Health and animal welfare campaigners concerned about the spread of superbugs in humans are calling for a ban on the overuse of antibiotics in farm animals.
They say routinely using antibiotics in livestock can lead to bacteria becoming resistant and such 'superbugs' could spread to humans.
Sample tests they carried out in rivers near farms, in slurry and in chicken litter found resistant bacteria.
The government said it is considering new restrictions on antibiotic use.
A spokesperson from the Department for Environment, Food & Rural Affairs (Defra) said: "We do not support routine preventative use of antibiotics in animals - they should not compensate for poor husbandry practices and we will continue to look into strengthening legislation in this area."
The National Farmers Union said UK farming was "a leader when it comes to the responsible use of antibiotics".
Antimicrobial resistance (AMR) has been described by the World Health Organisation as "one of the biggest threats to global health, food security, and development today."
The overuse of antibiotics, in both human medicine and agriculture, has seen them become less effective and led to the rise of 'superbugs' - strains of bacteria that can no longer be treated by certain drugs.
The latest data published by the UK Health Security Agency shows that the estimated total number of serious antibiotic resistant infections in England rose by 2.2% in 2021 compared to 2020, from 52,842 to 53,985.
Researchers for the Alliance to Save our Antibiotics and World Animal Protection carried out tests for superbugs in rivers alongside a dozen intensive and higher-welfare pig and poultry farms in Warwickshire, Herefordshire, Devon, Norfolk and the Wye Valley and in the slurry from four intensive dairy farms and in one chicken litter sample.