Researchers in the UK have identified a ‘switch’ that enables salmonella bacteria to sabotage host cells, a mechanism that could one day lead to new drugs to combat salmonella and possibly other bacterial infections.

The research, funded by the Wellcome Trust and published in the journal ‘Science’, identifies the molecular switch needed before the bacterial cell can inject its proteins into a host cell, interfering with the cell’s defences and allowing the bacteria to grow.

Lead author of the study, Professor David Holden from the Department of Medicine at Imperial College London, said that the way in which a salmonella cell delivers its virulence proteins to a host cell is a bit like the way in which a parked aeroplane delivers its passengers to a terminal building.

“The bacterial cell waits until it has assembled a special bridge before it delivers its passengers – the virulence proteins – to the host cell,” Holden said.

“On a plane there’s a safety catch to prevent the doors opening before the bridge is ready. Similarly, the bacterial cell holds back delivery of its proteins using a molecular safety catch, until it senses that the pore has been assembled.”

In humans, salmonella causes diseases ranging from gastroenteritis to typhoid fever. It also causes similar diseases in livestock.

Although the research is at an early stage, researchers believe their findings will enable them to design better drugs or vaccines to combat salmonella-related diseases.