Original Source

The Prevalence of Antibiotic-Resistant Staphylococcus aureus Nasal Carriage among Industrial Hog Operation Workers, Community Residents, and Children Living in Their Households: North Carolina, USA

Environmental Health Perspectives

Volume: 125: 560–569 Issue: 4

01 APR 2017

Hatcher, S, M., Rhodes, S. M., Stewart, J. R., Silbergeld, E., Pisanic, N., Larsen, J., et al.

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From the source: "Funding for this study was provided by E.W. “Al” Thrasher Award 10287 from the Thrasher Research Fund and National Science Foundation grant 1316318 as part of the joint National Science Foundation (NSF)–National Institutes of Health (NIH)–U.S. Department of Agriculture (USDA) Ecology and Evolution of Infectious Diseases program." "S.M.H. was supported by NSF Graduate Research Fellowship (award no. DGE-1144081) and National Institute of Environmental Health Sciences (NIEHS)–NIH award no. T32ES007018. S.M.R. was supported by NSF grant 1316318. N.P. was supported by NIEHS award no. 5T32ES007141-30. J.L. was supported by the National Institute of Allergy and Infectious Diseases (NIAID)–NIH grant 1R01AI101371-01A1. C.D.H. was supported by K01 grant 1K01OH010193-01A1 from the National Institute for Occupational Safety and Health (NIOSH) Centers for Disease Control and Prevention (CDC), by E.W. “Al” Thrasher Award 10287, and by NSF grant 1316318. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript."

From the source: "D.H. is Program Manager and co-founder of the Rural Empowerment Association for Community Help (REACH), a 501(c)(3) not for profit organization located in Duplin County, North Carolina. D.H. is a complainant in a Title VI administrative complaint against the North Carolina Department of Environmental Quality related to its statewide hog operation lagoon and sprayfield liquid waste management permitting system. There is no potential personal financial gain from this administrative complaint, which is not directly related to the research described in this manuscript and is not a lawsuit or litigation. S.M.H. served as an unpaid member of the board of directors of REACH between September 2013 and June 2015. The other authors declare they have no actual or potential competing financial interests."
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Summary

The authors investigated the prevalence of nasal carriage bacterium Staphylococcus aureus of North Carolina industrial hog operation (IHO) workers and children in their households compared to community residents (CR). IOH workers and their children were more likely to carry Staph. aureus than CR. MRSA and MDRSA (antibiotic resistant strains) were more prevalent in children from IHO households. Further investigations of the bacteria revealed that the found strains were not predominantly associated with livestock, implying that the children were not primarily infected via their adult household members. The authors highlight that more research is needed to understand infection pathways and potential sources. Among the strengths of this study are the relatively high sample size, the recruitment of a control group, and the further characterisation of the bacteria according to its origins (livestock or not). A limitation of this study is that the IHO and CR groups differed in characteristics such as sex and ethnicity. Additionally, the researchers were unable to compare antibiotic usage in IHOs and prevalence of Staph. aureus in pigs to the prevalence in exposed workers. In conclusion, this study suggests that children in households of IHO workers might be at higher risk for carrying antibiotic resistant strains of Staph. aureus. According to the authors further studies are needed to investigate the pathways of exposition and whether the carriage represents a risk factor to infection with resistant strains.

Background:
Antibiotic use in industrial hog operations (IHOs) can support the emergence of antibiotic-resistant (ABR) Staphylococcus aureus. The extent of ABR S. aureus exposure in IHO workers and children living in their households remains unclear.

Objective:
We investigated ABR S. aureus nasal carriage prevalence among adults with versus without occupational exposure to IHOs and among children living in their households.

Methods:
In total, 198 IHO worker–child household pairs and 202 community referent (CR) adult–child household pairs completed a questionnaire and provided a nasal swab which was analyzed for S. aureus, methicillin-resistant S. aureus (MRSA), multidrug-resistant S. aureus (MDRSA), absence of scn (putative marker of livestock association), and spa type.

Results:
S. aureus nasal carriage prevalence was higher among IHO (53%) compared with CR (31%) adults [adjusted prevalence ratio (aPR): 1.40; 95% confidence interval (CI): 1.07, 1.83], but MRSA nasal carriage prevalence was uncommon (2–3%) in IHO and CR adults. MDRSA nasal carriage prevalence was similar among IHO workers and CR adults (12% vs. 8%; aPR: 1.14; 95% CI: 0.56, 2.29). Nasal carriage prevalence was higher among IHO compared with CR children for S. aureus (49% vs. 31%; aPR: 1.50; 95% CI: 1.13, 1.99), MRSA (14% vs. 6%; aPR: 2.37; 95% CI: 1.14, 4.92), and MDRSA (23% vs. 8%; aPR: 2.64; 95% CI: 1.47, 4.75). We also found suggestive evidence of a higher prevalence of S. aureus, MRSA, and MDRSA among children living with an IHO worker who did versus did not report taking personal protective equipment (PPE) home from the IHO. Livestock-associated S. aureus nasal carriage predominated among IHO workers.

Conclusion:
Our findings support the importance of further research on the prevalence and potential sources of exposure to ABR S. aureus among children living with IHO workers.