Living Near Livestock May Increase Risk of Acquiring MRSA

Pigs

Published October 29, 2012, last updated on February 15, 2013 under Research News

People who live near livestock or in livestock farming communities may be at greater risk of acquiring livestock-related strains of Methicillin-resistant Staphylococcus Aureus, commonly known as MRSA, according to a new study led by a visiting scholar at the Duke Global Health Institute.

Along with a team of U.S. and Dutch researchers, lead author Beth Feingold found that livestock density near a place of residence, regardless of contact, is an important risk factor for contracting livestock-associated MRSA. The team’s research findings are featured in the November issue of Emerging Infectious Diseases. This is the first study to suggest the importance of indirect routes of transmission of livestock-associated MRSA. 

“This work has potential policy implications for MRSA surveillance in countries with a substantial percentage of total MRSA cases linked to livestock,” said Feingold. “Controlling the spread of livestock-associated MRSA requires attention to community members in animal-dense regions who are otherwise unaffiliated with livestock farming. 

Researchers found that as the density of veal calves, pigs or cattle doubles in the region around where one lives, the odds of carrying livestock-associated MRSA over other types of MRSA increased by a quarter and as much as 77 percent, depending on the animal. Using geographic information to locate livestock-associated MRSA cases, the team found a greater prevalence of this type of MRSA as compared to other types of staph infection in the Southeast region of the country—a major livestock production area of the Netherlands.

“In recent years, livestock-associated MRSA has been found with increasing frequency in individuals with no known contact with livestock,” said Jan Kluytmans, co-author and professor at VU University Medical Center Amsterdam and Amphia Hospital Breda, the Netherlands.  “It is important to determine the routes of transmission outside of the farms since this may have important consequences for public health.”

The authors suggest the study may have serious implications for individuals living in the U.S. due to the volume of pig farms. “Swine production is a significant industry in the Netherlands, but its density and scale are much less than in the United States,” said Ellen Silbergeld, co-author and professor at Johns Hopkins Bloomberg School of Public Health. “Future work should investigate the relationship between intensive livestock operations in the U.S. and exposures to drug-resistant microbes including MRSA.”

The research was funded by the Johns Hopkins Center for a Livable Future and the Pew Charitable Trusts and involved researchers from the Johns Hopkins Bloomberg School of Public Health, the Dutch Institute for Public Health and the Environment and VU University Medical Center in Amsterdam.

See related article from Johns Hopkins School of Public Health.

"Controlling the spread of livestock-associated MRSA requires attention to community members in animal-dense regions."

- Beth Feingold, DGHI

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