A recent study has confirmed that methicillin-resistant Staphylococcus aureus (MRSA) is being transmitted from animals to people (NY Times story, and NPR story). While this has long been suspected, the University of Cambridge study uncovered more concrete evidence by studying cases of MRSA in Denmark – a country where a generally low incidence of MRSA means sources for exposure are lower than in the rest of the world. Geneticists were able to compare MRSA samples from both patients and the infected livestock they owned, and discovered a similarity in the genes of the bacteria indicating likely transmission.
These findings highlight warnings issued by those in agricultural public health for years, who have long suggested that the overuse of antibiotics on livestock could pose huge risks for humans. Managers of factory farms have been known to use antibiotics on all animals to encourage growth, a practice which may encourage the development of drug-resistant pathogens. This study demonstrates that these new hard-to-treat germs could easily make people very sick.
The FDA has moved for voluntary action from farms to curb the spread of drug-resistant pathogens, asking those in the food industry to phase out blanket application of antibiotics. Previously, the FDA has pushed for stronger restrictions on antibiotics, partnering with the CDC in a statement condemning the current state of their use in agriculture. However, in 2011, the FDA veered away from efforts to regulate antibiotics, choosing the voluntary path instead.
HCFA has worked extensively with MRSA prevention in hospitals, and this new research poses an additional challenge to those efforts. Farm workers, for instance, who are unaware that they have been infected, may be hospitalized and introduce MRSA to the hospital, risking the health of other patients, especially those with weakened immune systems. With so much at stake, responsible use of antibiotics in animals is essential.