A “spoonful of sugar” may be what is needed to help the medicine overcome chronic infections, scientists have discovered.

Researchers in the US found that boosting antibiotics with sugar can dramatically improve their effectiveness.

Laboratory tests showed that glucose and fructose – a type of sugar found in plants – stimulated bugs and made them more vulnerable to drug treatments.

Chronic and recurrent infections often occur when bacteria shut down and become metabolically dormant.

This allows the bugs, known as “persisters”, to dodge the effects of antibiotics. Over the course of weeks or months, the bacteria return to life, often stronger and more aggressive than they were before, and the patient relapses.

Persistent bugs are different from those that develop antibiotic resistance through genetic mutations, but may be just as much of a problem.

Bacterial persistence can stretch illnesses out over months and cause infections to spread to kidneys and other organs.

The Boston scientists looked at a new way of tackling persistent bacteria by rousing them from hibernation using a simple weapon, sugar.

They found that sugar acts as a stimulant that switches on normal bacterial responses, rendering the bugs vulnerable to antibiotic attack.

The approach, reported in the journal Nature, was similarly effective against persistent Staphylococcus aureus bacteria, which can produce serious infections.