Bacteria, like all living things, need food to grow. The
bacteria that infect us are no exception to this and their food source is us! The
airways are surprisingly rich in nutrients for bacterial growth, some of this
comes from the food we ate (micro-inhalation) and some leaks out from the blood
or cells lining the airways. We know that underlying lung diseases increase the
risk of bacterial infection and have recently shown that this is related to the
levels of glucose in the airways.
We think that this works a little like leaving a jam jar open – bacteria will
colonise and grow on the available sugar.
New Treatments for Bad Bugs
Antibiotic resistance bacteria (bacteria that are not killed
by antibiotics) are a crisis in global health. If antibiotics stop working, as
well as an increase in the severity infections that are treatable, much of the
medical advances of the last 50 years including surgery and transplant also
become ineffective. We therefore need new ways of killing bacteria. This could
either be by finding drugs that directly attack the bacteria, or by changing
strategies.
War on bugs
Our finding that bacteria grow better when sugar is high opens
up new treatment strategies – to starve the bug, rather than attacking it. In our recent
study, we investigated whether an anti-diabetic drug (Dapagliflozin, made
by AstraZeneca) could prevent bacterial lung infection. Treating diabetic mice
with Dapagliflozin reduced the blood sugar; critically it also reduced the airway
sugar levels. The reduction in airway sugar led to a reduction in bacterial
infection in the drug treated mice. We have seen a similar effect using another
anti-diabetic drug – metformin. These studies suggest that reducing blood and
lung sugar will reduce the number of infections seen in people with diabetes.
