RESISTANCE TO antibiotics has previously been rare among livestock, but its prevalence has taken a worrying twist recently with the discovery of an enzyme in E coli which is resistant to all penicillins.

In a letter to Vet Record, Chris Teale of the Vet Lab Agency, Shrewsbury, says the discovery was made in E coli recovered from scouring calves on a Welsh dairy farm.

“This resistance is to all the current penicillins licensed for use in the UK. This has been detected in humans before, but never in livestock.”

While Mr Teale believes the enzyme is of little danger while it remains in the strain of E coli recovered from the calves, he suggests it would be more problematic if it spread to other organisms. “If resistance spread to another organism, such as salmonella, it could be a huge problem, both in livestock and humans.”

Resistance would be difficult to spot on farm, but producers may have an inkling of a problem when using cephalosporin-based products which fail to cure problems as expected, he adds.