In the year 2000 just 1 percent of the poultry tested carried resistant bacteria. That figure has now risen to 41 percent. Experts say the risk is slight, but if those bacteria spread to humans there could be problems in treating some infectious diseases.
The National Veterinary Institute, which has carried out the tests, says the increase is hard to explain, as the antibiotics involved have not been used here for 20 years. They were banned in the entire European Union in 1998.