5 December 1997

No evidence of transfer of antibiotic resistance

CLAIMS that antibiotic resistance has been transferred to humans via antibiotics present in food are unfounded, scientists told a London conference on Monday.

Christian Friis of Denmarks Royal Veterinary and Agricultural University, Copenhagen, told delegates that the lack of proof meant there was no scientific evidence to back the Danish governments call for an EU ban on in-feed antibiotic use.

Commenting on the resistance of Salmonella typhimurium DT104 in both livestock and humans, Dr Friis suggested that the resistant bugs themselves could have transferred from livestock to farm or abattoir staff.

"In-feed antibiotics, therefore, are not necessarily to blame for the problem in human medicine, and so the argument for a ban is flawed," said Dr Friis.

Nevertheless public pressure for a ban was growing in Europe, and growth enhancers would be banned for pigs over 30kg in Denmark from Jan 1.

British vet Paul McMullin told the conference, organised by NOAH, the representative body for animal health firms, that bans like that were non-scientific and would curtail development of new antibiotics for animal use.

Reduce competitiveness

"If an EU ban was imposed it could seriously reduce the competitiveness of the EU livestock industry on the world market because, with poorer performance, our production systems would carry higher costs.

"It is unlikely that there would be a worldwide ban on enhancers, and the Codex Alimentarius – the body which would assess whether the EU had grounds to ban imports of animals reared on enhancers – may not rule in our favour.

"This would allow cheaper imports of the very food we had banned, to flood the EU market and undercut EU prices," he said.

But Peter Bennett, a microbiologist at Bristol University, said that the greater the use of antibiotics, the greater the risk of resistant bacteria evolving.

He said that while no-one could prove antibiotic resistance in humans was linked to animal husbandry, excessive use of the drugs in any environment increased the risk of resistance.

He argued that certain antibiotics, such as the fluoroquinolones which were still highly effective in human medicine, should not be used for livestock but preserved for treating people.

Calls for testing to be tougher

ANTIBIOTICS for farm animals should undergo rigorous tests for resistance development before being granted marketing approval, according to the World Health Organisation.

Scientists meeting in Berlin recently said national governments should set up appropriate legislation and enforcement powers.

Poor practice

They insisted that antibiotics should not be used to compensate for poor practice in animal production. They must be used prudently and specifically.

The advice has been welcomed by COMISA (the representative body of the worldwide animal health industry), though it claimed a successful resistance prevention strategy could work only if the human health sector made simultaneous efforts.n