Half of all workers in industrial hog farms may carry potentially harmful bacteria in their nostrils, which can remain with the workers for up to four days after they are first exposed, days longer than researchers believed the workers harbored the microbes.
The bacteria detected by researchers, Staphylococcus aureus, was found to be largely antibiotic resistant, probably because of drugs used to treat sick hogs and to make them fatter for market quickly.
The researchers, from the Johns Hopkins Bloomberg School of Public Health, say that the longer the bacteria remains in workers’ nostrils, the greater the risk of spreading it to others including at hospitals where the bacteria detected has been linked to an increase risk of staph infections.
The researchers enrolled 22 hog workers in North Carolina to participate in a study for two weeks. During the first week workers swabbed their noses in the morning before work and in the evening after work whether they worked at the farm or not, and took two swabs as well on the 14th day of the study. The researchers analyzed 327 nose swabs to determine the type of Staph bacteria, whether it was typically found in hogs or humans and whether it was drug resistant and found that 19 of the hog workers, or 86 percent, carried at least one type of Staphylococcus aureus at some point during the study period and 16 (73 percent) carried the livestock-associated strain at some point. Six harbored multi-drug resistant kind of S. aureus, and once carried MRSA, which has been linked to many deaths in U.S. hospitals and other health facilities in recent years.
The researchers say the risk posed by the workers may be very serious; 2007 census data shows that there are close to 300,000 livestock workers in the U.S.
“We’re trying to figure out if this is mainly a workplace hazard associated with hog farming or is it a threat to public health at large,” said the study’s lead author, Christopher D. Heane, assistant professor in the departments of Environmental Health Sciences and Epidemiology at Johns Hopkins. “To do that,” said Heaney, “we need to learn more not just about how long workers carry bacteria in their noses, but how it relates to the risk of infection and other health outcomes in workers, their families, and communities.”
The study was published in Occupational and Environmental Medicine.