The food poisoning bug listeria was shown to respond to an antibiotic, even though the bacteria carry genes that should make it highly resistant, according to an announcement from the University of Edinburgh in the U.K.
Listeria infection -- also known as listeriosis -- is the most lethal foodborne disease known and is often fatal. It is caused by eating contaminated foods such as soft cheeses, smoked salmon, pates, meats and salads. The infection is particularly deadly for those with weak immune systems, such as older people and newborns. It can also cause miscarriage.
Researchers at the University of Edinburgh said the antibiotic fosfomycin should be reconsidered as a treatment for life-threatening listeria infections. Early lab tests had indicated that fosfomycin fails to kill listeria because it carries a gene that enables the bacteria to break down the drug. Further studies, however, found that the drug was effective at killing listeria in infected cells in the lab and in mice, the researchers said.
Genes that are activated only when the bacteria infect the body cancel out the effects of the drug-destroying gene, the University of Edinburgh researchers found. The findings suggest that fosfomycin could prove to be a useful treatment for life-threatening listeria cases despite these bacteria showing resistance based on laboratory tests.
These bacteria reproduce within the cells of the body and frequently affect the brain, which only certain medicines are able to treat. This limits the treatment options for serious infections, so fosfomycin may prove highly beneficial, the university said.
"Our study focused on listeria, but this important discovery may be relevant for other species of bacteria too. It is encouraging that we may be able to repurpose existing drugs in the race against antibiotic resistance," said professor Jose Vazquez-Boland with the Division of Infection Medicine and The Roslin Institute at the University of Edinburgh.
The study, published in the journal PLOS Genetics, was funded by the Wellcome Trust.