Progress made on potential treatment for ‘superbug’

The study, led by Monash University and published in Nature Microbiology, has found the use of bacteriophages (phages) can help in the treatment of one of the world’s leading superbugs.
 
Acinetobacter baumannii (A. baumannii), described as a ‘global threat’ in previous research papers, has been known to cause nosocomial infections in critically ill or debilitated patients, particularly ventilator-associated pneumonia and infections of the bloodstream, urinary tract, and wounds.
 
Since the 1990s, the superbug has been increasingly difficult to treat as it is intrinsically resistant to multiple antimicrobial agents, and has a ‘remarkable’ ability to acquire new resistance determinants via multiple mechanisms.
 
But now, scientists investigating the use of phages (viruses that kill bacteria but are not harmful to humans) to revert antibiotic resistance believe they have developed a strategy that can help successfully treat one of the world’s most dangerous superbugs.
 
‘We have a large panel of phages that are able to kill antibiotic-resistant A. baumannii,’ Dr Jeremy Barr, senior author of the study and Group Leader at Monash’s School of Biological Sciences, said. 
 
‘But this superbug is smart, and in the same way it becomes resistant to antibiotics, it also quickly becomes resistant to our phages.’
 
However, the new study not only pinpoints how A. baumannii is able to become resistant to these attacks from phages, but in doing so, how the superbug loses its resistance to antibiotics.
 
‘A. baumannii produces a capsule, a viscous and sticky outer layer that protects it and stops the entry of antibiotics,’ lead author Dr Gordillo Altamirano said.
 
‘Our phages use that same capsule as their port of entry to infect the bacterial cell. In an effort to escape from the phages, A. baumannii stops producing its capsule; and that’s when we can hit it with the antibiotics it used to resist.’
 
The study showed how this strategy can result in resensitisation to at least seven different antibiotics, but more research is needed before it can be applied in the clinic. 
 
‘The phages had excellent effects in experiments using mice, so we’re excited to keep working on this approach,’ Dr Altamirano said.
 
‘We’re showing that phages and antibiotics can work great as a team.’
 
Given researchers from the CSIRO have previously described A. baumannii as a truly challenging pathogen in Australian hospital acquired infection, and that it tops the World Health Organization’s ‘priority pathogens list for R&D of new antibiotics’, the new research has the potential to be an important marker in the global fight against antimicrobial resistance.
 
‘This greatly expands the resources to treat A. baumannii infections,’ Dr Barr said. ‘We’re making this superbug a lot less scary.’
 
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antimicrobial resistance bacteriophages superbugs