In a discovery that renews hope for antibiotic treatment, researchers at the University of Edinburgh in the UK have found that bacteria that were thought to be resistant to a powerful antibiotic may actually be susceptible to treatment.
Listeria monocytogenes, a bacterium that causes listeriosis – an infection that is usually caught from eating food containing Listeria – was shown to respond to an antibiotic, even though the bacteria carry genes that should make it highly resistant. Although the risk of Listeria for travellers is generally low, risk is increased by consumption of unpasteurised milk and milk products and prepared meat products and the World Health Organization advises travellers to avoid consumption of unpasteurised milk and milk products and for pregnant women and immunocompromised individuals to take strict precautions to avoid infection by listeriosis and other food-borne pathogens.
Scientists have said that the antibiotic that listeriosis responded to, fosfomycin, should be reconsidered as a treatment for life-threatening Listeria infections. Early lab tests had indicated that fosfomycin fails to kill Listeria because the bacteria carry a gene that enables it to break down the drug. Further studies, however, found that that drug proved effective at killing Listeria in infected cells in the lab and in mice.
The researchers said that these findings on Listeria could have far-reaching benefits. “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, Division of Infection and Pathway Medicine, the University of Edinburgh.