SOURCE: Johns Hopkins University, news release, Sept. 8, 2014
FRIDAY, Sept. 12, 2014 (HealthDay News) -- About half the workers at industrial hog farms likely carry drug-resistant bacteria in their noses after they leave the farms at the end of their shift, a new small study suggests.
What's more, that bacteria can stay with them for up to four days, reports the study.
The longer the potentially harmful livestock-associated Staphylococcus aureus bacteria remains in the workers' noses, the greater the chances they'll spread the bacteria to their families, other people in the community and hospitals, the researchers said.
"Before this study, we didn't know much about the persistence of livestock-associated strains among workers in the United States whose primary full-time jobs involve working inside large industrial hog-confinement facilities," study author Christopher Heaney, assistant professor in the departments of environmental health sciences and epidemiology at the Johns Hopkins Bloomberg School of Public Health, said in a university news release.
"Now we need to better understand not only how persistence of this drug-resistant bacteria may impact the health of the workers themselves, but whether there are broader public health implications," he added.
The study included 22 workers at industrial hog farms in North Carolina who were followed for two weeks. On average, they spent two days away from work during that time, with four consecutive days being the longest length of time spent away from work.
Researchers collected nasal swabs from the participants every morning and evening, whether they worked or not. The swabs were analyzed to see what kind of bacteria was present in the workers' noses.
Eighty-six percent of the workers had a least one type of S. aureus at some point during the study, while 73 percent had the livestock-associated strain at some point. Only about one-third of the general population carry a human-associated strain of S. aureus.
The researchers also found that 10 of the workers (46 percent) were "persistent carriers." That means they had livestock-associated S. aureus in their noses all or all but one of the times they were checked, even when they weren't at work.
In addition, six of those persistent carriers had multi-drug resistant S. aureus, and one persistently carried methicillin-resistant S. aureus (which is also known as MRSA), according to the study published online recently in the journal Occupational and Environmental Medicine.
Bacteria were still present in workers' noses even up to four days after they had last been at the hog operation, the investigators found.
The researchers are now trying to determine if hog workers who carry drug-resistant bacteria spread it to their families and communities, which could make them a threat to public health.
The U.S. National Library of Medicine has more about staphylococcal infections.