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.