Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2017 Nov:159:46-60.
doi: 10.1016/j.envres.2017.07.037. Epub 2017 Jul 31.

Swine exposure and methicillin-resistant Staphylococcus aureus infection among hospitalized patients with skin and soft tissue infections in Illinois: A ZIP code-level analysis

Glennon A Beresin  1 , J Michael Wright  2 , Glenn E Rice  2 , Jyotsna S Jagai  3
Affiliations

Swine exposure and methicillin-resistant Staphylococcus aureus infection among hospitalized patients with skin and soft tissue infections in Illinois: A ZIP code-level analysis

Glennon A Beresin et al. Environ Res. 2017 Nov.

Abstract

Background: Methicillin-resistant Staphylococcus aureus (MRSA), a bacterial pathogen, is a predominant cause of skin and soft tissue infections (SSTI) in the United States. Swine-production facilities have been recognized as potential environmental reservoirs of MRSA. To better understand how swine production may contribute to MRSA infection, we evaluated the association between MRSA infection among SSTI inpatients and exposure measures derived from national swine inventory data.

Methods: Based on adjusted odds ratios from logistic regression models, we evaluated the association between swine exposure metrics and MRSA infections among all Illinois inpatient hospitalizations for SSTI from January 2008 through July 2011. We also assessed if swine exposures had greater association with suspected community-onset MRSA (CO-MRSA) compared to suspected hospital-onset MRSA (HO-MRSA). Exposures were estimated using the Farm Location and Agricultural Production Simulator, generating the number of farms with greater than 1000 swine per residential ZIP code and the residential ZIP code-level swine density (swine/km2).

Results: For every increase in 100 swine/km2 within a residential ZIP code, the adjusted OR (aOR) for MRSA infection was 1.36 (95% CI: 1.28-1.45). For every additional large farm (i.e., >1000 swine) per ZIP code, the aOR for MRSA infection was 1.06 (95% CI: 1.04-1.07). The aOR for ZIP codes with any large farms compared to those with no large farms was 1.24 (95% CI: 1.19-1.29). We saw no evidence of an increased association for CO-MRSA compared to HO-MRSA with either continuous exposure metric (aORs=0.99), and observed inconsistent results across exposure categories.

Conclusions: These publicly-available, ecological exposure data demonstrated positive associations between swine exposure measures and individual-level MRSA infections among SSTI inpatients. Though it is difficult to draw definitive conclusions due to limitations of the data, these findings suggest that the risk of MRSA may increase based on indirect environmental exposure to swine production. Future research can address measurement error related to these data by improving exposure assessment precision, increased specification of MRSA strain, and better characterization of specific environmental exposure pathways.

Keywords: Antimicrobial resistance; Concentrated animal feeding operations (CAFOs); Methicillin-resistant Staphylococcus aureus (MRSA); Swine; Zoonosis.

PubMed Disclaimer

Conflict of interest statement

Conflict of interest

There are no conflicts of interest to report.

Figures

Fig. A.1
Fig. A.1
Decision flow chart depicting categorization as HA- and CA-MRSA
Fig. A.2
Fig. A.2
Conceptual model for CAFO swine operations and antibiotic resistance, MRSA colonization and infection
Fig. 1
Fig. 1
Map of the ZIP code aggregate swine density (swine/km2) categorical exposure groups across Rural and Urban Continuum Code (RUCC) urban-rural designations.
See this image and copyright information in PMC

References

    1. Akwar TH, Poppe C, Wilson J, Reid-Smith RJ, Dyck M, Waddington J, Shang N, Dassie SA, McEwen SA. Risk factors for antimicrobial resistance among fecal Escherichia coli from residents on forty-three swine farms. Microb Drug Resist. 2007;13(1):69–76. http://doi.org/10.1089/mdr.2006.9999. - DOI - PubMed
    1. Bisdorff B, Scholhölter J, Claußen K, Pulz M, Nowak D, Radon K. MRSA-ST398 in livestock farmers and neighbouring residents in a rural area in Germany. BMC Proc. 2011;5(Suppl 6):P169. http://doi.org/10.1186/1753-6561-5-S6-P169. - DOI - PubMed
    1. Burdett CL, Kraus BR, Garza SJ, Miller RS, Bjork KE. Simulating the distribution of individual livestock farms and their populations in the United States: An example using domestic swine (Sus scrofa domesticus) farms. PLoS One. 2015;10(11):e0140338. Epub 2015 Nov 16. - PMC - PubMed
    1. Carrel M, Schweizer ML, Sarrazin MV, Smith TC, Perencevich EN. Residential proximity to large numbers of swine in feeding operations is associated with increased risk of methicillin-resistant Staphylococcus aureus colonization at time of hospital admission in rural Iowa veterans. Infect Control Hosp Epidemiol. 2014;35(2):190–192. http://doi.org/10.1086/674860. - DOI - PubMed
    1. Casey JA, Cosgrove SE, Stewart WF, Pollak J, Schwartz BS. A population-based study of the epidemiology and clinical features of methicillin-resistant Staphylococcus aureus infection in Pennsylvania, 2001–2010. Epidemiol Infect. 2012;141(6):1166–1179. http://doi.org/10.1017/S0950268812001872. - DOI - PMC - PubMed

MeSH terms