Drug-resistant infection, already one of the world’s biggest killers, is expected to rise sharply. By 2050, the number of people dying due to antimicrobial resistance (AMR) is likely to increase by about 70%, with drug-resistant infections expected to cause 39 million deaths, and as many as 169 million associated deaths during this time.

We know that the most effective ways to prevent many of these deaths is by increasing equitable global access to essential antibiotics and better medical care, and by developing effective new tools. However, what is less clear is how this will be funded. At the recent United Nations general assembly, governments committed $100m (£76m) towards this effort. While this is encouraging, the scale of the challenge is such that it will fall way short of the $63bn a year that is needed.

The problem is that antibiotics are ubiquitous and required across entire health systems at every level. At some stage in our lives, we are all likely to require treatment with them. Given the long-term investment in health systems needed, no single donor, multilateral organisation or global fund can solve this; ultimately it will have to come from sovereign governments. This may seem improbable for low- and middle-income countries, where the burden of disease is the greatest, which often face historically high levels of debt. But there is a tried and tested way in which the international community can help: debt relief.

In the early 2000s, debt relief and the availability of more affordable antiretrovirals helped turn the tide at the height of the HIV/Aids epidemic. Today the economic landscape is arguably worse. According to UN Trade and Development, last year, global public debt reached a record high of $97tn. Although public debt in the poorest countries reached less than a third of the total, at $29tn, since 2010 it has grown twice as fast as in high-income economies.

For example, my home nation of South Africa has the largest economy in Africa, but still has debts the equivalent of three-quarters of its entire GDP, and rising. Because of this, for many countries the cost of servicing this debt is outpacing investment in critical public expenditure, with 3.3 billion people now living in countries that spend more on interest than on health or education.

Given this debt crisis, it is little wonder that, during the recent negotiations over a UN political declaration on AMR, one of the major disagreements was on how to finance the response. Low- and middle-income countries called for increased contributions to a multi-partner trust fund set up to help countries manage their response to AMR through national action plans. All countries committed in 2015 to these plans, designed to strengthen and coordinate measures to tackle drug resistance, but in some countries these remain largely incomplete and underfunded. Some wealthier nations have suggested that these countries should be spending more.

Debt relief is one way to reconcile both these positions. Debt swaps, for example, could be used to replace high-interest debt with low-interest debt, where the interest savings are redirected to tackling AMR. Alternatively, debt could be cancelled entirely in return for governments investing substantially in ways that support their action plans. Either way, resources that would have been servicing debt would instead be channelled into activities that would not only help to mitigate AMR, but also have wider benefits across entire health systems, as well as globally.

This could include anything from improved monitoring of infections and the use of antibiotics, filling vital gaps in our knowledge of what is driving drug resistance, to improved hygiene, sanitation and vaccination programmes. Debt relief could also help to improve access to and stewardship of antibiotics if funds were used to raise awareness among the public, practitioners and policymakers, and support research that is vital to the development of effective new antibiotics.

If adequately funded, such efforts to improve access to effective antibiotics and better healthcare would not only help to stop the rise and spread of AMR and prevent 92 million deaths, it would also strengthen the global economy by nearly $1tn. But as long as some countries face crippling debt, their ability to play their part will be significantly hampered, and in turn hamper all countries’ efforts.

The UN political declaration on AMR is a positive step demonstrating that governments are now committed to act. But it does not propose debt relief as a way to bridge the funding gap, or any other form of innovative financing – such as long-term development impact bonds or health taxes on the sale of tobacco, sugary drinks and alcohol – which is a missed opportunity. With debt burden high on the agenda of the G20 meeting in Rio next month, we now have a chance to remedy that.