256316 Crop field exposure and the risk of methicillin resistant Staphylococcus aureus (MRSA) infection in Pennsylvania, USA

Wednesday, October 31, 2012

Joan Casey, MA , Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
Frank Curriero, PhD, MA , Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, PA
Walter Stewart , Center for Health Research, Geisinger Health System, Danville, PA
Brian S. Schwartz, MD, MS , Department of Environmental Health Sciences, Johns Hopkins University, Baltimore, MD
Over the past decade in the United States, the incidence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection has increased and its epidemiology has changed. Recently, contact with livestock and agriculture have been identified as risk factors for MRSA colonization. Few studies exist that examine the association between agricultural exposure and MRSA infection in humans. To investigate this association we used electronic health record data on over 400,000 primary care patients of the Geisinger Health System, which provides primary care services from 41 community practice clinics and 4 hospitals in over 31 counties in northeastern Pennsylvania, an area with many concentrated animal feeding operations (CAFOs) and concentrated animal operations (CAOs). By federal law, CAFOs must hold a Nation Pollutant Discharge Elimination System (NPDES) permit, but in Pennsylvania the state oversees permitting of both CAFOs and CAOs in the form of nutrient management plans (NMPs). NMPs detail information about the farm including location, the number and type of animal, manure produced on site, as well as quantity, season and destination (at the township-level) of exported manure. Exported manure is generally spread on crop fields, which represents a potential source of exposure to MRSA bacteria for members of nearby communities. There are 275 swine and dairy/veal CAFOs and CAOs in Geisinger's catchment area, of which 61% export manure. A nested case-control study identified 1,713 CA-, 1,521 healthcare-associated (HA) MRSA cases and 3,336 frequency-matched controls from 2005 to 2010. Geocoded patients will be evaluated in relation to an exposure model based on the township and quantity of the manure exported and land use/land cover maps. Spatial analysis and multilevel logistic regression will be used to assess crop field manure application as a risk factor for MRSA infection while controlling for potential confounding variables (e.g. age, race/ethnicity, obesity, tobacco use, community socioeconomic deprivation).

Learning Areas:
Environmental health sciences
Epidemiology

Learning Objectives:
To describe whether and how crop field application of manure from concentrated animal feeding operations (CAFOs) is associated with community- and healthcare-associated MRSA infection.

Keywords: Epidemiology, Infectious Diseases

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I am a 3rd year PhD candidate and a Sommer Scholar at the Johns Hopkins University Bloomberg School of Public Health and have been intimately involved in the data collection, data analysis and writing of this abstract. This work represents a component of my dissertation research.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.

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