Naresh Singhal, professor of civil and environmental engineering at the University of Auckland, shares his fears about drug resistance.
Drug resistance is one of the worst threats of our time, but it’s a research blindspot in New Zealand. The threat is probably much greater than things like microplastics or PFAS – forever chemicals. But resistance to antibiotics and other drugs gets less attention and there’s a considerably larger gap in our understanding.
Antimicrobial resistance directly caused the deaths of 1.27 million people globally in 2019, and that figure is projected to grow to 10 million deaths a year by 2050. In New Zealand, 330 deaths were caused by antimicrobial resistance in 2019.
My biggest fear is that an epidemic driven by drug resistance will hit our shores one day – and we won’t be ready. Health professionals have been cautioned to prescribe fewer antibiotics, because bacteria are adapting to survive them. Farmers have been advised to reduce the amount of antibiotics they give animals, to slow the rise of resistance, which can pass from animals into humans.
The issue now is not just antibiotics, but other drugs such as antivirals, antifungals and antiparasitic drugs. This antimicrobial resistance can make common infections hard to treat and increase the risks of diseases spreading, or epidemics taking hold.
Although it helps to reduce the amount of drugs used in human healthcare and farming, the problem is now far bigger, because it has entered the natural environment. Antibiotics and other medicines are excreted by humans, and high concentrations enter sewerage systems. Farm animals treated with antibiotics add to the load of drug contaminants in the environment.
Wastewater treatment plants and farming are among the largest sources of drug-resistant microbes. Unfortunately, New Zealand’s wastewater systems are not up to scratch. About 20% of wastewater systems are operating without valid approvals and some systems regularly overflow, so raw sewage enters waterways.
Global evidence suggests wastewater plants discharge large amounts of drug-resistant microbes into rivers, lakes and the sea. Councils and water management organisations need to upgrade our wastewater treatment systems to ensure only low concentrations of antibiotics and other drugs are released into waterways.
It would be helpful to map hotspots of drug-resistant microbes and prepare for the potential spread. If people or animals ingest drug-resistant bugs from contaminated water, it could significantly lift the risk of a drug-resistant infection.
Climate change is heating up wastewater and waterways, allowing drug-resistant bacteria and viruses to flourish more than ever. Key drug-resistant pathogens such as Escherichia coli (E.coli) and Staphylococcus aureus are responsible for millions in hospital expenses, while infections linked to drug resistance cost about $226 million a year.
Antibiotic-resistant E.coli bacteria, which often stem from excrement, are picked up frequently in water samples from the clean-looking Avon River in Christchurch. These bacteria are resistant to the antibiotic ciprofloxacin, sometimes at concentrations 32 times higher than can be safely used on humans. The worrying thing is that ciprofloxacin is often used as a drug of last resort. What do you use when the drug of last resort no longer works?
The problem is complex and poorly understood. Senior lecturer Sam Trowsdale and I have been granted $20,000 to create a working group of experts from universities, government agencies, Māori environmental organisations and the wider community to collate information and begin to look at ways to tackle drug resistance in New Zealand ecosystems.
I hope we can put measures in place, so that if this threat materialises, we can control the problem.
