A new strain of MRSA that can cause life-threatening illness has been discovered in UK dairy herds and has already infected a small number of people, scientists have revealed. The drug-resistant superbug was found in cows' milk during a study of mastitis, an udder infection, marking the first time MRSA has been detected on British farms.
The strain has caused serious blood infections and minor conditions in humans, though health officials downplay the risk to the general public, as standard UK hospital tests should detect it. The exact route of transmission is unknown, but likely involves contact with infected cattle or farm workers. Pasteurisation kills the bug, making milk safe to drink, and unpasteurised cheese is also considered low risk.
Dr Mark Holmes of the University of Cambridge, who led the study, said early tests suggest nearly 3% of UK dairy farms are affected. A more extensive survey begins this summer. The strain has been found in samples from Scotland, England, Ireland, Denmark and Germany, with the oldest dating back to a Danish patient in 1975, indicating it has gone unnoticed for at least 35 years.
Human cases in England and Scotland rose from one in 2002 to 12 last year, according to a report in The Lancet Infectious Diseases. While detectable by standard UK tests, the strain's different genetic makeup means it may evade the 'gold standard' test used in some European hospitals. Calls have been made to rethink antibiotic use on farms to prevent further resistance.
A Dairy UK spokesman emphasised that infection occurs through physical contact, not milk consumption, and that hygiene practices minimise risks. Helen Browning of the Soil Association urged reduced antibiotic dependency, even if it increases milk costs, to preserve the effectiveness of these drugs.
