Researchers have found another way to fight listeria infections that can cause severe illness in pregnant women and people with immune deficiencies.

The team from the University of Queensland discovered a new method of blocking the bacteria from making the proteins that allow it to survive and multiply in immune cells.

"Listeria is found in the soil and sometimes in raw foods. Once ingested it can hide from the immune system and multiply inside immune cells," Professor Antje Blumenthal says.

"Instead of killing the bacteria, the immune cells are used by the bacteria to multiply and are often killed by listeria growing inside them."

Until now, studies into listeria's 'master regulator' - which controls the proteins that make it virulent - have focused on engineered bacteria, or mutated versions of these proteins.

"Our study showed the bacteria could be cleared with a small drug-like inhibitor that targets the master regulator," Prof Blumenthal said.

"The inhibitor helped the immune cells survive infection and kill the bacteria."

Listeria infection does not cause disease in most people, but can be deadly for the immunocompromised.

It is a major health concern during pregnancy and can lead to miscarriage, stillbirth and premature birth.