Concern is mounting over the growing use of antibiotics on farm animals, often with no medical supervision.
Fears are particularly acute over the US where authorities say the antibiotics contribute significantly to resistance. Estimates say that 80% of all antibiotics purchased in the US are for farm animals.
The drugs are used to prevent illnesses which are easily transmitted when animals are confined in pens. Drugs are also used to increase the animal’s weight.
But late last year the US Center for Disease Control said infections resistant to drugs were causing 23,000 deaths each year, underscoring a suggested link between antibiotics in animals and infections in humans.
The situation has been exacerbated by medical supervision being ignored.
A survey by the Department of Agriculture found that less than half of dairy farmers followed a vet's recommendations on using antibiotics.
In Europe, drugs on farms are more tightly controlled and their use as a growth aid is banned.
These concerns were expressed at a meeting of the World Organisation for Animal Health, which said it was working to prevent negotiations between the US and the EU over trade did not result in compromises in the area of animal medicine.
The negotiations are trying to reduce or remove trade barriers in order to increase trade between the two regions.
The scale of the threat from both human and animal was underlined at this meeting by the director-general of the World Health Organization (WHO), Dr Margaret Chan, who warned that the world was headed to a "post-biotic" era.
"If you need a hip replacement, if you need a stent in your heart vessels, no surgeon will operate on you. No one will provide treatment to cancer patients without coverage of antibiotics," she said.
