Farm workers who work on farms where high levels of antibiotics are used in farm animals carry a high proportion of antibiotic resistant bacteria compared with farms that are antibiotic-free.
The implication of this finding is that this is a further source of the spread of antibiotic resistant bacteria into the general community, which presents problems for the treatment of disease.
The reason for the issue coming to light stems from a study of industrial livestock workers in North Carolina. A range of swab samples were taken from the noses of different farm workers and then analyzed in a laboratory.
The farm workers who worked on farms where antibiotics are used carried far higher levels of antibiotic resistant bacteria, most notably methicillin-resistant Staphylococcus aureus (MRSA). MRSA is a strain of staphylococcus bacteria that is resistant to methicillin and certain first-line antibiotics called beta-lactams. The bacteria can cause serious infections of the skin, blood, lungs and bones. Infections with drug-resistant strains, like MRSA, can be particularly difficult to treat.
Many industrial livestock operations raise animals in large conferment buildings and use antibiotics, including non-therapeutically in animals' feed and water to promote their growth. Those concerned with the overuse of antibiotics and the resultant rise in antibiotic resistant bacteria have cautioned against such practices.
The study was a collaboration between Johns Hopkins Bloomberg School of Public Health, the University of North Carolina at Chapel Hill, the Rural Empowerment Association for Community Help, the George Washington University, and the Statens Serum Institute. The findings have been published in the journal PLOS ONE in a paper titled “Livestock-Associated Methicillin and Multidrug Resistant Staphylococcus aureus Is Present among Industrial, Not Antibiotic-Free Livestock Operation Workers in North Carolina.”