Research uncovers how a superbug is spreading infections in hospitals 

Research uncovers how a superbug is spreading infection in hospitals
© iStock/miodrag ignjatovic

Hospital superbugs are using thin, stretchy fibres to attach themselves to surfaces and cause infections, according to new research from the University of Turku. 

Researchers at the University of Turku have found that the superbug known as Acinetobacter baumannii, is using ultrathin fibres to cling onto surfaces and spread infection. Acinetobacter baumannii is antibiotic resistant and is, therefore, one of the most globally harmful bacteria. The researchers have revealed how these fibres are formed on bacterial surfaces and have suggested new approaches to preventing bacterial infection.  

Superbugs are a major issue in healthcare

Hospital infections caused by superbugs like Acinetobacter baumanniiare a major healthcare issue across the globe, and these infections are associated with the pathogen’s ability to colonise both biotic and anti-biotic surfaces

“The pan-antibiotic resistantAcinetobacter baumanniiis one of the most troublesome pathogens for healthcare institutions globally and currently tops the World Health Organization’s priority pathogens list for the development of new antibiotics,” explained Anton Zavialov, Head of the Joint Biotechnology Laboratory at the University of Turku’s Faculty of Medicine. Zavialov and his team discovered that unique surface structures we 

re enabling the Acinetobacte baumannii to colonise medical devices and infect patients.  

“This discovery may help fight many bacterial infections, because the same surface attachment mechanism is used by many important bacterial pathogens, including Pseudomonas aeruginosa, the second top priority pathogen on the WHO list,” said Zavialov.  

How Acinetobacter baumannii causes infection

How the Acinetobacter baumannii superbug can colonise medical devices is known as archaic chaperone-usher (ACU) pili. ACU pili are ultrathin hair-like protein fibres found on the surface of many pathogenic bacteria 

Acinetobacter baumannii is capable of colonising medical devices using archaic chaperone-usher (ACU) pili. ACU pili are hair-like protein fibres found on the surface of many pathogenic bacteria. The researchers used cryo-electronic microscopy to examine the superbug. They found that the ACU pili had a unique, ultrathin zigzag architecture. Using this, the fibres can transmit the bacterium from the superbug to the surface by firmly attaching the fibres with microscopic sticky, finger-like structures at their ends. Once these ‘fingers’ grip the surface they become difficult to detach as the superbug can stretch by changing its conformation from a zigzag shape to a linear one.  

“This phenomenon is well known to sailors. It is now common to use stretchable elements in mooring lines to dock boats safely in relatively rough water. If you imagine a bacterium the same size as a human, then the attachment fibres of this giant bacterium will still be 100 times thinner than human hands. The ability to stretch is critical for such thin fibres to withstand high shear forces which bacteria experience in their environment,” explained Zavialov.  

The research team are optimistic their findings can lead to improvements in healthcare, “Theoretically, we can develop drugs preventing this conformational change. Such drugs would block fibre biogenesis, abolishing bacterial attachment,” said Henri Malmi, senior researcher on the project. 


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