Research at the University of Leicester in the United Kingdom offers further evidence that particular viruses represent an alternative to antibiotics to treat diseases in farm livestock. The latest results support their practical application on farms.

Working with pigs, Martha Clokie, PhD, of the university’s Department of Infection, Immunity and Inflammation has identified 20 of these viruses, known as bacteriophages or phages, that are effective in combating 72 bacterial strains that cause gut diseases and are resistant to more than one antibiotic. Each phage virus type specifically attacks one pathogenic bacterial species, reducing the risk of the pathogen developing resistance over time, unlike conventional antibiotic treatments.

The latest research, funded by the Agriculture and Horticulture Development Board (AHDB Pork) and scheduled to be published later this year, shows that it is possible to dry out the phages to form a powder that can be added to the animals’ feed and still maintain high efficacy against the target bacteria. After two hours’ contact with the phages, there was a 4-log reduction in the number of disease-causing bacteria, meaning the count was down by a factor of roughly 10,000.

The bacteria had been sourced from field cases, further confirming the likelihood of the treatment being effective in commercial situations.


Phages as an antibiotic alternative

With 40 percent of the UK’s antibiotics used in animals, and the same drugs also prescribed for humans, this latest work confirms the potential of phages for the treatment of both human and animal diseases in future.

“There are many infections that we just can’t treat with antibiotics because they have become resistant to them,” said Clokie. “So using the phage therapy for specific diseases could change the way we treat infection.”

Following previous research two years ago, Professor Clokie concluded that phages have potential to treat Brachyspira and Salmonella infections in pigs.

Under experimental conditions, phages have also been effective in helping to address a leading food safety issue by reducing the contamination by Campylobacter on chicken carcasses.