Superbug advance: detecting hidden bacteria opens door for treatment

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University of Adelaide researchers have successfully identified and analysed previously undetectable superbug bacteria, paving the way for new therapies and—particularly importantly for less developed regions—improved water purification.

The rise of antibiotic-resistant bacteria, so-called superbugs, has been identified by the World Health Organisation as one of the greatest current threats to human health. Around 700,000 deaths per year are already attributed to it worldwide, and by 2050 that figure could rise to as many as 10 million—with an associated annual economic cost of USD$100 trillion—unless alternative treatments are found.

A major contributing factor is that bacteria have been shown to possess the remarkable ability to switch into hidden, low-growth forms when placed under stress; and in this alternative state become tolerant of antimicrobial processes. Triggering stresses include not only antibiotic attack, but water purification treatments—a major issue in less developed countries with poor water management systems.

Undetectable by traditional means, the hidden bacteria remain dangerous and still can have an impact on environmental, industrial or health systems. But most worryingly, they can subsequently revert to their active form, giving rise to continuing infections.

Recently, however, a major breakthrough has been made. Researchers from the University of Adelaide School of Biological Sciences utilised novel techniques to identify, grow and genetically analyse populations of hidden-state bacteria in two superbug species.

“It’s a very exciting step,” says lead researcher Dr Stephen Kidd. “Our studies open pathways to understand bacteria in a hidden state and will allow future decontamination processes and therapies to target them. We may even be able to prevent them switching into this state in the first place.”

The Adelaide team first grew a population of the bacteria Staphylococcus aureus for a prolonged period, and from that were able to develop and sustain a population of hidden, low-growth cells.

“We were able to analyse the hidden type’s gene regulation and genetics compared to the parental type, which was a world-first. We then used the same approach with other bacteria, and found for the first time that Streptococcus pneumoniae can similarly switch to a hidden state, which we’ve also characterised.”

Dr Kidd says his team’s work provides an important contribution to two overarching national projects relating to the containment of superbugs, each led by University of Adelaide researchers.

These are: the Australian Commission on Safety and Quality in Health Care’s national surveillance program for antimicrobial resistance (AMR) in humans, led by Professor John Turnidge; and development of a national plan for AMR surveillance in animal populations, for which Associate Professor Darren Trott has been appointed to write an advisory report for the Australian Government.