Cholesterol-lowering drugs have a useful side effect - killing bacteria, scientists have discovered.
The statin drugs taken by millions of people around the world to cut their risk of heart disease may protect against serious infections such as pneumonia, researchers believe.
A US study found that the medications activate the bacteria-killing properties of white blood cells.
In laboratory experiments, phagocyte blood cells that kill and ingest foreign invaders became more effective after being exposed to statins.
The phagocytes were prompted to release "extracellular traps" - net-like webs of DNA-based filaments embedded with anti-microbial molecules. The traps ensnare and kill bacteria before they have a chance to spread in the body.
Professor Victor Nizet, from the University of California at San Diego, who led the research, said: "We found these drugs fundamentally alter how white blood cells behave upon encountering bacteria."
The study was reported today in the journal Cell Host & Microbe.
Cathy Ross, from the British Heart Foundation, said: "The results are scientifically interesting and support the fact that we know statins have extra health benefits, in addition to lowering cholesterol.
"However, this is not a reason to prescribe them to the general population. For those already taking statins for heart disease, these added benefits may offer a small level of protection against bacterial infections."