Fresh concerns over use of antibiotics in farming

A little closer to home is the story of MRSA ST398 (methicillin-resistant Staphylococcus aureus CC398). Scientists first spotted this strain nine years ago in the Netherlands. A sickly child was taken to hospital by her parents, who were pig farmers. When scientists tested the pigs, they found the same strain of Staph. aureus as was identified in the child. “Pig MRSA” was born.

Last year, US scientists discovered that when this strain first jumped from humans to pigs, it acquired resistance “as a result of farm antibiotic exposure”. In the Netherlands, ST398 accounts for just under 40 per cent of human MRSA cases. It can cause fatal infections in humans, including damage to the heart and blood infections.

To the alarm of the UK dairy industry, last year scientists discovered MRSA ST398 in milk. In October, it was discovered that a retired part-time cattle farmer in the west of Ireland had been infected with the same MRSA ST398.

Beef output

Ireland’s Health Protection Surveillance Centre reported that “it is impossible to completely rule out a link between the patient and animal sources” and that if further cases of this strain of MRSA are identified in humans, then screening for admission to hospital will include those who have had contact with livestock.

MRSA ST398 is resistant to an antibiotic called tetracycline. According to an Irish Medicine Board report in 2010, tetracyclines accounted for 36 per cent of all antibiotics sold in Ireland for veterinary use that year.

Is the discovery of MRSA ST398 in British milk a warning for Irish dairy farmers? Irish dairy and beef farms are expanding. The Department of Agriculture’s Food Harvest targets specify an increase in milk output by 50 per cent and beef output by 40 per cent by 2020. Positive stuff, but this will come with its own pressures.

“If we start intensifying our food production, we need to do this in a sustainable way,” says Prof Séamus Fanning, food safety expert in UCD. “We must withdraw our dependence on antibiotics in farming and keep the drugs for other things.”

Dr Mark Holmes, who led the UK team which discovered MRSA ST398 in milk, says the downward price pressures put on farmers by major retailers can increase antibiotic usage.

“If farmers were not screwed into the ground by the supermarkets and allowed to get a fair price for their milk,” he said in 2012, “they would be able to use fewer antibiotics.”

The use of antibiotics on farms is of concern across Europe. Antibiotics as growth promoters – still allowed in the US – has been banned in Europe since 2006. In 2011, the European Commission published a five-year plan to reduce resistance. Half of the proposed actions address the use of antibiotics in agriculture.

Some believe that with the emerging horse meat scandal, the opportunity for Europe in general – and Ireland in particular – to establish a global reputation for high-quality standards in food production, is significant .