry is almost certain to have been the major contributory factor to the resistance shown in this latest report.
Growing recognition of the global challenges of AMR control has given the issue increasing prominence in high-level policy discussions. From international platforms such as the G20 and G7 to specialized UN agencies such as the World Health Organization, countries are committing to investment in developing and improving the coordination of effective control strategies. The strategies must focus on the adoption of policies that ensure equitable access to effective antimicrobials for everyone while curbing the excess inappropriate use of these live-saving drugs.
These intimately linked issues form the focus of a new Lancet series, also published this week to coincide with World Antibiotic Awareness Week. Central to the conclusions of this wide-ranging review is the need for ‘One Health’ approaches to AMR strategy and policy development; approaches that bridge the interface between human, animal and environmental health and account for the concerns of trade and commerce – particularly in relation to food production in livestock and aquaculture.
Recommendations are made as to how these can be practically developed at national, regional and global levels and what policies and interventions are likely to be effective given the current evidence base. These include policies to encourage responsible use of antimicrobials, improve infection prevention and control (e.g. diagnostics, vaccines and clean water and sanitation) and build surveillance capacities across all sectors. Finally the series also considers options for funding innovation and new drug development.
Positively, the increased awareness and attention in recent years to AMR at a policy level is now starting to bear fruit; the adoption by the World Health Assembly of a resolution to tackle AMR earlier this year was an important milestone in achieving global action. Member states are now committed to developing National Action plans for AMR control. However, across low- and middle-income countries in particular, these initiatives are not yet sufficiently financed. Sustained success will require adequate resource allocation to all relevant sectors for AMR control (human, animal and environmental), and importantly, a flexibility for member states to determine their own priorities, adapting policies to local context while ensuring good governance and accountability.
Globally, a comprehensive cross-sectoral endeavour of this nature is likely to require significant investment of several billion dollars per year. Financing new drug development will require a separate commitment and an overhaul of current market structures. Some options for these necessary reforms are already being considered. Where sufficient financing is not made available, national AMR control strategies will inevitably narrow their focus to specific areas within the human health sector and leave poorer countries less able to determine their own policy development process.
The development of resistance is a natural evolutionary phenomenon that predates human civilization and no global strategy will stop it completely. However collective, coordinated and concerted efforts can certainly mitigate its effects.
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