A case control study of environmental and occupational exposures associated with methicillin resistant Staphylococcus aureus nasal carriage in patients admitted to a rural tertiary care hospital in a high density swine region

Authors

Leah Schinasi, University of North Carolina at Chapel Hill
Steve Wing, University of North Carolina at Chapel Hill
Kerri L. Augustino, East Carolina University
Keith M. Ramsey, Vidant Health, Greenville, NC
Delores L. Nobles, Vidant Health, Greenville, NC
David B. Richardson, University of North Carolina at Chapel Hill
Lance B. Price, George Washington UniversityFollow
Maliha Aziz, Translational Genomics Research Institute, Flagstaff, AZ
Pia MacDonald, Social & Scientific Systems, Inc., Durham, NC
Jill R. Stewart, University of North Carolina at Chapel HillFollow

Document Type

Journal Article

Publication Date

2014

Journal

Environmental Health

Volume

Volume 13

Inclusive Pages

Article number 54

Abstract

Background

Distinct strains of methicillin resistant Staphylococcus aureus (MRSA) have been identified on livestock and livestock workers. Industrial food animal production may be an important environmental reservoir for human carriage of these pathogenic bacteria. The objective of this study was to investigate environmental and occupational exposures associated with nasal carriage of MRSA in patients hospitalized at Vidant Medical Center, a tertiary hospital serving a region with intensive livestock production in eastern North Carolina.

Methods

MRSA nasal carriage was identified via nasal swabs collected within 24 hours of hospital admission. MRSA carriers (cases) were gender and age matched to non-carriers (controls). Participants were interviewed about recent environmental and occupational exposures. Home addresses were geocoded and publicly available data were used to estimate the density of swine in residential census block groups of residence. Conditional logistic regression models were used to derive odds ratio (OR) estimates and 95% confidence intervals (CI). Presence of the scn gene in MRSA isolates was assessed. In addition, multi locus sequence typing (MLST) of the MRSA isolates was performed, and the Diversilab(R) system was used to match the isolates to USA pulsed field gel electrophoresis types.

Results

From July - December 2011, 117 cases and 119 controls were enrolled. A higher proportion of controls than cases were current workforce members (41.2% vs. 31.6%) Cases had a higher odds of living in census block groups with medium densities of swine (OR: 4.76, 95% CI: 1.36-16.69) and of reporting the ability to smell odor from a farm with animals when they were home (OR: 1.51, 95% CI: 0.80-2.86). Of 49 culture positive MRSA isolates, all were scn positive. Twenty-two isolates belonged to clonal complex 5.

Conclusion

Absence of livestock workers in this study precluded evaluation of occupational exposures. Higher odds of MRSA in medium swine density areas could reflect environmental exposure to swine or poultry.

Comments

Reproduced with permission of BioMed Central Environmental Health.

Creative Commons License

This work is licensed under a Creative Commons Attribution 3.0 License.

APA Citation

Schinasi, L., Wing, S., Augustino, K.L., Ramsey, K.M., Nobles, D.L. et al. (2014). A case control study of environmental and occupational exposures associated with methicillin resistant Staphylococcus aureus nasal carriage in patients admitted to a rural tertiary care hospital in a high density swine region. Environmental Health, 13:54.

Peer Reviewed

1

Open Access

1