Washington, Aug 19 - A specific protein found on the surface of a common bacterial pathogen allows it to subvert the brain, triggering deadly meningitis in infants, scientists have found, possibly opening the way to better vaccines.

'Streptococcus pneumoniae, commonly known as pneumococcus, is responsible for half the cases of bacterial meningitis in humans,' said senior study author Victor Nizet, professor of paediatrics at the University of California, San Diego's School of Medicine (UCSD-SM).

'As many as 30 percent of patients can die from this rapidly progressing infection, while half of survivors may be left with permanent neurological problems including deafness, seizures, intellectual deficits or motor disabilities,' said Nizet.

Meningitis develops when bacteria penetrate the 'blood-brain barrier' (BBB). Comprising a single layer of highly specialised micro-vascular cells, BBB prevents most large molecules from breaching the cerebrospinal fluid in the brain.