Scientists are turning to Auckland's sewer network to get a better handle on antibiotic resistance – a fascinating approach that's also been used to flush out drug use and now coronavirus.

Discovering more about superbugs' ability to defy our drugs is critical: an estimated 700,000-plus people worldwide die each year due to drug-resistant infections and that figure could climb to 10 million by mid-century.

The new study's leader, well-known University of Auckland microbiologist Associate Professor Siouxsie Wiles, said New Zealand currently monitors antibiotic-resistant bacteria by analysing samples collected from hospital and community laboratories.

Although this was a tried and true system, its main drawback is that it failed to capture information about resistant bacteria carried by healthy people with no symptoms.

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"So far studies looking at antibiotic-resistance use samples taken from people who have been to the doctor or hospital," she said.

"We don't have a clear idea of what superbugs are out there in the general public."
Wiles explained that healthy people could harbour some of these superbugs in their nose or gut without any woes.

"However, one day they might end up needing surgery and perhaps that organism will end up in their bloodstream where it will become very difficult to treat," she said.

"Or they could inadvertently pass it on to someone else."

Her two-year study, supported with a $150,000 grant from the Health Research Council, would sample hospital effluent and compare that to samples from wastewater treatment plants serving "healthy" communities without a primary care facility in the catchment area.

A variety of different testing methods would be used to see which achieved the best result.

That included trying to identify the antibiotic-resistant bacteria themselves, looking for genetic material from the bacteria - similar to the test for Covid-19 - or using a more "shotgun" sequencing approach where all material in the sample is sequenced to see what was present.

"We don't have a clear idea of what superbugs are out there in the general public," Associate Professor Siouxsie Wiles says. Photo / Natalie Slade

It was possible that the researchers end up with an archive of samples that could be analysed for all sorts of pathogens, not just antibiotic-resistant bacteria.

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While the data gathered would not be able to pinpoint individuals carrying antibiotic-resistant bacteria and resistance genes, it could be used to model and map outbreaks at a neighbourhood level, something Wiles was wary of.

"One of the key things we want to determine through this study is at what scale is it appropriate to go down to.

"Just because we have the technology to model the level of antibiotic-resistant genes down to a neighbourhood level, it does not necessarily mean that we should," she said.

"We are acutely aware of the need to carry out this work safely and ethically so that it doesn't stigmatise communities or perpetuate inequalities."

HRC Chief Executive Professor Sunny Collings said the information gathered from this study could give clinicians advance notice of which antibiotics are going to work on their patients and which are not, saving vital time – and possibly lives.

It could also help public health officials make better informed decisions on where infection control policies would best be applied – policies that were crucial for preventing infections in vulnerable patients as well as those undergoing routine surgeries such as knee or hip replacements.

"The World Health Organisation has called for drastic action to avert a return to the pre-antibiotic era.

"It's becoming more and more difficult and expensive to treat people who have antibiotic-resistance, and while we aren't yet seeing widespread deaths globally like we're currently experiencing with the Covid-19 pandemic, it will happen at some point if we don't tackle it head on."

Wiles' study was one of 17 Explorer Grants announced today by the Health Research Council, worth a combined total of $2.55m.