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

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Leah,Wing,Steve,Augustino,Kerri L.,Ramsey,Keith M.,Nobles,Delores L.,Richardson,Da Schinasi (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: Background: Distinct strains of methicillin resistant Staphylococcus aureus (MRSA) have been identified on livestockand livestock workers. Industrial food animal production may be an important environmental reservoir for humancarriage of these pathogenic bacteria. The objective of this study was to investigate environmental andoccupational 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 aboutrecent environmental and occupational exposures. Home addresses were geocoded and publicly available datawere used to estimate the density of swine in residential census block groups of residence. Conditional logisticregression models were used to derive odds ratio (OR) estimates and 95% confidence intervals (CI). Presence of thescn gene in MRSA isolates was assessed. In addition, multi locus sequence typing (MLST) of the MRSA isolates wasperformed, and the Diversilab® 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 controlsthan cases were current workforce members (41.2% vs. 31.6%) Cases had a higher odds of living in census blockgroups with medium densities of swine (OR: 4.76, 95% CI: 1.36-16.69) and of reporting the ability to smell odor froma farm with animals when they were home (OR: 1.51, 95% CI: 0.80-2.86). Of 49 culture positive MRSA isolates, allwere scn positive. Twenty-two isolates belonged to clonal complex 5.Conclusions: Absence of livestock workers in this study precluded evaluation of occupational exposures. Higherodds of MRSA in medium swine density areas could reflect environmental exposure to swine or poultry.

Additional Information

Publication

Other

Language: English

Date: 2014

Keywords

: Methicillin resistant Staphylococcus aureus, Livestock, Bacterial antibiotic resistance, Concentrated animal feeding operations, North Carolina

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