Occurrence of methicillin-resistant Staphylococcus aureus in surface waters near industrial hog operation spray fields.
Industrial hog operations (IHOs) have been identified as a source of antibiotic-resistant Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA). However, few studies have investigated the presence of antibiotic-resistant S. aureus in the environment near IHOs, specifically surface waters proximal to spray fields where IHO liquid lagoon waste is sprayed. Surface water samples (n=179) were collected over the course of approximately one year from nine locations in southeastern North Carolina and analyzed for the presence of presumptive MRSA using CHROMagar MRSA media. Culture-based, biochemical, and molecular tests, as well as matrix-assisted laser desorption/ionization-time of flight mass spectrometry were used to confirm that isolates that grew on CHROMagar MRSA media were S. aureus. Confirmed S. aureus isolates were then tested for susceptibility to 16 antibiotics and screened for molecular markers of MRSA (mecA, mecC) and livestock adaptation (absence of scn). A total of 12 confirmed MRSA were detected in 9 distinct water samples. Nine of 12 MRSA isolates were also multidrug-resistant (MDRSA [i.e., resistant to ≥3 antibiotic classes]). All MRSA were scn-positive and most (11/12) belonged to a staphylococcal protein A (spa) type t008, which is commonly associated with humans. Additionally, 12 confirmed S. aureus that were methicillin-susceptible (MSSA) were recovered, 7 of which belonged to spa type t021 and were scn-negative (a marker of livestock-adaptation). This study demonstrated the presence of MSSA, MRSA, and MDRSA in surface waters adjacent to IHO lagoon waste spray fields in southeastern North Carolina. To our knowledge, this is the first report of waterborne S. aureus from surface waters proximal to IHOs.
Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7431, United States. Electronic address: smhatcher@unc.edu.
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Hatcher
Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7431, United States. Electronic address: kmyers@hria.org.
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Myers
Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7431, United States; Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, Maryland 21205, United States; Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, Maryland 21205, United States. Electronic address: cheaney1@jhu.edu.
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Heaney
Microbiology and Infection Control, Statens Serum Institute, 5 Artillerivej, 46/104, DK-2300 Copenhagen S, Denmark. Electronic address: JRL@ssi.dk.
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Larsen
Rural Empowerment Association for Community Help, 2389 W. Wards Bridge Road, Warsaw, NC 28398, United States. Electronic address: Djhall7@aol.com.
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Hall
Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7525, United States. Electronic address: Melissa.Miller@unchealth.unc.edu.
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Miller
Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7431, United States. Electronic address: Jill.Stewart@unc.edu.
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Stewart
D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D008712:Methicillin / Q000494:pharmacology*; D016106:Methicillin Resistance; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification*; D008826:Microbial Sensitivity Tests; D009657:North Carolina; D010641:Phenotype; D045483:Rivers / Q000382:microbiology*; D034421:Sus scrofa
D000900:Anti-Bacterial Agents; D008712:Methicillin
Antibiotic resistance; Industrial hog operations; MRSA; Staphylococcus aureus; Water quality