A new study suggests that young children residing with adults who work in large industrial hog farming operations in a rural North Carolina county had a higher prevalence of two types of antibiotic-resistant staph bacteria in their nasal passages than did children who live with adults in the same community who do not work in such operations.
[Photo: Dr. Jill Stewart and a scanning electron micrograph of staphylococcus aureus]
The study, published Oct. 18 in the journal Environmental Health Perspectives and co-authored by Dr. Jill Stewart, associate professor of environmental sciences and engineering at the University of North Carolina Gillings School of Global Public Health, suggests a high prevalence of exposure to MRSA (methicillin-resistant S. aureus) and MDRSA (multidrug-resistant S. aureus) among these children.
Although children are susceptible to developing staph infections, the researchers caution that none of the children or adults participating in the study reported becoming sick during the course of the study. It is still too early, the investigators say, to draw any conclusions about possible infection and transmission.
People who carry antibiotic-resistant S. aureus – often in their nasal passages – do not necessarily get sick themselves or sicken others. In health-care settings such as hospitals, however, patients often are tested for MRSA carriage so precautions can be taken, as MRSA carriers possess a potentially increased chance of falling ill or transmitting the bacteria along to other patients.
“What remains unclear is whether hog farm workers pick up these antibiotic-resistant bacteria through their contact with pigs and bring them home,” said Dr. Stewart. “It also is unclear whether there is a potential for adverse outcomes if a child acquires and carries these bacteria in his/her nose.”
The study, a collaboration between researchers at UNC, the Johns Hopkins Bloomberg School of Public Health and community residents at the Rural Empowerment Association for Community Help in Duplin County, N.C., examined 400 adult-child pairs in the top 10 hog-producing counties in the state. (North Carolina is the second largest hog-producing state in the United States.)
Of the adult-child pairs, 198 included an adult who worked on a hog farm and a child under age seven living in the same household. The other 202 pairs consisted of an adult who did not work on a hog farm and a cohabiting child age seven or younger. The research team collected nasal swabs from all participants during home visits performed between March and October 2014. Adults in both groups also completed a questionnaire about themselves and the child participating in the study.
The researchers found that 14 percent of children who lived with a hog operation worker were carrying MRSA, compared to six percent of children who lived with adults who weren’t livestock workers. Meanwhile, 23 percent of children living with hog operation workers were carrying MDRSA, compared to eight percent of children not living with livestock workers.
The researchers also found that children who lived with a hog worker who reported bringing home personal protective equipment such as masks, coveralls, boots and/or hats from the hog operation had a higher prevalence of carrying MRSA and MDRSA in the nose than children who lived with a hog worker who did not bring this equipment home.
Funding for the study was provided by the National Science Foundation (NSF) as part of the joint NSF-National Institutes of Health-U.S. Department of Agriculture Ecology and Evolution of Infectious Diseases program.