A new study conducted on livestock production and drug resistance has revealed that the immune system of livestock workers exposed to antibiotics is at a greater risk of harm. Researchers arrived at the conclusion after examining a collection of nose swabs from workers at two North Carolina farms.

The study was conducted by researchers from Johns Hopkins Bloomberg School of Public Health, the University of North Carolina at Chapel Hill, Rural Empowerment Association for Community Help, the George Washington University, and the Statens Serum Institute.

Experts analysed two farms, one farm raised the animals in large buildings using antibiotics and the other farm grew animals on pastures, sans antibiotics.

They found livestock related drug-resistant bacteria in the noses of industrial workers. However, the bacteria was absent in the noses of workers from the other farm.

As a result, the Staphylococcus aureus bacterium, which includes the well-known bug MRSA, are twice as likely to be found in workers on factory farms than the other anti-biotic free farms.

S. aureus, a multidrug-resistant bacterium, was 19 times more prevalent in employees of the factory farms.

"This study shows that these livestock-associated strains are present among workers at industrial livestock operations and that these strains are resistant not just to methicillin, but to multiple antibiotics -- including antibiotics that are used to treat human infections," said Christopher Heaney, PhD, corresponding author of the study and assistant professor of Environmental Health Sciences and Epidemiology at the Johns Hopkins Bloomberg School of Public Health.

The study also said that workers of the industrial-scale farms, who were not in direct contact with the animals, were also affected.

Researchers said that the findings are not at all surprising as shockingly high amounts of antibiotics are given to animals on factory farms.

In humans, infections caused by drug-resistant bacteria are difficult to treat. Although new drugs have been developed in recent years, the rate of development is not at par with the rate of resistance.