Bacteria are developing resistance at an alarming pace, and aggressive multi-resistant infections constitute an increasing health problem all over the world, researchers said.
Tim Holm Jakobsen, from University of Copenhagen, said that ajoene - the substance present in garlic - specifically prevents the bacteria from secreting the toxin rhamnolipid which destroys white blood cells in the body.
White blood cells are indispensable because they play a crucial role in the immune defence system, not only warding off infection, but also killing bacteria, he said.
When bacteria clump together in what is known as biofilm - where they surround themselves with a tough film of organic materials - they become resistant to antibiotics.
Researchers have been devoting much of their attention to Pseudomonas aeruginosa bacteria, which cause infections in patients with chronic leg ulcers, for example, and in the lungs of patients suffering from cystic fibrosis.
"Ajoene supports and improves treatment with conventional antibiotics. We have clearly demonstrated this on biofilm cultivated in the laboratory and in trials involving mice," Jakobsen said.
"When we add antibiotics to biofilm they have very little effect, and ajoene alone barely makes any difference. It is only when the two are combined that something significant happens," Jakobsen added.
Combination treatment with ajoene and antibiotics kills more than 90 per cent of the normally virulent biofilm, he said.
From a technical perspective, the ajoene blocks the communication system - known as Quorum Sensing - in the bacteria, which is used for purposes including creating infection.
"Garlic contains so little ajoene that you would need to eat around 50 a day to achieve the desired effect. This means we have to pick up the ball from Mother Nature and run with it," Jakobsen said.