Bacterial ‘armour' could provide a target for new antibiotic drugs

Scientists have been surprised by the strength and structural role of the membrane surrounding many types of bacteria.

Targeting the “suit of armour” that surrounds many types of bacteria could usher in a new generation of antibiotics, say scientists.

Until now the thin membrane that wraps like cling film around the  bugs has been largely ignored in the search for new antimicrobial treatments.

The new research shows it to be far more vital to bacterial survival than was previously thought.

Lead scientist Dr KC Huang, from Stanford University in the US, said: “We’ve discovered that the outer membrane can act as a suit of armour that is actually stronger than the cell wall.

“It’s humbling to think that this function had been hiding in plain sight for all these years.

“If we can attack the outer membrane, infectious bacteria will be pre-weakened for targeting with antibiotic treatments that disrupt cells in other ways.”

All bacteria have a cell wall that protects the cell’s inner workings.

Decades ago scientists discovered that roughly half of all bacterial species have an additional outer membrane surrounding the cell wall.

Those with  the membrane, known as gram-negative bacteria, tend to be more resistant to antibiotics.

Researchers had thought that the membrane simply acted as an annoying barrier to antibiotic drugs. But the new research suggests that it is surprisingly strong, acting like a bacterial exoskeleton.

Tests on Escherichia coli (E.coli) bacteria showed that even when pressure within the bugs was lowered, the outer membrane remained rigid and ensured they maintained their cucumber shape.

But when the outer membrane was weakened, the bacteria quickly collapsed and died.

Dr Huang said: “The presence or absence of a strong outer membrane is the difference between life and death.”

The experiments identified a handful of components that gave the outer membrane its strength, but which could also be targeted by drugs.

The research is reported in the journal Nature.

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