Meningitis and pneumonia bacteria smash into our lungs and cells to steal sugar, which helps them survive, according to research presented from King's College and Guy's Hospital London, (Monday, 04 April 2005) at the Society for General Microbiology's 156th Meeting at Heriot-Watt University, Edinburgh.
The way bacteria grow and spread is a key to the way they cause infectious diseases, say scientists trying to find ways to stop antibiotic resistant strains of bacteria responsible for pneumonia and meningitis.
Now researchers from King's College Dental Institute based at Guy's Hospital in London have demonstrated for the first time how bacteria can manufacture sugar to use as food from common proteins they find in our bodies.
"Life-threatening disease-causing bacteria get into our systems through our lungs, though our skin cells and through our blood," says Dr Karen Homer of King's College. "But these sites are also all places where we have glycoproteins, which are a type of protein with a chain of linked sugar molecules. The bacterium Streptococcus pneumoniae, which is responsible for pneumonia and meningitis, can produce enzymes which snip off the sugars, providing food for the bacteria to multiply."
The researchers also found that some of the sugars released from glycoproteins may be used to form protective capsules for the bacteria when they are attacked - for instance when someone takes antibiotics. The capsules are similar to a sugar coating put on pills, forming a hard armour which defends the bacteria from our bodies' defences.
"Now we know that S. pneumoniae can use the sugars on glycoproteins for growth, we might be able to design drugs that interfere with this process and give us another tool to fight diseases. These drugs could target the enzymes that release sugars from glycoproteins, or the transport systems which take the sugars inside the cell. Such drugs could provide a new way of treating infections or give us new antibiotics," says Dr Homer.
The researchers are now investigating compounds which stop the bacteria from breaking down glycoproteins, to see if these can slow down or prevent the bacteria from growing. New drugs based on these compounds could significantly reduce the number of deaths from pneumonia and meningitis infections, and produce drugs that bacteria are less likely to be able to resist.
It is estimated that more than 18,000 people in the UK are treated in hospital for pneumococcal pneumonia each year, with at least 3,400 deaths.